Hello everyone,

I found an issue with Nero AAC (nero 6.3.0.2 - Foobar says tool=Nero AAC Codec 2.6.1.1),

it applies only to AAC High-Efficiency profile (probably)


I think it's easy to reproduce.

If you seek track about 10 seconds ahead and then seek back 5 seconds it starts to sound different - it's some kind of noise/hiss - sometime louder sometimes not.

It doesn't depend on player, I test it on foobar 0.7.7a with foo_nero.dll and Winamp 2.91 with in_mp4.dll (2.0 rc3).

sample is here (180kB) so all of you could try and confirm (or not).

Thanks.

Confirmen in foobar2000 at least. I have no idea what causes this. I think it has something to do with the SBR decoder (considering the hiss is in the upper frequencies) but this is all just speculation.

Edit: In all the tests I've done the hiss seems to stop at just over 9 seconds into the song (no matter where you seek back to).

Hmm that's just weird. I also confirm the problem. The sound is like some sort of high pitched fast ringing.

I confirm the issue with your sample: there's a clear ringing when seeking back to sec. 2-3 from sec >11. It stops at about sec. 9.
I checked with foobar2000 and Winamp 5; iTunes (no SBR support) did not product any artifact when playing the sample. I think it's quite reasonable to say that it's a SBR matter.

I didn't manage to reproduce the issue with other tracks; who knows, maybe SBR has a strange hate for Kurt...

It's not Nero AAC issue, it's a problem in FAAD2 with aac-he which appears sometimes you seek the stream. I've reported this problem some time ago, and Menno knows about it.

Thanks.