Which is really higher quality...WAV or ALAC ??

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Level 1

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Which is really higher quality...WAV or ALAC ??

This might seem an age old question but I cant get my head round it. I understand both are lossless (perfect) formats, HOWEVER when I convert say for example a DJ mix from WAV to apple lossless, like i did this morning...it compressed by 33%, the file size shrank from 1.12GB to 778MB and the bitrate decreased from 1411kbps to 956kbps.

Surely this would signal a loss of playback quality?? Otherwise why would WAV an other lossless formats need to be that much bigger if the first place? But whats more confusing is that I thought I'd try converting it backwards (from ALAC to WAV) to see what happened and what d'ya know...it appeared to uncompress back to o% and its original size and bitrate.

Can anyone explain what happens here?? And if no quality is lost, then why?

The reason I choose ALAC is because I can add artwork and other metadata but I hope im not sacrificing quality in the process. And I use dbpoweramp converter.

Thanks

Posted on Aug 14, 2012 6:22 AM

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Answer 1

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turingtest2

Level 10

274,055 points

Aug 14, 2012 7:34 AM in response to JamesID

ALAC is a lossless compression format. It takes the original data and packs it in a way that takes up less room, but without throwing any data away. In comparrison MP3, AAC and WMA are all lossy formats. Depending on the amount of data discarded you may or may not notice the difference, but there is one.

The audio quality of WAV and ALAC is identical, but ALAC is both smaller and more versatile since you can add a tag.

tt2

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Answer 2

turingtest2

Level 10

274,055 points

Aug 14, 2012 10:17 AM in response to JamesID

The bitrate tells you how many bits of the source file need to be read each second to produce the output. Uncompressed WAV or AIFF clocks up 1411 kbps. The one file I have in ALAC format comes up to 953kbs which is 68% of the output bit rate. The lossless file is also, unsurprisingly, 68% of the size of the WAV original. When playing back the lossless file all the original 1411 kbps information will be extracted on the fly so that you hear exactly what was captured at CD quality. The reason for the different bitrates of lossless files will be that some can be squeezed more than others while still maintaining a reversible process that can restore all the initial information.

tt2

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Answer 3

JamesID Author

Level 1

8 points

Aug 14, 2012 9:51 AM in response to turingtest2

Ok thanks a lot. But would you not agree that the higher the bitrate the higher the audio quality? If that is the case then would ALAC not be a slighty lower quality since it has a lower bitrate?

Also - why do many ALAC files have different bitrates? Hardly any seem to be the same unlike WAV/FLAC etc.

Thanks again

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