EP1504598A4

EP1504598A4 - Content identification in a digital video recorder

Info

Publication number: EP1504598A4
Application number: EP03724522A
Authority: EP
Inventors: Joseph C Engle; Akinyemi Odutola
Original assignee: Thomson Licensing SAS
Current assignee: THOMSON LICENSING
Priority date: 2002-05-09
Filing date: 2003-05-08
Publication date: 2009-07-01
Also published as: CN1653809A; MXPA04011027A; WO2003096686A1; KR20040106500A; AU2003230353A1; JP2006511980A; CN100411434C; EP1504598A1; KR100960342B1; JP4541139B2

Abstract

The invention concerns a method and apparatus for controlling a video-media recording device configured for automatically identifying and selectively skipping commercial message segments of a video signal. The method can include the steps of recording (206) the video signal on a digital recording medium (124) in a digital format; monitoring the video signal to detect an event start and an event end (208) corresponding to a beginning and an end of at least one commercial message; and selectively storing in a memory location (220) digital data identifying an event start information and an event end information. At least one of the event start information and the event end information can identify the location of the one or more commercial messages. The method can also include selectively skipping (312) in a playback mode the commercial portion of the video signal responsive to the digital data identifying the event start information and the event end information.

Description

CONTENT IDENTIFICATION IN A DIGITAL VIDEO RECORDER

Background of the Invention Technical Field

The. invention concerns digital video recorder, and more particularly a method and apparatus for removing commercial interruptions from video programming.

Description of the Related Art

Various devices have been developed to enable consumers to record video and/or audio programs for later presentation. Such devices include tape recorders, videocassette recorders, recordable compact discs, and most recently, recordable digital video discs (DVD). Hard drives and magneto optical discs have also been used.

One feature that is desirable for an MPEG media recorder is the ability to automatically identify and selectively skip segments of a recorded video signal. For example, such a feature may be useful for automatically editing out commercial messages from recorded television broadcast signals. Commercial skip is an important feature in the field of videocassette recorders. In this regard, various systems have been disclosed in the context of video cassette recorders to address this problem.

Conventional commercial skip technology in VCRs has used fading to dark frames as a cue for identifying and deleting commercial advertisements. These dark or black frames are used to generate a map of possible commercials in recorded television programming. However, this conventional approach is not entirely satisfactory because it requires one to wait while the system returns to the beginning of the segment to mark the commercial, and it uses tape sync or control pulse encoding of events/Startskip/StopSkip. Moreover, because conventional VCRs do not use MPEG type encoding, they cannot take advantage of more sophisticated video processing methods that can be applied for detecting video program transitions such as may occur during commercial advertisements.

In recent years, more advanced systems that record video programs to a hard disk have also implemented commercial skip features. Such systems use a specific set of rules for identifying commercials and commercial groups. In general, commercials are separated from each other and from programs by video fades to black, and audio fades to silence. Accordingly, commercials can be identified by the occurrence of certain events that are simultaneous black video and no audio. A commercial skipping device can be configured to determine when a video signal is sufficiently black and the audio is at a sufficiently low level so as to determine the occurrence of an event.

Commercial groups are groups of individual commercials that are to be skipped. The various rules for determining commercial groups are rules specifying commercial lengths, and number of commercials together. For example, if there were five events detected, with exactly one minute between them, it can fairly be assumed that these collectively represented a commercial group. The goal is to skip commercial groups. Thus, for example, the device can use "A" marks at the beginning of the commercial group (to tell the device to start skipping), and "B" marks at the end of the commercial group (to tell the device to stop skipping and resume normal video and audio playback output). However, these systems continue to use techniques based on principals of analog tape recording, and the skip information is a simple manipulation of the control track pulse width.

Summary of the Invention

The invention concerns a method for controlling a video media recording device configured for automatically identifying and selectively skipping commercial message segments of a video signal. The method can include the steps of recording the video signal on a digital recording medium in a digital format; monitoring the video signal to detect an event start and an event end corresponding to a beginning and an end of at least one commercial message; and selectively storing in a memory location digital data identifying an event start information and an event end information. At least one of the event start information and the event end information can identify the location of the one or more commercial messages. The method can also include selectively skipping in a playback mode the commercial portion of the video signal responsive to the digital data identifying the event start information and the event end information.

