[Ffmpeg-devel] New/extended filter API discussion

[Robert Swain]

Hello,

I'm interested in working on some filters for use within FFmpeg. The fairly 
recent addition of libswscale suggested to me that, unless it was hacked in, 
there is some sort of filter API currently part of FFmpeg. The natural 
progression from the layout of the code would also lead to the conception of 
something like "libavfilter".

I thought it would be a good idea to approach such a problem by developing an 
LGPL library of filters for inclusion in FFmpeg but allow them to be used by 
other software if possible as is the intent of libavformat and libavcodec.

Some brief enquiries as to the state of FFmpeg containing any sort of filter API 
uncovered that vhook is present for use with video filters but the same does not 
exist for audio. Subsequently the discussion appears to seed with one of two 
implementations - add "ahook" to extend for the possibility of audio filters or 
design some new filter API suitable for multiple applications. Which of these 
would be preferable? Does anyone have any suggestions for design or any 
significant issues for consideration?

I'm willing be a code monkey for this project but I don't quite feel experienced 
or qualified to design such an interface and it's possible that someone more 
experienced with FFmpeg would be better suited to conducting this work.

Kind regards,
Rob