CA2695645A1 - Segmented metadata and indexes for streamed multimedia data - Google Patents

Abstract

A method of organizing streamed data includes storing streamed data in a file, identifying metadata applicable to a subset of the streamed data, and forming at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a metadata type. The file may be in accordance with ISO base media file format. The storing streamed data in a file may include storing in a reception hint track. The at least one group may be indicated in a sample group description box. The metadata type may be indicated by a grouping type and grouping instance data, the grouping type specifying semantics of the grouping instance data and the metadata content.
The metadata content may comprise a metadata payload and zero or more metadata payload extensions, where the metadata payload is included in a first structure and the zero or more metadata payload extensions are included in a second structure.

Description

SEGMENTED METADATA AND INDEXES FOR STREAMED
MULTIMEDIA DATA

FIELD OF THE INVENTION

100011 The present invention relates generally to the field of streamed multimedia data and, more specifically, to the organization of such multimedia data with metadata and/or indexes.

BACKGROUND OF THE INVENTION

100021 This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless othenvise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
[00031 The multimedia container file format is an important element in the chain of multimedia content production, manipulation, transmission and consuinption.
There are substantial differences between the coding format (a.k.a. elementary stream format) and the container file format. The coding format relates to the action of a specific coding algorithm that codes the content information into a bitstream.
The container file format comprises means of organizing the generated bitstream in such way that it can be accessed for local decoding and playback, transferred as a file, or streamed, all utilizing a variety of storage and transport architectures.
Furthermore, the file format can facilitate interchange and editing of the media as well as recording of reccived real-time streams to a file.
100041 Available media file format standards include ISO base media file format (ISO/IEC 14496-12), MPEG-4 file format (ISO/IEC 14496-14, also known as the MP4 format), AVC file format (ISO/IEC 14496-15) and 3GPP file format (3GPP TS
26.244, also known as the 3GP format). Other formats are also currently in development.

[0005] It is desirable that such media file formats enable the use of metadata. In many applications, such as reception and storage of media streams, such as audio and video streams, it is desirable that the file format enable the use of metadata that is specific to segments of the content of the streamed data to facilitate organization and access to desired sections or segments of the streamed data.

SUMMARY OF THE IhiVENTION

[0006] One aspect of the invention relates to a method of organizing streamed data.
The method includes storing streamed data in a file, identifying metadata applicable to a subset of the streamed data, and forming at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a mctadata type.
[0007] In one embodiment, the at least one group is identified in a file.
[00081 In one embodiment, the file is in accordance with ISO base media file format, The storing streamed data in a file may include storing in a reception hint track. The at least one group may be indicated in a sample group description box.
[0009] In one embodiment, the metadata type includes titles of segments of the streamed data.
[0010] In one embodiment, a group includes samples from two or more tracks.
The method may further comprisc identifying the group including samples from two or more tracks with metadata associated with all related tracks. Alternatively, the method may comprise identifying the group including samples from two or more tracks with metadata associated with a master track.
[0011] In one embodiment, the method further includes creating a timed metadata track for the streamed data. In one embodiment, the at least one group of one or more samples of the streamed data is indicated in a sample group description box for the timed metadata track through associating the at least one group of one or more samples of the streamed data with respective timed metadata samples in the timed metadata track.

-2-[0012] In one embodiment, the tiined metadata track associates timing metadata with one or more timelines. The timed metadata track may associate timing metadata with two or more timelines.
[0013] In another aspect, the invention relates to a computer program embodied on a computer-readable medium. The computer program is configured to provide a method comprising storing streamed data in a file, identifying metadata applicable to a subset of the streamed data, and forming at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a metadata type.
[0014] In another aspect of the invention, a receiver adapted to receive streamed data includes a storage unit for storing streamed data in a file, and a processor. The processor is adapted to identify metadata applicable to a subset of the streamed data and form at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a metadata type.
[0015] In various embodiments, the metadata type maybe indicated by a grouping type and grouping instance data, the grouping type specifying semantics of the grouping instance data and the metadata content. The metadata content may comprise a metadata payload and zero or more metadata payload extensions, where the metadata payload is included in a first structure and the zero or more metadata payload extensions are included in a second structure.
[0016] These and other advantages and features of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the several drawings described below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 illustrates a graphical representation of an exemplary multimedia communication system within which embodiments of the present invention may be implemented;

-3-10018] Figure 2 illustrates an exemplary box in accordance with the ISO base media file format;
[0019] Figure 3A is an exemplary box illustrating sample grouping;
100201 Figure 3B illustrates an exemplary box containing a movie fragment including a SampletoToGroup box;
[0021] Figures 4 illustrates an exemplary box with segmented metadata according to grouping type according to an embodiment of the present invention;
100221 Figure 5A is a flowchart illustrating an exemplary method of organizing streamed data according to an embodiment of the present invention;
[0023] Figure 5B is a flowchart illustrating an exemplary method of organizing streamed data according to another embodiment of the present invention;
[0024] Figure 6 is a block diagram of an exemplary device for receiving, storing and organizing streamed data according to an embodiment of the present invention;
[00251 Figure 7 is a representation of a simplified box hierarchy indicating the nesting structure for the DVBSampleToGroup box when group_description index is not referred;
[0026] Figure 8 is an illustration of an example file containing a movie fragment including a DVBSamp] eToGroup box;
100271 Figure 9 is an illustration of a simplified box hierarchy indicating the nesting structure for the DVBGroupinglnstance, DVBSampleGroupDescription, DVBSamp]eToGroup, and DVBSampleToGroupExtension boxcs; and 100281 Figure 10 is an illustration of a file including two sample groupings according to the DVBSampleToGroup box for the timecode index.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

100291 Figure 1 is a graphical representation of a generic multimedia communication system within which various embodiments of the present invention may be implemented. As shown in Figure 1, a data source 100 provides a source signal in an analog, uncompressed digital, or compressed digital format, or any combination of these formats. An encoder I 10 encodes the source signal into a coded media bitstream. It should be noted that a bitstream to be decoded can be received

-4-directly or indirectly from a remote device located within virtually any type of network. Additionally, the bitstream can be received from local hardware or software. The encoder 110 may be capable of encoding more than one media type, such as audio and video, or more than one encoder 110 may be required to code different media types of the source signal. The encoder 110 may also get synthetically produced input, such as graphics and text, or it may be capable of producing coded bitstreams of synthetic media. In the following, only processing of one coded media bitstream of one media type is considered to simplify the description. It should be noted, however, that typically real-time broadcast services comprise several streams (typically at least one audio, video and text sub-titling stream). It should also be noted that the system may include many encoders, but in Figure 1 only one encoder 110 is represented to simplify the description without a lack of generality. It should be further understood that, although text and examples contained herein may specifically describe an encoding process, one skilled in the art would understand that the same concepts and principles also apply to the corresponding decoding process and vice versa.
[00301 The coded media bitstream is transferred to a storage 120. The storage may comprise any type of mass memory to store the coded media bitstream. The format of the coded media bitstream in the storage 120 may be an elementary self-contained bitstream format, or one or more coded media bitstreams may be encapsulated into a container file. Some systems operate "live", i.e. omit storage and transfer coded media bitstream from the encoder 110 directly to the sender 130. The coded media bitstream is then transferred to the sender 130, also referred to as the server, on a need basis. The format used in the transmission may be an elementary self-contained bitstream format, a packet stream format, or one or more coded media bitstreams may be encapsulated into a container file. The encoder 110, the storage 120, and the server 130 may reside in the same physical device or they may be included in separate devices. The encoder 110 and server 130 may operate with live real-time content, in which case the coded media bitstream is typically not stored permanently, but rather buffered for small periods of time in the content encoder 110

-5-

6 PCT/IB2008/053321 and/or in the server 130 to smooth out variations in processing delay, transfer delay, and coded media bitrate.
[00311 The server 130 sends the coded media bitstream using a communication protocol stack. The stack may include but is not limited to Real-Time Transport Protocol (RTP), User Datagram Protocol (UDP), and Internet Protocol (IP). Wien the communication protocol stack is packet-oriented, the server 130 encapsulates the coded media bitstream into packets. For example, when RTP is used, the server encapsulates the coded media bitstream into RTP packets according to an RTP
payload format. Typically, each media type has a dedicated RTP payload format.
It should be again noted that a system may contain more than one server 130, but for the sake of simplicity, the following description only considers one server 130.
[0032] The server 130 may or may not be connected to a gateway 140 through a communication network. The gateway 140 may perform different types of functions, such as translation of a packet stream according to one communication protocol stack to another communication protocol stack, merging and forking of data streams, and manipulation of data stream according to the downlink and/or receiver capabilities, such as controlling the bit rate of the forwarded stream according to prevailing downlink network conditions. Examples of gateways 140 include multipoint conference control units (MCUs), gateways between circuit-switched and packet-switched video telephony, Push-to-talk over Cellular (PoC) servers, IP
encapsulators in digital video broadcasting-handheld (DVB-H) systems, or set-top boxes that forward broadcast transmissions locally to home wireless networks. When RTP is used, the gateway 140 is called an RTP mixer or an RTP translator and typically acts as an endpoint of an RTP connection.
[0033] The system includes one or more receivers 150, typically capable of receiving, de-modulating, and de-capsulating the transmitted signal into a coded media bitstream. The coded media bitstream is transferred to a recording storage 155.
The recording storage 155 may comprise any type of mass memory to store the coded media bitstream. The recording storage 155 may alternatively or additively comprise computation memory, such as random access memory. The format of the coded media bitstream in the rccording storage 155 may be an elementary self-contained bitstream format, or one or more coded media bitstreams may be encapsulated into a container file. If there are inany coded media bitstreams, such as an audio stream and a video stream, associated with each other, a container file is typically used and the receiver 150 comprises or is attached to a container file generator producing a container file from input streams. Some systems operate "live," i.e. omit the recording storage 155 and transfer coded media 6itstream from the receiver 150 directly to the decoder 160. In some systems, only the most recent part of the recorded stream, e.g., the most recent 10-minute excerption of the recorded stream, is maintained in the recording storage 155, while any earlier recorded data is discarded from the recording storage 155.
[0034] The coded media bitstream is transferred from the recording storage 155 to the decoder 160. If there are many coded media bitstreams, such as an audio stream and a video stream, associated with each other and encapsulated into a container file, a file parser (not shown in Figure 1) is used to decapsulate each coded media bitstream from the container file. The recording storage 155 or a. decoder 160 may comprise the file parser, or the file parser is attached to either recording storage 155 or the decoder 160.
[0035] The codec media bitstream is typically processed further by a decoder 160, whose output is one or more uncompressed media streams. Finally, a renderer may reproduce the uncompressed media streams with a loudspeaker or a display, for example. The receiver 150, recording storage 155, decoder 160, and renderer may reside in the same physical device or they may be included in separate devices.
[0036] The Digital Video Broadcasting (DVB) organization is currently in the process of specifying the DVB File Format. 'l'he primary purpose of defining the DVB File Format is to ease content interoperability between implementations of DVB
technologies, such as set-top boxes according to current (DVT-T, DVB-C, DVB-S) and future DVB standards, IP (Internet Protocol) television receivers, and mobile television receivers according to DVB-H and its future evolutions. The DVB
File Format will allow exchange of recorded (read-only) media betwecn devices from different manufacturers, exchange of content using USB mass memories or siinilar

