Ok, I have a nice MP4 test file that's audio only, AAC-LC, that I'm parsing apart with qtdemux from gStreamer and supposedly the file is encoded as AAC-HE.. but my decoder isn't getting any information that tells me that (I'm getting 2 bytes of ESDS that says AAC-LC, 16KHz, mono).
Is there a box somewhere in the MP4 file that has the additional encoding information beyond what is in the ESDS? And (additionally) what part of the spec describes the ESDS box in the MP4 container?
Sorry to be clueless here, I have about 50 PDFs of spec and the ones I thought should have it.. didn't.
All help appreciated.
..ed..
Full Version: Determining HE/HEV2 from MP4 file?
What is in the ESDS is described in the audio specification (14496-3). Given that it is only 2 bytes you're probably dealing with implicitly signalled HE AAC data (so signalled just like LC AAC). You will not know that it is HE AAC until you decode 1 frame.
QUOTE(menno @ Jul 1 2008, 15:49) 
What is in the ESDS is described in the audio specification (14496-3). Given that it is only 2 bytes you're probably dealing with implicitly signalled HE AAC data (so signalled just like LC AAC). You will not know that it is HE AAC until you decode 1 frame.
Ok, that makes total sense to me. Looks like I'll have to go talk to the decode folks about this! Thanks for the reply and the spec number!
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