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MPEG-2 demux - coding questions

Posted: 24 Mar 2006 08:17
by nelliekins
Hi everyone.

This is my first post, so please be gentle! :oops:

I have run through dozens of archive entries, but can't find an answer to the following questions:

1. Where in the source code does VLC manage ISO 13818-1 (MPEG-2 TS) PMT descriptors?

2. Is there a (simple) mechanism for implementing preprocessing of an MPEG-2 stream (e.g. from a Kasenna MB server) _before_ it gets demuxed?

Basically, I would like to implement a mechanism for handling of Conditional Access descriptors, ECMs, EMMs, Transport_scrambling_control, etc - but have no idea where to begin looking! `grep -ir descriptor *` in the source tree doesn't find me anything of meaning, so I am a bit stuck!

I believe that VLC uses libdvbpsi to manage the PAT/PMT entries in a stream, but I can't even see any calls into the library made by the VLC code...

If anyone has a clue where I can start on this, it would be greatly appreciated!

Posted: 24 Mar 2006 08:26
by nelliekins
Ok... what a difference a day makes!

I've now managed to find the "modules/demux/" folder (stupidly, I assumed that all source would live under the "src/" folder! :roll: ). I have also found the "ts.c" file under there...

...However, its not particularly well commented and, unfamiliar as I am to VLC's coding structures etc, is rather difficult to follow!

So if anyone can assist me in finding suitable hook points within ts.c (or if thats not the right place, the appropriate file) to provide detection & processing of scrambled MPEG-2 TS streams, it would be greatly appreciated!

Posted: 24 Mar 2006 22:26
by The DJ
Look for CSA in the VLC sources. btw. vlc uses libdvbpsi to decoder specific descriptors.