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Topic: ALAC (or m4a) <-->FLAC (Read 5243 times) previous topic - next topic
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ALAC (or m4a) <-->FLAC

Loseless blows my mind, but I know I need to adopt the format.  I'm a DJ, everything I have I have backed up in mp3 format and then reburnt it so that I DJ with copied discs, and not the originals.  I've written a program to fully automate and organize my DJ library, but it relies heavily on iTunes for burning support and my program is made to read iTunes exported tracklists.  Unfortunately to date, the only loseless format iTunes supports is this m4a format.  OK, my first question

I'm assuming m4a is loseless, or at least the results of Apple Loseless encoding is loseless.  Is the m4a file the result of the Apple Loseless encoder (apple only format)?  Or is m4a the generic (and potentially lossy) MPEG layer-4 suffix and ALE is just the codec that puts the sond in that format loselessly?

Second question.  Now that I've got all this loseless music, my main concern is what if one day I have to seperate myself from iTunes, or I go completely digital for DJing and my software only supports mp3's or (preferably) FLAC, is there a way to get back andforth from (for the sake of arguement) FLAC and m4a for portability sake?

Hopefully you guys can help me out.
-EMAN

ALAC (or m4a) <-->FLAC

Reply #1 –
Use iTunes to encode an AAC (lossy) file. It's also .m4a. So all .m4a (MPEG 4 Audio) files are not lossless. Yes, going ALAC to FLAC to Monkeys, etc. will keep things lossless. You can move back and forth without quality loss. Just be careful to keep TAGs, but otherwise you're fine.

ALAC (or m4a) <-->FLAC

Reply #2 –
Firstly thanks, that alone is a huge help, just knowing that it can be done it great. 

I'm assuming ALAC stands for Apple Loseless Audio Codec.  However, I don't think my real question came out in my original post.  My main question is, can it be done?  I can rip in iTunes to loseless m4a using ALAC, but how (what program, frontend, etc) should I be using to get between formats?

ALAC (or m4a) <-->FLAC

Reply #3 –
Quote
I'm assuming m4a is loseless, or at least the results of Apple Loseless encoding is loseless.  Is the m4a file the result of the Apple Loseless encoder (apple only format)?  Or is m4a the generic (and potentially lossy) MPEG layer-4 suffix and ALE is just the codec that puts the sond in that format loselessly?

M4A is the MPEG 4 Audio container that can contain either AAC audio (lossy) or ALAC audio (lossless). iTunes puts both formats into an M4A file.

Quote
Second question.  Now that I've got all this loseless music, my main concern is what if one day I have to seperate myself from iTunes, or I go completely digital for DJing and my software only supports mp3's or (preferably) FLAC, is there a way to get back andforth from (for the sake of arguement) FLAC and m4a for portability sake?
[a href="index.php?act=findpost&pid=290064"][{POST_SNAPBACK}][/a]

foobar now has a beta ALAC decoder, so in theory you could use that and the transcoder to convert from ALAC to FLAC. I have not tried it, but I assume it'll work.

Nobody has created an open source ALAC encoder yet, but you could use foo_clienc with iTunesEncode to convert from anything to ALAC, if you wanted.

ALAC (or m4a) <-->FLAC

Reply #4 –
Quote
foobar now has a beta ALAC decoder, so in theory you could use that and the transcoder to convert from ALAC to FLAC. I have not tried it, but I assume it'll work.


I found foobar2000.org which looks like the site's homepage.  I see support for MPEG-4 AAC (lossy) but not for ALAC.  Not that I am questioning you, becuase I'm probably blind and didn't see it, but where did you find this beta at?

ALAC (or m4a) <-->FLAC

Reply #5 –
Quote
....
Not that I am questioning you, becuase I'm probably blind and didn't see it, but where did you find this beta at?
[{POST_SNAPBACK}][/a]



Hmmm-mm... is it here?:
[a href="http://www.saunalahti.fi/cse/foobar2000.php]http://www.saunalahti.fi/cse/foobar2000.php[/url]
 

ALAC (or m4a) <-->FLAC

Reply #6 –
OK, I downloaded that beta (thanks for the link btw), and I was testing bitcompare on a wav ripped from iTunes and the m4a created by ALAC in iTunes.  I tried playing the ALAC to make sure that it plays now that I've got that beta, and it did, but I got this output as well:

ERROR (foo_input_std) : MP4: unable to find correct sound track in the MP4 file.
INFO (foo_input_std) : location: "file://Path/File.m4a" (0)

So I guess it doesn't suprise me when the wav and the ALAC didn't compare very well.  My output was:

INFO (foo_bitcompare) : differences found: 16550349 sample(s), starting at 0. second(s), peak: 1.829834 at 16.74122 second(s), 2ch
INFO (foo_bitcompare) : Finished successfully.

I'm was assuming this has something to do with the missing sound track, whatever that is. 

For comparison, I converted the same ALAC to WAV using foobar this time, and no differences were found, and the resulting file sounded just fine.  Does anybody know what that missing sound track is?  or why the ALAC and wav from iTunes didn't compare well if all wavs are supposed to be the same?

EDIT:  Just realized that the foobar support forum is on another part of this site, I think I may have to jump over there at this point.