[Libav-user] how to translate avcodec to vfw?

[Anton Shekhovtsov]

2016-08-28 16:36 GMT+03:00 Anton Shekhovtsov <shekh.anton at gmail.com>:

> I am trying to encode with ffv1 codec and write avi file (not using
> avformat, by intent).
> Since vfw codec can only return single block of data per frame I am trying
> to pass AVPacket data and this actually works with small frame size.
> However with bigger frames the produced avi file is invalid (ffplay shows
> all kinds or errors about missing header data).
>
> Looks like the problem is related to AVCodecContext::extradata.
> The description says "encoding: Set by libavcodec". But then what? Does it
> get into muxing somewhere? I could`n find anything relevant in examples,
> ffmpeg.c, avienc.c, mux.c
>
> So can somebody explain the workflow of extradata or more specifically how
> to write it to avi file?
>
> Or maybe there is something else involved in "avcodec to vfw" problem?
>
>
Found it in riffenc.c
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