-7-read/write devices, and shared access to common disk storage on a home network, as well as much other functionality.
[0037] The ISO file format is the basis for most current multimedia container file formats, generally referred to as the ISO family of file formats. The ISO base media file format may be the basis for the development of the DVB File Format as well.
100381 Referring now to Figure 2, a simplified structure of the basic building block 200 in the ISO base media file format, generally referred to as a "box", is illustrated.
Each box 200 has a header and a payload. The box header indicates the type of the box and the size of the box in terms of bytes. Many of the specified boxes are derived from the "full box" (FullBox) structure, which includes a version number and flags in the header. A box may enclose other boxes, such as boxes 210, 220, described below in further detail. The ISO file format specifies which box types are allowed within a box of a certain type. Furthermore, some boxes are mandatory to be present in each file, while others are optional. Moreover, for some box types, more than one box may be present in a file. In this regard, the ISO base media file format specifies a hierarchical structure of boxes.
[00391 According to ISO family of tile formats, a file consists of media data and metadata that are enclosed in separate boxes, the media data (mdat) box 220 and the movie (moov) box 210, respectively. The movie box may contain one or more tracks, and each track resides in one track box 212, 214. A track can be one of the following types: media, hint or timed metadata. A media track refers to samples formatted according to a media compression format (and its encapsulation to the ISO basc media file format). A hint track refers to hint samples, containing cookbook instructions for constructing packets for transmission over an indicated communication protocol. The cookbook instructions may contain guidance for packet header construction and include packet payload construction. In the packet payload construction, data residing in other tracks or items may be referenced (e.g., a reference may indicate which piece of data in a particular track or item is instructed to be copied into a packet during the packet construction process). A timed metadata track refers to samples describing referred media and/or hint samples. For the presentation one media type, typically one media track is selected.

-8-100401 ISO base media file format does not limit a presentation to be contained in one file, and it may be contained in several files. One file contains the metadata for the whole presentation. This file may also contain all the media data, whereupon the presentation is self-contained. The other files, if used, are not required to be formatted to ISO base media file format, are used to contain media data, and may also contain unused media data, or other information. The ISO base media file format concerns the structure of the presentation file only. The format of the media-data files is constrained the ISO base media file format or its derivative formats only in that the media-data in the media files must be formatted as specified in the ISO base media file format or its derivative formats.
(00411 Movie fragments can be used when recording content to ISO files in order to avoid losing data if a recording application crashes, runs out of disk, or some other incident happens. Without movie fragments, data loss may occur because the file format insists that all metadata (the Movie Box) be written in one contiguous area of the file. Furthermore, when recording a file, there may not be sufficient amount of RAM to buffer a Movie Box for the size of the storage available, and re-computing the contents of a Movie Box when the movie is closed is too slow. Moreover, movie fragments can enable simultaneous recording and playback of a file using a regular ISO file parser. Finally, smaller duration of initial buffering is required for progressive downloading (e.g., simultaneous reception and playback of a file, when movie fragments are used and the initial Movie Box is smaller compared to a file with the same media content but structured without movie fragments).
[0042] The movie fragment feature enables splitting of the metadata that conventionally would reside in the moov box 210 to multiple pieces, each corresponding to a certain period of time for a track. "I71us, the movie fragment feature enables interleaving of file metadata and media data. Consequently, the size of the moov box 210 can be limited and the use cases mentioned above be realized.
[0043] "I1ie media samples for the movie fragments reside in an mdat box 220, as usual, if they are in the same file as the moov box. For the meta data of the movie fragments, however, a moof box is provided. It comprises the information for a certain duration of playback time that would previously have been in the moov box

-9-210. The moov box 210 still represents a valid movie on its own, but in addition, it comprises an mvex box indicating that movie fragments will follow in the same file.
The movie fragments extend the presentation that is associated to the moov box in time.
[0044] The metadata that can be included in the moof box is limited to a subset of the metadata that can be included in a moov box 210 and is coded differently in some cases. Details of the boxes that can be included in a moof box can be found from the ISO base media file format specifications ISO/IEC International Standard 14496-12, Second Edition, 2005-04-01, including Amendments I and 2, incorporated herein by reference in their entirety.
100451 In addition to timed tracks, ISO files can contain any non-timed binary objects in a meta box, or "static" metadata. The meta box can reside at the top level of the file, within a movie box, and within a track box. At most one meta box may occur at each of the file level, movie level, or track level. The meta box is required to contain a`hdlr' box indicating the structure or format of the "meta" box contents. The meta box may contain any number of binary items that can be referred and each one of them caii be associated with a file name.
[0046] In order to support more than one meta box at any level of the hierarchy (file, movie, or track), a meta box container box ('meco') has been introduced in the ISO base media file format. The meta box container box can carry any number of additional meta boxes at any level of the hierarchy (file, move, or track).
This allows, for example, the same meta-data to be presented in two different, alternative, mcta-data systems. The meta box relation box ("mere") enables describing how different meta boxes relate to each other (e.g., whether they contain exactly the same metadata, but described with different schemes, or if one represents a superset of another).
[0047] Referring now to Figures 3A, 3B and 4, the use of sample grouping in boxes is illustrated. A sample grouping in the ISO base media file format and its derivatives, such as the AVC file format and the SVC file format, is an assignment of each sample in a track to be a member of one sample group, based on a grouping criterion. A sample group in a sample grouping is not limited to being contiguous samples and may contain non-adjacent samples. As there may be more than one

-10-sample grouping for the samples in a track, each sample grouping has a type field to indicate the type of grouping. Sample groupings are represented by two linked data structures: (1) a SampleToGroup box (sbgp box) represents the assignment of samples to sample groups; and (2) a SampleGroupDescription box (sgpd box) contains a sample group entry for each sample group describing the properties of the group.
There may be multiple instances of the SampleToGroup and SampleGroupDescription boxes based on different grouping criteria. These are distinguished by a type field used to indicate the type of grouping, as illustrated in Figure 4.
[0048] Figure 3A provides a simplified box hierarchy indicating the nesting structure for the sample group boxes. The sample group boxes (SampleGroupDescription Box and SampleToGroup Box) reside within the sample table (stbl) box, which is enclosed in the media information (minf), media (mdia), and track (trak) boxes (in that order) within a movic (moov) box.
100491 The SampleToGroup box is allowed to reside in a movie fragment. Hence, sample grouping can be done fragment by fragment. Figure 3B illustrates an example of a file containing a movie fragment including a SampleToGroup box. As illustrated in Figure 4, the SampleGroupDescription Box and SampleToGroup Box may identify a grouping_type based on an index or metadata type.
[0050] A key feature of the DVB file format is known as reception hint tracks, which may be used when one or more packet streams of data are recorded according to the DVB file format. Reception hint tracks indicate the order, reception timing, and contents of the received packets among other things. Players for the DVB file format may re-create the packet stream that was received based on the reception hint tracks and process the re-created packet stream as if it was newly received.
Reception hint tracks have an identical structure compared to hint tracks for servers, as specified in the ISO base media file format. For example, reception hint tracks may be linked to the elementary stream tracks (i.e., media tracks) they carry, by track references of type `hint'. Each protocol for conveying media streams has its own reception hint sample format.

-11-[0051] Servers using reception hint tracks as hints for sending of the received streams should handle the potential degradations of the received streams, such as transmission delay jitter and packet losses, gracefully and ensure that the constraints of the protocols and contained data formats are obeyed regardless of the potential degradations of the received streams.
100521 The sample formats of reception hint tracks may enable constructing of packets by pulling data out of other tracks by reference. These other tracks may be hint tracks or media tracks. The exact form of these pointers is defined by the sample format for the protocol, but in general they consist of four pieces of information: a track reference index, a sample number, an offset, and a length. Some of these may be implicit for a particular protocol. These `pointers' always point to the actual source of the data. If a hint track is built `on top' of another hint track, then the second hint track must have direct references to the media track(s) used by the first where data from those media tracks is placed in the stream.
100531 Conversion of received streams to rnedia tracks allows existing players compliant with the ISO base media file format process DVB files as long as the media formats are also supported. However, most media coding standards only specify the decoding of error-free streams, and consequently it should be ensured that the content in media tracks can be correctly decoded. Players for the DVB file format may utilize reception hint tracks for handling of degradations caused by the transmission, i.e., content that may not be correctly decoded is located only within reception hint tracks.
The need for having a duplicate of the correct media samples in both a media track and a reception hint track can be avoided by including data from the media track by reference into the reception hint track.
[00541 Currently, three types of reception hint tracks are being specified:

transport stream (MPEG2-TS), Real-Time Transport Protocol (RTP), and Real-Time Transport Control Protocol (RTCP) reception hint tracks. Samples of an MPEG2-TS
reception hint track contain MPEG2-TS packets or instructions to compose MPEG2-TS packets from references to media tracks. An MPEG-2 transport stream is a multiplex of audio and video program elementary streams and some metadata infonnation. It may also contain several audiovisual programs. An RTP
reception hint

-12-track represents one RTP stream, typically a single media type. An RTCP
reception hint track may be associated with an RTP reception hint track and represents the RTCP packets received for the associated RTP stream.
[0055) RTP is used for transmitting continuous media data, such as coded audio and video streams in networks based on the Internet Protocol (IP). The Real-time Transport Control Protocol (RTCP) is a companion of RTP, i.e. RTCP should be used to complement RTP always when the network and application infrastructure allow.
RTP and RTCP are usually conveyed over the User Datagram Protocol (UDP), which, in turn, is conveyed over the Inteniet Protocol (IP). There are two versions of IP, IPv4 and IPv6, differing by the number of addressable endpoints among other things.
RTCP is used to monitor the quality of service provided by the network and to convey information about the participants in an on-going session. RTP and Rl'CP are designed for sessions that range from one-to-one communication to large multicast groups of thousands of endpoints. In order to control the total bitrate caused by RTCP
packets in a multiparty session, the transmission interval of RTCP packets transmitted by a single endpoint is proportional to the number of participants in the session. Each media coding format has a specific RTP payload format, which specifies how media data is structured in the payload of an RTP packet.
[0056] The metadata requirements for the DVB file format can be classified to four groups based on the type of the metadata: 1) sample-specific timing metadata, such as presentation timestamps; 2) indexes; 3) segmented metadata; and 4) user bookmarks (e.g., of favorite locations in the content).
[0057] For sample-specific timing metadata, there can be different timelines to indicate sample-specific timing metadata. Timelines may be required to cover the entire length of the recorded streams. Further, timelines may be paused. For example, timeline A may be created in the final editing phase of a movie. A
service provider or another entity may insert commercials and provided timeline B for the commercials. Timeline A may be paused while commercials are ongoing. Timelines may also be transmitted after the content itself. In onc embodiment, a timeline samples may be carried within MPEG-2 program elcmentary streams (PES). A PES
conveys an elementary audio or video bitstream, and hence, timelines are accurately

