[FFmpeg-user] Detecting signal change on Decklink devices

Chris Bisset chris at gurucomputing.com.au
Mon Sep 10 01:53:03 EEST 2018


I’ve done some searching, but can’t seem to find an answer for this. If I
set up a stream in ffmpeg with a decklink card as the source (autodetecting
input), that works fine. If I then change the source (from 1080p30 to
1080p25, for example), the stream continues as a colour bar (as if the
signal did not return). The only indication that there was a change is a
single dropped frame. I can (theoretically) crash ffmpeg on this drop and
restart, but I would prefer not to have ffmpeg stop every time a frame is

Is there a better method of detecting a signal change? I do not need ffmpeg
to gracefully handle it (I am OK with stopping and restarting when this
happens), but I do need a way to catch when a different input is plugged in.

Chris Bisset
E: chris at gurucomputing.com.au
M: 0422 365 324

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