Apple Lossless extension

Question

Level 2

230 points

Apple Lossless extension

If I import an aiff file to Apple Lossless, the file extension is m4a and the "Kind" is MPEG-4, same as AAC.

Is that correct and can someone explain why?

Posted on Oct 26, 2005 11:03 AM

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Answer 1

Oct 26, 2005 4:43 PM in response to Ralphjh

Yes, Ralph, this is correct. The extension of Apple Lossless files is the same as AAC files: .m4a. Both types of files are MPEG-4 files.

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Answer 2

Ralphjh Author

Level 2

230 points

Oct 27, 2005 11:50 AM in response to Michael Allbritton

Thanks for the info. The next question is: How does one determine at a later time whether the file is an AAC file or an Apple Lossless?

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Answer 3

Oct 27, 2005 12:22 PM in response to Ralphjh

You can use Smart Playlists. Create a new Smart Playlist by pulling down File > New Smart Playlist (Apple OptionN on the keyboard) and make the criteria "Kind is: Apple Lossless audio file."

This playlist will then have all the Lossless audio files in it so you can see them at a glance.

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Answer 4

slowth

Level 1

100 points

Oct 27, 2005 12:32 PM in response to Ralphjh

One way to distinguish between the two is to examine the respective bit rates.

The upper limit for AAC is 320 kbps, whereas Apple Lossless could possibly reach 1411 kbps if the source file is difficult to compress. So if a file has a bit rate larger than 320 kbps, then it should be an Apple Lossless file as opposed to AAC.

Apple Lossless can occasionally create average bit rates which are lower than 320 kbps, so it is not always possible to distinguish between the two solely based on bit rate.

One other tedious way is to use the "Get info" command in iTunes for each audio file.

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Answer 5

Ralphjh Author

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230 points

Oct 27, 2005 2:58 PM in response to Ralphjh

Thanks to all for the informative responses. One more question: I imported a particular aiff file to Apple Lossless, then back to aiff. The resulting file is about 8 percent larger than the original file. Does anyone have an explanation for that?

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Answer 6

Oct 27, 2005 4:25 PM in response to Ralphjh

Hm. That should not have happened. Did you add album artwork to the Lossless file?

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Answer 7

Ralphjh Author

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230 points

Oct 27, 2005 4:49 PM in response to Michael Allbritton

No, what I did was set the iTunes Preferences for Importing to "Import Using Apple Lossless Encoder" prior to converting the original file from AIFF to Apple Lossless, then changing the preferences back to AIFF prior to converting the compressed file back to AIFF. In both cases, I used the iTunes Advanced menu to do the conversions.

I'll try it again with a different file and see what happens.

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Answer 8

Oct 27, 2005 4:59 PM in response to Ralphjh

You should have wound up with an AIFF file that was exactly like the original AIFF file. The should have been no difference.

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Answer 9

Ralphjh Author

Level 2

230 points

Oct 27, 2005 5:10 PM in response to Michael Allbritton

OK, I tried it again with a smaller file, a 3 minute song (Frenesi, Artie Shaw) and the result is similar but not nearly as large an increase, only 1688 bytes out of 30 MB, an increase nevertheless.

The original aiff file was 31,599,044 bytes: it resulted in an Apple Lossless file of 12,645,941 bytes (a 60% decrease). When converted back to aiff it was 31,600,732 bytes.

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Answer 10

Ralphjh Author

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230 points

Oct 27, 2005 6:44 PM in response to Ralphjh

The main reason for posting the original question is that I have a large collection of audio files in AIFF format and I am running out of hard drive storage. Rather than purchase another large hard drive (and backup drive), I decided to convert all of the files to Apple Lossless thereby doubling my storage capacity. However that fact that the few files that I converted to Apple Lossless and back to AIFF have ended up with different file sizes troubles me. If someone could assure me that the different file size is normal, I could proceed with my plan without worry.

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Answer 11

Oct 27, 2005 7:29 PM in response to Ralphjh

Ralph, can you describe how you are doing the transcoding? Also, how are you determining that the resulting files are larger than the original file? The AIFF files you get from Lossless files should be exactly the same size as the original AIFF file.

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Answer 12

Oct 27, 2005 8:06 PM in response to Ralphjh

Hello Ralphjh,

Just out of curiosity but what version of iTunes are you using? I remembered an older version of iTunes would cause something like this. This bug was fixed in a more recent release. If you are using an older version, have you tried upgrading to version 6.0.1?

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Answer 13

slowth

Level 1

100 points

Oct 27, 2005 8:20 PM in response to Ralphjh

I just took an AIFF, then converted to Apple Lossless, then converted that back to AIFF...and the file size is identical to the original, even to the byte.

The change in file size you are experiencing is not normal, so let's figure this out. Answering Mr. Allbritton's last question is a good place to begin the troubleshooting.

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Answer 14

Ralphjh Author

Level 2

230 points

Oct 27, 2005 8:22 PM in response to Michael Allbritton

The encoding is done in iTunes. I create a new playlist in iTunes. I drag an AIFF file from the Finder window into the empty playlist window. I set the iTunes Preferences to "Import Using Apple Lossless Encoder." Then, under the Advanced menu, I select "Convert Selection to Apple Lossless." iTunes places the resulting file in a folder named Unknown Album (within an Unknown Artist folder). I then repeat the process with the new compressed file, that is, I add the file to an iTunes playlist, change the Preferences to "Import Using AIFF" and select "Convert Selection to AIFF" under the Advanced menu. I Then compare the 2 AIFF files with the Finder's Get Info menu item. The file sizes are different as I indicated above.

If you have a small AIFF file handy, try it yourself and tell me what you get.

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Answer 15

slowth

Level 1

100 points

Oct 27, 2005 8:28 PM in response to Ralphjh

Please try this: Import a track directly from a cd into your library using AIFF and then convert to Lossless and back again, all while still inside your library but not a playlist...then compare the file sizes.

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