-13-synchronized with audio and video fraines. In this regard, reference is made to ETSI TS 102 823, "Specification for the carriage of synchronized auxiliary data", which is hereby incorporated by reference.
100581 Indexes may include, for example, video access points and trick mode support (e.g., fast forward/backward, slow-motion). Such operations may require, for example, indication of self-decodable pictures, decoding start points, and indications of reference and non-reference pictures.
100591 In the case of segmentcd metadata, the DVB services may be described with a service guide according to a specific metadata schema, such as Broadcast Content Guide (BCG), TV-Anytime, or Electronic Service Guide (ESG) for IP datacasting (IPDC). The description may apply to a part of the stream only. Hence, the file may have several descriptive segments (e.g., a description about that specific segment of the program, such as "Holiday in Corsica near Cargese") information.
[00601 In addition, the metadata and indexing structures of the DVB file format are required to be extensible and user-defined indexes are required to be supported.
Additionally, there should bc a mcthod for fast acccss to elements in the file (e.g., via index tables). Furthermore, it should be possible to signal the accuracy of any index.
For example, the index might be perfectly accurate, accurate to a specified amount or a heuristic guess only.
100611 Various techniques for performing indexing and implementing segmented metadata have been proposed. Such techniques include, for example, sample events and sample properties. The sample event mechanism enables the listing of samples associated with a particular event type and event description index in onc data structure, referred to as the SampleToEvent box. Each entry in the list may be additionally accompanied by a value or description, having a determined size in terrns of bytes. Samples are listed with reference to their sample number within the associated track. It is not required to have all samples listed for a particular event type. The allowed values of the event type are predetermined and specified, e.g., in the DVB File Format specification. For each used event type in any SampleToEvent box, there is a respective SampleEventDescription box associated with the same evcnt type. A SampleEventDescription box contains a list of sample event description

-14-entries, each associated with a unique everit description index (staring from 1 and incremented by ) per each entry in the list). The syntax and semantics of sarnple event description entries are determined by the event type and are specified e.g. in the DVB File Format specification. The semantics specified for a particular sample description index and event type apply to those samples that are associated with that sample description index and event type in SampleToEvent boxes. The SampleToEvent box is allowed to reside in a movie fragment. Hence, a listing of sample events can be performcd fragment by fragment. There may be multiple instances of the SampleToEvent and SampleEventDescription boxes for different event types, but there can be at most one SampleToEvent box of a particular event type per a movie fragment and at most one SampleEventDescription box of a particular event type within a file.
[00621 Syntax of the SampleToEvent box and the SampleEventDescription box is specified as follows:
aligned(8) class SampleToEventBox extends Fu11Box(õsteb") {
unsigned int(32) event type;
unsigned int(32) entry count;
for(i=1; i<=entry count; i++) {
unsigned int(32) event desc index;
unsigned int(32) sample_count;
for(j-1; j<~sample_count; j++) {
unsigned int(32) sample_number;
unsigned int(8) value[event data length];
~
f }
}
{
aligned(8) class SampleEventDescriptionBox extends FullBox(,,sedb") unsigned int(32) event type;
unsigned int(32) entry count;
for(i=1; i<=entry_count; i++) {
SampleEventDescriptionEntryO;

-15-~
}
[0063] Semantics of the syntax elements used in the SampleToEvent box and the SampleEventDescription box are spccified as follows:
event type is a 32-bit unsigned integer which shall contain the four-character code of an event type, built of ASCII characters.
entry_count is a 32-bit unsigned integer with the number of entries in the following loop.
event_desc index is a 32-bit unsigned integer with the index of the SampleEventDescriptionEntry.
sample_count is a 32-bit unsigned integer with the number of entries in the following loop which contains the sample numbers of the samples the event applies to.
value is an array of event-specific data. The length of this field is specified by event data length in the corresponding SampleEventDescriptionEntry. This field is constant size for all indexes in this loop and padding shall be applied for variable-length indexes.
[00641 In unicast, multicast, and broadcast streaming applications the available streams are announced and their coding formats are characterized to enable each receiver to conclude if it can decode and render the content successfully.
Sometimes a number of different format options for the same content are provided, from which each receiver can choose the most suitable one for its capabilities and/or end-user wishes. The available media streams are often described with the corresponding media type and its parameters that are included in a session description formatted according to the Session Description Protocol (SDP). In unicast streaming applications the session description is usually carried by the Real-Time Streaming Protocol (RTSP), which is used to set up and control the streaming session. In broadcast and multicast streaming applications, the session description may be carricd as part of the electronic service guide (ESG) for the service. "1'hc SDP
information for a broadcast stream may be updated during the broadcast. Hence, SDP for a recorded stream should be stored in such a manner that it can be updated later.

-16-[00651 Referring now to Figure 5A, a method 500 according to an embodiment of the invention by which streamed data is advantageously stored and organized is illustrated. According to an embodiment of the invention, streamed media is received at, for example, a receiving unit or another device (block 510). The streamed data, which may be at least one media or multimedia stream, is stored in a file (block 520).
In terms of the ISO base media file format, the at least one received media or multimedia stream may be stored in a reception hint track in a file. Metadata which is applicable to a subset of the streamed data is identified (block 530). For example, metadata applicable to certain samples of the reception hint track may be identified.
Groups of samples of the streamed data having identical metadata content of a certain metadata type are formed and identified in a file (block 540). In this regard, sample grouping based on a certain metadata type may be indicated with the sample group description box, and samples can be mapped to certain metadata content included in the sanlple group description box with the sample-to-group box. In another embodiment, a certain metadata type is considered to comprise both the type indicating the syntax and semantics of the metadata content and a part of the metadata content that remains unchanged in the grouping. For example, the metadata type can indicate timeline metadata, and the part of the metadata remaining unchanged in the grouping can comprise an identifier of the timeline.
100661 Referring now to Figure 513, a niethod 505 according to another embodiment of the invention is illustrated. In the embodiment of Figure 513, streamed media is received at, for example, a receiving unit or another device (block 515). The streamed data, which may be at least one media or multimedia stream, is stored in a file and associated with a reception hint track in a file (block 525). At least one metadata sample applicable to a reception hint sample is identified (block 535). The at least one metadata sample is then stored in the file and associated with a timed metadata track (block 545). Groups of samples of the streamed data having identical metadata content of a certain metadata type are formed and identified in a file (block 555). Sample grouping based on a certain metadata type is indicated with the sample group description box, and metadata samples can be mapped to certain metadata content included in the sample group description box with the sample-to-group box.

-17-As above, a certain nietadata type can also be considered to comprise both the type indicating the syntax and semantics of the metadata content and a part of the metadata content that remains unchanged in the grouping. It is noted that the sequential processing blocks suggested in Figure 5B can be applied to differcnt granularities of multimedia data and metadata, ranging from a subset of a sample to an entire stream.
Different blocks can also apply to a different granularity of data. In one arrangement, blocks 515, 525, 535, 545 are iteratively applied to individual reception hint samples and metadata sainples.
[0067) One grouping type is deCined per metadata or index type in the DVB file format specification. Examples of potential grouping types include the following:
Any metadata specified by handler_type used for the meta box. Each sample group is associated with one item of the metadata scheme. The metadata scheme may be one of those specified in DVB specifications (BCG, TV-Anytimc, IPDC ESG);
Any index type (e.g., those proposcd in DVB document TM-FF0035, such as indication of self-decodable pictures, decoding start points, and indications of reference and non-reference pictures); and SDP information for received RTP streams.
[0068] Referring now to Figure 6, an exemplary device according to an embodiment of the present invention is illustrated. The device 600, such as a receiver, is provided with a DVB file generator 610, a storage unit 620, and a processor 630. Of course, those skilled in the art will understand that the various components may bc scparated into further components or combined into fewer components. Further, the various components may include executable code for performing their functions. Upon receipt of streamed data, the DVB file generator 610 creates a DVB file from received packets. In this regard, the DVB file generator 610 receives the packet stream(s) themselves and associated metadata (such as BCG, TV-Anytime, or IPDC ESG). The device 600 stores the received packets to a file (in an mdat section of a file, if the rnoov and mdat boxes reside in the same file) as samples of a reception hint track in the storage unit 620. The receiver 600 may also derive file metadata that will be later stored within the moov box or the moof box, depending on whether or not movie fragmcnts arc in use. For any received piece of metadata, the receiver 600 (e.g., the

-18-processor 630) analyzes its type and creates a new sample group description box, if the type of metadata did not exist before. The receiver 600 also checks whether or not the content of the piece of metadata differs from all metadata stored earlier in the file.
If the content is novel, then a new entry is created for the sample group description box and the metadata content is copied into the entry. The SampteToGroup box is maintained for each grouping type and samples of the rcception hint track are mapped to one of the entries in the respcctive sample group description box.
100691 In another embodiment, the DVB file generator 610 of the device 600 ereates one or more reception hint tracks and file metadata for the moov box or the moof box. The device 600 also derives indexes, such as a randomly accessible intra picture indication, from received packets. This may be performed by the DVB
file generator 610 or by another component of the device 600, such as the processor or another component not shown in Figure 6. If one or more indexes or pieces of metadata are derived or received for a received packet, the device 600 creates a timed metadata sample containing the indexes or the picccs of inetadata. Again, this may be performed by a component of the device 600, such as the DVB file generator 610 or the processor 630. The timed metadata sample is associated with a timed metadata track, and the timed metadata track is associated with the reception hint track. For any received or derived piece of metadata or index, the processor 630 of the device 600 analyzes its type and creates a new sample group description box, if the type of metadata did not exist before. The processor 630 also checks whether or not the content of the piece of metadata differs from all metadata stored earlicr in the file. If the content is novel, then a new entry is created for the sample group description box and the metadata content is copied into the entry. The SampleToGroup box is maintained for each grouping type and samples of the timed metadata track are mapped to one of the entries in the respective sample group description box.
[0070] In this embodiment, one metadata sample can be created for every reception hint sample, regardless of whether or not an index or a piece of metadata is associated with that reception hint sample. The payload of the corresponding metadata samplc indicates if no index or piece of metadata is associated with a reception hint sample.
Further, potential track fragments of a timed metadata track can be aligned to the

