Method and system to improve the transport of compressed video data

• US 20050281330A1
• Filed: 08/19/2005
• Published: 12/22/2005
• Est. Priority Date: 08/28/2001
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: SBC Technology Resources, Inc. (AT&T, Inc.)
• Inventors: Costa, Pierre, Ansari, Ahmad, Erickson, John Robert
• Granted Patent: US 7,580,462 B2
• Time in Patent Office: Days
• US Class Current: 375/240.01
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• 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 19/15 by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/169 characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/188 the unit being a video data packet, e.g. a network abstraction layer [NAL] unit
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 19/88 involving rearrangement of data among different coding units, e.g. shuffling, interleaving, scrambling or permutation of pixel data or permutation of transform coefficient data among different blocks
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
• CPC Class Codes: H04N 21/23418 involving operations for analysing video streams, e.g. detecting features or characteristics television picture signal circuitry for scene change detection H04N5/147; filtering for image enhancement G06T5/00; methods or arrangements for recognising scenes G06V20/00; arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/2343 involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements video transcoding H04N19/40; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/238 : Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams hybrid fiber coaxial [HFC] networks for downstream channel allocation for video distribution H04L12/2801; flow control in packet networks H04L47/10; real-time communication protocols in data switching networks H04L65/00; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/23805 : Controlling the feeding rate to the network, e.g. by controlling the video pump
• CPC Class Codes: H04N 21/4305 : Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/435 : Processing of additional data, e.g. decrypting of additional data, reconstructing software from modules extracted from the transport stream
• CPC Class Codes: H04N 21/44004 : involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/8456 : by decomposing the content in the time domain, e.g. in time segments

Abstract

A method comprises determining a plurality of time intervals Tp and Tn within a variable bit rate (VBR) representation of an image sequence. The time intervals Tp are those in which a number of blocks of information per unit time is greater than a baseline value. The time intervals Tn are those in which a number of blocks of information per unit time is less than the baseline value. A second representation of the image sequence is created in which some blocks of information Bp are removed from the time intervals Tp and interlaced with blocks of information Bn in the time intervals Tn to reduce a variation in a number of blocks of information per unit time between the time intervals Tp and Tn.

Claims

1. A system comprising:

an encoder to provide a variable bit rate (VBR) representation of an image sequence, the VBR representation comprising a plurality of blocks of information; and

a processor to determine a first plurality of blocks of information per unit time within the VBR representation that is greater than a second plurality of blocks of information per unit time within the VBR representation, and to create a second representation of the image sequence in which some blocks of information from the first plurality of blocks of information are interlaced with blocks of information of the second plurality of blocks of information.

3. The system of claim 1, wherein a number of block of information per unit time in the second representation of the image sequence is about equal to a baseline value.

4. The system of claim 1, wherein the processor is further operative to determine a bit rate for encoding the image sequence to the VBR representation which produces a desired information content of the second representation.

5. The system of claim 4, wherein the processor is further operative to constrain a maximum bit rate of the second representation to be less than or equal to a predetermined value.

6. The system of claim 1, wherein the processor is further operative to determine a bit rate for encoding the image sequence to the VBR representation which substantially maximizes a desired information content of the second representation.

7. The system of claim 6, wherein the processor is further operative to constrain a maximum bit rate of the second representation to be less than or equal to a predetermined value.

8. The system of claim 1, wherein the processor is further operative to populate a header in the second representation of the image sequence indicating the blocks of information from the first plurality of blocks of information which were interlaced with blocks of information of the second plurality of blocks of information.

9. The system of claim 1, further comprising:

a transmitter to stream the second representation of the image sequence vial a communication network.

10. The system of claim 9, further comprising:

a receiver to receive the second representation of the image sequence via the communication network;

a buffer; and

a second processor responsive to the receiver to reconstruct frames of the image sequence concurrently with the second representation being received.

11. The system of claim 10, wherein the second processor is operative to store blocks of information form the first plurality of blocks of information in the buffer.

12. The system of claim 11, wherein the second processor reconstructs the image sequence based on blocks of information received in real time and blocks of information stored in the buffer.

2. The system of claim 2, wherein interlacing the first plurality of blocks of information per unit time with blocks of information form the second plurality of blocks of information reduces the variation in a number of blocks of information per unit time.

13. A system for reconstructing an image sequence originally encoded in a variable bit rate (VBR) representation, the VBR representation comprising a plurality of blocks of information, the system comprising:

a receiver to receive a second representation of the image sequence via the communication network, the second representation comprising a header indicating blocks of information from a first plurality of blocks of information of the second representation interlaced in a second plurality of blocks of information of the second representation;

a buffer to store blocks of information of the second representation; and

a processor responsive to the receiver to extract the data indicating the blocks of information from the first plurality of blocks of information interlaced in the second plurality of blocks of information and to reconstruct frames of the image sequence based on the extracted data and the second representation of the image sequence.

14. The system of claim 13, wherein the processor is operative to store blocks of information from the first plurality of blocks of information in the buffer and to reconstruct the frames of the image sequence based on blocks of information of the second representation stored in the buffer and blocks of information of the second representation received in real time.

15. The system of claim 13 wherein the number of blocks of information per unit time in the second representation is about equal to a baseline value.

16. A system for reconstructing an image sequence originally encoded in a variable bit rate (VBR) representation, the VBR representation comprising a plurality of blocks of information, the VBR representation defining a plurality of time intervals Tp in which a number of blocks of information per unit time is greater than a baseline value and a plurality of time intervals Tn in which a number of blocks of information per unit time is less than the baseline value, the system comprising:

a receiver to receive a second representation of the image sequence via the communication network, the second representation comprising a header with data indicating time intervals Tn;

a buffer; and

a processor responsive to the receiver to extract the data indicating the time intervals Tn from the header, and to reconstruct frames of the image sequence concurrently with the second representation being received, the reconstruction based on the data indicating the time intervals Tn;

wherein during the time intervals Tn, the processor is to reconstruct frames of the image sequence based on blocks of information Bn received about in real time, and to store the blocks of information Bp in the buffer; and

wherein during the time intervals Tp, the processor is to reconstruct frames of the image sequence based on the blocks of information Bp stored in the buffer and blocks of information received about in real time.

17. The system of claim 16 wherein the number of blocks of information per unit time in the second representation is about equal to the baseline value in the time intends Tp and Tn.