Encoding/transkoding/transmuxing
Sum up audio-channels of a DV file:
ffmpeg -i <dvfile> -ac 1 intermadiate.wav ffmpeg -i <dvfile> -i intermediate.wav -map 0:0 -map 1:0 -ac 2 -f dv <dvfile>-dual-mono.dv
Streaming still image
Takes a still image like a jpg or png and you can use it as a source in dvswitch
ffmpeg -loop_input -f image2 -i <PATH TO IMAGE> -target pal-dv - | dvsource-file /dev/stdin
Feedback to secondary-cameramonitor
dvsink-command -- vlc -
Stream from X11 to dvswitch
Remember to adjust resolution to your local screen
ffmpeg -f x11grab -s 1680x1050 -r 25 -i :0.0 -target pal-dv -y - | dvsource-file /dev/stdin