-19-corresponding reception hint track in terms of the first and last included sample in the frab nents. It can be indicated within a file in a track-header-level box or structure whether or not there is one timed metadata sample per each reception hint sample, and whether or not track fragments of a timed metadata track are identical to those of the associated reception hint track. When one metadata sample is created per each reception hint sample, corresponding track fragments of a timed metadata track and a reception hint track may contain samples having identical sample numbers.
[0071] It is noted that the creation of sample grouping may be implemented in a number ways. For example, the creation of sample grouping inay not happen simultaneously with the reception and storage of the samples themselves.
Instead, sample grouping may be performed off-line, based on an intermediate format for storing metadata or based on the timed metadata track. Referring to Figure 5A, blocks 530 and 540 would happen after the reception of the stream has been completed. Referring to Figure 513, block 555 would happen after the reception of the stream has been completed. Referring again to Figure 1, the off-line creation of sample grouping would result into two additional blocks getting their input from the recording storage 155 and outputting to the decoder 160. The first block in processing order can be referred to as a file re-writer, which inputs a file without sample grouping for a particular metadata type and outputs a file with that type of sample grouping. The second block in processing order can be referred to as a second recording storage, which may have similar properties to the recording storage 155.
[0072] The file re-writer and the second recording storage referred to above may reside in the same device as the receiver 150, the recording storage 155, the decoder 160, or a different device. Moreover, the fi1e re-writer and the second recording storage may reside in the same device or different devices from each other.
[00731 Received streams can be of different nature - they may contain several media types and programs in a multiplexed format (MPEG-2 transport streams) or they may contain a single media type of a single program (RTP streams).
Consequently, the receiver operation and file format structures are adapted accordingly as follows.

-20-100741 It should be noted that the various embodiments of the present invention are not limited to any particular type of sample grouping, such as the sample grouping specified in ISO/IEC 14496-12. The following embodiment describes a sample grouping mechanism that can be applied with various embodiments of the invention.
[0075] In addition to the grouping type, a sample grouping may be characterized by zero or more global parameters. Examples of global parameters include a program identifier (PID) within an MPEG-2 transport stream and a timeline identifier.
When parsing sample groups, only a particular value of the global parameter is of interest at a time, e.g., a desired timestamp within a particular timeline. In addition to enumerated sample group description entries, it can advantageous to allow local parameters that may change for each entry in the SamplcToGroup box. For example, a timecode can be associated with an entry in the SampleToGroup box. When parsing a sample grouping, different values of local paraineters are interleaved into the same structure, i.e. in the same SampleToGroup box.
[0076] Syntax of a sample grouping mechanism of this embodiment is presented below.
aligned(8) class DVBSampleToGroupBox extends FullBox('dstg', version = 0, flags) {
unsigned int(32) grouping type;
if (flags & 1) {
unsigned int(8) info_length;
unsigned int(8) instance_info[info_length];
~
if (flags & 16) {
unsigned int(8) static length;
unsigned int(8) static info[static_length];
if (flags & 2) unsigned int(8) payload-length;
unsigned int(32) entry count;

-21-for (i=1; i <= entry_count; i++) {
if (flags & 4) unsigned int(32) sample-number;
if (f(flags & 8)) unsigned int(32) sample_count;
if (flags & 2) unsigned int(S) payload[payload_length];
else unsigned int(32) group_description index;
}
}
[00771 The presented DVBSampleToGroup box is structurally compatible with the SampleToGroup box, i.e., if flags (of the box header) are 0, then the syntax is identical to the SampleToGroup box. Global parameters as specified above are represented by grouping instance information (instance info). static info represents static values remaining unchanged for all grouped samples. The semantics of static info depend on grouping type. For example, static info may be formatted according to the payload of the DVBlndexBox (presented subsequently), giving timing and sample number inaccuracy ranges. Local parameters are represented by payload or group_description_index. The DVBSampleToGroup box can be parsed without semantic knowledge of grouping type thanks to info_length, static_length, and payload length. A file editor software program or device that is unaware of a particular grouping_type can edit the box (e.g. as responsc of removal or insertion of samples), even if it did not have knowledge about the semantics of a particular grouping type. sample_number indicates the first sample for which the payload or group_description_index apply, and the persistence of the payload or group_description_index in terms of number of consecutive samples is indicated by sample_count. If salnple number is not present, then the first sample for which the payload or group description index apply is subsequent to the last sample for which the previous entry in the loop applied. Values of sample count in a DVBSampleToGroup box is increasing in appearance order. A sample can be

-22-included only once in a DVBSampleToGroup box, i.e., the sum of previous values of sample_number and sample_count is less than the present value of sample number. It is not required that each sample in a track is mapped in a DVBSampleToGroup box.
The DVBSampleGroupDcscription box and group_description_index can be used for enumerated indexes. The value of payload or group_deseription index for those samples that are not mapped in a DVBSanipleToGroup box is unspecified. The semantics of instance info and payload are specified for each grouping_type.
100781 An alternative definition for the syntax of the DVBSampleToGroup box is presented below. A primary difference compared to the previous case is that varying-length payloads are enabled.

aligned(8) class DVBSam.pleToGroupBox extends k'ullBox(`dstg', version = 0, flags) {
unsigned int(32) grouping type;
if (flags & 1) {
unsigned int(8) info_length;
unsigned int(8) instance info[info_length];
if (flags & 16) {
unsigned int(S) static_length;
unsigned int(8) static info[static length];
) if (flags & 2) unsigned int(8) payload_length;
unsigned int(32) entry count;
for (i=1; i <= entry_count; i++) {
if (flags & 4) unsigned int(32) sample_number;
if(!(flags & 8)) unsigned int(32) sample count;

-23-if (flags & 2) unsigmed int(8) payload[payload_length];
else if (flags & 32) {
unsigned int(8) varying_length;
unsigned int(8) payload[varying length];
}
else unsigned int(32) group_description index;
}

[00791 Figure 7 provides a simplified box hierarchy indicating the nesting structure for the DVBSampleToGroup box 700 when group_description index is not referred ((flags & 2) is equal to 1). DVBSampleToGroup boxes 700 reside within the sample table (stbl) box 710, which is enclosed in the media information (minf) 720, media (mdia) 730, and track (trak) boxes 740 (in that order) within a movie (moov) box 210.
[00801 The DVBSampleToGroup box 700 is allowed to reside in a movie fragment.
Hence, sample grouping can be done fragment by fragment. Figure 8 illustrates an example of a file containing a movie fragment 800 including a DVBSarnpleToGroup box 700.
100811 Syiitax of DV13SampleGroupDescription box is presented below.
aligned(8) class DVBSampleGroupDescriptionBox (unsigned int(32) handlertype) extends FullBox(`dsgd', version, flags) {
unsigned int(32) grouping type;
if (flags & 1) {
unsigiled int(8) info_lEngth;
unsigned int(8) instance info[info length];
}
i f (version>-= 1)

-24-unsigned int(32) default_length;
unsigned int(32) entry count;
int i;
for (i = 1 i<= entry count ; i+-f-) {
if (version>=l && default length==0) unsigned int(32) description length;
switch (handler_type){
case `vide': // for video tracks VisualSampleGroupEntry Q;
break;
case `soun': // for audio tracks Audio S ampl eGroupEntryO;
break;
case `hint': // for hint tracks HintSampleGroupEntryQ;
break;
}
}
}
[0082] The structure of the DVBSampleGroupDcscription box is compatible with the SampleGroupDcscription box, i.e., if flags (in the box header) are set to 0, the syntax is identical to the SampleGroupDescription box. Global parameters as defined above are represented by grouping instance information (instance_info). The inclusion of instance info in the DVBSampleGroupDescription box enables different enumerations (i.e., sample group entries) for different values of the global parameters.
100831 The syntax presented above for the DVBSampleToGroup box only allows a fixed-length payload or group_description index being specified for each entry in the loop. It may be desirable for some grouping types to have varying-length payloads for any entry specified in a particular DVBSampleToGroup box. The following extension mechanism, referred to as DVBSampleToGroupExtension box is depicted below for this purpose.

-25-

26 PCT/IB2008/053321 aligned(8) class DVBSampleToGroupExtensionBox extends FullBox('dsge', version = 0, flags) unsigned int(32) grouping typc;
if (flags & 1) {
unsigned int(8) info_length;
unsigned int(8) instance_info[info length];
}
if (flags & 2) unsigned int(32) extension type;
if (!(flags & 4)) unsigned int(16) ext length;
unsigned int(32) entry_count;
for (i=1; i<= entry_count; i++) {
if (flags & 4) unsigned int(16) ext length;
unsigned int(8) extension[ext length];
}
}
[0084] Each entry in the loop corresponds to the respective entry (having the same loop counter value) in the DVBSampleToGroup box having identical grouping type and global parameter values (i.e., identical values ofinfo length and instance info).
In other words, extension applies to the same samples as payload when the loop counter value is the same in respective DVBSampleToGroupExtension and DVBSampleToGroup boxes. If extension-type is not present, then the default semantics for an extension of a grouping_ type are applied. When extension-type is present, then it determines the semantics of extension. Similarly to the DVBSampleToGroup box, a DVBSampleToGroupExtension box of a particular global parameter and extension type can be includcd for each movie fragment.
[0085] In addition to varying-length local parameters for sample groups, the DVBSampleGroupExtcnsion box can be used for providing new pieces of information for a sample grouping while maintaining compatibility with existing sample group definitions and parsers. In other words, a parser not capable of interpreting the DVBSampleToGroupExtension box or a particular extension type can still parse the corresponding DVBSampleToGroup box successfully.
[0086] In one embodiment, the instance info used above in the syntax for DVBSampleToGroup, DVBSamplcGroupDescription, and DVBSampleToGroupExtension boxes is an index to the loop included in the DVBGroupinglnstance box having an identical value of grouping type as the aforementioned boxes. The syntax of the DVBGroupingInstance box can be specified as follows. The semantics of instance descr are determined by grouping type.
aligned(8) class DVBGroupinglnstanceBox extends Fu11Box(`dgri', version = 0, flags) }
unsigned int(32) grouping type;
unsigned int(32) default lcngth;
unsigned int(32) entry_count;
for (i=1; i<=entry count; i++) {
if (default length === 0) {
unsigned int(32) descr_length;
unsigned int(8) instance descr[descr length];
else unsigned int(8) instance descr[default length];
}
}
[0087] In one embodiment, extension type can be parameterized similarly to global and local parameters discussed previously. In other words, rather than identifying an extension based on its extension type only, it can be associated with a parameter further specifying its intent and scope. The associated parameter can also be an index to a loop in another box, which contains the actual parameter values.

