Author Topic: Familiar with ALAC files??? Need help...  (Read 6711 times)

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Offline twatts

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Familiar with ALAC files??? Need help...
« on: January 09, 2014, 02:53:26 PM »
I DLed some ALAC files...  How do I convert to WAV?

I know iTunes can do it, but is this process "lossless", ie will it produce WAVs that are EXACTLY like the originals???

If not, how do I go about re-creating those original WAV files???  I would rather not buy dbPowerAmp...

Thanks,

Terry
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Offline kellerb

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Re: Familiar with ALAC files??? Need help...
« Reply #1 on: January 09, 2014, 03:15:58 PM »
I DLed some ALAC files...  How do I convert to WAV?

I know iTunes can do it, but is this process "lossless", ie will it produce WAVs that are EXACTLY like the originals???

If not, how do I go about re-creating those original WAV files???  I would rather not buy dbPowerAmp...

Thanks,

Terry

I know foobar2000 can convert ALAC to WAV.  I *assume* it is a lossless process, but I don't have documentation that it is bit-perfect.

Offline twatts

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Re: Familiar with ALAC files??? Need help...
« Reply #2 on: January 09, 2014, 03:20:19 PM »
I DLed some ALAC files...  How do I convert to WAV?

I know iTunes can do it, but is this process "lossless", ie will it produce WAVs that are EXACTLY like the originals???

If not, how do I go about re-creating those original WAV files???  I would rather not buy dbPowerAmp...

Thanks,

Terry

I know foobar2000 can convert ALAC to WAV.  I *assume* it is a lossless process, but I don't have documentation that it is bit-perfect.


Maybe I need to reinstall Foobar, but mine came up with errors whenever I tried to use it...

I'd hate to assume, though I'm going to have to do so anyways...  The person who provided the ALAC refuses to provide a WAV MD5...

Terry
Oh! That! No, no, no, you're not ready to step into The Court of the Crimson King. At this stage in your training an album like that could turn you into an evil scientist.

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Offline VDB

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Re: Familiar with ALAC files??? Need help...
« Reply #3 on: January 09, 2014, 03:34:11 PM »
ALAC is lossless, so would not any other lossless format you convert it into also be lossless? Where would the losses be lost to?
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Offline twatts

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Re: Familiar with ALAC files??? Need help...
« Reply #4 on: January 09, 2014, 03:54:09 PM »
ALAC is lossless, so would not any other lossless format you convert it into also be lossless? Where would the losses be lost to?

My question is not about whether or not its "lossless", I'm sure that it is...

My question is whether or not there is a process by which I can re-create the original WAV files from the ALAC, like you can do with FLAC. 

I'm concerned about my WAV MD5s matching the originals...

Terry
Oh! That! No, no, no, you're not ready to step into The Court of the Crimson King. At this stage in your training an album like that could turn you into an evil scientist.

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Offline Superfreakie

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Re: Familiar with ALAC files??? Need help...
« Reply #5 on: January 09, 2014, 09:08:58 PM »
You only need the trial version for dbpoweramp if you are only going to use it to do conversions. Get the trial version and the necessary codecs, then when the 21 days are up, all that happens is that you can no longer use it as a CD burner nor use it to encode tracks BUT you will always be able to use it to convert files. Which is why you wanted it for in the first place. It's a a great program and really accurate. 
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Offline twatts

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Re: Familiar with ALAC files??? Need help...
« Reply #6 on: January 10, 2014, 12:16:20 AM »
You only need the trial version for dbpoweramp if you are only going to use it to do conversions. Get the trial version and the necessary codecs, then when the 21 days are up, all that happens is that you can no longer use it as a CD burner nor use it to encode tracks BUT you will always be able to use it to convert files. Which is why you wanted it for in the first place. It's a a great program and really accurate.

Converting ALAC to WAV isn't really an issue, it whether or not the resulting WAV files would be the exact same as the original WAV files... 

Testing on my own part:  converting ALAC > WAV with iTunes and again with Foobar give you (2) different results, which produce (2) different MD5s, which (of course) fail verification when used with the "other" set of WAV files... 

Terry

Oh! That! No, no, no, you're not ready to step into The Court of the Crimson King. At this stage in your training an album like that could turn you into an evil scientist.

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Offline twatts

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Re: Familiar with ALAC files??? Need help...
« Reply #7 on: January 10, 2014, 12:18:49 AM »
You only need the trial version for dbpoweramp if you are only going to use it to do conversions. Get the trial version and the necessary codecs, then when the 21 days are up, all that happens is that you can no longer use it as a CD burner nor use it to encode tracks BUT you will always be able to use it to convert files. Which is why you wanted it for in the first place. It's a a great program and really accurate.


Yeah...  I must have had dbPA installed at one point b/c it won't install now for whatever reason...  It says I have to buy it for it to do anything... 

Terry
Oh! That! No, no, no, you're not ready to step into The Court of the Crimson King. At this stage in your training an album like that could turn you into an evil scientist.

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Offline slslbs

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Re: Familiar with ALAC files??? Need help...
« Reply #8 on: January 10, 2014, 02:16:30 PM »
try XLD
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Offline twatts

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Re: Familiar with ALAC files??? Need help...
« Reply #9 on: January 10, 2014, 02:57:40 PM »
try XLD

Will this what I need, or is just another converter???  And I have a PC, not a MAC, can I still use it??? 

