Oui, à l’écoute, aucune différence n’est perceptible.
Perso, cest plutôt lAPE que j’utilise vu que cest un format très utilisé par les musiciens américains pour les échanges de pistes audio via internet. Possible quen Europe le FLAC soit plus utilisé mais soit, si des milliers de musiciens US utilisent lAPE, cest que ce format doit plus ou moins tenir la route.
Jajoute que je suis bien incapable dentendre la différence entre un fichier audio original et ce même fichier après décompression APE. Même lors dune écoute minutieuse, pour moi, il ny a pas la moindre différence. Ce qui ne veut pas dire quun auditeur attentif écoutant sur une install à cent mille euros ne constatera pas de différence.
Jajoute aussi que jai effectué le test dinversion de phase indiqué dans le mail du technicien audio (dont copie ci-dessous) et que pour moi, no problem, ce test était concluant. La compression APE (modérée) était bien transparente.
Mais pour certains, ce test dinversion de phase nest quun petit test, il ne constitue pas une preuve. Et le fait que lon nentende aucune dégradation ne prouve rien non plus. Je suppose quils font allusion au fait que des artéfacts minimes et inaudibles dans le fichier décompressé pourraient, lors de copies de ce fichier, être amplifiés et donc devenir audibles.
Quoi quil en soit, il semble prudent de ne pas compresser à plus de 50% de la taille du fichier original. Lidéal et le plus safe étant bien sûr de ne pas compresser du tout. Après tout, est-on certain que le simple fait de copier un fichier audio, donc sans aucune compression, ne peut pas déjà induire des erreurs ? Je ne parierais en tous cas pas un franc là-dessus.
Si le sujet tintéresse, voici une copie du mail de ce technicien audio, juste pour info.
Le gars travaillant dans le mastering audio depuis un certain nombre dannées, je suppose quil a une certaine expérience
APE files and other “lossless” files experiments:
Can I give you a bit “history” of my experiences of “compressed” files and why I prefer “native” files ?
Are you sitting comfortably?.. then I’ll begin…
About 3 years ago, along with a friend of mine who lives in Virginia, USA, we carried out some fairly exhaustive tests on compressed audio files. What we found was that the files that were highly compressed files lost some of their quality after being expanded (re-converted) back to WAV or AIFF. Even although these files “restored” back to the original data size, they did lose quality if compressed smaller than 50 percent of the original size. Now, this may be precisely why Steinberg recommends WinZip… I can only guess.
People generally say that good MP3’s are almost indistinguishable from CD quality, but when you’re starting off with “compromised” audio files [data], the mix will always be compromised too.
The next question one would ask about these “compromised” (compressed) files is how does one actually know that the audio is not exactly the same when comparing the original WAV or AIFF with the file that has been highly compressed once that’s been re-expanded. The fact is the “difference” can be heard… and this is how: Take the original file into your multi-track and do the same with the file that was compressed and re-expanded. If they are identical, they should be precisely time aligned (i.e., start playing at exactly the same time, have no “slippage” - and end at exactly the same time). What’s done next is to invert the phase of one of the files [and it doesn’t matter which one], then playback both. If these files are identical, the phase cancellations between the two files will produce absolute silence. That is the only “perfect” audible proof that the files are exactly the same. In our tests, we were only ever able to achieve this “perfect” result when using files that had been compressed down to about half their data size before re-expanding them.
The smaller compressed / expanded files in these tests always produced “noise” and other artefacts.
You hear lots of people getting really defensive about “lossless” compression - and many actually believe they’ll get a lossless file from ALL the Monkeys Audio compression codecs. However, this is only possible with some of them.
I had a guy in England swearing to me that nobody can tell the difference between the compressed (down to 3.5MB and expanded back to 45MB) file and the original. I got the files from him… and the compressed on was trashed beyond belief. Turns out the guy was a software developer working on audio compression and was an audio “expert” who had never been in a recording studio. I gave him my results and never heard from him again.
This is why “ultra” compressed files are not worth working with. It’s always best to get either “untouched” WAV or AIFF tracks - or if compressing them, to get tracks that have been compressed down to about 50 percent of their original size. To me, compression isn’t worth it… because, it means that you are introducing potential points of failure each time a file is “tampered” with. One batch job on WinZip and you’re home free each time.
It’s important to me to get mixes and masters as good as possible because the musicians and singers deserve that much after spending many hours themselves in the music creation process. I think they deserve the very best I can give them 
I think that’s enough reading for this evening, Pit.
Thanks for your patience with my “moans”… I just want to get you the best “product” that I can.