According to one aspect of the invention, the event start information and the event end information can be either an elapsed time since a start of recording of the video signal; or a frame number corresponding to a number of frames of the video signal recorded since the start of recording of the video signal. The storing step can comprise recording data identifying the event start information and the event end information as part of a digital data stream comprising the recorded video presentation. In that case, it can be advantageous for the data identifying the event start information to also include the event end information. If the digital format in which the video signal is encoded is MPEG the event start information and the event end information can be stored following an MPEG picture header in a data field known as extensions_and_user_data(2). This information would be used internally by the invention.

According to another aspect of the invention, the digital data stream comprising the recorded video presentation can be modified by deleting from the digital data stream the commercial portion of the video signal identified by the event start information and the event end information. The modifying step can be performed by accessing the event start information, the event end information, and the digital data stream from a memory location. The digital data stream can then be modified to remove the commercial portion of the video signal. The user could originally select from a menu, whether to remove/keep the commercials from the data stream or keep them. If the user chose 'remove', this would be advantageous, as it would use less storage space. If the user chose to 'keep' commercials, they could be viewed later, as the invention knows their start and stop points. The commercials could be played 'skipping the PROGRAM'. This might be preferable to the user, as some devices have added interactivity to commercials and are targeted to certain customers.

According to an alternative embodiment, the storing step can also include recording data identifying the event start information and the event end information in a data file separate from the recorded video presentation. In that case, the system accesses the data file for the digital data identifying an event start information and event end information, prior to the skipping step. Advantageously, the data file can be stored on the digital recording medium.

According to an alternative embodiment, the invention can also include a recording device configured for automatically identifying and selectively skipping commercial message segments of a video signal. The recording device can operate in accordance with the method described above. Brief Description of the Drawings

Fig. 1 is a block diagram of a digital video device that is useful for describing the inventive arrangements.

Fig. 2 is a flow chart illustrating a process that can be used for recording digital data identifying a location of a commercial message in a video presentation.

Fig. 3 is a flow chart illustrating a process that can be used for skipping a commercial message in a video presentation.

Detailed Description

Fig. 1 is a block diagram of a digital video recording system 100 that can be used in accordance with the inventive arrangements. A system controller such as microprocessor 120 can be used for controlling the operation of the system and performing selected signal processing tasks. Microprocessor 120 can preferably include a suitable high-speed memory (not shown) as is convention for such devices. Control inputs for microprocessor 120 can be received from user interface 130 via control buffer 128. Microprocessor 120 can communicate with the various system components as shall hereinafter be described by means of system bus 126. In Fig.1 , connections to the system bus 126 from each of the various components have been omitted from the drawing for greater clarity.

The system 100 can comprise an RF tuner section 102 for receiving and down-converting an RF video signal. The RF tuner section can convert a selected channel of analog or digital RF video to a baseband signal that can be fed to an analog output section 104 or a digital output section 106.

Conventional analog video and audio circuits 108 are preferably provided for processing baseband analog video signals received from the RF tuner analog output section 104. The output of analog video and audio circuits 108 can be communicated directly to a video display monitor for directly viewing a video presentation. In addition, a digital encoder 116 is preferably provided for converting the analog video and audio output signal into a digital format. According to a preferred embodiment, the digital format can be an MPEG format or any variant thereof such as MPEG-1 or MPEG-2. However, it should be understood that the invention is not limited in this regard and any suitable digital video format can be used. Once converted into a digital format, the video presentation can be stored on a storage medium 124. Storage medium 124 can be any one of a variety of data systems that are capable of storing digital video data for later presentation. Such devices can include, but are not limited to, recordable compact discs, recordable digital video discs in various formats including DVD-R, DVD+R , DVD-RW, DVD- RAM. Magnetic hard drives and magneto optical discs can also be used for this purpose.

