Voctomix

Voctomix ist ein Softwaremischer der es uns erlaubt auf Konferenzen HD-Recording und -Streaming anbieten zu können. Voctomix wird aktuell von mazdermind fürs VOC entwicklet und ist gst-switch's kleine Schwester. Sie lebt im Git unter git@c3voc.de:voctomix und read-only auf Github.

• Voctomix Lecture at FROSCON12 by Mazdermind
  • slides

The Installation on VOC Machines (Encoder-Cubes and Mixer-Notebooks) is managed through Ansible. The Ansible Deployment creates the following Things on the Encoder-Cubes:

• Source of last Release in /opt/voctomix/release
• Config-File for Voctocore in /opt/voctomix/voctocore-config.ini
• Scripts to source/sink/playout Video-Content into/out of the Voctocore in /opt/voctomix/scripts
• Systemd-Units in /etc/systemd/system/*.service
• A System-Status-Script in /usr/bin/voctomix-status

Ansible always resetd the Setup to a default configuration, where all SDI-Ports are used as Campera-INs, no Playout is active and all Supporting-Scripts are enabled. Ansible generated the following Systemd-Units for Voctomix:

All Supporting Units are WantedBy=voctocore.service as well as the request Requires=voctocore.service and After=voctocore.service. This means:

• The Supporting Units only start up when the Core has successfully started up first
• When enabled, the Supporting Units automatically start up when the Core is up
• The Supporting Units go down when the Core goes down

In practice this means, that to restart the whole chain, you can do:

sudo systemctl restart voctocore.service

Stop recording at night and schedule re-start in the morning:

for i in 1 2 3 4 5 6 41 42; do echo "10.73.${i}.3"; ssh 10.73.${i}.3 'sudo systemctl stop recording-sink.service'; done
for i in 1 2 3 4 5 6 41 42; do echo "10.73.${i}.3"; ssh 10.73.${i}.3 'echo "sudo systemctl restart voctocore.service" | at 09:00'; done

Similar to stop or start everything you can use

sudo systemctl stop voctocore.service

and

sudo systemctl start voctocore.service

To see which units are actually started, you can call

voctomix-status

To Reconfigure a Decklink-Duo Port as Playout, in order for it to survive a restart/reboot, you can do:

sudo systemctl disable decklink-source-decklink-sdi-2.service                                                                                                     sudo systemctl stop decklink-source-decklink-sdi-2.service                                                                                                        

sudo systemctl enable stream-to-decklink-sdi-2-playout.service                                                                                                   
sudo systemctl start stream-to-decklink-sdi-2-playout.service  

If you leave out the enable/disable the change will be temporary and restarting the voctocore-Unit or the encoder-Cube will reset the change.

Similar to enable Playout to the Framebuffer, you can do:

sudo systemctl start stream-to-framebuffer-playout.service                                                                                                        sudo systemctl enable stream-to-framebuffer-playout.service

Leaving out the enable/disable the change will also here be temporary.

Playout to the Framebuffer can always be interrupted by funny tty0 printouts at any time :) Also think about whether you want to playout the Program-Output (before the Streamblanker) or the Streaming-Output (after the Streamblanker).

Creating a background for the supersource from an image file

ffmpeg -loop 1 -i background.png -f s16le -i /dev/zero -ar 48000 -ac 1 -r 25 -t 00:01:00 -s 1920x1080 -c:v mpeg2video -q:v 0 -aspect 16:9 -f mpegts bgloop.ts

Creating a background for the supersource from a MP4 file in correct resolution

ffmpeg -i bgloop.mp4 -filter:v fps=25 -c:v mpeg2video -q:v 0 -aspect 16:9 -f mpegts bgloop.ts

To see the Output of the various Units, you can use a command like this:

journalctl -au decklink-source-decklink-sdi-2.service  

Alternative version:

journalctl -a -f -u  grabber-source.service

Some Useful Control-Commands when you only have a Shell (see also example-scripts/control-server: For more details see https://github.com/voc/voctomix/blob/voctopanel/voctocore/lib/commands.py

echo set_audio cam1 | nc -q0 localhost 9999
echo set_audio cam2 | nc -q0 localhost 9999

echo set_composite_mode fullscreen | nc -q0 localhost 9999
echo set_composite_mode picture_in_picture | nc -q0 localhost 9999
echo set_composite_mode side_by_side_equal | nc -q0 localhost 9999
echo set_composite_mode side_by_side_preview | nc -q0 localhost 9999

echo set_stream_blank pause | nc -q0 localhost 9999
echo set_stream_live | nc -q0 localhost 9999

echo set_video_a cam1 | nc -q0 localhost 9999
echo set_video_a cam2 | nc -q0 localhost 9999
echo set_video_a grabber | nc -q0 localhost 9999

echo set_video_b cam1 | nc -q0 localhost 9999
echo set_video_b cam2 | nc -q0 localhost 9999
echo set_video_b grabber | nc -q0 localhost 9999

here you can see the commands together with replays from the core

=> set_video_a cam1
<= video_status cam1 cam2

=> set_composite_mode fullscreen 
<= composite_mode fullscreen
<= video_status cam1 cam2

=> set_composite_mode side_by_side_equal
<= composite_mode side_by_side_equal
<= video_status cam1 cam2

=> get_config
<= server_config {"stream-blanker": {"sources": "pause,nostream", "enabled": "true"}, "DEFAULT": {}, "side-by-side-equal": {}, "fullscreen": {}, "side-by-side-preview": {}, "mix": {"sources": "cam1,cam2,grabber", "videocaps": "video/x-raw,format=I420,width=1920,height=1080,framerate=25/1,pixel-aspect-ratio=1/1", "audiocaps": "audio/x-raw,format=S16LE,channels=2,layout=interleaved,rate=48000"}, "previews": {"deinterlace": "false", "enabled": "false"}, "output-buffers": {"mix_out": "10000"}, "picture-in-picture": {}}

=> get_video
<= video_status cam1 cam2

=> get_composite_mode
<= composite_mode side_by_side_equal