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Topic: ALAC actually lossless? (Read 34518 times) previous topic - next topic
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ALAC actually lossless?

Reply #25 –
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I doubt a fault in a decoder would result in the differences he is describing. It's more likely a faulty decoder would just give garbled output. It could be a difference in replaygain or equalizing...
[a href="index.php?act=findpost&pid=342223"][{POST_SNAPBACK}][/a]

Most likely. Just taking any possibilities into consideration.

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In any case, the only method to prove if a codec is lossles is not, is by doing a bit-by-bit comparison. ABX/listening tests are worthless in this case.
[a href="index.php?act=findpost&pid=342223"][{POST_SNAPBACK}][/a]

ABX are pretty useless for considering lossless, yes. But as the poster is a newbie, and the term was mentioned without expanation:
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Couldn't have said it better myself.  I have come across some people that don't like the ALAC format simply because they can "hear" the differences between the CD and ALAC file eventhough they don't conduct ABX tests or bit comparisons.  That would be false advertising if Apple released a lossless codec that wasn't truely lossless.
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I thought it could be helpful to contribute a link for reference.

As mentioned, only bit-comparing of decoded PCM stream (like foobars "bit-compare tracks") will really be useful, as simple MD5 hashes could give different results with codecs like FLAC, which writes a new RIFF header upon decoding.
[a href="index.php?act=findpost&pid=342262"][{POST_SNAPBACK}][/a]


I guess I should have clarified.  I like to put my friends through ABX tests.  I had one room mate that would rip everything to 320kbps mp3 using MusicMatch.  He commented on how inferior iTunes was and how he tried the ALAC format and could "easily" hear that it wasn't lossless.  So I put him through a ABX test using the 128kbps mpeg-4 AAC format, ALAC, and the source wav.  Well, he failed miserably and he actually went back to his collection (only 1000 songs) and re-ripped to the Lame mp3 format as I suggested.  I have also come across some people on the ilounge forums that say that they can hear a difference in the CD and the ALAC format.  So I have them setup blind ABX tests to put their minds at rest.

I know ABX tests shouldn't be relied on for lossless formats but often time people want to hear the quality, not see a bit identity test done.  In any case, the only thing that can be used to identify a lossless file is to conduct a bit comparison test.  So, I just thought I would explain why I threw ABX in there.


As for ALAC, I use it as my CD backup lossless format.  I have my library at -V 2 --vbr-new with Lame 3.97b1 for my iPod, car mp3 CD deck, and other portable uses while I have my secondary library encoded at the ALAC format on a external hard drive.  I don't use my ALAC library for anything other than a backup of my CD collection, I stick with mp3's even when listening to music on my computer.  I chose ALAC because it is integrated into iTunes, works with EAC, takes nominal processor power to decode (I am on a 2GHz P4 2002 based desktop with 256mb ram so this is important to me), and I can put it on my iPod if need be.

ALAC actually lossless?

Reply #26 –
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And even then you're not entirely correct, as the open source ALAC format plugin implemented for foobar 2000 would support gapless playback, if it worked properly. I don't know what the status on that plugin is. It worked at one point, then there were issues with it. But nevertheless, it would do gapless, if it was working. It's the player, not the format.
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I guarantee you that if ALAC were a documented, open format the plugins would be fine.  I still fail to see the point of a single-vendor proprietary lossless format.  To say that ALAC is technically fine isn't really saying much since it's not that difficult to write a lossless audio compressor.

ALAC actually lossless?

Reply #27 –
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So I took a WAV file, made an md5sum.  Compressed it to FLAC and then uncompressed it back to wav and made another MD5 sum.  I also compressed the same wav to ALAC and then back to wav and made an MD5sum.  Results:

Code: [Select]
Original WAV: 15a7e53a20e6b7c7de08570717620766 *Nirvana - Lithium - 04 D7.wav

Decompressed from FLAC: 15a7e53a20e6b7c7de08570717620766 *Nirvana - Lithium - 04 D7.wav

Decompressed from ALAC: 15a7e53a20e6b7c7de08570717620766 *Nirvana - Lithium - 04 D7.wav


So that concludes it.  It's lossless.  So your imagining the difference.
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Technically speaking, I don't think that identical md5 proves that files are identical

ALAC actually lossless?

