ffplay -f lavfi -graph testsrc2=d=1[out0];sine=d=1[out1] test.mp4
works fine. But the same arguments for
ffmpeg (instead of
ffmpeg -f lavfi -graph testsrc2=d=1[out0];sine=d=1[out1] test.mp4
produce only the error
[NULL @ 00000000006934c0] Requested output format 'lavfi' is not a suitable output format test.mp4: Invalid argument
What's wrong with it?
From the FFmpeg documentation for the lavfi:
Currently only video data is supported.
It seems that's not true nowadays, at least
ffplay works fine with audio (see my first command).
Or I incorrectly interpret this sentence?
But just in case I tried using the filtergraph
testsrc2=d=1[out0];testsrc=d=1[out1] instead, with the same results —
ffplay — OK,
ffmpeg — the same error.