Trick play method for digital storage medium

• US 7,212,727 B2
• Filed: 04/11/2001
• Issued: 05/01/2007
• Est. Priority Date: 04/21/2000
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Senoh, Takanori
• Primary Examiner(s): Tran; Thai Q.
• Assistant Examiner(s): DANG, HUNG Q
• Application Number:
  US09/926,762
• Publication Number:
  US 20030007780A1
• Time in Patent Office: 2,211 Days
• Field of Search: 386/68, 386/69, 386/70, 386/109, 386/111, 386/112, 386/125
• US Class Current: 386/351
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/61 wherein solid state memory is used for storing A/V content storing computer data in solid state memories G06F
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 27/005 Reproducing at a different information rate from the information rate of recording for television signals H04N5/783
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 27/107 of operating tapes
• CPC Class Codes: G11B 27/328 on a tape [TTOC]
• CPC Class Codes: G11B 27/329 on a disc [VTOC]
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

When trick play modes are implemented using a lookup table cross-referencing content divided into sectors of specific size with content encoding unit information, an accurate playback start time code cannot be detected because the total content playback time is not clear. A trick play method for digital storage media used to record and reproduce multimedia content resolves this problem and enables random access playback, fast-forward play, fast-reverse play and other trick play modes from any desired position in the content by recording program content segmented into media object units, each recorded as a separate file; recording a program manager file containing a media object information table; recording a media object information file containing playback time information and entry points at a specific time interval for each media object, and recording a playlist manager file containing a table of user-specified playback start program IDs and playback start time and end time information.

Claims

1. A trick play method for achieving a trick play mode with a digital storage medium used to record and reproduce multimedia content including compression coded digital audio and video data, the digital storage medium comprising

a directory segmenting the content into programs, further segmenting the content into a plurality of media objects, and recording each media object as a separate file,

a program manager file storing a table including an identifier (ID) for each program of recorded content and information about the media objects in each program,

a media object information file storing a table including playback time information and entry points at a specific time interval for each media object,

a playlist manager file comprising playlist information including a user-specified playback start program ID and a specified playback start time and end time of a program,

a management data file including a resume marker comprising a program ID for a program where playback was last interrupted and playback interrupt time where playback was interrupted in the program,

the trick play method achieving a fast-forward play mode when the user selects fast-forward play, the trick play method comprising:

reading a media object information in a program specified by a resume marker in sequence from the beginning;

sequentially comparing a playback time in the media object information with an interrupt time to detect media object k where a cumulative playback time first exceeds the interrupt time;

detecting an entry point identified by a number determined by calculating the difference of the interrupt time specified by the resume marker minus a total playback time to an immediately preceding media object, and dividing this difference by a time search table resolution in the media object information of media object k;

reading and supplying, to a decoder, entry frame data for a media object data corresponding to said entry point;

repeating the above steps to supply entry frame data for a next media object data to the decoder; and

rewriting the resume marker when fast-forward play ends with the program ID of the program at which playback is interrupted and the interrupt time in said program.

2. A trick play method for achieving a trick play mode with a digital storage medium used to record and reproduce multimedia content including compression coded digital audio and video data, the digital storage medium comprising

a directory segmenting the content into programs, further segmenting the content into a plurality of media objects, and recording each media object as a separate file,

a program manager file storing a table including an identifier (ID) for each program of recorded content and information about the media objects in each program,

a media object information file storing a table including playback time information and entry points at a specific time interval for each media object,

a playlist manager file comprising playlist information including a user-specified playback start program ID and a specified playback start time and end time of a program,

a management data file including a resume marker comprising a program ID for a program where playback was last interrupted and playback interrupt time where playback was interrupted in the program,

the trick play method achieving a fast-reverse play mode when the user selects fast-reverse play, the trick play method comprising:

reading a media object information in a program specified by a resume marker in sequence from the beginning;

sequentially comparing a playback time in the media object information with an interrupt time to detect media object k where a cumulative playback time first exceeds the interrupt time;

detecting an entry point identified by a number determined by calculating the difference of the interrupt time specified by the resume marker minus a total playback time to an immediately preceding media object, and dividing this difference by a time search table resolution in the media object information of media object k;

reading and supplying to a decoder entry frame data for a media object data corresponding to said entry point;

thereafter repeating the above steps to supply entry frame data for a preceding media object data to the decoder; and

rewriting the resume marker when fast-forward play ends with the program ID of the program at which playback is interrupted and the interrupt time in said program.

