Hello,
I am trying to create a video device using another video device, adding a 20
seconds extra delay.
Also, i will create on the fly a custom countdown video before my delayed
stream starts.
I create my virtual video device using v4l2loopback:
modprobe v4l2loopback exclusive_caps=1 video_nr=20 card_label="LIVE"
The command writting to file works pretty good (an initial 20 seconds countdown
with bg.jpg background):
ffmpeg -loglevel 43 -y -loop 1 -r 28 -t 20 -i bg.jpg -f v4l2 -thread_queue_size
512 -i /dev/video0 -filter_complex
"[0:v:0]setpts=N/(28*TB),drawtext=fontfile='/usr/share/fonts/truetype/msttcorefonts/Georgia.ttf':fontcolor=yellow:fontsize=40:x=(w-text_w)/2:y=(h-text_h)/2:text='%{eif\:20-t\:d}'[count];
[count] [1:v:0] concat=n=2:v=1:a=0:unsafe=1 [v];[v]scale=852:480[out]" -map
"[out]" -an -pix_fmt yuv420p -c:v libx264 -preset ultrafast s1.mp4
But whenever i try to push the stream back to the the /dev/video20 device, it
works, but the countdown goes real fast (like 10x faster), and then video tries
to catch up and keeps around a 2 second delay:
ffmpeg -loglevel 43 -y -loop 1 -r 28 -t 20 -i bg.jpg -f v4l2 -thread_queue_size
512 -i /dev/video0 -filter_complex
"[0:v:0]setpts=N/(28*TB),drawtext=fontfile='/usr/share/fonts/truetype/msttcorefonts/Georgia.ttf':fontcolor=yellow:fontsize=40:x=(w-text_w)/2:y=(h-text_h)/2:text='%{eif\:20-t\:d}'[count];
[count] [1:v:0] concat=n=2:v=1:a=0:unsafe=1 [v];[v]scale=852:480[out]" -map
"[out]" -an -pix_fmt yuv420p -f v4l2 -r 28 /dev/video20
Any ideas on how to output as v4l2 correctly or achiving what i am trying using
another approach?
Thanks in advance!
--
Jabi
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