Quote:
Originally Posted by filler56789
Surely you haven't understood the problem. I am not talking about channel *mapping*, I'm talking about (properly-flagged) channel *layouts*. I still see no good-reason why AAC does not (or should not) support 2.1, 3.1 or 4.1, for example.
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I thought it did, it's just that none of the encoders we use have bothered with channel layouts that are obsolete or nobody will use. I'm not even sure if I can recall any discreet 2.1/3.1/4.1ch audio in the wild. Do you actually have a need to encode it?
8.5.3.2 Explicit channel mapping using a program_config_element()
Any possible channel configuration can be specified using a program_config_element().There are 16 available PCE’s, and each one can specify a distinct program that is present in the raw data stream.
Not that I have any 2.1/3.1/4.1ch audio, but I created some for testing and I've at least managed one proof of concept sample. Some encoders spat out all the non-supported formats. Some took (for example) 4.1ch audio and converted the LFE to a centre channel. That's assuming my assumption of what would constitute 4.1ch audio is correct (front stereo, rear stereo and LFE) otherwise maybe it's not the encoder's fault, but it'd be better to refuse to encode it rather than only appear to encode it correctly.
NeroAAC is quite 2.1ch friendly though. That's the one exception so far. For the other formats it outputs them using the default layouts, but for 2.1ch it was co-operative. Unless my concept of 2.1ch is wrong....
