Patent ID: 8638849

Claim:
Stream conversion apparatus for converting an encoded stream into a re-encoded stream, comprising: receiving means for receiving the encoded stream, a current quantization scale utilized to produce the received encoded stream, and history quantization scales utilized in different generations of past encoding or decoding processes prior to the current quantization scale for the received encoded stream; selection means for selecting, from among the received history quantization scales and current quantization scale, the largest quantization scale to be utilized as a utilization quantization scale in converting the encoded stream into the re-encoded stream; conversion means for converting the encoded stream into the re-encoded stream utilizing the utilization quantization scale selected by said selection means; and quantization scale calculation means for calculating a present quantization scale which is produced when the encoded stream is converted into the re-encoded stream by said conversion means, said selection means selecting, from among the received history quantization scale and current quantization scale and the calculated present quantization scale, the largest quantization scale as the utilization quantization scale to be utilized for conversion.