Patent ID: 8295345
Filing Date: 2012-10-23
Classification: H04N

Abstract:
1. A transcoder for transcoding a first compressed bit stream having a first bit rate to a second compressed bit stream having a second bit rate, the transcoder comprising: a receiver configured to receive the first compressed bit stream having the first bit rate, a motion vector and video frame headers; an inverse quantizer configured to receive the first compressed bit stream and generate, based on the first bit rate corresponding to a first quantization level, a stream of coefficients; a transcoder loop configured to perform inter-frame motion compensation based on the stream of coefficients from the first compressed bit stream and a stream of coefficients from a previous frame of the first compressed bit stream; a quantizer configured to quantize the stream of coefficients at a second quantization level based on the inter-frame motion compensation to generate a stream of coefficients at the second quantization level; and wherein the transcoder is configured to generate, based on the stream of coefficients at the second quantization level, the second compressed bit stream having the second bit rate, and wherein the second compressed bit stream includes the motion vector without modification and the video frame headers without modification.