3. A playback method for reproducing multimedia content from a digital storage medium starting from a playback start time, the digital storage medium recording multimedia content comprising compression coded digital video data segmented into programs, each program segmented into media objects, and each media object segmented into media object data of which the first frame is a reproducible entry frame;

and

recording management information including a time search table defining a time search entry at each specific time interval from a beginning of each media object, a playback time for each media object, and a playback start time for a specified program,

the time search table including an offset indicating a data length from a beginning of the specified program to a beginning of a media object data including the time search entry, and a frame count indicating a number of frames from the beginning of the media object data to the time search entry;

the playback method reproducing content from the playback start time in a playback mode, the playback method comprising;

detecting a media object at a playback start time by sequentially subtracting a playback time of each media object from a playback start time starting from a first media object, and comparing a resulting difference with a playback of a next media object;

detecting a time search entry closest before the playback start time and a remaining time from said time search entry to the playback start time using said resulting difference and a specific time interval;

accessing a data offset in a specified program based on a time search table of the detected time search entry;

decoding a number of counted frames from an accessed point based on the time search table of the detected time search entry;

continuing decoding for a remaining time; and

displaying the decoded result after the remaining time passes.

4. A playback method according to claim 3, wherein the playback start time is a playback start time edited and specified by a user.

5. A playback method according to claim 3, wherein the playback start time is a playback start time specified by a resume marker containing time information indicating where playback was interrupted.

6. A playback method for reproducing multimedia content from a digital storage medium starting from a playback start time, the digital storage medium recording multimedia content comprising compression coded digital video data segmented into programs, each program segmented into media objects, and each media object segmented into media object data of which the first frame is a reproducible entry frame;

and

recording management information including a time search table defining a time search entry at each specific time interval from a beginning of each media object, a playback time for each media object, and a playback start time in a specified program,

the time search table including an offset indicating a data length from a beginning of the specified program to a beginning of a media object data including the time search entry, and a frame count indicating a number of frames from the beginning of the media object data to the time search entry;

the playback method reproducing content from near the playback start time in a fast-forward play mode, the playback method comprising;

detecting a media object at a playback start time by sequentially subtracting a playback time of each media object from a playback start time starting from a first media object, and comparing a resulting difference with a playback of a next media object;

detecting a time search entry closest before the playback start time using said resulting difference and a specific time interval;

accessing a data offset position in a specified program based on a time search table of the detected time search entry;

decoding an entry frame at which playback can start at the accessed data offset position and displaying a decoded content;

detecting a next time search entry;

accessing a next data offset position in the specified program based on the time search table of the detected next time search entry; and

decoding a next entry frame at which playback can start at the next accessed data offset position and displaying the decoded content.

7. A playback method for reproducing multimedia content from a digital storage medium starting from a playback start time, the digital storage medium recording multimedia content comprising compression coded digital video data segmented into programs, each program segmented into media objects, and each media object segmented into media object data of which the first frame is a reproducible entry frame;

and

recording management information including a time search table defining a time search entry at each specific time interval from a beginning of each media object, a playback time for each media object, and a playback start time in a specified program,

the time search table including an offset indicating a data length from a beginning of the specified program to a beginning of a media object data including the time search entry, and a frame count indicating a number of frames from the beginning of the media object data to the time search entry;

the playback method reproducing content from near the playback start time in a fast-reverse play mode, the playback method comprising;

detecting a media object at a playback start time by sequentially subtracting a playback time of each media object from a playback start time starting from a first media object, and comparing a resulting difference with a playback of a next media object;

detecting a time search entry closest before the playback start time using said resulting difference and a specific time interval;

accessing a data offset position in a specified program based on a time search table of the detected time search entry;

decoding an entry frame at which playback can start at the accessed data offset position and displaying a decoded content;

detecting a previous time search entry;

accessing a next data offset position in the specified program based on the time search table of the detected time search entry; and

decoding an entry frame at which playback can start at the next accessed data offset position and displaying the decoded content.

