[Mp4-tech] Encoding information in MP4 file

[Adam Potolsky]

Good day,
In continuing work on MP4 file, I have found that there is more data that I
need to gather form the MP4 files and I am having difficulty finding this
information. In particular, I am hunting down a definitive way to know the
specific encoding used for the video and audio channel. In the case of an
MPEG4-P2 track, I want to know which Profile was used. (Simple Profile,
Advance Simple Profile, etc.) I have looked at the 'stsd' atom and it looks
like the "compressor" name can be set to 0 for size so this seems an
unreliable source for this data. In the 'ftyp' atom, there appears to be the
data I might be able to use, however, I'm not sure of its reliability in
terms of what I want. 
For example: 
... ftyp3gp6....
3gp63g2aisomavc1
..&.moov...lmvhd
.
.
.....stbl....sts
d............avc
.
..*avcC.B...!..'
B....m.... ...Dx
7474  .....(....
Uses H.264 encoding, but the 'ftyp' doesn't state that explicitly.
Is there a way to tell the specific encoding box data?
If so, how, and If not, can anyone recommend another way to find this
information out?
Thank you in advance for you assistance,
Adam Potolsky
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