In the case where the tuner 102 receives RF modulated video signals in a digital format, these signals can be processed in digital section 106. An encoded digital video signal can then be passed from digital section 106 to digital decoder 109. Decoder 109 is preferably configured for converting the received encoded digital format baseband video signal and converting it to an analog output signal for display. For example, the digital decoder 109 can be an MPEG digital decoder. In that case it is preferably configured for receiving an MPEG video data signal and using that data to recreate audio and video information that was compressed using systems such as MPEG-1 and MPEG-2. The digital decoder 109 can include digital circuits 10 for parsing the digital bit stream, and providing all the data structures and digital information for the digital event detector. The digital circuits 110 also provide digital data to drive D/A (digital to analog) converters that are preferably included in the Analog Output block 112.

The digital circuits section 110 can communicate the decoded digital video signal to analog output section 112 where a digital to analog converter (not shown) and other necessary circuitry can be provided for converting the signal to a conventional analog video format. Subsequently, the analog video signal from analog output 112 can be communicated to the display unit output for display.

One or more event detectors 114, 118, 122 can be provided for detecting the occurrence of a commercial message event. Event detectors 114 and 118 are preferably digital event detectors configured for detecting events in a digital video signal using the rules described below. By comparison, event detector 122 can detect events in an analog video signal.

Commercial message events are any combination of video signal or program characteristics that can be used to identify the occurrence of a commercial message. The combination of one or more of these "events" can be used to identify the occurrence of a commercial message. Event messages can be communicated from the event detectors 114, 118, 122 to microprocessor 120 through system bus 126.

It is difficult to ensure 100% accuracy when implementing a commercial detection and skip feature. However, one or more rules can be used to increase the accuracy of detecting events corresponding to the occurrence of commercial messages. In the present invention, the digital event detector 114, digital circuits 110 and microprocessor 120 can work together to detect events. According to a preferred embodiment, the digital event detector 114 can check the data structures in the digital circuits and look for changes in the incoming video to determine when an event has occurred. According to a preferred embodiment, the rules are used to determine when an event has occurred, by checking for various parameters that have changed, or gone to some particular state. The invention uses intelligence (microprocessor and digital event detector logic) to implement one or more of these rules to identify commercials and commercial groups. All of these events may not occur for each commercial, but by checking for the occurrence of one or more of these events the invention increases the probability of accurately detecting commercials and/or groups of commercials.

Event Detection Rules

Copyright Extension

According to one aspect of the invention, the event detector can make use of copyright information encoded in a digital bit stream to help detect the presence of a commercial message. The program material may have copyright information, and when a commercial is transmitted it may have other copyright information or maybe none at all. Detecting a change would certainly help identify commercials.

For example, in the case of MPEG-2, the event detector can utilize information provided by digital circuits 110 to check for changes in the "Copyright Extension" information as defined in Section 6.2.3.6 of ISO/IEC 13818-2:2000 "Information Technology-Generic Coding of Moving Pictures and Associated Audio Information: Video" (hereinafter referred to as "ISO/IEC-13818-2"). This document sets forth an international standard for MPEG picture coding and is available from the International Organization for Standardization. According to a preferred embodiment, the "video data stream" can be parsed using conventional techniques in the digital circuits 110. When the copyright extension is encountered, the copyright extension structure data is made available to the digital event detector 114. In the case of MPEG-2, the copyright information is defined in section 6.3.15 of ISO/IEC-13818-2. Section 6.3.15 defines the following parameters:

Extension_start_code_identifier - 4 bits. Identifies start of copyright structure. Copyrightjdentifier - 8 bits. Identifies copyright authority. Original_or_copy - 1 bit. 1=original, 0=copy. Copyright_number - total of 64 bits. Actual copyright number.

One or more of these parameters can be monitored for change. For example, the copyright number can be monitored for change. Program material will typically have a different number as compared to commercials. Changes indicate an event. The Original_or_copy bit can be monitored for change, as this would indicate an event. The Copyrightjdentifier can be monitored for change, as this would indicate an event. Additionally, the "Copyright Extension" may exist only for program material and not commercials, and vice-versa. Therefore, this structure may come and go, at these transitions. Therefore, monitoring the occurrence or non-occurrence of the Extension_start_code_identifier would help indicate an event. In the case of the Extension_start_code_identifier, the occurrence or non-occurrence may not be conclusive as to the presence of a commercial message since this information might not be continuously sent.

