Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
2000-01-05
2003-04-29
Diep, Nhon (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
C348S398100
Reexamination Certificate
active
06556624
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to video coding. More particularly, the present invention relates to a method for utilizing temporal prediction and motion compensated prediction to accomplish multiple description video coding.
BACKGROUND
Most of today's video coder standards use block-based motion compensated prediction because of its success in achieving a good balance between coding efficiency and implementation complexity.
Multiple Description Coding (“MDC”) is a source coding method that increases the reliability of a communication system by decomposing a source into multiple bitstreams and then transmitting the bitstreams over separate, independent channels. An MDC system is designed so that, if all channels are received, a very good reconstruction can be made. However, if some channels are not received, a reasonably good reconstruction can still be obtained. In commonly assigned U.S. patent application Ser. No. 08/179,416, a generic method for MDC using a pairwise correlating transform referred to as (“MDTC”) is described. This generic method is designed by assuming the inputs are a set of Gaussian random variables. A method for applying this method for image coding is also described. A subsequent and similarly commonly assigned U.S. Provisional Application Ser. No. 60/145,937, describes a generalized MDTC method. Papers describing MDC-related work include: Y. Wang et al., “Multiple Description Image Coding for Noisy Channels by Pairing Transform Coefficients,” in
Proc. IEEE
1997
First Workshop on Multimedia Signal Processing
, (Princeton, N.J.), June, 1997; M. T. Orchard et al., “Redundancy Rate Distortion Analysis of Multiple Description Image Coding Using Pairwise Correlating Transforms,” in
Proc. ICIP
97, (Santa Barbara, Calif.), October, 1997; Y. Wang et al., “Optimal Pairwise Correlating Transforms for Multiple Description Coding,” in
Proc. ICIP
98, (Chicago, Ill.), October 1998; and V. A. Vaishampayan, “Design of Multiple Description Scalar Quantizer,” in
IEEE Trans. Inform. Theory
, vol. 39, pp. 821-834, May 1993.
Unfortunately, in existing video coding systems when not all of the bitstream data sent over the separate channels is received, the quality of the reconstructed video sequence suffers. Likewise, as the amount of the bitstream data that is not received increases the quality of the reconstructed video sequence that can be obtained from the received bitstream decreases rapidly.
Accordingly, there is a need in the art for a new approach for coding a video sequence into two descriptions using temporal prediction and motion compensated prediction to improve the quality of the reconstructions that can be achieved when only one of the two descriptions is received.
SUMMARY OF THE INVENTION
Embodiments of the present invention provide a block-based motion-compensated predictive coding framework for realizing MDC, which includes two working modes: Intraframe Mode (I-mode) and Prediction Mode (P-mode). Coding in the P-mode involves the coding of the prediction errors and estimation/coding of motion. In addition, for both the I-mode and P-mode, the MDTC scheme has been adapted to code a block of Discrete Cosine Transform (“DCT”) coefficients.
Embodiments of the present invention provide a system and method for encoding a sequence of video frames. The system and method receive the sequence of video frames and then divide each video frame into a plurality of macroblocks. Each macroblock is then encoded using at least one of the I-mode technique and the P-mode technique, where, for n channels the prediction mode technique generates at least n+1 prediction error signals for each block. The system and method then provide the I-mode technique encoded data and the at least n+1 P-mode technique prediction error signals divided between each of the n channels being used to transmit the encoded video frame data.
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Y Wang et al, Multiple Description Image Coding for Noisy Channels by Pairing Transform Coefficients, 1997, IEEE, P419-423.*
V. A. Vaishampayan, Design of Multiple Scalar Quantizers, 1993, IEEE, p 821-834.
Jafarkhani Hamid
Orchard Michael
Reibman Amy
Wang Yao
AT&T Corp.
Diep Nhon
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