Reply #28 –
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In practice, from the user point of view ALAC is not lossless at the moment, because there are no players that can play the current version gaplessly.[{POST_SNAPBACK}][/a]


The format itself provides everything a player needs to implement gapless, and there is an open source decoder available.  So there is no technical reason preventing gapless ALAC.

[a href="http://www.rockbox.org]Rockbox[/url] enables the iriver H1x0 DAPs to play back ALAC gaplessly.  Ports of Rockbox to the iriver H3x0 and the iPod are in progress, and when they are finished, those devices will also be able to play ALAC gaplessly.

I thought foobar had an ALAC decoder, or was that abandoned?[a href="index.php?act=findpost&pid=342319"][{POST_SNAPBACK}][/a]


Did you read this too?
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... The iTunes 5 / QT 7 update broke the ALAC compatibility with foobar2000 v. 0.8.3 and the current 0.9 beta has no ALAC support.

I have searched for other programs that could play the current ALAC format gaplessly, but I couldn't find any.[a href="index.php?act=findpost&pid=342273"][{POST_SNAPBACK}][/a]

ALAC has the capability to store every bit of the original audio CD or other sources in separated track files. I have no doubt about that. I have converted ALAC files and played the converted files gaplessly.

I am speaking about the present situation and the playback choices that are available now.

Apple changed the format somehow. It might be something minor, perhaps just a header thing. However, that broke ALAC decoding for example with foobar and dBpowerAMP.

ALAC actually lossless?

Reply #29 –
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Did you read this too?
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... The iTunes 5 / QT 7 update broke the ALAC compatibility with foobar2000 v. 0.8.3 and the current 0.9 beta has no ALAC support.



Obviously not properly  I just saw the "iTunes 5" at the start of the sentence and skipped it....

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Apple changed the format somehow. It might be something minor, perhaps just a header thing. However, that broke ALAC decoding for example with foobar and dBpowerAMP.
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It was _very_ minor and was caused by the m4a parser distributed with the ALAC decoder.  Point the developers of those programs in the direction of the Rockbox CVS repository and they can see the change that was required to get it working again:

[a href="http://www.rockbox.org/viewcvs.cgi/apps/codecs/libalac/Attic/demux.c?r1=1.2&r2=1.3]http://www.rockbox.org/viewcvs.cgi/apps/co...c?r1=1.2&r2=1.3[/url]

However, the real solution is to not use that m4a parser at all, but something more robust instead.

Dave.

ALAC actually lossless?

Reply #30 –
Foobar 0.9 beta has no Problem with ALAC gapless playback ... to say it can't playback gapless is pure disinformation!

ALAC actually lossless?

Reply #31 –
>that broke ALAC decoding for example with foobar and dBpowerAMP

We fixed that (was just extra chunk headers in the stream).

...also we have a native ALAC encoder (not using iTunes or quicktime) avaliable soon.

ALAC actually lossless?

Reply #32 –
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...also we have a native ALAC encoder (not using iTunes or quicktime) avaliable soon.
[a href="index.php?act=findpost&pid=342357"][{POST_SNAPBACK}][/a]


That's exciting news.  Will the source be available?

ALAC actually lossless?

Reply #33 –
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Foobar 0.9 beta has no Problem with ALAC gapless playback ... to say it can't playback gapless is pure disinformation![a href="index.php?act=findpost&pid=342344"][{POST_SNAPBACK}][/a]
No it is not disinformation. I downloaded and installed Foobar 0.9 beta 10 and tried ALAC playback a couple of weeks ago because v.0.83 coudn't play the iTunes 5/QT 7 ALAC files. A few minutes ago I tried it again on the just released new beta 11. Foobar 0.9 beta 9, 10 and 11 do not play ALAC at all because of this:
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Sep 24 2005, 12:12 PM Post #3
Beta 9 out.

Changes include:
redone most of converter and rgscan
fixed issues with cuesheet handling
removed ALAC decoder (stability issues)
removed recorder
removed tag update queue; you can now update tags on currently playing file

Foobar 0.9 beta says this when I try to play iTunes 5/QT 7 encoded ALAC files:
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Error opening file for playback (Unsupported format or corrupted file):
"C:\iTunes\samples\08 Livin Thing.m4a"

In any case 0.9 beta is not ready yet. I hope that v.0.83 ALAC support can be fixed.

ALAC actually lossless?

