[Libav-user] help with raw fifo as movie src & overlay

[gstream at ccc2.com]

> Hey, got an idea for you. Try
>
> ffmpeg  -loop_input -i 800x600.jpg -an -s 1288x360 -vf
> 'movie=rtsp\\://192.168.20.112\\:551/channel1,select='gte(t\,1)',scale=640:352[wm];
>  movie=rtsp\\://192.168.20.111\\:551/channel1,scale=640:352[wm2];
> [in][wm] overlay=2:4[in+wm];
> [in+wm][wm2] overlay=646:4 [out]'
> -s 1288x360 -vcodec rawvideo /home/fifo/mpegpipe99.yuv
>
> This should skip first second of video from first source. Amount of
> time can be adjusted (second operand in gte( ).
> I can't test it, so i'm looking forward for your results.
> --
> Andrey Utkin
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> Libav-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/libav-user
>
Hi Andrey,

no joy I'm afraid. it just makes both streams break up and jitter. I
assume its because of the RTSP codec and timestamps not being the most
accurate.
I am keen for advice on constructing the filter you mentioned, are there
any tutorials?

Also a bit of a NooB Q. but is there a way to update/change parameters
once the cmd has been started? In particular if we can get this delay
fixed, I am assuming some form of drift over a 60+ period and we would
need to dynamically adjust this over time.

Thx for the idea and help
Art.