Video sequence information

The digital circuits 110 can also parse the "video data stream". When a "video sequence and video sequence header" are encountered this temporal occurrence can also be made available to the digital event detector 114. The structure of this information is defined in ISO/IEC-13818-2, section 6.2.2 and 6.2.2.1. Section 6.1.1 of the standard states that the video sequence commences with a "sequence header". These then indicate beginnings (and endings) of video. These are sent relatively frequently, for example, every 2 seconds. If commercials were digitally spliced into a stream, it would probably begin with a new "video sequence". Therefore, the timing of these could be used to indicate more accurately when an event occurred.

Sequence display extension

The digital circuits can also parse the "video data stream" for the occurrence of the

"sequence display extension". When the "sequence display extension" is encountered, its structure data can also be made available to the digital event detector 114. The sequence display information is defined in ISO/IEC 13818-2, section 6.2.2.4 and section 6.3.6. The document defines several parts of this structure as:

Extension_start_codeJdentifier - 4 bits. Identifies start of this structure.

Colour_description - 1 bit. 1=colour-primaries and transfer-characteristics structure information does exist, and immediately follows.

colour_primaries - 8 bits. Defines color related information intended for the display. For example this accurately defines the colors red, green, and blue, and white. There are 5 specific colour primaries defined.

Transfer_characteristics - 8 bits. Defines brightness related information intended for the display. For example this accurately defines what the display should do when the signal data increases in value. That is, should the display increase in brightness proportionally, or increase exponentially. There are 7 specific transfer characteristics defined.

According to a preferred embodiment of the invention, the colour_primaries data and transfer_characteristics data can be monitored for change. Program material may have different colour_primaries data and transfer_characteristics as compared to commercials. Changes indicate an event. The Colour_description bit is monitored for change, as this would indicate an event. Additionally, the "sequence display extension" structure itself may exist only for program material and not commercials, and vice-versa. Consequently, this structure may come and go at these transitions. Accordingly, monitoring the sequence_display_extensionJD, for occurring and not occurring, would indicate an event.

Group Of Pictures information

The event detector can also look at the MPEG "group of picture" (GOP), which is composed of l-frames and optionally B-frames and P-frames. l-frames start every new group of pictures, and typically are followed by B-frames and P-frames. These frames are compressed pictures or parts of the picture to ultimately be displayed.

Section 6.2.3 of ISO/IEC 13818-2 defines these frame types as "picture_codingJype" in the "picture header" structure as follows:

Picture_coding Jype - three bits.

From ISO/IEC 13818-2 table 6-12 the types are: Bits Coding Method 001 intra-coded (I)

010 predictive-coded (P)

011 bidirectionally- predictive-coded (B)

The number of the 'frames', in each GOP and order of the I, B, P frames is determined by the MPEG encoder used, and the encoding operator. For example, the amount of compression selected by the operator, or automatically implemented by the encoder may affect the length of the GOP and the order of the frames. Therefore, the number of frames in the GOP and the order of the I, B, P frames may differ from program material and commercial advertisements. The digital event detector 114 would preferably monitor these parameters and look for changes, which could indicate an event.

Splice Points

SMPTE Standard "312M-1999 Splice Points for MPEG-2 Transport Streams", defines table constructs, that are to be used for networks to signal downstream (local) stations as to when to insert or splice commercials into the program stream. As defined by the SMPTE Standard "312M-1999", these tables pertain to a specific program and are carried in program ID (PID) stream referred to by the specific program's program map table. These tables define a schedule for splice points, that is, beginning and end times, for the insertion of commercials. The tables also define when to execute the insertion, as well as "pre-roll" downstream warning flag. These are called splice_commandJypes and are 8 bits, defined as follows:

splice_command_type value Command

0x01 Preroll

0x02 Execute

0x03 Schedule

The digital decoder 109, provides transport stream information and structures to the digital outputs 110. Accordingly, the event detector 114 can check for the presence of these tables. Information may or may not exist in these tables, as they may be empty, or downstream stations may have stripped the data out, or the data could be inaccurate, or the data could be accurate. If the data does not exist in these tables, then they cannot be used. If data does exist in these tables, then they would be useful in checking the invention's estimate of when commercials have occurred. If the times correspond, then there is greater assurance that the commercial time, determined by the invention, is correct.

Dark Frames and Low Audio

Currently, in the United States, most programs fade to black, and the audio is faded to silence (or close to black and silence), separating commercials and programs. Individual commercials are also separated by these events.

