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Topic: iTunes AAC "Killer Sample" (Read 12359 times) previous topic - next topic
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iTunes AAC "Killer Sample"

With this sample the iTunes AAC-encoder has it's problems and so has WMA ('standard' and 'professessional'). 'Professional' does however much better than 'standard'.
I tested iTunes from 4.2-4.9 (Windows) and the 'piff-paffs' in the Background just won't go away ... meanwhile it's encoded by QuickTime 7.02 but the effect it's still there. Not very annoying at 320kbs but still there!
I did not have these problems with MPC/Vorbis/AAC(Real or NERO)/MP3 (not even the iTunes MP3-Encoder!).

iTunes AAC "Killer Sample"

Reply #1 –
Do you have a lossless version for reference?

Edit: Since it doesn't seem to play in anything except iTunes, here's a 1018kb lossless WavPack version (note that this is encoded from the lossy AAC file, not the original). It's actually smaller than the AAC source.

iTunes AAC "Killer Sample"

Reply #2 –
Quote
Do you have a lossless version for reference?

Edit: Since it doesn't seem to play in anything except iTunes, here's a 1018kb lossless WavPack version (note that this is encoded from the lossy AAC file, not the original). It's actually smaller than the AAC source.
[a href="index.php?act=findpost&pid=319575"][{POST_SNAPBACK}][/a]


First I uploaded a Wavpack-File, but I thought it would be easier to use a ALAC-File because people interested in iTunes would probably have iTunes installed.
So no, my upload is the lossless version and the wavpack version should be too.

EDIT: They are bit-identical so choose freely.

iTunes AAC "Killer Sample"

Reply #3 –
You have to upload the uncompressed version for reference.

iTunes AAC "Killer Sample"

Reply #4 –
Quote
First I uploaded a Wavpack-File, but I thought it would be easier to use a ALAC-File because people interested in iTunes would probably have iTunes installed.
So no, my upload is the lossless version and the wavpack version should be too.
[a href="index.php?act=findpost&pid=319591"][{POST_SNAPBACK}][/a]
You misunderstand me. I'm asking for an uncompressed version for reference, not a lossless version of the compressed song.

I provided the WavPack version so people who don't have iTunes installed (like me, except on one PC) can listen to the sample. If this is a global AAC issue (occours with other encoders like Nero or FAAC) then it is of interest to everybody, not just iTunes users. The reason why I would like the uncompressed version is to test other encoders.

iTunes AAC "Killer Sample"

Reply #5 –
Sorry, my first upload here 

Here it is:
[attachment=1680:attachment]

iTunes AAC "Killer Sample"

Reply #6 –
Quote
...the 'piff-paffs' in the Background just won't go away
[a href="index.php?act=findpost&pid=319569"][{POST_SNAPBACK}][/a]
What do you mean by piff-paffs?

I converted the lossless to AAC @ 128 kbps and there is no significant difference between the two.

iTunes AAC "Killer Sample"

Reply #7 –
This WAV file is already full of piff-paffs for me, so let me just double check. Is this the original lossless file or the decompressed result of the already lossy (compressed) file. What we want is the original lossless source file.

Personally I am an Vorbis guy, but interested in this because I am currently doing listening tests to find out my -q value to encode my collection. So I just what to check how does Vorbis fare with this sample.

Gabor

iTunes AAC "Killer Sample"

Reply #8 –
I've tried ABXing this sample with LAME 3.96.1 and --alt-preset 128 (no problems in picking out the encoded sample).

I think I can hear what is meant by piff-paffs. Yes, they are already in the song, but the artifactiing is strange and it sounds like there are extra piff-paffs at this bit-rate. It almost sounds like a different mix rather than artifacting.
daefeatures.co.uk

iTunes AAC "Killer Sample"

Reply #9 –
Quote
I converted the lossless to AAC @ 128 kbps and there is no significant difference between the two.
[a href="index.php?act=findpost&pid=319663"][{POST_SNAPBACK}][/a]


Critical moments are ca. after 4-5 sec and 8-9 sec ... there are some low level elements added. I Just made the ABX test with the  iTunes (4.9/QT 7)encoded version (320 kbs) and got 10/10!
 

iTunes AAC "Killer Sample"

Reply #10 –
Quote
You misunderstand me. I'm asking for an uncompressed version for reference, not a lossless version of the compressed song.

Perhaps you misunderstood him.

The original file, in the first post, is an ALAC file. Lossless. It's not an AAC file.

Now, whether that was created directly from the original source or not, I cannot say.

iTunes AAC "Killer Sample"

Reply #11 –
Quote
Now, whether that was created directly from the original source or not, I cannot say.
[a href="index.php?act=findpost&pid=319691"][{POST_SNAPBACK}][/a]

Yes, it was 

iTunes AAC "Killer Sample"

Reply #12 –
Quote
Perhaps you misunderstood him.
The original file, in the first post, is an ALAC file. Lossless. It's not an AAC file.

Yes, his first reply indicated this. As foobar2000 can't play it, and iTunes doesn't seem to display the format on playback, this wasn't immediantly apparent. I assumed due to the fact the title referred to an AAC sample and it was in the MPEG4 container it was AAC.

iTunes AAC "Killer Sample"

Reply #13 –
I tried "VelvetRealm" again with Itunes 6 ... the Problem remains ... no Problems with Nero's AAC encoder (4.2)