1. Standalone Voctomix Machine

The simplest setup that is able to record a talk is a webcam connected to a PC running Voctomix. This can be done as follows:

Install Debian Stable on a machine. Make the hostname voctomix1. We recommend a minimal install: only the base system and optionally, an SSH server. The netinstall image is good for this.
Edit /root/.ssh/authorized_keys and add plublic ssh key to allow connection from my laptop
Edit /etc/ssh/sshd_config and uncomment the line:
```
PermitRootLogin prohibit-password
```
Install ansible:
```
$ apt install ansible
```

1.1. My laptop

Clone repository:

$ git clone git@salsa.debian.org:debconf-video-team/ansible.git

Edit /etc/hosts and add the IP provided by tp-link router to voctomix1:
```
192.168.0.101 voctomix1
```

Edit inventory/group_vars/all and change:

user_password: xxxxx

dhcp_range: 192.168.0.100,192.168.0.199,6h
firewall_internal_networks: [192.168.0.1/24]
# IPs provived by tp-link router
#domain: video.example.org

time_zone: America/Sao_Paulo

frequency: 60
# for my webcam fifine

voctomix:
  display_system: gl
  previews: true
  mirrors: false
  framerate: 25
  autostart_gui: false
  loop_url: http://192.168.0.101/loop/loop.ts
  bgloop_url: http://192.168.0.101/loop/bgloop.ts

room_name: main

ssh_public_keys:
  - keys:
  - ssh-ed25519....

Edit inventory/group_vars/onsite and change:

conference_name: MiniDebConf Belo Horizonte 2024
conference_town: Belo Horizonte
conference_country: Brasil
ssh_password_auth: true

Edit inventory/host_vars/voctomix1 and change:

irc_room_channel: "#minidc-bh-main"
irc_nick: videoteam_bh_main
room_name: main

#voctolights:
#  - camera: Cam1
#    plugin: serial_dtr
#    port: /dev/ttyUSB0

ingest_sources:
  - description: "webcam fifine"
    video_source: hdmi2usb
    video_attribs: device=/dev/video0
    audio_source: alsa
    port: 10000

streaming:
  rooms:
    - main
  method: rtmp
  rtmp:
    vaapi: false
    location: "rtmp://backend.live.debconf.org:1935/stream/{{ room_name }}"
  dash:
    video_codec: libsvtav1
    audio_codec: libopus
    preset: 8
    video_variants:
      - crf: 23
      - scale: 640x360
        crf: 23
      - scale: 320x180
        bitrate: 192k
        maxrate: 256k
    audio_variants:
      - bitrate: 128k
      - bitrate: 64k
  hq_config:
    hls_bandwidth: 2176000
    video_bitrate: 2000 # kbps
    audio_bitrate: 128000 # bps
    keyframe_period: 60 # seconds
    width: 1280
  adaptive:
    video_codec: libx264
    audio_codec: aac
    variants:
      high:
        hls_bandwidth: 1152000
        video_bitrate: 1024k
        audio_bitrate: 128k
        extra_settings: -tune zerolatency -preset veryfast -crf 23
        width: 900
      mid:
        hls_bandwidth: 448000
        video_bitrate: 768k
        audio_bitrate: 96k
        extra_settings: -tune zerolatency -preset veryfast -crf 23
        width: 720
      low:
        hls_bandwidth: 288000
        video_bitrate: 256k
        audio_bitrate: 48k
        extra_settings: -tune zerolatency -preset veryfast -crf 23
        width: 480
  dump: False
  mix_channels: false

Ansible can be run from a laptop or other external source. This makes testing changes much faster than running it locally. You will require a network that resolves hostnames to IP addresses correctly. It also requires your SSH key to be present in the authorized_keys file for root (this will be the case if your key is in the ssh_public_keys list and you have run ansible before). In this case run:

$ ansible-playbook --inventory inventory/hosts -l voctomix1 site.yml

When it completes successfully, restart the machine.

You should now have a working voctomix machine. Since there is only one input at the moment, you cannot really mix different streams. The next step is to build an opsis machine to get a second input. To do this, you might need to build a gateway machine first.

1.2. Streaming

Streaming to services such as YouTube is very easy using this setup. It requires setting up the stream on YouTube and then configuring Voctomix to connect to this stream.

Open YouTube Live Dashboard.
Change the Name and Description, setting the Category and Privacy as required.
Note down the Server URL and Stream name/key (which will be displayed as a hidden password until the Reveal button is pressed). These will be used to configure Voctomix using Ansible.

Create an Ansible Vault file for the vault password:

$ echo "changeme" > /root/.ansible-vault
$ chmod 600 /root/.ansible-vault

Encrypt the URL and stream name in the form <URL>/<Stream name>:

$ ansible-vault encrypt_string --vault-password-file=/root/.ansible-vault --name=location <URL>/<Stream name>

Edit inventory/host_vars/voctomix1.yml and include the following, changing the bitrates as required:

streaming:
  method: rtmp
  hq_config:
    video_bitrate: 2500 # kbps
    audio_bitrate: 128000 # bps
    keyframe_period: 60 # seconds
  rtmp:
    vaapi: true
    <Output of ansible-vault encrypt_string>
    location: !vault |.....

Rerun ansible:

$ ansible-playbook --vault-password-file=/root/.ansible-vault --inventory inventory/hosts -l voctomix1 site.yml

Once ansible is finished, opening Voctomix and selecting Stream Live or Stream Loop will start streaming to YouTube. If you wish to run more than one room or schedule when your stream goes live, use the Event tab and schedule the stream. Here you can add cameras for additional rooms (one per room).

1.3. Notes

The Voctomix loops are shown on the stream when there is no talk happening. In Voctomix the loop_url is downloaded and used for the Stream Loop button when the stream is blanked. bgloop_url is downloaded and used as the background for Picture-In-Picture mode when the sources do not cover the entire frame. If you have loops to use, put the URL for them here:

voctomix:
  loop_url: http://example.org/loop/loop.ts
  bgloop_url: http://example.org/loop/bgloop.ts