In the digital domain, the event detector 114 can check for detection of video going to "dark" (black), and audio going low. This can be accomplished in a variety of ways. According to a preferred embodiment, the video can be decoded and stored in a frame buffer included as part of the digital circuits 110. The digital event detector 114 can scan each frame, checking to determine if all the digital values are black, representing a black frame. In actual practice there will be a predetermined, "low level" value, where any higher values, are no longer considered "black".

In the digital domain, the event detector 114 can also check for low audio. For example, the audio can be decoded and kept in an audio buffer, in the digital circuits 110. The digital event detector 114 can then scan this buffer, checking that all the digital values are 'silence', representing silenced audio. In actual practice there will actually be a predetermined, "low level" value, where any higher values, are no longer considered 'silence'. This technique has the advantage of being available for use with analog TV programs that do not include the digital data required by the other rules as described herein for identifying the occurrence of events. Using digital event detector 118 and the associated video and audio buffers described above.

Event detectors 114, 118, 122 can be programmed or pre-configured with one or more of the foregoing set of rules for determining the occurrence of an event. Commercial groups comprising two or more commercial messages can be identified using similar techniques. For example, it is conventional to make use of rules that will identify the occurrence of a commercial group when a number of events are detected by an event detector 114, 118, 122 with standard commercial lengths between each event. Examples of standard commercial lengths include, but are not limited to 1 minute, 30 seconds, and 15 seconds. Other methods for identifying the occurrence of a commercial message or messages in a video signal are also known in the art and the invention is not intended to be limited to the exclusive use of the foregoing rules for indicating the occurrence of an event. Instead, event detectors 114, 118, 122 can be any combination of software and/or hardware that will generate a suitable output signal or notification when an event is detected.

Further, it will be appreciated by those skilled in the art that the functionality provided by event detectors 114, 118 can be provided in a variety of ways. For example, these detectors can be implemented as field programmable gate arrays (FPGA's), application specific integrated circuits (ASIC's) or general purpose microprocessors programmed to perform these tasks. Further, the event detector functionality can be implemented in software as part of the processing handled by microprocessor 120. In that case, picture data can be provided directly to microprocessor 120 from digital circuits 110 and digital encoder 116 using system bus 126.

A plurality of signal switches SW1, SW2, SW3, SW4 can be controlled by microprocessor 120 responsive to user input or the switches can be under automatic control in response to certain formats of detected digital or analog video. The operation of the device in Fig. 1 shall now be described relative to several operating modes with reference to the flow charts in Figs. 2 and 3.

ANALOG NTSC OPERATION

Recording Phase

In step 202 of Fig. 2, the system can monitor control buffer 128 for user inputs. In step 204, if a record command is received, the system can begin recording as shown in step 206. According to a preferred embodiment, the microprocessor 120 can control the device 100 to set the switches in the position, SW1=A, SW2=X (any connection) SW3=A, SW4=A. Subsequently, the system can have analog signals from analog tuner output 104 go to the analog video and audio circuits 108. In step 208, digital event detector 118 can monitor the video signal from encoder 116 to detect the occurrence of commercial events. Since the coded output of the digital event detector is based on a purely analog signal, the event detector will generally be limited to identifying the occurrence of events based on fades to black and low audio associated with the occurrence of commercial messages. If such events are detected, then in step 210 the event detector 118 can communicate this information in step 214 to the control processor, in this case microprocessor 120. In step 218 the microprocessor 120 can track the events and determine when one or more commercial messages have occurred and where their beginning and end is.

When one or more commercial messages have been identified by the microprocessor 120 in step 218, this information can be recorded in step 220. This information can be recorded in memory associated with microprocessor 120, stored in a separate file on the storage medium 124, or stored as part of the MPEG digital data. In step 216, the system can check to determine if the recording process is complete. If not, the system continues the recording process.

