[M4IF Technotes] problem with hinted MP4 files

[G Chandra Sekhar Reddy]

Hi All,
As I understand, in the MP4 (MPEG4 File Format) file,
The SampleTableAtom of any track which references some data,
shall contain the mandatory atoms SampleDescription, SampleSize,
SampleToChunk, and ChunkOffset atoms.
All these atoms collectively give the time, size, offset... of every sample
in that Track.
This is the case with all of the normal MP4 files I have gone through.
But the problem comes with HINTED MP4 files.
In the hinted (for RTP) MP4 file (the files I have gone through),
These Atoms in SampleTableAtom of the original track DO NOT give any of
these time, size offset... etc. for any samples
The entry_count field in all of these atoms is 0 (ZERO).
The Atoms in SampleTableAtom of the HINT track (which hints the above said
original track) will have some info regarding that protocol (RTP in my
case).
SUMMARY OF THE STORY:
The problem is that the original track in hinted MP4 files is useless (not
useful without hint track) in this case.
What I expected was that the original track will give all info as usually,
but the optional hint track should help in sending the data through that
protocol.
And there can be multiple hint tracks (for different protocols) for the same
track.
I am missing anything?
Chandra
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Chandra Sekhar Reddy G.,
DSP & Multimedia Group, (DD2),
TATA ELXSI Ltd.,
WhiteField Road, Hoody,
BANGALORE, INDIA - 560048.
TEL: +91-80-8410148, 8411811, 8411812 (Ext:254/255),
FAX: +91-80-8410152, 8411813.
EMAIL: gchandra   tataelxsi.co.in
WEB: www.tataelxsi.com
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