Patent ID: 6081295
Filing Date: 2000-06-27
Classification: H04N

Abstract:
A method for transcoding a block based, variable length coded, quantized, DCT transformed, compressed bit stream of video data and which includes motion vectors and compression mode information, said method comprising;receiving the compressed bit stream of video data;separating motion vectors and mode information from the bit stream of video data;variable length decoding blocks of data in the bit stream of video data to produce non-variable length coded data;inverse quantizing the non-variable length coded data to produce blocks of non-quantized DCT coefficients;applying non-quantized DCT coefficients to a quantizer and quantizing said DCT coefficients to produce blocks of quantized coefficients which are quantized differently than corresponding original blocks of received video data;variable length coding the said produce blocks of quantized coefficients; andmultiplexing variable length coded said blocks of quantized coefficients with associated separated said motion vectors and mode information to provide a transcoded bit stream of video data of different volume than received said bit stream of video data.