Patent EP0723345A2 successfully refreshed from Google Patents.
EP0723345A2
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EP
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Encoder/decoder buffer control for variable bit-rate channel
Assignee: AT&T Inc
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Filing: 1996-01-16
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Granted: —
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Expires: 2016-01-16
Abstract
Abstract Encoder/decoder buffer overflow and underflow encountered when employing actually variable or effectively variable bit-rate channels (101) for communicating encoded video images and corresponding audio signals are overcome by adjusting the parameters of a video encoder (in 100) in response to to a representation (J dec ) of cell delay variation, i.e., jitter, determined at a remote decoder (in 102).
Inventors
- 👤 Barin G. Haskell
- 👤 Amy R. Reibman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 09:23
CPC Classifications
H; H04; H04N; H04N21/00; H04N21/20; H04N21/23; H04N21/234; H04N21/2343; H04N21/234354; H04J; H04J3/00; H04J3/02; H04J3/06; H04J3/062; H04J3/0626; H04J3/0632; H04J3/16; H04J3/1682; H04J3/1688; H04N21/23406; H04N21/24; H04N21/2402; H04N21/242; H04N21/40; H04N21/43; H04N21/4302; H04N21/4305; H04N21/44; H04N21/44004; H04N21/60; H04N21/63; H04N21/637; H04N21/6373; H04N21/643; H04N21/64307
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
389 words
Apparatus for use in an encoder unit (100) for encoding an original video signal including frames, wherein cach frame contains at least one image representation, and for supplying as an output for transmission, to a variable bit-rate channel (101), an encoded version of said original video signal including encoded frames containing at least one encoded image representation, the variable bit-rate channel being adapted for supplying said encoded version of said original video signal to a remote decoder unit (102) including at least one decoder buffer (302) for storing the encoded version of the original video signal and at least one video decoder (304) for generating a reconstructed version of the original video signal, the apparatus comprising: an adjustable encoder (202) responsive to a range indication for encoding each of said frames of said original video signal into a first encoded version in which each frame of said original video signal is represented by a plurality of bits, the actual number of said bits for each frame being within said range, each of said first encoded frames being supplied as an output as a first encoded version of said original video signal; an encoder buffer (203) for storing said first encoded version of said original video signal and for supplying as an output each frame of said first encoded version of said original video signal; apparatus (208) responsive to a representation of jitter ( J dec ) at the remote decoder unit (102) and to an actual number of bits ( E i ) within at least one frame of said first encoded version of said original video signal for generating bit-rate requests ( R i ) for a current frame to be supplied to said channel and for generating a set of estimated transmission rates ( R i ,..., R i+ L -1 ) that are expected to be supplied by said channel for a predetermined number of future frames of said encoded version of said original video signal; and apparatus (209) responsive to said jitter representation and to said actual nunber of bits within at least one frame of said first encoded version of said original video signal and said sct of estimated transmission rates, for developing said range such that overflow or underflow of said encoder buffer means and said at least one decoder buffer is avoided.
Claim 2
Dependent Claim
48 words
The apparatus as defined in claim 1 further including apparatus (212) for generating an encoder time clock (Enc_TC) and apparatus (210) being responsive to the encoder time clock for generating encoder clock reference signals (Enc_CR) for transmission to the remote decoder unit (102) in an encoded signal (CODETR).
Claim 3
Dependent Claim
31 words
The apparatus as defined in claim 2 further including apparatus (301) in the decoder unit (102) for decoding encoder clock reference signals received in a version of the encoded signal (cODETR').
Claim 4
Dependent Claim
23 words
The apparatus as defined in claim 3 wherein the decoder unit further includes apparatus (308, 310) for generating a decoder time clock (Dec_TC).
Claim 5
Dependent Claim
38 words
The apparatus ad defined in claim 4 wherein the decoder unit further includes apparatus (310) for generating a difference signal representative of the difference between the decoded encoder clock reference signal and the decoder time clock (Enc_CR -Dec_TC),
Claim 6
Dependent Claim
31 words
The apparatus as defined in claim 5 wherein the decoder unit further includes apparatus (317) responsive to the generated difference signal for generating a representation of jitter ( J dec ).
Claim 7
Dependent Claim
28 words
The apparatus as defined in claim 6 wherein the representation of jitter is representative of delay variation of asynchronous transfer mode (ATM) cells at the decoder unit (102).
Claim 8
Dependent Claim
31 words
The apparatus as defined in claim 7 wherein the decoder unit further includes apparatus (301) for inserting the representation of jitter into a signal for transmission to the encoder unit (101).
Claim 9
Dependent Claim
26 words
The apparatus as defined in claim 8 wherein the encoder unit (101) further includes apparatus (210) for extracting the representation of jitter from a received signal.
References Cited (Backward Citations)
No citation records indexed.
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