Method and apparatus for partially recompressing digital signals

摘要

A method and apparatus are provided for changing the compression level of digital information, such as digital video information. After having been compressed by a first compression scheme that provides quantized transform coefficients, the digital information is partially decompressed to recover the transform coefficients as they were prior to quantizing. The transform coefficients are then requantized at a different compression level. The previously compressed information is only partially decompressed and requantized to modify its compression level.