[FFmpeg-devel] Help deciphering AAC-LATM in DVB

Nico Sabbi nicola_sabbi
Thu Oct 4 13:13:48 CEST 2007


Hi,
I'm trying to decipher how AAC in LATM format is stored in DVB 
streams, but many informations seem to be lacking.
Reading ETSI 300-468 v. 1.1.1 there's an AAC audio descriptor
that doesn't explain what's the meaning of AAC_TYPE byte:
it only says that it indicates whether the stream is AAC or HE-AAC,
but how to decode that byte?

Second question: how can I find out the values of muxConfigPresent
and epConfigPresent? I guess they should be in the additional_bytes
in the AAC descriptor, but in the samples I have those bytes aren't 
even present (the descriptor doesn't include them).

Third question: I guess and hope that LOAS isn't used, is it?

Does anyone have any experience with this abominable shit?
Any help is welcome.
Thanks,
	Nico




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