[FFmpeg-user] overlay with video offset not starting audio with same offset

[Paul B Mahol]

On 8/29/15, Chad Horton <chorton at hotsalsainteractive.com> wrote:
> I didn't provide my attempts because I was randomly throwing adelay and then
> atrim into my command and nothing worked.   My hope is that someone could
> show me how to do it properly with my current command and adding in the
> atrim and/or adelay filter.

This works for me:

ffmpeg -i ~/matrixbench_mpeg2.mpg -itsoffset 00:00:20.000 -i
~/GoneNutty.avi -lavfi
"scale=640:512,vstack;[0:a]atrim=20[a],[1:a][a]amix" output.avi