8. A playback apparatus for reproducing multimedia content from a digital storage medium starting from a playback start time, the digital storage medium recording multimedia content comprising compression coded digital video data segmented into programs, each program segmented into media objects, and each media object segmented into media object data of which the first frame is a reproducible entry frame;

and

recording management information including a time search table defining a time search entry at each specific time interval from a beginning of each media object, a playback time for each media object, and a playback start time for a specified program,

the time search table including an offset indicating a data length from a beginning of the specified program to a beginning of a media object data including the time search entry, and a frame count indicating a number of frames from the beginning of the media object data to the time search entry;

the playback apparatus comprising;

a media object detector configured to detect a media object at a playback start time by sequentially subtracting a playback time of each media object from a playback start time starting from a first media object, and comparing a resulting difference with a playback of a next media object;

a time search entry detector configured to detect a time search entry closest before a playback start time and a remaining time from said time search entry to the playback start time using said resulting difference and a specific time interval;

an accessor configured to access a data offset in a specified program based on a time search table of the detected time search entry;

a frame count decoder configured to decode the frame count number of frames from an accessed point based on the time search table of the detected time search entry; and

a display configured to display a decoded result after the remaining time passes.

9. A playback apparatus according to claim 8, wherein the playback start time is a playback start time edited and specified by a user.

10. A playback apparatus according to claim 8, wherein the playback start time is a playback start time specified by a resume marker containing time in formation indicating where playback was interrupted.

11. A playback apparatus for reproducing multimedia content from a digital storage medium in a fast-forward play mode starting from a playback start time, the digital storage medium recording multimedia content comprising compression coded digital video data segmented into programs, each program segmented into media objects, and each media object segmented into media object data of which the first frame is a reproducible entry frame;

and

recording management information including a time search table defining a time search entry at each specific time interval from a beginning of each media object, a playback time for each media object, and a playback start time in a specified program,

the time search table including an offset indicating a data length from a beginning of the specified program to a beginning of a media object data comprising the time search entry, and a frame count indicating a number of frames from the beginning of the media object data to the time search entry;

the playback apparatus comprising;

a media object detector configured to detect a media object at a playback start time by sequentially subtracting a playback time of each media object from the playback start time starting from a first media object, and comparing a resulting difference with a playback of a next media object;

a time search entry detector configured to detect a time search entry closest before the playback start time using said resulting difference and a specific time interval;

an accessor configured to access data offset position in the specified program based on a time search table of the detected time search entry;

an entry frame decoder configured to decode an entry frame at which playback can stan at the accessed data offset position and displaying a decoded content; and

a next time search entry detector configured to detect a next time search entry.

12. A playback apparatus for reproducing multimedia content from a digital storage medium in a fast-reverse play mode starting from a playback start time, the digital storage medium recording multimedia content comprising compression coded digital video data segmented into programs, each program segmented into media objects, and each media object segmented into media object data of which the first frame is a reproducible entry frame;

and

recording management information including a time search table defining a time search entry at each specific time interval from a beginning of each media object, a playback time for each media object, and a playback start time in a specified program,

the time search table including an offset indicating a data length from a beginning of the specified program to a beginning of a media object data comprising the time search entry, and a frame count indicating a number of frames from the beginning of the media object data to the time search entry;

the playback apparatus comprising;

a media object at detector configured to detect a media object at a playback start time by sequentially subtracting a playback time of each media object from a playback start time starting from a first media object, and comparing a resulting difference with a playback of a the next media object;

a time search entry detector configured to detect a time search entry closest before the playback start time using said resulting difference and a specific time interval;

an accessor configured to access a data offset position in the specified program based on a time search table of the detected time search entry;

an entry frame decoder configured to decode an entry frame at which playback can start at the accessed data offset position and displaying a decoded content; and

a previous time search entry detector configured to detect a previous time search entry.