Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
2006-03-07
2006-03-07
Wong, Allen (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
C375S240000, C375S240010, C375S240020, C375S240120
Reexamination Certificate
active
07010034
ABSTRACT:
The concept of B-frames gives the MPEG video compression standard its high encoding efficiency. However, B-frame encoding roughly doubles the complexity of an MPEG encoder. In view thereof, MPEG encoders have been developed which produce I-frames and P-frames only. They are less complex but also less efficient. To improve the efficiency of such “IPP encoders”, selected P-frames are quantized more coarsely than other P-frames, for example, by multiplying the conventional quantization step size by 1.4. Although this results in isolated frames (“virtual B-frames”) being encoded with a lower quality, the overall perceptual quality is not affected. It has been found that the gain in bit rate obtained by the coarser quantization is not lost in subsequent P-frames, even though the subsequent frames are encoded with reference to the lower quality frames.
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Stephan Wenger, “Temporal Scalability Using P-Pictures for Low-Latency Applications”, 1998 IEEE Second Workshop on Multimedia Signal Processing (Cat No. 98EX175), 1998 IEEE Second Workshop on Multimedia Signal Processing, Dec. 7-9 1998, pp. 559-564, XP002177102.
Bruls Wilhelmus Hendrikus Alfonsus
Klein Gunnewiek Reinier Bernardus Maria
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