| 摘要 |
An encoded video data re-compressing apparatus further compresses, for further transmission or storage, an encoded video data stream that includes quantization parameters and quantized coefficients without having to decompress the encoded video data streams and subsequently re-compress the decompressed video data. The encoded video data stream is parsed for extracting the quantization parameters and quantized coefficients from other side information. The quantized coefficients are either divided by a predetermined integer or selectively discarded to reduce the total number of bits. In the former case, the corresponding quantization parameters are multiplied by a predetermined integer. The manipulated coefficients and quantization parameters are multiplexed with the side information, such that they occupy the location of the corresponding original coefficients and quantization parameters in the video data stream. Equipped with a digital data recorder and a set of switches, the encoded digital video data stream could be recorded in either its original form (a normal recording mode) or a more compact form (a long recording mode) by dividing the quantized coefficients by a predetermined integer or selectively discarding some of the coefficients.
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