-27-[0088] Figure 9 provides a simplified box hierarchy indicating the nesting structure for the DVBGroupinglnstance box 900, DVBSampleGroupDescription box 910, DVBSampleToGroup box 700, and DVBSampleToGroupExtension box 920. The above-identified boxes reside within the sample table (stbl) box 710, which is enclosed in the media information (minf) 720, media (mdia) 730, and track (trak) boxes 740 (in that order) within a movie (moov) box 210. Arrows 950, 960 and indicate a logical connection. Arrows 950 indicate that DVBSampleGroupDescription box 910, DVBSampleToGroup box 700, and DVBSampleToGroupExtension box 920, if present, refer to the DVBGroupingInstance box 950 (with certain values of grouping_type). Arrow 960 indicates that with certain grouping_type and value of flags a DVBSampleToGroup box 700 refers to the respective DVBSampleGroupDescription box 910. Arrow 960 indicates that a DVBSampleToGroupExtension box 920 always refers to the respective DVBSampleToGroup box 700.
(0089] When sample grouping is applied to MPEG2-TS reception hint track (or any other multiplexcd stream), the following holds:
Sample groups associated with the reception hint track are capable of representing metadata for the audio-video multiplex, e.g., toextual descriptive inetadata;
Indices and metadata for a single media type can be represented by specific grouping types;
Approximate indices can be represented with specific grouping types.
Alternatively or complementarily, the accuracy of the indices can be indicated by including more than one contiguous sample into a sample group, which indicates that the indexed feature should be true in one of the contiguous samples. For example, an approximate random access point could be indicated by including N contiguous samples to a sample group of type random access point, indicating that one of the N
samples should be a decoding start position.
[00901 When sample grouping is applied to a media track or RTP reception hint track, indices and metadata for a single media type can be represented by specific grouping types. However, as sample grouping mechanism operates only within one

-28-track, inetadata that applies to more than one media track or reception hint track (later referred to as "multi-track" metadata) should be represented. This issue can materialize in two cases. First, both media tracks and reception hint track(s) may be created from the received stream. Second, there may be multiple RTP reception hint tracks. It is suggested that the sample grouping mechanism of the invention is associated with reception hint tracks whenever they are present in the file.
Thus, the first case above can be avoided. For the second case, several options are contemplated.
[00911 First, "multi-track" metadata may be associated with any related track.
When the metadata is associated to a reception hint track or a media track, the metadata implicitly applies to all reception hint tracks or media tracks, respectively, within the same period of decoding time. This alternative requires parsers to check all tracks for potential "multi-track" inetadata.
[00921 Alternatively, "multi-track" metadata may bc associated with a "master"
track. The master track may be explicitly indicated with a new box within the moov box, for example. The new box may also list all the inter-linked tracks for the "multi-track" metadata.
100931 In another embodiment, timed inetadata track may be associated with many media tracks or RTP reception hint tracks. Sample grouping may be applied to the timed metadata track. The refei red media and reception hint tracks may be listed as track references of type `cdsc'. This serves as an explicit indication which tracks the metadata pertains to. If used, sample duration can be set to match the persistence of each metadata item.
[00941 In one embodiment of the present invention, in the embodiment of the "master" track described above, the new box is referred to as a track relation box and indicates relationship between tracks. The track relation box is defined as follows:
Box Type: `trel' Container: Movie Box (`moov') Mandatory: No Quantity: Zero or One

-29-[0095] The syntax for the track relation box is as follows:
aligled(8) class TrackRelationBox extends Fu1]Box(`trel', version = 0, flags) {
int i,j;

if(flags & Ox000001 == 1) unsigned int(16) num reception_groups;
for(i=1; i<=num rcccption_groups; i++) {
unsigned int(16) num_tracks_in reception_ group;
for(j=1; j<=num_tracks_in reception_group; j++) unsigned int(32) track id;

}
}
}
[0096] In the above syntax, "version" is an integer that specifics the version of the track relation box (0 as described above), and " flags" is a 24-bit integer with flags.
The following bits are defined, where bit 0 is the least significant bit, bit 1 is the second least significant bit, etc. When bit 0 is equal to 1, this indicates that information of reception groups is present in this box, When bit 0 is equal to 0, this indicates that information of reception groups is not present in this box. It is obvious for a person skilled in the art that other types of track relations could also be specified and indicated with a different bit number than bit 0.
10097] "num reception_groups" indicates the number of rcception groups that are signaled. A reception group comprises reception hint tracks that are received simultaneously or are otherwise part of the same recording. In addition, a reception group may comprise media tracks that are derived based on reception hint tracks.
"track_id" indicates the track identifier of the j-th track in the i-th reception group that is signaled. The first track_id of a reception group is a master track that may contain

-30-seglnented metadata that is indicated with sample groups and is associated jointly with all the tracks in the reception group. No other track than a master track may be allowed to contain seginented metadata associated with all the tracks in the reception group.
100981 When timed metadata tracks for indexes or segmented metadata are created, in one embodiment, the following practices may be followed, [00991 One timed metadata track is created for program-specific indexes and metadata of a single-program MPEG-2 transport stream. Program-spccific indexes and metadata apply equally to audio and video streams of a program and to any other potential components of the program, such as subtitle streams.
101001 One timed metadata track per program is created for program-specific indexes and metadata of a multi-program MPEG-2 transport stream. In this regard, a timed metadata track may contain metadata of only one program. The program can be identified by its progam_number value, which is a 16-bit unique identifier for programs within an MPEG-2 transport stream, used in program association and program map tables of an MPEG-2 transport stream, for example. In one embodiment, the parameter program_number can be included in the sample entry structure for timed metadata tracks associated with MPEG2-TS reception hint tracks.
[0101] One timed metadata track is created for media-specific indexes of each elementary stream of an MPEG2-TS program. Media-specific indexes may apply only to a particular media type. For example, they can be indications of reference and non-reference frames of video or indications of the temporal scalability level of video.
101021 One timed metadata track may be created for media-specific indexes for an RTP stream. Further, one timed metadata track may be created for program-specific indexes of multiple RTP streams. 'I'hc timed metadata track is associated with the RTP reception hint tracks using track references. In another embodiment, the timed metadata track is associated with the "inaster" reception hint track with a track reference and the other associated reception hint tracks are indicated through the TrackRelationBox as presented above.
[0103j Even though one program-specific timed metadata track and one media-specific timed metadata track per elementary media stream may often be preferable,

-31-more than one timed metadata tracks can be created. For example, if an altemative timeline for the program is provided subsequently to the program itself, it is more practical from the file arrangement point of view to create a new timed metadata track for the provided timeline.
[0104] For embodiments using timed metadata tracks, a receiver in accordance with an embodiment of the present invention can operate as follows as a response to each received packet:
Convert the received packet to a reception hint sample in the mdat box.
Derive indexes and segmented metadata. Write associated metadata sample(s), if any, to the mdat box (immediately after the corresponding reception hint sample).
Update boxes within the track header of the reception hint track.
Update boxes within the track header of the timed metadata track.
If the memory reserved for track header is about to be fully occupied (and cannot be dynamically re-allocated), start a new movie fragment.
[01051 A receiver with a greater ainount of buffer memory may arrange several metadata samples and reception hint samples in continuous chunks of memory and, therefore, save in the storage space required for the sainple to chunk box and the chunk offset box.
[0106] Indexes and segmented metadata have the following characteristics when it comes to reception hint samples that are associated with them. An index may indicate a characteristic to be valid from the associated reception hint sample onwards, usually until the next index of the same type. For example, an index may indicate a polarity changc of scrambling in MPEG-2 transport stream. An indcx may indicatc a characteristic of a single reception hint sample or an event that is synchronized with a reception hint sample. A bookmark is an example of such an index.
101071 An index may indicate a characteristic of the stream in between the associated reception hint sample and the previous reception hint sample. An indication of missing packets is such an index.
[01081 An index may indicate a characteristic of a coded media sample. It is noted that timed metadata tracks proposed in this invention are associated to reception hint

-32-samples, reccption hint samples do not usually contain exactly one media sample, and data for one media sample may or may not reside in contiguous reception hint samples (e.g., because elementary audio and video streams are multiplexed in an MPEG-2 transport stream). Consequently, there are at least two options how to index media samples: (1) an index is associated only with the first reception hint sample containing data for a media sample; and (2) an index is associated with all reception hint samples containing data for a media sample.
101091 Sample groups associated with timed metadata tracks that contain indexes and segmented metadata can be created in any of the following ways:
A sample group can indicate the value of the index. For example, video sample characteristics can be indicated (random access intra picture, temporal level of the picture). In one embodiment, the sample group description box contains the allowed or used values for the index, in another embodiment, the payload or the extension fields included in a DVBSampleToGroup box or DVBSampleToGroupExtension box, respectively, can indicate the values of indexes.
A sample group can indicate whether or not the index of a particular type changed compared to the previous sample, i.e., the persistence of indexes. For example, changes of protection key for encrypted content can be indicated. In one embodiment, the DVBSampleToGroupExtension box can be used to contain the values of indexes when the sample to group box only contained an indication whether the index value changed.
A sample group can indicate bookmarks. The sample group description box contains the bookmarks themselves.
A satnple group can indicate titles and other information for segmented metadata. The sample group description box contains the titles. One mechanism for linking structured metadata according to any particular mctadata schema to sample groups is as follows. The metadata section formatted according to any particular metadata schema is included as an item in a meta box associated with the timed metadata ti-ack, the movie, or the whole file. Rather than including the metadata section as such in the sample group description box, the sample group description box contains links (typically as item identifiers) to the items containing the associated

