[FFmpeg-devel] about participating in the development of FFmpeg

Vitor Sessak vitor1001
Thu Nov 19 17:55:04 CET 2009

Hi, and thanks for coming up!

sam lewis wrote:
> On Wed, Nov 18, 2009 at 5:47 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
>> sam lewis <sam.lews <at> gmail.com> writes:
>>> I agree that it is proper to choose some simpler task to get fammilar with
>>> the project. On the interesting patches list, I found 'PES packetizer' quite
>>> interesting. I would like to help clean up this patch. Would you please
>>> give me some more information about this patch?
>> It needs svn cp libavformat/mpegenc.c libavformat/mpeg_pes_enc.c
> Sorry, I do not understand what this means. Would you please give me some
> more detailed description?

Normally when one split a file in two, one tries to make in a way that 
tools like "svn blame" still works (i.e., one can trace who committed 
each particular line of code). So they do it by making a copy of the 
file with "svn cp" (that copies both the file and it's history) and them 
remove the duplicated code. See this commit for an example of how it is 
. For this patch you should do something like:

$ svn cp libavformat/mpegenc.c libavformat/mpeg_pes_enc.c
$ patch -p0 < pes.diff

>>> Or should I choose another to work on?
>> I'd just like to add that I believe the "G722 decoder by Chas Williams" might be
>> the simplest task (to start).
> According to the description on the interesting patch list, the thing
> needs to be
> done to clean up this patch seems to be removing the encoder part.
> Any mistakes?

Mostly removing the encoder (it is much easier to get the encoder and 
the decoder committed separately), but also doing the changes requested 
in this review from Michael: 
http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2009-April/067611.html .

>>> As to the RealAudio encoder, I would like to continue working on it but
>>> as a long term task. The RealAudio decoder seems to be contained
>>> in ra144.c and ra288.c. I think it will take me about 1-2 moths to finish the
>>> encoder.

I suggest you start with either 144 or 288 but not both at the same 
time. They are two quite different codecs. See also 
http://wiki.multimedia.cx/index.php?title=RealAudio_14.4 and 
http://wiki.multimedia.cx/index.php?title=RealAudio_28.8 . They have 
links to specifications for a very similar codecs (VSELP and G.728 
respectively) that contain advice on how to write an encoder.


More information about the ffmpeg-devel mailing list