Quote:
Originally Posted by filler56789
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To be honest I'm not quite sure I understand the problem.
When you decode audio it should be decoded using the wave file channel mapping, that's fed to the encoder and it remaps it as required. AAC uses the same channel mapping as DTS by default (at least for 5.1ch). I think in the early days of AAC encoding there were some mapping issues with specific encoders/GUIs, and I kind of remember an issue with Ogg, but I can't remember why. As far as I know it's all a thing of the past. I've never had an issue with AAC channel mapping myself.
I haven't checked every combination thoroughly but the information offered in the post you linked to seems to be correct according to QAAC. If you look at the pics of the command prompt windows
in this post you'll see the default channel order list as displayed by QAAC and in the second pic you'll see it's showing (for 5.1ch audio) the input using wave file channel mapping and the output having standard AAC channel mapping, and all is as it's supposed to be.
It's nothing unique to AAC. DTS and AC3 use different channel mappings by default and you can specify explicit channel mapping. Chances are many of the encoders most of us use have a method of specifying the input channel mapping (the
Aften AC3 encoder does), but I'm not sure about specifying a different channel mapping for encoding. I'm not sure why there'd be much need to fiddle with that anyway.
There's a list of audio channel mappings for the common formats at the bottom of this page:
http://avisynth.nl/index.php/GetChannel
Another list here:
http://en.wikipedia.org/wiki/Surroun...identification