Reply #34 –
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>that broke ALAC decoding for example with foobar and dBpowerAMP

We fixed that (was just extra chunk headers in the stream).[a href="index.php?act=findpost&pid=342357"][{POST_SNAPBACK}][/a]

Are you sure the fixed codec for dBpowerAMP is available? I downloaded and installed the "m4a, mp4 and Apple Lossless Codec Rel. 3" file today, but it was exactly the same file I tried two weeks ago. The result was also the same:
Code: [Select]
Errors Whilst Converting:
The file 'C:\iTunes\Samples\08 Livin Thing.m4a' could not be opened.


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...also we have a native ALAC encoder (not using iTunes or quicktime) available soon.
That is great news.

ALAC actually lossless?

Reply #35 –
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Foobar 0.9 beta has no Problem with ALAC gapless playback ... to say it can't playback gapless is pure disinformation![a href="index.php?act=findpost&pid=342344"][{POST_SNAPBACK}][/a]
No it is not disinformation. I downloaded and installed Foobar 0.9 beta 10 and tried ALAC playback a couple of weeks ago because v.0.83 coudn't play the iTunes 5/QT 7 ALAC files. A few minutes ago I tried it again on the just released new beta 11. Foobar 0.9 beta 9, 10 and 11 do not play ALAC at all because of this:

hmmm, strange I'm using ALAC for Months without any Problems with the f2k-betas ... however I'm not a ALAC Fan but it's nice to see the bitrate changing through playback (unlikeWavPack/FLAC).

ALAC actually lossless?

Reply #36 –
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No DRM on ALAC?  I did not know that.

Actually, there's no DRM on anything you make with iTunes. DRM is only on files you purchase from the iTunes Music Store. There'd be no point in putting DRM on files you make yourself.
[a href="index.php?act=findpost&pid=342292"][{POST_SNAPBACK}][/a]

Heh, Microsoft obviously thinks different. (Hah! Got the uber leet hidden reference joke?)

ALAC actually lossless?

Reply #37 –
In the end, what good is the best format in the world if nothing can play it?  ALAC is great for people who use iPods and iTunes.  And just because that is good enough for people that do, it's completely useless if you don't.  I suppose it works both ways.  But a technically good codec with hardly anything you can use it with isn't very useful.  To each his own though. 

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So I took a WAV file, made an md5sum.  Compressed it to FLAC and then uncompressed it back to wav and made another MD5 sum.  I also compressed the same wav to ALAC and then back to wav and made an MD5sum.  Results:

Code: [Select]
Original WAV: 15a7e53a20e6b7c7de08570717620766 *Nirvana - Lithium - 04 D7.wav

Decompressed from FLAC: 15a7e53a20e6b7c7de08570717620766 *Nirvana - Lithium - 04 D7.wav

Decompressed from ALAC: 15a7e53a20e6b7c7de08570717620766 *Nirvana - Lithium - 04 D7.wav


So that concludes it.  It's lossless.  So your imagining the difference.
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Technically speaking, I don't think that identical md5 proves that files are identical
[a href="index.php?act=findpost&pid=342334"][{POST_SNAPBACK}][/a]

Perhaps you could give an example of where this is not true?  I hope your joking though.  If not I'd like to see two different files give the same md5sum, as I don't think it is possible.

ALAC actually lossless?

Reply #38 –
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Technically speaking, I don't think that identical md5 proves that files are identical
[a href="index.php?act=findpost&pid=342334"][{POST_SNAPBACK}][/a]

Perhaps you could give an example of where this is not true?  I hope your joking though.  If not I'd like to see two different files give the same md5sum, as I don't think it is possible.
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It's very possible, just not probable.  If there was only one file with a given md5sum then we could just use md5 to compress a file.  There are an infinite number of files with the same md5 hash, it's just very very difficult to find an instance of a second file which hashes to the same value.  In fact there have been recent publications which show it's relatively easy now to produce two files with the same md5 hash.  But thankfully it's still hard to find a second file that matches the md5 hash of a given file.  When two different files have the same hash value it's called a hash collision.

This is all basic cryptography stuff.

ALAC actually lossless?

Reply #39 –
>Are you sure the fixed codec for dBpowerAMP is available? I downloaded and installed the "m4a, mp4

We tend to beta our new codecs for atleast 1 month (you need R3.5), the updated ALAC decoder compatible with the latest iTunes is here:

http://forum.dbpoweramp.com/showthread.php?t=8950

>That's exciting news. Will the source be available?