-33-metadata section.
A sample group can indicate the value of a set (or tuple) of indexes or segmented metadata of any characteristic. For example, a sample group can indicate the value of a pair of indexes, such as temporal level in a hierarchical temporal scalability structure and picture type (intra, inter, or bi-predictive picture) for coded video elementary stream.
[0110] If an index is associated with a coded media sample, a sample group may indicate only the first reception hint sample containing data for the media sample or all reception hint samples containing data for the media sample.
101111 Exemplary sample entry formats may be provided as follows:
abstract class IndexSampleEntryO extends MetadataSampleEntry (`ixse') {
unsigned int(16) entry_count;
for (i = 1; i<- entry_ count; i unsigned int(32) index type 4cc;
}

class MPEG2TSlndexSampleEntryO extends Index S ampl eEntry (`m2ix`) {
unsigned int(16) program_number;
}
class MPEG2TSMedialndexSampleEntryO extends IndexSampleEntry (`m2mi`) {
unsigned int(3) reserved;
unsigned int(13) pid;
}

class RTPIndexSampleEntryO extends IndexSampleEntry (`rtix`) {
}

{
class RTPReceptionGrouplndexSamp]cEntryO extends lndexSampleEntry ('rgix') }

-34-[0112] "IndexSampleEntry" indicates the types of indexes that may be present in samples associated with this sample entry. If "entry_count" is equal to 0, any indexes may be included in samples associated with this sample entry. If "entry_count"
is greater than 0, a loop of "index type_4cc" values is given and each value of "index typc_4cc" indicates a four-character code for a box that may be present in samples associated with this sample entry. The sample entries for a timed metadata track therefore indicate the types of metadata that may occur in the timed metadata track. It is noted that other mechanisms to indicate the types of metadata present or allowed in a timed metadata track can be envisioned, e.g., as extensions of track header boxes.
[0113] "MPEG2TSIndexSampleEntry" is used for timed metadata tracks containing program specific indexes and mctadata and associated with an MPEG2-TS
reception hint track. "program number" identifies a program within the MPEG-2 tracisport stream.
[0114] "MPEG2TSMedialndexSampleEnhy" is used for timed metadata tracks containing inedia-spec.ific indexes and metadata and associated with an elementary stream contained in an MPEG2-TS reception hint track. pid is an identifier for an elementary stream within an MPEG-2 transport stream.
[0115] "RTPlndexSampleEntry" is used for timed metadata tracks containing media-specific indexes and metadata and associated with an RTP reception hint track.
[0116] "RTPReceptionGrouplndexSampleEntry" is used for program-specifc indexes and metadata and associated to more than one RTP reception hint track.
[0117] An exemplary sample format for a timed metadata track containing indexes and segmented metadata is provided below:

aligned(S) class IndexSample {
box index box[];
}

-35-[0118] "IndexSainple" contains zero or more index boxes. The four-character code for the included index boxes must bc among those indicatcd by the associated sample entry.
[01191 Exemplary index boxes which can be used with the invention and which were originally proposed in DVB document TM-FF0058r0 are provided as follows:
abstract aligned(8) class DVBlndexBox (type) extends Box(type) {
unsigned int(4) time accuracy;
unsigned int(4) sample_accuracy;
if(time accuracy >= 8) unsigned int(3 2) max timing_inaccuracy;
if(samplc_accuracy >= 8) unsigned int(32) max_sample accuracy;
}

[0120] The following values are specified for "time_accuracy" and "sample accuracy": OxO: accurate, Oxl: unspecified, 0x2: heuristic, 0x3:
reserved (no maximum provided), 0x4 - 0x7: application-specific (no maximum provided), 0x8:
maximum inaccuracy specified, 0x9: reserved (maximum inaccuracy provided), OxA
- OxF: application-specific (maximum inaccuracy provided).

aligned(8) class DVBVideoIndex extends DVBlndexBox('idvi') {
unsigned int(S) video_event mask;
unsigned int(24) video_event length;

101211 "video event mask" is a bit mask indicating the video event(s) that start in the indicated sample, as per Table 1 below.

Table 1: Mask values used for "video event mask"
F Mask ~ ~ Meaning ~

Ox01 video decode start point (e.g. a Random Access Point) 0x02 Sclf decodable picture (e.g. I frame) 0x04 Reference Picture 0x08 P Picture ----OxIO B Picture [01221 "video event Iength" is the number of samples (transport packets) that make up this video picture, including the current packet. The value `0' shall be used to mean "unlaiown". The Sync Sample Box can also carry the indexes to the events of type Ox01.

aligned(8) class DVBPCRIndex extends DVBlndexBox('idpi') {
unsigned int(1) PCR discontinuity_flag;
unsigned int(5) reserved_0;
unsigned int(42) PCR Value;
}
[012-1] "PCR discontinuity_flag" is a field that is set to `1' if there is a program clock reference (PCR) discontinuity in the associated PCR event; otherwise it is set to `0'.
101241 "PCR_value" is the 27-MHz value extracted from the PCR that is indexed, for example, as per equation (2-1) in ISO/IEC Intern.ational Standard 13818-1.
aligned(8) class DVBPolarityChange extends DVBlndexBox(`idpc') {
unsigned int(8) polarity;
i [01251 "polarity" is the polarity of the associated event, as per Tab)e 2 below:
Table 2: Interpretation of Polarity values [Valuc Meanmg ~
:iiiiiiiiiiiiii +ICIcar dd polarity 2 Even polarity [01261 This value indicates the new polarity value which applies, and the timed rnetadata sample corresponds to the first reception hint sample with this new polarity.
A polarity change index shall only be deemed to occur when the polarity of a stream of packets on a given PID changes, and not when it changcs between packets of different PIDs.

aligned(8) class DVBCAIndex extends DVBIndexBox(`idci') {
unsigned int(8) polarity;
unsigned int(8) ca event_data[];
}

[01271 "caevent data" is the bytes that comprise the packet carrying the conditional access (CA) event; typically, this will be an ECM. The "ca event_data"
continues until the end of the box. I'he length of the "ca event data" can be detennined from the length of the box.

{
aligned(8) class DVBTimecodeindex extends DVBlndexBox('idtc') unsigned int(8) timeline_id;
unsigned int(2) reserved 0;
unsigned int(6) tick fornlat; // as per table 6 in TR 102 823 unsigned int(32) absolute ticks;

}
[01281 "timcline_id" is the identifier of the timeline, as per ETSI TS 102 823, clause 5.2.2.4, and "tick fonnat" is a field which specifies the format that the "absolute ticks" field takes, as per the Synchronized Auxiliary Data (SAD) specification, ETSI TS 102 823. "absolute ticks" is the timecode, coded as indicated by the field "tick foimat", {
aligned(8) class DVBSectionUpdateIndex extends DVBlndexBox('idsu') unsigned int(8) table id;
unsigned int(16) table id extension;
unsigned int(8) section no;
unsigned int(n*8) section_data; optional }

101291 "DVBIDTab1e" box can be included, for example, in a sample table box for a timed metadata track. "table id" is the table id of the section version update that is being indexed. "table id_extension" (or "program number" for PMT, or "transport_stream id" for PAT) from the section version update is being indexed.
"seetion no" is the section nuinber to which this update applies.
"section_data" is the field may not be present. If it is present it contains the section data of the new version.
The section data shall continue until the end of the box. The length of the "section data" can be determined from the length of the box.
aligned(8) class DVBIDIndex extends DVBlndexBox('didi') {
unsigned int(5) reserved;
unsigned int(3) running_status; l/ As per table 105 in 102 323 unsigned int(24) ID Table index;
}

[01301 "running_status" is the field which indicates the status of the ID that is referenced by the "ID Table_index" field (e.g., if the ID is running or paused). The value of this field is dcfine in table 105 of TS 102 323. "ID Table index" is an index into the "DVBID'I'ableBox", indicating the ID that applies at this location with the indicated running_status.

aligiled(S) class DVBIDTable extends Fu11Box('didt', version = 0, 0) {
unsigned int(32) IDticount;
for(i=(.~;i<ID count;i++) {
string ID; !/in URI Format ~

}
[0131] "[D count' is the number of IDs that follow in the "DVBIDTab1e". "ID"
is the URI formatted ID.
[0132] Further examples of index boxes are provided below:
aligned(8) class SDPUpdate extends DVBIndexBox(`idsd') {
string sdp text;
}
[01331 "sdp_tcxt" is a null-terminatcd string containing ati SDP description that is valid starting from the indicated sample.

aligned(8) class KeyUpdate extends DVBlndexBox('idkm') {
string key message;
}
[01341 "key_message" contains the cryptographic key to be used for deciphering the packet payloads starting from the related reception hint sample.

aligned(8) class Errortndex extends DVBIndexBox(`idei') {
iuzsigned int(2) packet header_error;
unsigned int(2) packet_payload_error;
unsigned int(2) packet sequenec_gap;
unsigned int(2) reserved;

}

[01351 For "packet header error", a value OxO indicates that the packet header contains no errors, Value Oxl indicates that the packet header may or may not contain errors. Value 0x2 indicates that the packet header contains errors. Value 0x3 is reserved.
[01361 For "packet_payload error" a value OxO indicates that the packet payload contains no errors. Value Ox 1 indicates that the packet payload may or may not contain errors. ValueOx2 indicates that the packet payload contains crrors.
Value 0x3 is reserved.
[0137] For "packet sequence_gap", a value OxO indicates that the packet immediately follows the previous packet in the reception hint track in transmission order, Value Oxl indicates that the packet may or may not immediately follow the previous packet in the reception hint track in transmission order. Value 0x2 indicates that the packet does not immediately follow the previous packet in the reception hint track in transmission order, for example, that a there is at least one missing packet preceding this packet. Value 0x3 is reserved.
101381 In another embodiment, an Index Sample Entry format for a timed metadata track containing indexes is as follows:
class IndexSampleEntryO extends MetadataSamplchntry (`ixse') {
unsigned int(16) program_numbcr;
unsigned int(16) entry_count;
int(32) sample number_offset;
for (i = 1; i<- entry count; i++) {
unsigned int(32) index type_4cc;
unsigned int(8) instance info_length;
unsigned int(8) payload_length;
unsigned int(8) extension_count;

}

[0139] An lndexSamplel?ntry indicates the types of indexes that may be present in samples associated with this sample entry. program number identifies aprogam within the MPEG-2 transport stream. If entry count is equal to 0, then any indexes may be included in samples associated with this sample entry, and default values (according to the first release of the DVB File Format specification) of instance info length, payload length, and extension count are used.
sample_number_ offset specifies an offset to be added to the sample_number in the associated timed metadata samplcs to obtain the sample number in the referred track, index_type4cc indicatcs an index type that may be present in samples associated with this sample entry. instance info length, payload_length, and extension count indicate the values of these fields used in index samples. A DVB File Format parser ignores those bvtes index instance info, index_payload and index extension that are beyond the byte range specified in this document for the respective indcx type_4ce.
This mechanism allows appending fields in a backward-compatible manner in later index format versions. If there are many timed metadata tracks for a reception hint track, then index type__4ec values can be used to locate the track containing the desired indexes.
[0140] An index sample contains one or more index events, each having the following abstract syntax. The semantics of index instance_info and index_payload arc determined by the 32-bit index type and the semantics of index_extension is determined by extension type as specified subsequently. index_type corresponds to grouping_type in sample grouping.
abstract class lndexEvent(index_type, info_length, payload_length, extension_count) {
unsigned int(8) index_instance info[info length];
unsigned int(8) index_payload[payload length];
for (i=1; i<=extension count; i++) {
unsigned int(32) extension_type;
unsigned int(16) extension length;
unsigned int(8) index extension[extension ] ength];

unsigned int(8) pad[];

