Method for generating information sub-streams for FF/REW applications

• US 6,510,554 B1
• Filed: 04/27/1998
• Issued: 01/21/2003
• Est. Priority Date: 04/27/1998
• Status: Expired due to Term

• Current Assignee: Sedna Patent Services LLC
• Original Assignee: DIVA Systems Corporation
• Inventors: Conover, Mark D., Gordon, Donald F.
• Primary Examiner(s): Mehta, Bhavesh
• Assistant Examiner(s): BROWN, RUEBEN M
• Application Number:
  US09/067,427
• Time in Patent Office: 1,730 Days
• Field of Search: 725/88-91, 725/131-150, 375/240.25, 375/240.26, 348/425.1, 348/385.1, 386/68, 386/5-8, 386/27, 386/109-130
• US Class Current: 725/90
• CPC Class Codes: H04L 12/5602 Bandwidth control in ATM Networks, e.g. leaky bucket
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6483 Video, e.g. MPEG
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence
• CPC Class Codes: H04N 21/234381 by altering the temporal resolution, e.g. decreasing the frame rate by frame skipping
• CPC Class Codes: H04N 21/2387 Stream processing in response to a playback request from an end-user, e.g. for trick-play
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/6587 Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests
• CPC Class Codes: H04N 9/8042 involving data reduction
• CPC Class Codes: H04N 9/8227 the additional signal being at least another television signal

Abstract

A method and apparatus for processing an information stream comprising a plurality of compressed information frames to produce an information sub-stream having a reduced number of information frames. In the case of an MPEG video information stream, the information sub-stream is suitable for use as a fast-forward (FF) or rewind (REW) stream in, e.g., a video on demand (VOD) system utilizing such streams.

Claims

1. A method for processing a compressed information stream to produce one or more compressed information sub-streams, said method comprising the steps of:

(a) identifying an Nth compressed information frame in said compressed information stream, where N is an integer greater than one;

(b) decoding said identified Nth compressed information frame to produce an uncompressed information frame;

(c) storing, in a memory, said uncompressed information frame;

(d) repeating steps (1), (2) and (3) until a plurality of said Nth compressed information frames in said compressed information stream has been processed and stored to form a stored uncompressed information sub-stream;

(e) retrieving, from said memory, said stored uncompressed information sub-stream; and

(f) encoding, using a compression encoder, said retrieved uncompressed information frames to produce an encoded information sub-stream.

2. The method of claim 1, wherein:

in a fast-forward (FF) mode of operation, said stored uncompressed information sub-stream is retrieved in a standard temporal order and encoded to produce an encoded FF information sub-stream; and

in a fast-rewind (REW) mode of operation, said stored uncompressed information sub-stream is retrieved in a reverse temporal order and encoded to produce an encoded REW information sub-stream.

3. The method of claim 2, further comprising the step of:

storing, in said fast-forward (FF) mode of operation and said fast-rewind (REW) mode of operation, respectively, said encoded FF information sub-stream and said encoded REW information sub-stream in a mass storage unit.

4. The method of claim 1, wherein said step of identifying further comprises the step of:

determining if said identified information frame is a non-predicted information frame or a predicted information frame; and

in the case of said identified information frame being a predicted information frame of a first type;

examining each of up to M compressed information frames subsequent or prior to said identified information frame to identify a one compressed information frame that is not a predicted information frame of said first type, where M is an integer; and

substituting, for decoding purposes, said identified one information frame for said identified information frame.

5. The method of claim 4, wherein said information stream comprises an MPEG-like information stream, and said first type of information frame comprises a bi-directionally predicted frame.

6. The method of claim 1, wherein said step of identifying further comprises the step of:

determining if said identified information frame is a non-bidirectionally predicted information frame or a predicted information frame; and

in the case of said identified information frame being a bidirectionally predicted information frame of a first type;

examining each of up to M compressed information frames subsequent or prior to said identified information frame to identity a one compressed information frame that is not a bidirectionally predicted information frame of said first type, where M is an integer; and

substituting, for decoding purposes, said identified one information frame for said identified information frame.

