Sycraft
100+ Head-Fier
- Joined
- Jul 6, 2004
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So some people seem to be confused in to thinking that FLAC, or ALAC alter the sound of files, like MP3 does. That's just not the case. Lossless compression is just that, lossless. All information that was present in the original is present in the compressed version. When it's decompressed, the reconstruction is bit-identical.
The upshot of this is that, barring you having a broken encoder or decoder, FLAC will sound precisely the same as WAV, and one lossless compression will sound the same as another. Don't believe me? Here's a test:
I took a short audio file that I recorded for a presentation and dumped it to WAV on my computer, it was called orignal.wav. I encoded that to FLAC, then decoded the FLAC to WAV, using the FLAC encoder from flac.sourceforge.net. I ran a diff on those two files, which will note any byte that is different. Here's the result:
As you can see, the two files are bit-identicle, right down to the headers. As another test, I loaded both files in to Wavelab, I took the orignal, inverted the phase, and added it to the FLAC'd version. The result?
Digital silence. The files were identical, so they canceled each other out.
If you want you can get the difference WAV and listen yourself, but you won't hear anything except noise your soundcard makes.
If you want to test yourself you can look at:
http://sycraft.org/flac/a.wav
http://sycraft.org/flac/b.wav
http://sycraft.org/flac/c.wav
One of those is the original WAV, two are the de-FLAC'd versions. You can listen and see if you can tell the difference. You can't, they are bit identical, but if you want to waste your time trying, be my guest and post your guesses.
I would have tested ALAC as well, but unfortunately, Apple gives no way to route decoding to disk. Doesn't matter, unless they broke their decoder, the results would be the same.
The moral of the story is that lossless encoding is just that: Lossless. It's not like MP3 where it's using perceptual data to try and reconstruct something, it's a mathematical reduction of data that is exact. The same thing, to the very bit, is sent to the soundcard.
If you believe you hear a difference you are either fooling yourself, or you don't have your player configured right. For example, you might enable something like Realplay gain for FLAC files, which tries to normalize audio levels. That would change the sound of it for sure, because it changes the volume. However that's post processing, not a property of the FLAC encoding itself.
You can use FLAC with confidence that it reproduces your original data completely accurately. It's just up to you to configure your player to leave that unmodified (if that's what you want).
Edited for spelling, since I suck at that.
The upshot of this is that, barring you having a broken encoder or decoder, FLAC will sound precisely the same as WAV, and one lossless compression will sound the same as another. Don't believe me? Here's a test:
I took a short audio file that I recorded for a presentation and dumped it to WAV on my computer, it was called orignal.wav. I encoded that to FLAC, then decoded the FLAC to WAV, using the FLAC encoder from flac.sourceforge.net. I ran a diff on those two files, which will note any byte that is different. Here's the result:
As you can see, the two files are bit-identicle, right down to the headers. As another test, I loaded both files in to Wavelab, I took the orignal, inverted the phase, and added it to the FLAC'd version. The result?
Digital silence. The files were identical, so they canceled each other out.
If you want you can get the difference WAV and listen yourself, but you won't hear anything except noise your soundcard makes.
If you want to test yourself you can look at:
http://sycraft.org/flac/a.wav
http://sycraft.org/flac/b.wav
http://sycraft.org/flac/c.wav
One of those is the original WAV, two are the de-FLAC'd versions. You can listen and see if you can tell the difference. You can't, they are bit identical, but if you want to waste your time trying, be my guest and post your guesses.
I would have tested ALAC as well, but unfortunately, Apple gives no way to route decoding to disk. Doesn't matter, unless they broke their decoder, the results would be the same.
The moral of the story is that lossless encoding is just that: Lossless. It's not like MP3 where it's using perceptual data to try and reconstruct something, it's a mathematical reduction of data that is exact. The same thing, to the very bit, is sent to the soundcard.
If you believe you hear a difference you are either fooling yourself, or you don't have your player configured right. For example, you might enable something like Realplay gain for FLAC files, which tries to normalize audio levels. That would change the sound of it for sure, because it changes the volume. However that's post processing, not a property of the FLAC encoding itself.
You can use FLAC with confidence that it reproduces your original data completely accurately. It's just up to you to configure your player to leave that unmodified (if that's what you want).
Edited for spelling, since I suck at that.
