On Fri, Apr 12, 2024 at 01:06:10PM +0200, Dan wrote:
> Hello,
>
> Intringuing this subject from my daughter watching mum doing
> lessons at the computer using her mobile. It came out that from
> her sparkling mind mum need to connect her mobile to the laptop
> (an old 2011 mac) to watch to her student.
>
> Do you think remote the possibility to have some screen mirroring
> functionalities embedded in our favorit desktop environemnt under
> OpenBSD?
>
> I imagine a more *flexible* desk environment where sort of universal
> screen mirroring is allowed among devices exacly how today we can
> do in our livingroom on Samsung or other brand TVs..
>
> -Dan
>
You can use ffmpeg to capture the screen and then multicast the
video/audio stream. You can choose to stream only a specific window by
using `xwininfo` to pick which one first, e.g.:
#!/bin/sh
IP=239.255.0.1
PORT=9000
eval `xwininfo | awk '
/Absolute.*X:/ { print "XOFFSET="$4 }
/Absolute.*Y/ { print "YOFFSET="$4 }
/Width/ { print "WIDTH="$2}
/Height/ { print "HEIGHT="$2 } '`
ffmpeg -f x11grab -s ${WIDTH}x${HEIGHT} -grab_x $XOFFSET -grab_y $YOFFSET \
-framerate 10 -i :0.0 \
-vcodec libx264 -x264-params nal-hrd=cbr:force-cfr=1:keyint=250 \
-preset medium -profile high -pix_fmt yuv420p -tune zerolatency \
-b:v 2000K -minrate 2000K -maxrate 2000K -bufsize 4000k \
-f mpegts "udp://${IP}:${PORT}?ttl=12&pkg_size=1316"
Note: you have to enable multicasting, and consider this as untested.
It's been a loooong time since I wrote and used it. You can adapt it
easily to capture the whole screen. I also have a different version
that uses Xephyr to simulate an entirely new desktop on a smaller
window.
There are a lot of variants for this out there, much more polished that
this. Just search for "ffmpeg screencast", and you're bound to find a
few.
--
