[M4IF Technotes] multiple audio tracks into an mp4 file

[Cyril Concolato]

Hi,
> I found what the problem was. It is not yet what I want it to be, but
> for research it was sufficient. What I did first was different updates
> of OD's at the time that I updated the scene. Now I update all the OD's
> from the different tracks at time 0. The problem I have for the moment
> is that all tracks internally start playing from time 0 and when I do an
> update of the scene at time 15000, the second track is already playing
> for 15s. This is probably because I update all the OD's at time 0.(??)
This is definitely a bug, it is not because you update an OD at some
point in time that the associated medias should start at this same point
in time. The starting and stopping of medias is controled by the scene.
> Now I am looking for a way to convert a textual description (something
> like bifstext) into a BIFS and OD track, not immediatly an mp4 file.
> (probably I need to use BIFSenc from the standard reference software?)
Yes you can do that or use mp4tool to create an mp4 file and then use
the -export option of mp4tool to extract the tracks you want to have.
The advantage of the second method is that you will get a file
containing the media (bifs or od) plus a file containing the
DecoderConfigDescriptor and a file containing some hints about the media
AUs like DTS, CTS, size of the AU, RAP ...
> I'm using Realplayer One with the envivio plugin, also winamp with an
> mp4 plugin (only audio) and Quicktime 6.
I now that the Envivio plugin has some bugs regarding OD updates so that
might explain the bug you had with the first scene.
Cyril
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