I like to watch Anime and for some reason I can playback certain sub-groups release properly while other's don't. The problem is with 6ch AAC. From my understanding 6ch AAC is like AC3. With 5.1 AC3 the voice is supposed to come out from the center channel while sounds and other stuff comes out from the other 4 channels. The problem I'm having with some sub-groups 6ch AAC is that their voice does not come out from the right channel or their voice sounds muffled in the background.

I'm using the following player and codecs to play the files

TCMP v4.11 build 452
Mastroka Pack Full v1.1.2
I do no use codec packs and only install codecs I need
CoreAAC v1.2.0.575

When I check the AAC properties of other group's releases (a4e & zx) it shows this:
Profile: AAC+SBR
Sample rate: 22050 -> 44100 Hz
Channels 6 -> 6

Ani-Kraze releases show <- the group whose 6ch AAC works properly

Profile: AAC LC
Sample rate: 48000 -> 48000 Hz
Channels 6 -> 6

So my question is, what is Anime-Kraze doing correctly while other sub groups aren't.

Funny thing is, with other groups releases, it plays properly when I load it into Nero Showtime. I also tried it with VLC player but VLC just downmixes it to 2 channels. I wouldn't mind using Nero Showtime since it works but soft-subs doesn't load when using Nero Showtime.

Does anyone have answers to my dilemma?

The only time I ever tried encoding a multichannel aac file myself, I had similar problems... Maybe try something instead of the coreAAC codec. MPC has a built-in aac filter. Also the audio codec part of ffdshow can decode aac.

I tried using ffdshow to decode aac and no avail.

I think the problem lies with SBR because the open source AAC filter does not support SBR. SBR can only be played back on Nero Showtime and no other player.

I really don't understand why sub-groups decided to add SBR to their AAC releases when the open source AAC does not have support for SBR yet.

CoreAAC can decode SBR, so that cannot be the problem and not decoding the SBR part shouldn't cause anything you are describing. It could be they messed up the channel order with encoding.

I take back my earlier assumptions about SBR because I was wrong.

WMP 10 and Nero played these files back properly and TCMP didn't so I narrowed the problem down to TCMP itself.

The problem lies in TCMP's DynEQ which does not support or alters the signal. I did some research and this is what I came up with:

I discovered in TCMP that Dynamic Equalizer is enabled by default and DynEQ either 1) does not support SPDIF, 2) alters the SPDIF signal, or 3) bypasses SPDIF. AAC packets cannot be altered or your sound card will not detect the stream properly. TCMP would not play AAC HE audio properly because AAC HE transmits it's signal through SPDIF and enabling DynEQ in TCMP either alters or disables this transmission, but I suspect it most likely alters the signal because if it disabled it I would not hear any sounds. However AAC LC, I assume, does not use or transmit it's signal through SPDIF and uses software to decode so enabling DynEQ in TCMP has no effect on AAC LC

Once I disabled DynEQ in TCMP all the channels playback properly.

LC/HE-AAC has nothing whatsoever to do with SPDIF. I don't understand the problem (or should I say, the solution).

From your first message this simply seems to be a channel order problem. The channel order in AAC is not the same as the MS channel order. The software needs to reorder the output of the AAC decoder.

Under audio options in TCMP there's a note at the bottom stating: in order play properly AC3 through SPDIF output you must disable the Dynamic Equalizer and Visualization & DSP plug-ins support.

When I read that I assumed DynEQ had some kind of effect on multi-channel streams being played through SPDIF. Afterall, disabling DynEQ fixed my AAC HE audio problem.

What's interesting is that 6ch AAC LC plays properly even with DynEQ on. There has to be something different between LC/HE AAC that's causing me to play AAC HE improperly while AAC LC plays properly. The channel orders seems to be messed up whenever I play files with AAC HE while DynEQ is on, once I turn it off the channels play properly again. Again, I do not have this problem playing AAC LC with DynEQ on, it's only files that use AAC HE I have problems with

That's AC3, not AAC. AC3 is often decoded externally via SPDIF and this requires the data be passed unaltered (and undecoded). As I already said, that has nothing to do with AAC.



It looks like TCMP is just very buggy because there are no relevant differences between HE AAC and LC AAC in this area.

Is is safe to say there is a bug with TCMP's DynEQ? Since it plays LC properly and not HE. Then my question would be, if there are no relevant differences btween LC & HE why does TCMP play one format and not the other?

How can I do it? Does Nero Digital Audio support this? Can I recode the input wav w/ modified channel order e.g. using mencoder? (Clearly I can't pipe it through wine... or can I? Or can I get a linux version somewhere?) Or is it only a playback issue? Can mplayer deal w/ it?

BTW Does AAC couple channels for encoding in case of multichannel?

This might be all stupid, so thx very much.