}
abstract class Indexlnstancelnfo(index_type, infolength) {
}
abstract class IndexPayload(index_type, payload length) {
i ~
abstract class IndexExtension(extension_type, extension length) {
}
[01411 The semantics of index instance info, index_payload, extension type, and index extension in the ]ndexEvent structure are identical to the semantics of index_instance info, index payload, extension type, and index extension, respectively, used in DVBSampleToGroup, DVBSampleGroupDescription, and DVBSampleToGroupE;xtension boxes. This match enables the straightforward conversion between indexes included in timed metadata tracks and indexes indicated by DVBSampleToGroup boxes.
[0142] Syntax of some index events are provided below, where the semantics of the syntax elements is the same as described in the einbodiment presented previously.
class Videolndex extends IndexEvent("idvi", 0, 2, 0);
class VideoIndexPayload extends IndexPayload("idvi", 2) {
unsigned int(2) reserved = 0;
unsigned int(2) sample_depends_on;
unsigned int(2) sample is depended on;
unsigned int(2) sequence_depends_on;
unsigned int(8) dependency level;
}
class 1'CRlndex extends IndexEvent("idpc", 0, 6, 0);
class PCRlndexPayload extends IndexPayload("idpc", 6) {

unsigned int(1) PCR_ discontinuity_ flag;
unsigned int(5) reserved_0;
unsigned int(42) PCR Value;

class Polaritylndex extends IndexEvent("idca", 2, 1, 1);

class Polarity Instancelnfo cxtends IndexlnstanceInfo("idca", 2) {
unsigned int(13) pid;
unsigned int(3) resewed;
}

class Polarityindex extends IndexEvent("idca", 0, 1, 1);

class Polaritylnde;tPayload extends IndcxPayload("idca", 1) {
unsigned int(6) reserved_0;

unsigned int(2) polarity;
l class PolaritylndexExtension extends IndexExtension("idca", extension length) {
unsigned int(8) ca event data[extension_length];
}
class Tirnecodelndex extends IndexEvent("idte", 1, 5, 0);

class Timecodelndexlnstancelnfo extends IndexInstanceInfo("idtc", 1) {
unsigned int(8) tiirieline_id;
}
class TitnecodelndexPayload extends IndexPayload("idtc", 5) {
unsigned int(2) reserved_0;

unsigned int(6) tick format; r`/ as per table 6 in TR 102 823 unsigned int(32) absolute ticks;
~

class Timelndex extends IndexEvent("idti", 0, 0, 0);

class SectionE7pdatelndex extends IndexEvent("idsu", 0, 4, t);

class SectionUpdatelndexPayload extends IndexPayload("idsu", 4) {
unsigned int(S) table id;
unsigned int(16) table_id_extension;
unsigned int(8) section no;
}
class SectionUpdatelndexExtension extends IndexExtension("idsu", extension_length) {
unsigned int(S) section_data[extension length];
}
[0143] There are at least two types of usage for descriptive metadata. First, whcn a broadcast is recorded continuouslv (e.g., as a response of user initiating an instantaneous record operation rather than a scheduled recording of a particular program), contcnt from more than one program may be recorded to a single file, Thus, Electronie Service Guide (ESG) information is also stored for more than one program within the file. An indexing ulechanism can be used to map a group of samples comprising a progratn with the respective fragments of ESG
information.
Second, different "storylines", such as summaries or special cuts, can be provided by broadcasters. For example, a broadcaster can provide information, in particular the time periods and descriptions, about the goals of a soccer game, general highlights of the game, or highlights of a particular player during the game. These "storylines" can be provided af`ter the rceording and may use a specific timeline (as discussed in the timecode index presented earlier). An indexing mechanism can be used for indicating "storylines" in a recorded file.
[01441 The DVBSarnpleToGroup box can be used for descriptive or segmented metadata as follows. 'lhe value of grouping type can be differentiate ESG and "storyline" mtadata, even though they may be structurally identical and the same grouping type could also be used. The global parameter, instanceinfo, is used to differentiate between storylines. For ESG metadata, instance_info can contain the item id of the metadata item for initiating the ESG metadata (such as giving information about the F;SG provider) or it may be used to differentiate between different programs of ESG metadata. In practice, instance_info can contain the item id of a metadata item containing the infonnation about storylines or ESG.
Alternatively, instanee info may point to the DVBGroupingInstancebox, which can e.g. contain a textual name of each storyline or URIs pointing to descriptions. The entries in the loop included in the DVBSampleToGroup box can be used as follows.
If the constant-size payload field is used, it may contain the item id of the metadata item containing a description of the grouped samples, such as respective ESG
fragment or descriptive data about an event in the storyline. If group description _index is used within the loop, the DVBSampleGroupDescription box may contain the URIs of the respective ESG fragments or descriptive XML
fragments about an event in the storyline. Alternatively, the DVBSampleGroupDcscription box may contain textual description of the storyline events. When the syntax for DVIBSampleToGroup box that allows varying-length payloads is usecl, the payload can be an URI used for purposes mentioned above or a textual description ofan event.
[01451 Figure 10 illustrates a file including two sample groupings according to the DVBSampleToGroup box for tho timecode index. As the syntax above specifies, the value of timeline id serves as the global parameter for a timecode index sample grouping. In 1010, the timeline id is equal to 100, whereas in 1020, the timeline id is equal to 200.

[01461 When sample groups are included in a reception hint track or a media track, seeking to a position in a file based on a desired segmented metadata or index property can be done by a file parser with the following steps:
1. Select an appropriate sample group description box (based on its grouping type).
2. Select a desired group description index within the sample group description box.
3. Seek for the desired group description index from the SampleToGroup box(es) (of the selected grouping type). This reveals the sample number of the desired metadata/index property.
4. Use the sample table box to locate the sample in a file based on its sample nutnber.
[0147] When sample groups according to the DVBSampleToGroup box are included in a reception hint track or a media track and payload rather than group_description index is used, seeking a position in a file based on a desired segmented metadata or index property can be done by a file parser with the following processes:
1. Select aui appropriate DVBSampleToGroup box (based on its grouping type and instance info).
?. Seek for the desired value of payload in the DVBSampleToGroup box(es). This reveals the sample number having the desired metadata/index property.
3. U se the sample table box to locate the sample in a file based on its samplc number.
[0148] Wen sample groups are inctuded in a timed metadata track, seeking to a position in a file based ou a desired segmented metadata or index property can be done by a file parser with the following processes:
1. Select an appropriate sample group description box (based on its grouping type).
2. Select a desired group description index within the sample group description box.
3. Seek for the desired group description index from the SampleToGroup box(es) (of the selected grouping ty~pz). This reveals the sample number of the desired metadata/index property urithin the ti7ned nieta.data track.
4. Map the sample of thc timed metadata track to a sainple of the associated reception hint track. Ifone metaclata sample is created for each reception hint sample, the desired sample number i.n the reception hint track is identical to that of the timed metadata track. Otherwise, derive the decoding timestamp of the timed metadata sample (using the (lecodu-tg time to sample box) and seek for a reception hint sample having an identical decoding timestamp (or a reception hint sample that pertains at the time of the decoding timestamp) 5. Use the sample table box of the reception hint track to locate the sample in a file based on the sample number of the reception hint sample identified in the previous step.
[01491 When sample groups are included in a reception hint track or a media track, obtaining the indexes and segmented inetadata valid for a particular reception hint sample or a media sample, respectively, can be done by a file parser with the following processes:
1. Select each sarnplc to group box (one at a time) associated with the reception hint track or the media track and find the sample group description index of the of the particular reception hint sample or media sample, respectively.
2. Obtain the inclex or segn-iented mtadata corresponding to the sample group description index from the respective sample group description box.
[01501 When sample groups are included in a timed metadata track, obtaining the indexes and segm.ented metadata valid for a particular reception hint sample can be done by a file parser with the following processes:
1. Map the reception hint sample to a metadata sample as follows. If one metadata sample is created for each reception hint sample, the desired sample number in the reception hint track is identical to that of the timed metadata track.
Otherwise, derive the decodizig timtstamp of the reception hint sample (using the decoding time to sample box) and seek for a timed metadata sample having an identical decoding timestamp (or a timed metadata sample that pertains at the time of the decoding timestamp).

