On 2015-08-23 20:45, James Knott wrote:
I just started experimenting with ffmpeg and was wondering if the sound quality is maintained during conversion. I converted an ogg file to mp3 and see the mp3 is smaller. Did I lose audio quality in the process?
Absolutely yes, by definition. Whether you can perceive it, that's different. Both mp3 and ogg are lossy audio compressors. They both remove information from the audio stream so that it occupies less space, but /feels/ the same to the human ear+mind system. Thus, by definition, encoding in any of those loses data. Now, going by educated guess work. The converter can work by converting the data stream to an "audio" stream (so to speak). I mean, it regenerates the originally recorded audio data as best as it can approximate (because it is lossy, thus not all data was recorded). A second step would analyze this audio stream and, using its techniques for removing what the ear can not feel, compresses it again to another lossy format. Two lossy conversions chained. Thus, worse overall result. The only way to do that is that the converter copies the data from one to other format, just changing the "format". If legally possible at all. This is what I don't know. My guess is "no". Me, I would do no conversion at all, unless you need to play on a device that doesn't support the format you have. I would try to use the higher conversion quality settings possible and experiment. Which is why I compress to mp3, not ogg... :-( -- Cheers / Saludos, Carlos E. R. (from 13.1 x86_64 "Bottle" at Telcontar)