[Libav-user] Syncing multiple sources.

[Carl Eugen Hoyos]

2019-01-31 12:41 GMT+01:00, Hristo Ivanov <hivanov.ffmailing at gmail.com>:

>> How can I reproduce this (major?) issue with ffmpeg (the application)?
>
> .\ffmpeg.exe -y -loop 1 -r 30 -t 5 -i .\frame.png -filter_complex
> "[0]settb=expr=1/60[tb];[tb]split[s0][s1];[s1]setpts=PTS+1[offset];[s0][offset]vstack[out]"
> -map [out] -c:v h264 -vsync 0 -f mp4 out.mp4

Your original email gave the impression that vstack somehow changed
the framerate of your video from 30 to 60fps.
In this example, it looks as if the input already has 60fps.

Please note that "-vsync 0 -f mp4" is not valid as FFmpeg's mp4 muxer
only support cfr.

Carl Eugen