because music, as photo (not drawings, some can be compressed) and films, can be only "compressed" with data losses.I don't agree. Music, photos and films can very well be compressed aslong as they are not already compressed (lossy or not). Yes, most usualformats nowadays are already compressed, but that still doesn't make music un-compressible.
Well... actually, you are true, but I know about no lossless efficient (or at least correct) audio algorithms. And, like so many other people (well, I hope to not be the only one), I do the mental merge between mp3 and a format, but not with a compression format, which is an error, since mp3 is a compression format only: music needs to be uncompressed before being played. I know that, but... shortcuts are so easy. My apologies, and thanks for the correction.