Method and apparatus for matching compressed video signals to a communications channel

摘要

A method and apparatus for matching compressed video signals to a communications channel. The compressed bitstream is partially decompressed and the bitstream is regenerated with a reduced bit rate to match the channel capacity. Specifically, control information is decoded and entropy decoding is performed on the entropy coded, quantized frequency domain data. Then, the quantized frequency domain data is re-quantized and re-entropy coded so that the resulting compressed bitstream does not exceed the channel capacity bit rate. However, this entire rate conversion process is performed without converting the frequency domain data out of the frequency domain (and back again) as is done by prior art techniques. That is, the frequency domain data is not inverse transformed (out of the frequency domain) in the process of re-quantization. In this manner, a compressed and stored video signal can be matched to the constraints of a given communications channel with substantially less computational cost than is required by the techniques of the prior art. <IMAGE>