7. A method for generating an information sub-stream, said method comprising the steps of:

(a) identifying an Nth compressed information frame in an information stream comprising a plurality of compressed information frames, where N is an integer greater than one;

(b) decoding said identified Nth compressed information frame to produce an uncompressed information frame;

(c) storing, in a memory, said uncompressed information frame; and

(d) repeating steps (a) through (c) until each of said Nth compressed information frames in said received information stream has been processed.

8. The method of claim 7, wherein said step of identifying further comprises the step of:

determining if said identified information frame is a non-predicted information frame or a predicted information frame; and

in the case of said identified information frame being a predicted information frame of a first type;

examining each of up to M compressed information frames subsequent or prior to said identified information frame to identify a one compressed information frame that is not a predicted information frame of said first type, where M is an integer; and

substituting, for decoding purposes, said identified one information frame for said identified information frame.

9. The method of claim 8, wherein said information stream comprises an MPEG-like information stream, and said first type of information frame comprises a backward predicted frame.

10. The method of claim 7, further comprising the steps of:

(e) retrieving, from said memory, said stored uncompressed information frames; and

(f) encoding, using a compression encoder, said retrieved uncompressed information frames to produce an encoded information sub-stream.

11. The method of claim 10, wherein:

in a fast-forward (FF) mode of operation, said stored uncompressed information frames are retrieved in a standard temporal order and encoded to produce an encoded FF information sub-stream; and

in a fast-rewind (REW) mode of operation, said stored uncompressed information frames are retrieved in a reverse temporal order and encoded to produce an encoded REW information sub-stream.

12. The method of claim 11, further comprising the step of:

storing, in said fast-forward (FF) mode of operation and said fast-rewind (REW) mode of operation, respectively, said encoded FF information sub-stream and said encoded REW information sub-stream in a mass storage unit.

13. The method of claim 12, wherein said information stream comprising a plurality of compressed information frames is stored in the same mass storage unit as said encoded FF information sub-stream and said encoded REW information sub-stream.

14. The method of claim 7, wherein said information sub-stream comprises a fast-forward video information stream.

15. Apparatus for processing an information stream to produce an information sub-stream, said information stream comprising a plurality of compressed information frames, said apparatus comprising:

a decoder, for decoding said information frames coupled to said frame controller output and producing a frame-decoded information stream therefrom;

said decoder further comprising;

a parser, for examining a header portion of at least every Nth compressed information frame in said information stream, and for generating an indicium of a compression type associated with said examined frame; and

a frame controller, coupled to said parser, for causing the decoding of every Nth information frame if said Nth information frame is of a desired compression type, where N is an integer greater than one.

16. The apparatus of claim 15, wherein:

said frame controller, in response to said Nth information frame being of a non-desired compression type, decodes a first information frame of a desired compression type proximally located within M information frames of said Nth information frame, where M is an integer.

17. The apparatus of claim 16, wherein:

said frame controller, in response to said Nth information frame and said proximally located M information frames being of a non-desired compression type, decoding said Mth information frame following said Nth information frame.

18. The apparatus of claim 15, further comprising a storage unit, coupled to said decoder, for storing said frame-decoded information stream.

19. The apparatus of claim 18, wherein said storage unit, in response to one or more control signals, selects for access one of a plurality of stored frame-decoded information streams, accesses said one selected stream at a desired location within said one selected stream, and sequentially couples to an output an information frame corresponding to said desired location and a plurality of information frames either preceding or succeeding information frames.

20. The apparatus of claim 15, wherein said information stream comprises an MPEG-like video information stream having a first effective video frame rate, and said frame-decoded information stream comprises a video information stream having a second effective video frame rate, said second video frame rate being approximately N times greater than said first video frame rate.