Terry
Oh! That! No, no, no, you're not ready to step into The Court of the Crimson King. At this stage in your training an album like that could turn you into an evil scientist.

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Offline slslbs

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Re: Familiar with ALAC files??? Need help...
« Reply #10 on: January 10, 2014, 04:07:08 PM »
It is a convertor, but it may do what you want and convert w/o changing the MD5. I never checked it.

It is a free MAC program.

I didn't know you can run ALAC on a PC
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Offline jasonsobel

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Re: Familiar with ALAC files??? Need help...
« Reply #11 on: January 11, 2014, 06:27:35 PM »
ALAC should be natively supported by foobar.

When playing a FLAC file in foobar, there's an easy way to view the audio checksums.  I assume that it does the same thing with ALAC. After you use foobar to decode, generate a set of shntool md5's (aka st5's) with trader's little helper on the wav files.  The st5 should match the audio checksum of the ALAC file in foobar, and this will confirm that the decode back to WAV was lossless.
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Offline twatts

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Re: Familiar with ALAC files??? Need help...
« Reply #12 on: January 11, 2014, 06:39:13 PM »
ALAC should be natively supported by foobar.

When playing a FLAC file in foobar, there's an easy way to view the audio checksums.  I assume that it does the same thing with ALAC.

How do I do this???  OK I figured it out...  When you view the Properties on a FLAC file, it shows the checksum...  Does NOT do the same thing for ALAC...

After you use foobar to decode, generate a set of shntool md5's (aka st5's) with trader's little helper on the wav files.  The st5 should match the audio checksum of the ALAC file in foobar, and this will confirm that the decode back to WAV was lossless.

Thanks!

Terry
« Last Edit: January 11, 2014, 06:55:06 PM by twatts »
Oh! That! No, no, no, you're not ready to step into The Court of the Crimson King. At this stage in your training an album like that could turn you into an evil scientist.

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Offline jasonsobel

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Re: Familiar with ALAC files??? Need help...
« Reply #13 on: January 11, 2014, 08:27:18 PM »
When you view the Properties on a FLAC file, it shows the checksum...  Does NOT do the same thing for ALAC...

bummer.  probably displays the checksum for FLAC, because FLAC stores the checksum in the header as a metadata tag (which is why it's so quick to generate an FFP file, it's just reading the FFP that is already calculated and stored in the metadata, rather than calculating the checksum again).  I guess ALAC doesn't store the checksum in the header?  (I've never used ALAC, so I don't really know).

anyway, not sure if the st5 of the decoded WAV file will help, if foobar doesn't give you the checksum of the ALAC, then you have nothing to compare it to.

like I said, I've never used ALAC.  I'm curious now, can you send me one of the ALAC files?

also, just generally speaking, foobar is a great program, and even if we can't figure out a way to verify that the files was losslessly decoded, I think it's safe to "trust" foobar.  for example, if you try to convert between lossy formats (mp3 to ogg, for example), it'll give you a warning and tell you why a lossy to lossy transcode is bad.  based on this experience, I would expect foobar to give you some error or warning if it wasn't a lossless conversion from ALAC to WAV.  The folks behind foobar definitely know what they're doing, and since ALAC went open source a few years ago, it's very easy to have ALAC implemented correctly.  So you really should not have any issues.


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Offline twatts

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Re: Familiar with ALAC files??? Need help...
« Reply #14 on: January 11, 2014, 09:34:39 PM »
When you view the Properties on a FLAC file, it shows the checksum...  Does NOT do the same thing for ALAC...

bummer.  probably displays the checksum for FLAC, because FLAC stores the checksum in the header as a metadata tag (which is why it's so quick to generate an FFP file, it's just reading the FFP that is already calculated and stored in the metadata, rather than calculating the checksum again).  I guess ALAC doesn't store the checksum in the header?  (I've never used ALAC, so I don't really know).

anyway, not sure if the st5 of the decoded WAV file will help, if foobar doesn't give you the checksum of the ALAC, then you have nothing to compare it to.

like I said, I've never used ALAC.  I'm curious now, can you send me one of the ALAC files?

also, just generally speaking, foobar is a great program, and even if we can't figure out a way to verify that the files was losslessly decoded, I think it's safe to "trust" foobar.  for example, if you try to convert between lossy formats (mp3 to ogg, for example), it'll give you a warning and tell you why a lossy to lossy transcode is bad.  based on this experience, I would expect foobar to give you some error or warning if it wasn't a lossless conversion from ALAC to WAV.  The folks behind foobar definitely know what they're doing, and since ALAC went open source a few years ago, it's very easy to have ALAC implemented correctly.  So you really should not have any issues.

I did get an error:

Quote
1 out of 1 tracks converted with minor problems.

Source: "F:\_ARCHIVE\Malkmus\2009\malkmus2009-05-08\original ALAC files\09.m4a"
  Error flushing the decoder: Unsupported format or corrupted file

I did some Googling and found this:  http://www.hydrogenaudio.org/forums/index.php?showtopic=65895
and this:  http://www.head-fi.org/t/656315/alac-md5-checksum-inconsistency

I'll email you a file to play with...

Terry
« Last Edit: January 11, 2014, 09:50:12 PM by twatts »
Oh! That! No, no, no, you're not ready to step into The Court of the Crimson King. At this stage in your training an album like that could turn you into an evil scientist.

----------------------

I want super-human will
I want better than average skill
I want a million dollar bill
And I want it all in a Pill