Playback Phase

A flowchart illustrating playback operation is show in Fig. 3. In step 302, the microprocessor 120 can monitor control buffer 128 to determine if a playback command has been receive. If so, then in step 304 the system begins playback as show in step 306. When playback operation begins, the switches can be set in the positions SW1= X (any position), SW2=B, SW3=B, SW4=X (any connection). Recorded encoded video, such as MPEG video, can be played from the recording medium 124 into the digital decoder 109. Digital decoder 109 generates a decoded digital bit stream that is output from digital circuits 110. The digital bit stream can be converted to an analog format in analog output 112. The analog output signal is communicated to a display unit through analog output 112. In step 308, microprocessor 120 can use the stored information concerning the location of commercial messages to determine whether a particular portion of the playback presentation corresponds to a commercial message. If not, playback continues in step 310. However, if the portion of the playback presentation does correspond to a commercial message then the microprocessor 120 can control the playback in step 312 so as to skip over commercial messages, preferably without interruption to the program. Finally, in step 314, the system checks to see if playback is complete. If not, playback continues in step 310.

DIGITAL OPERATION Recording Phase

The recording process for digital operation is the same as described above relative to Fig. 2, with the following exceptions. With the switches in the position, SW1=X (any connection), SW2=A, SW3=B, SW4=B, the system can access digital R.F. modulated signals from tuner 102. The digitally encoded signals from block 106 supply decoder 109 and switch SW4B for recording by storage medium 124. These digital signals can be decoded in digital decoder 109 and converted to analog format in analog output 112. The digital event detector 114 can detect commercial message events using the rules as previously described. Commercial message events are communicated to microprocessor 120. Events can be stored in memory and used by microprocessor 120 to determine the location of commercial messages. When one or more commercial messages have been identified by the microprocessor 120, this information can be recorded on storage medium 124. This information can be recorded in memory associated with microprocessor 120, in a separate file on the storage medium 124, or as part of the MPEG signal. Plavback Phase

The playback operation in digital mode is essentially the same as described above relative to Fig. 3 with the following exceptions. In playback mode, the switches are in positions SW1= X (any connection), SW2=B, SW3=B, SW4=X (any connection). Encoded video, for example MPEG video, can be played from the storage medium 124 into the digital decoder 109. The digital decoder decodes the MPEG video and communicates the digital bit stream to analog output 112. The analog output signal from analog output 112 is sent to the display unit. Using the stored information concerning the location of commercial messages, microprocessor 120 can control the playback so as to skip over commercial messages, preferably without interruption to the program.

According to a preferred embodiment, event start information and event end information can be used to identify the location of a commercial message in a video presentation. This start and end information can be stored in any convenient manner. For example, each of the start and end location of the commercial message can be identified by an elapsed time since a start of recording of said video signal. Alternatively, a frame number can be used for this purpose. The frame number can correspond to a number of frames of the video signal that have been recorded since the start of recording. In either case it should be understood that the invention is not limited to any specific location identifying indicia.

Data identifying an event start and event end can be stored in a data file separate from the recorded video presentation. Microprocessor 120 can then access the data file for digital data identifying event start information and event end information, prior to the skipping step.

Instead of, or in addition to storing event start and stop data in a separate data file, such data can be recorded as part of a digital data stream comprising the recorded video presentation. For example, if the digital encoding format is MPEG the event information can be recorded following an MPEG picture header in the MPEG field identified as "extensions_and_user_data(2)". This field is provided after each picture header in an MPEG encoded signal, following the "picture coding_extension()" field. Bits can be defined in the extensions_and_user_data(2) field to indicate the start or stop events. This field can also be used to indicate that the particular picture is part of a commercial message. In the event that start and stop event data is encoded in this manner, decoder 109 is preferably configured to detect and respond to such indications appropriately. For example, a notification can be sent to microprocessor 120 when an event has been detected. The microprocessor can then selectively control playback to remove the display of the commercial message.

If the start event and end event data is stored as part of the video bit stream, the microprocessor can use this data to skip the portions of the video presentation associated with the commercial message. A video buffer can be provided in order to avoid any apparent interruption of the video programming. To avoid the need for a large buffer, the start event data encoded in the extensions_and_user_data(2) field can be modified after recording to also indicate the location of an end event. In this manner, when a start event is encountered the microprocessor can immediately determine the location of the end event and direct the decoder 109 to skip to that location.

