Transcoding Transparent -> Transparent 2010-03-16 17:56:23 While I understand in theory why transcoding lossy -> lossy is a bad idea, I'm very curious if there are any empirical results on the following scenario: Assume you have a lossy file encoded using codec A, but at a bitrate that produces perceptual transparency compared to the original lossless file. Then you transcode the lossy file produced by codec A into codec B, but at a bitrate that usually produces perceptual transparency relative to the source material. In this case, this means codec B should produce perceptual transparency relative to its source, which is the output of codec A. Has anyone ever actually done any listening tests to prove that this kind of transcoding, where the results of codec A are transparent compared to the lossless source and the results of codec B are transparent compared to the results of codec A, can result in output from codec B that is not transparent relative to the lossless source in real world conditions, i.e. a reasonable number of generations and going from, say, MP3 to Vorbis?