We are a commercial licensee of the code and are restricted as to the details of the deal, however we are able to say that the code will become open source in around 1 years time.

ALAC actually lossless?

Reply #40 –
Quote from: bawjaws on
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I don't like ALAC due to the DRM and the evil iTunes.


ALAC doesn't have any DRM. (It's strange that people seem to  make a point of being misinformed about Apple + iTunes + DRM.)

Well to be precise, they probably could wrap it in their fairplay DRM just as well as they have put it on AAC audio and MPEG4 videos. They (or anyone else) could also do the same to FLAC or whatever.

However the point is moot as it would be trivial to capture the output of such a DRM'd lossless file and re-encode it as ALAC (or any other losselss format) minus the DRM and without any quality loss since you don't get the generational degredation associated with lossy compressors.

iTunes gets evil points (re: lossless) for:

* not supporting an existing open format (i.e. FLAC)
* not being widely supported beyond iTunes/Quicktime

But the nature of lossless and consequent ease of transcoding makes both minor evils, in my opinion.


It has ALWAYS been possible to remove the DRM using digital audio capture techniques on ALL of Apple's music.  Yes that hasn't stopped the labels from allowing Apple to sell their stuff.  Don't get it

Part of that may have to do with the fact that such audio capture software is illegal (I believe TuneBite is legal only because it utilizes analog capture).  But that hardly matters; it's available.

Bottom line is I don't understand why the labels are so excited about circumventable DRM.

ALAC actually lossless?

Reply #41 –
Quote from: spoon on
>Are you sure the fixed codec for dBpowerAMP is available? I downloaded and installed the "m4a, mp4

We tend to beta our new codecs for atleast 1 month (you need R3.5), the updated ALAC decoder compatible with the latest iTunes is here:

http://forum.dbpoweramp.com/showthread.php?t=8950

>That's exciting news. Will the source be available?

We are a commercial licensee of the code and are restricted as to the details of the deal, however we are able to say that the code will become open source in around 1 years time.

Now that solletica has kicked this thread, I'm curious where the source for the dbpoweramp ALAC encoder is? Would be great if that code would actually be opensourced, because that would mean me using it  (having an iPod and all).

ALAC actually lossless?

Reply #42 –
Quote from: Duble0Syx on
I don't like ALAC due to the DRM and the evil iTunes.  I'm sure it's a fine format, seems to compress decently fast and as much as FLAC.  Had a hard time figuring out how to convert it to ALAC and back again using iTunes.  I'll be uninstalling it as soon as possible.  EAC, FLAC (WavPack too) and Foobar for me.


What DRM? If you are encoding yourself you can't really complain about DRM unless I am missing something here?

Edit : Doh, just noticed this is an old thread .

ALAC actually lossless?

Reply #43 –
Am I the only one interested in a FLOSS ALAC encoder?

ALAC actually lossless?

Reply #44 –
FFmpeg has both an encoder and a decoder.

ALAC actually lossless?

Reply #45 –
That one has been commited just a few daays ago and I believe is very experimental. I also havn't seen any compiles with it yet.

ALAC actually lossless?

Reply #46 –
This topic is really interesting. Thanks to it, i will probably give ALAC some tries. THX

ALAC actually lossless?

Reply #47 –
Quote from: Brent on
That one has been commited just a few daays ago and I believe is very experimental. I also havn't seen any compiles with it yet.


I'm not quite sure what you mean by "experimental". I haven't really seen any problems in practice and it does compress quite okay and exploits most of the format semantics. As for compiles, you could always make your own!

ALAC actually lossless?

Reply #48 –
And iTunes (and iPods) support gapless playback of MP3, AAC and ALAC now AFAIK.

ALAC actually lossless?

Reply #49 –
I'd use ALAC, (since iTunes doesn't support WavPack...), but it seems like when syncing to an iPod other than the shuffle, it won't convert, and that's useless to me since I'll be trading in my (destroyed) Zune for an iTouch.

I'd use ALAC, (since iTunes doesn't support WavPack...), but it seems like when syncing to an iPod other than the shuffle, it won't convert, and that's useless to me since I'll be trading in my (destroyed) Zune for an iTouch.