[FFmpeg-devel] custom codec

[Stevens, Andrew J]

I wasn't sure whether this should be in devel, but decided to post here since it is about codecs.

I currently have a program for video analysis using the ffmpeg libs that does the following:
1. open video file (and stream etc.)
2. for each frame: convert to RGB24 (swscale) then use the frame data to compute a bunch of numbers (corresponding to an individual frame)
3. print the numbers in a text file (human readable) two options here:
3a. each set of numbers is a row in the text file
3b. each set of numbers is its own text file

I want to turn this into a codec.
I have read the "tutorial" on media wiki, but I only have a vague idea of what I need to do to create a codec. As of now I only need to be able to "encode".

 What should my frame encoding function look like?
Do I need to write a demuxer?
Anything else I am being ignorant of?

Thanks in advance.
Andrew