[FFmpeg-user] Use multiple lavfi input generators

Elliott Balsley elliottbalsley at gmail.com
Tue Jul 24 00:26:27 EEST 2018

Ah, I figured it out!  It works in ffmpeg, not in ffplay.  Now is there any way to make the sine filter output 24bit?  I can convert it on output like this, but I wonder if it would be faster to do it on input instead.

ffmpeg -f lavfi -i testsrc=1920x1080 -f lavfi -i sine=frequency=800:sample_rate=48000 -c:a pcm_s24be ffmpeg.mov

> On Jul 23, 2018, at 2:02 PM, Elliott Balsley <elliottbalsley at gmail.com> wrote:
> I’m having trouble figuring out the syntax for this.  I want to generate a test file using video testsrc and audio sine wave.  I can do both separately, but how can I get both together?
> ffplay -f lavfi -i testsrc=s=1920x1080 (this works)
> ffplay -f lavfi -i sine=frequency=800 (this works)
> ffplay -f lavfi -i testsrc=s=1920x1080 -i sine=frequency=800
> Argument 'sine=frequency=800' provided as input filename, but 'testsrc=s=1920x1080' was already specified.
> ffplay -f lavfi -i testsrc=s=1920x1080,sine=frequency=800
> [lavfi @ 0x7faf0e821400] Too many inputs specified for the "sine" filter.
> testsrc=s=1920x1080,sine=frequency=800: Invalid argument

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