I have some aac raw data from an mp4 file which does not have moov header. I want to know the number of samples in this data and size of each sample. I have the decoder specific info as well. After searching I have found out that aac samples in m4 files does not have ADTS header, they are just CPE/SCE. I want to know the size of each CPE/SCE.
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For what I know AAC frames does not encode their own size so usually the framing is provided by a container. That said with some luck and some heuristics maybe you can guess the start of each frame, e.g. looks for 0x01 (SCE with instance tag 0 and part of global gain field) or 0x2? (CPE) and usually the samples don't very that much is size.
Mattias Wadman
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