[FFmpeg-devel] GSoC 2009: FFmpeg is in

Luca Abeni lucabe72
Sun Mar 22 18:22:22 CET 2009

Luca Abeni wrote:
>>> After this first step, I believe that there are some bugs to fix (RTCP
>>> RR) and features to improve (better recovery after lost packets, handling
>>> of packets arriving in the wrong order, etc...)
>>> Only after this it will be possible to start adding new features.
>> Update the wiki =)
> Ok; I'll try to write something during the weekend

Sorry; for some reason I've not been able to create an account on the 
wiki (this might be due to a terrible allergy to wikis that I developed 
in the last years :).

Anyway, I searche for some old notes I took about the RTP demuxer... 
Here they are:
 > - The RTCP RR packets generated by libavformat looks very wrong (they
 >   are generated at the wrong rate, contain some useless information,
 >   and miss some important statistics - the comment before
 >   rtcp_update_jitter() is scary...)
 > - The AAC payload parser does strange things, returning many audio
 >   frames together (there is a comment about multiple AU Sections which
 >   seems to imply some bug somewhere)
 > - I suspect that we can set need_parsing = 0 (the RTP demuxer should
 >   be able to properly identify audio and video frames, without using
 >   the parser). But this might require some interface changes and some
 >   code restructuring
 > - The payload header can be used for being more robust against packet
 >   loss (currently, it is just discarded)
 > I suspect there are more problems, but I think the list above is
 > enough to give an idea... In general, I think the whole rtpdec.c file
 > should be carefully checked, comparing the implementation with the
 > relevant RFCs.

And here is something I wrote one years ago about some possible 
qualification tasks:
 > Some possible qualification tasks can be:
 > - Implement some currently unsupported RTP packetization (and
 >   demuxing). For example, H.263 or H.261 video, AMR audio, some audio
 >   codecs used in SIP conferences, vorbis, H.264 SVC ...
 > - Implement a wrapper for libnemesi

>>> I think a nice qualification task can be to get the H.263 depacketisation
>>> patch that has been recently posted and improve it so that it can be
>>> included in svn (not sure if this is too simple - an almost working patch
>>> already exists - but being able to receive H.263 over RTP seems to be a
>>> feature that many people want in svn).
>> Is it already in the wiki?
> The wiki mentions h263 and h263+ support as a goal of the SoC project. 
> I'll add it as a qualification task, with a link to the email containing 
> the patch.
Here it is:

The patch needs some cleanup and fixes (AFAIR it ad some a/v 
synchronisation problems), but this should be a nice qualification task.


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