According to an alternative embodiment, a digital data stream comprising the recorded video presentation can be modified by entirely deleting from the digital data stream the commercial message portion of the video signal. Using this approach will permit the benefit of commercial message removal to be gained on players without the event detectors and associated processing circuitry as described herein. The microprocessor 120 can access event start information, event end information, and a selected portion of the digital data stream. The digital data stream can then be modified to remove the commercial message portion of the video signal.

Claims

Claims:

1. A method for controlling a video media recording device configured for automatically identifying and selectively skipping commercial message segments of a video signal, comprising: recording (206) said video signal on a digital recording medium in a digital format; monitoring (208) said video signal to detect at least one event start and at least one event end corresponding to a beginning and an end of at least one commercial message; selectively storing (220) digital data identifying at least one of an event start information and an event end information as part of a digital data stream comprising said recorded video presentation, at least one of said event start information and said event end information identifying the location of said at least one commercial message.

2. The method according to claiml further comprising the step of selectively skipping in a playback mode (312) said commercial portion of said video signal responsive to said digital data identifying said event start information and said event end information.

3. The method according to claim 1 wherein said event start information and said event end information (208) is selected from the group comprising at least one of a. an elapsed time since a start of recording of said video signal; and b. a frame number corresponding to a number of frames of said video signal recorded since the start of recording of said video signal.

4. The method according to claim 1 wherein said data identifying said event start information also includes said event end information. ^■17-

5. The method according to claim 1 wherein said digital format is MPEG and said storing step (220) is further comprised of recording at least one of said event start information and said event end information following an MPEG picture header in a extensions_and_user_data(2) location.

6. The method according to claim 1 further comprising by the step of modifying a digital data stream comprising said recorded video presentation by deleting from said digital data stream (308, 312) said commercial portion of said video signal identified by said event start information and said event end information.

7. The method according to claim 6 wherein said modifying step comprises a. accessing said event start information, said event end information, and said digital data stream from a memory location (308); b. modifying said digital data stream to remove said commercial portion of said video signal (312).

8. The method according to claim 1 wherein said storing step further comprises recording data identifying said event start information and said event end information in a data file (220) separate from said recorded video presentation.

9. The method according to claim 8 further comprising the step of accessing said data file for said digital data identifying an event start information and an event end information (220), prior to said skipping step (312).

10. The method according to claim 8 wherein said data file is stored on said digital recording medium. PU020056

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11. A recording device configured for automatically identifying and selectively skipping commercial message segments of a video signal, comprising: a memory storage device (124) for recording said video signal on a digital recording medium in a digital format; an event detector (114, 118, 122) for monitoring said video signal to detect at least one event start and at least one event end corresponding to a beginning and an end of at least one commercial message; a control processor (120) for selectively storing as part of a digital data stream comprising said recorded video presentation, digital data identifying at least one of an event start information and an event end information, at least one of said event start information and said event end information identifying the location of said at least one commercial message.

12. The device according to claim11 wherein said control processor (120) in a playback mode selectively skips said commercial portion of said video signal responsive to said digital data identifying said event start information and said event end information.

13. The device according to claim 11 wherein said event start information and said event end information is selected from the group comprising at least one of a. an elapsed time since a start of recording of said video signal; and b. a frame number corresponding to a number of frames of said video signal recorded since the start of recording of said video signal.

14. The device according to claim 11 wherein said data identifying said event start information also includes said event end information.

15. The device according to claim 11 wherein said digital format is MPEG and said memory storage device (124) records at least one of said event start information and said event end information following an MPEG picture header in a extensions_and_user_data(2) location. PU020056

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16. The device according to claim 11 wherein said control processor (120) selectively causes said digital data stream comprising said recorded video presentation to be modified by deleting from said digital data stream said commercial portion of said video signal identified by at least one of said event start information and said event end information.

17. The device according to claim 16 wherein said control processor (120) modifies said digital data stream by: a. accessing said event start information, said event end information, and said digital data stream from a memory location; b. modifying said digital data stream to remove said commercial portion of said video signal.

18. The device according to claim 11 wherein said event start information and said event end information are recorded in a data file separate from said recorded video presentation.

19. The device according to claim 18 wherein said control processor (120) accesses said data file for said digital data identifying an event start information and an event end information, prior to said skipping step.

20. The device according to claim 18 wherein said data file is stored on said digital recording medium (124).