[FFmpeg-user] [SOLVED] taking audio and video inputs from different devices

Ricardo Kleemann ricardo at americasnet.com
Sun Aug 2 07:14:05 CEST 2015

Thanks Carl,

One of the things also that was happening was insufficient thread queue size. I was seeing this error:

Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)

I’ve been able to get audio and video sync’ed properly, video coming from one input device and audio from the other as follows:

ffmpeg -y -thread_queue_size 512 -f decklink -vsync 0 -i 'UltraStudio Mini Recorder at 12' -thread_queue_size 512 -f avfoundation -async 1 -i "none:1" -c:v libx264 -preset veryfast -vf scale=720:405 -c:a libfdk_aac -ac 2 -ar 48000 -map 0:1 -map 1:0 out.mp4

So far things seem to be working ok


> On Jul 28, 2015, at 9:04 AM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> Ricardo Kleemann <ricardo <at> americasnet.com> writes:
>> ffmpeg -f avfoundation -i "none:1" -f decklink -i 
> You could try to move -vsync 0 in front of the 
> first input.
> If this does not help, it may be possible to insert 
> the setpts filter to make the timestamp of the first 
> frame "0" (so it matches the audio starting timestamp).
> Carl Eugen
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