2. Select each sample to group box (one at a time) associated with the timed metadata track and f nd the sainple group description index of the of the particular timed metadata sample, respectivelv.
3. Obtain the index or segmented nletadata corresponding to the sample group description index from the respective sample group description box.
101511 A player, ttipically comprising a fite parser, a decoder 160, and a renderer 170, can provide a list of indices, bookmarks. or other types of inetadata to the end-user by analyzing and re-producing solne part of the content of the sample group description boxes.
[01521 A player may provide booklnarking operation to end-users. Bookinarks can be stored to a file using sample grouping similarly as described above for the receiver operation [01531 Thus, in accordance with embodiments of the present invention, sample groups can be used with movie fragments seamlessly, because SampleToGroup box can reside in a track fragment box. Hence, simultaneous recording and playback of a single filc is fully supportcd. Further, the sample group mechanism is extensible, as new grouping types can he specified. Persistence ofinetadata is clear:
contiguous samples with the same value of group description index (of the same grouping type).
Further, getting a table of contents of the file based on SarnpleGioupDescription boxes is straightforward. Thus, when storing metadata associated with single samples, e.g. bookmarks, the salnple grouping mechanism can be better than timed metadata tracks.
101541 While ernbodiments of the invention have mostly concerned a receiver 150, a recording storage 155, a file parser, and a dccoder 160, the presented file structures can also be used by an encoder 1 10 when ca-e,ating a file. In particular, when a file is provided for playback without convei-ting its inedia contents to a packetized format, it is often useful to provide segmented metadata and indices structured as proposed in the invention. In accordance with the I50 base media file format, the encoder derives file metadata that will be later stored within the moov box or the moof box, depending on whether or not movie fi-agnlents are in use. For any received piece of metadata, the encoder 1 10 identifies its tvpe and creates a new sample group description box, if the type of inetadata did not exist before. The encoder 110 also checks whether or not the content of the piece of metadata differs from all metadata stored earlier in the file. If the content is novel, then a new entry is created for the sample group description box and the rnetadata content is copied into the entry. The SampleToGroup box is inaintained for each grouping type and samples of a media track or a hint track are mapped to one of the entries in the respective sample group description box.
101551 It is noted that the above-described creation of sample grouping may be implemented in a number ways. For example, the creation of sample grouping may not happen simultaneouslv with the encoding and storage 120 of the samples themselves, tnstead, sarnple grouping rnay be performed off-line, based on an intermediate format for storing metadata. Keferring again to Figure 1, the off-line creation of sample grouping would result into two additional blocks getting their input from the storage 120 and outputting to the server 130. The first block in processing order can be referred to as a setvei- file re-writer, which inputs a file without sample grouping for a particular inetadata type and outputs a file with that type of sample grouping. The second block in processing order can be referred to as a second storage, which may have similar properties to the storage 120.
[01561 The server file re-writer and the second storage referred to above may reside in the same dcvice as the encoder 1 10, the storage 120, the server 130, or a different device. Moreover, the server file re-writer and the second storage may reside in the same device or different devices from eacli other.
101571 In one embodiment, the server 130 typically includes a file parser (not shown in Figure i). The file parser follows the instructions provided in one or more hint tracks to generate a packet streain from coded media bitstreams included in a container file. The file parser further processes the information given in the sample group description boxes associated with the hint tracks. The processing may include, for example, creation of SDP infornlativn or parts of an electronic service guide based on the information given in the sample group description boxes. The processing may also include processing ofthe SanlpleToGroup boxes to resolve the relation of pieces of metadata (associated with a certain group description index) given in the sample group description boxes with media or hint samples, and the persistence of metadata provided in the sample group description boxes. For example, the server may check when new SDP inf(irmation is required for decoding of the transmitted packet stream and send the new SDP information such a way that it is available for a receiver when it is needed for decoding packets. In one embodiment, the file provided to the server is created by a receiver 150 and stored in a recording storage 155, which is opcrationally connected to the server 130.
101581 While particular embodiments of the present invention have been disclosed, it is to be understood that various different modifications and combinations are possible and are contemplated within the true spirit and scope of the appended claims.
There is no intention, therefore, of limitations to the exact abstract and disclosure herein presented.
[01591 Various embodiments of present invention described herein are described in the general context of method steps, which inav be implemented in one embodiment by a program product including computer-exeeutable instructions, such as program codc, executed by computers in networked environmcnts. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Randorn Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Generally, progran-i modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for i.mplementing the functions described in such steps. Various elnbodiments of the present invention can be implemented directly in software using any common programming language, e.g. C/C++ or assembly language.
[01601 Software and web irnplementations of the present invention could be accomplished with standard programming teeliniques with rule based logic and other logic to accomplish the various database searehing steps, correlation steps, comparison steps and decision steps. It should also be noted that the words "component" and "module," as used herein and in the claims, is intended to encompass implementations using one or more lines of software code, andlor hardware iinplementLitions, and?or equipment for receiving manual inputs.
[01611 Ind] vidual and specific stnictures deserihed in the foregoing examples should be understood as constituting repr-c;sentative structure of means for performing specific functions deseribed in the following the claims, atthough limitations in the claims should not be inteipreted as constituting -`rneans plus function"
limitations in the event that the term "means" is not used therein. Additionally, the use of the term "step" in the foregoing description should not be used to construe any specific limitation in the claims as constituting a"step plus function" limitation. To the extent that individual references, including issued patents, patent applications, and non-patent publications, are described or othenvise mentioned herein, such references are not intended and should not be interpreted as limiting the scope of the following claims.
[01621 The foregoing description of embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the present invention. The embodiments were ehosen and described in order to explain the principles of the present invention and its practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated. The features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, systems, and computer program products.

Claims (61)

WHAT IS CLAIMED IS:

1. A method of organizing streamed data, comprising:
storing streamed data in a file;
identifying metadata applicable to a subset of the streamed data; and forming at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a metadata type.

2. The method of claim 1, wherein the at least one group is identified in a file.

3. The method of claim 1, wherein the file is in accordance with ISO base media file format.

4. The method of claim 3, wherein the storing streamed data in a file includes storing in a reception hint track.

5. The method of claim 3, wherein the metadata type is indicated by a grouping type and grouping instance data, the grouping type specifying semantics of the grouping instance data and the metadata content.

6. The method of claim 5, wherein the metadata content comprises a metadata payload and zero or more metadata payload extensions, wherein the metadata payload is included in a first structure and wherein the zero or more metadata payload extensions are included in a second structure.

7. The method of claim 5, wherein the at least one group is indicated in a sample group description box.

8. The method of claim 3, wherein the at least one group is indicated in a sample group description box.

9. The method of claim 1, wherein the metadata type includes titles of segments of the streamed data.

10. The method of claim 1, wherein a group includes samples from two or more tracks.

11. The method of claim 10, further comprising:
identifying the group including samples from two or more tracks with metadata associated with all related tracks.

12. The method of claim 10, further comprising:
identifying the group including samples from two or more tracks with metadata associated with a master track.

13. A computer program embodied on a computer-readable medium, the computer program configured to provide a method comprising:
storing streamed data in a file, identifying metadata applicable to a subset of the streamed data; and forming at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a metadata type.

14. The computer program of claim 13, wherein the at least one group is identified in a file.

15. The computer program of claim 13, wherein the file is in accordance with ISO base media file format.

16. The computer program of claim 15, wherein the storing streamed data in a file includes storing in a reception hint track.

17. The computer program of claim 15, wherein the metadata type is indicated by a grouping type and grouping instance data, the grouping type specifying semantics of the grouping instance data and the metadata content.

18. The computer program of claim 16, wherein the metadata content comprises a metadata payload and zero or more metadata payload extensions, wherein the metadata payload is included in a first structure, and wherein the zero or more metadata payload extensions are included in a second structure.

19. The computer program of claim 15, wherein the at least one group is indicated in a sample group description box.

20. The computer program of claim 13, wherein the metadata type includes titles of segments of the streamed data.

21. The computer program of'claim 13, wherein a group includes samples from two or more tracks.

22. The computer program of claim 21, the method further comprising:
identifying the group including samples from two or more tracks with metadata associated with all related tracks.

23. The computer program of claim 21, the method further comprising:
identifying the group including samples from two or more tracks with metadata associated with a master track.

24. A receiver adapted to receive streamed data, comprising:
a storage unit for storing streamed data in a file; and a processor adapted to:
identify metadata applicable to a subset of the streamed data;
and form at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a metadata type.

25. The receiver of claim 24, wherein the processor is further adapted to identify the at least one group in a file stored in the storage unit.

26. The receiver of claim 24, wherein the tile is in accordance with ISO
base media file format.

27. The receiver of claim 26, wherein the storage unit is adapted to store the streamed data in a reception hint track.

28. The receiver of claim 26, wherein the metadata type is indicated by a grouping type and grouping instance data, the grouping type specifying semantics of the grouping instance data and the metadata content.

29. The receiver of claim 28, wherein the metadata content comprises a metadata payload and zero or more metadata payload extensions, wherein the metadata payload is included in a first structure, and wherein the zero or more metadata payload extensions are included in a second structure.

30. The receiver of claim 26, wherein the at least one group is indicated in a sample group description box.

31. The receiver of claim 24, wherein the metadata type includes titles of segments of the streamed data.

32. The receiver of claim 24, wherein a group includes samples from two or more tracks.

33. The receiver of claim 34, wherein the processor is further adapted to identify the group including samples from two or more tracks with metadata associated with all related tracks.

34. The receiver of claim 32, wherein the processor is further adapted to identify the group including samples from two or more tracks with metadata associated with a master track.

35. The method of claim 1, further comprising creating a timed metadata track for the streamed data.

36. The method of claim 35, wherein the file is in accordance with ISO
base media file format.

37. The method of claim 36, wherein the storing streamed data in a file includes storing in a reception hint track.

38. The method of claim 36, wherein the at least one group is indicated in a sample group description box.

39. The method of claim 38, wherein the at least one group of one or more samples of the streamed data is indicated in a sample group description box for the timed metadata track through associating the at least one group of one or more samples of the streamed data with respective timed metadata samples in the timed metadata track.

40. The method of claim 35, wherein timed metadata track associates timing metadata with one or more timelines.

41. The method of claim 40, wherein timed metadata track associates timing metadata with two or more timelines.

42. The computer program of claim 13, wherein the method further comprises:
creating a timed metadata track for the streamed data.

43. The computer program of claim 42, wherein the file is in accordance with ISO base media file format.

44. The computer program of claim 43, wherein the storing streamed data in a file includes storing in a reception hint track.

45. The computer program of claim 43, wherein the at least one group is indicated in a sample group description box.

46. The computer program of claim 45, wherein the at least one group of one or more samples of the streamed data is indicated in a sample group description box for the timed metadata track through associating the at least one group of one or more samples of the streamed data with respective timed metadata samples in the timed metadata track.

47. The computer program of claim 42, wherein timed metadata track associates timing metadata with one or more timelines.

48. The computer program of claim 47, wherein timed metadata track associates timing metadata with two or more timelines.

49. The receiver of claim 24, wherein the processor is further adapted to create a timed metadata track for the streamed data.

50. The receiver of claim 49, wherein the file is in accordance with ISO
base media file format.

51. The receiver of claim 50, wherein the storage unit is adapted to store the streamed data in a reception hint track.

52. The receiver of claim 50, wherein the at least one group is indicated in a sample group description box.

53. The receiver of claim 52, wherein the at least one group of one or more samples of the streamed data is indicated in a sample group description box for the timed metadata track through associating the at least one group of one or more samples of the streamed data with respective timed metadata samples in the timed metadata track.

54. The receiver of claim 49, wherein timed metadata track associates timing metadata with one or more timelines.

55. The receiver of claim 54, wherein timed metadata track associates timing metadata with two or more timelines.

56. An apparatus, comprising:
means for identifying metadata applicable to a subset of the streamed data;
and means for forming at least one group of one or more samples of the streamed data, each sample in a group having identical metadata content for a metadata type.

57. The apparatus of claim 56, wherein the file is in accordance with ISO
base media file format.

58. The apparatus of claim 57 wherein the storing streamed data in a file includes storing in a reception hint track.

59. The apparatus of claim 57, wherein the metadata type is indicated by a grouping type and grouping instance data, the grouping type specifying semantics of the grouping instance data and the metadata content.

60. The apparatus of claim 59, wherein the metadata content comprises a metadata payload and zero or more metadata payload extensions, wherein the metadata payload is included in a first structure, and wherein the zero or more metadata payload extensions are included in a second structure.

61. The apparatus of claim 57, wherein the at least one group is indicated in a sample group description box.