The Carbonio VideoServer is a WebRTC stream aggregator that improves Carbonio Chats‘s performance by merging and decoding/re-encoding all streams in a Meeting.
While the default WebRTC creates one incoming and one outgoing stream per meeting participant, with the Carbonio VideoServer, each client will only have one aggregated inbound stream and one aggregated outbound stream. This applies for both video and audio.
In our simple scenario, 5 people are participating in a meeting.
Without Carbonio VideoServer: each client generates 4x outgoing video/audio streams and receives 4 incoming video/audio streams
With Carbonio VideoServer: each client generates 1 outgoing video/audio stream and receives 1 incoming video/audio stream
4 (1 from each other client)
4 (1 to each other client)
By default, the Carbonio VideoServer uses conservative Codecs (VP8 and Opus) to ensure the broadest compatibility, but more codecs can be enabled. It also splits the Webcam and Screen Sharing streams and reserves the same bandwidth for both.
A properly set up Carbonio VideoServer will supersede the need of a TURN server, provided that all clients can reach the Carbonio VideoServer’s public IP and that UDP traffic is not filtered.
Carbonio VideoServer Installation#
Architecture and Service Control#
A Carbonio Chats meeting is hosted on one mailbox, which also keeps the state of the meeting. It is a responsibility of that mailbox to communicate with a videoserver instance to start a meeting and controlling it.
Therefore, each mailbox has its own connection pool, which can be controlled via the Carbonio CLI. The commands to control the service are straightforward:
Start the connection pool
zextras$ carbonio chats doStartService chats-video-server-connection-pool
Shutdown the connection pool
zextras$ carbonio chats doStopService chats-video-server-connection-pool
Check a connection pool status. This command reports information about the node on which it is executed.
zextras$ carbonio chats clusterstatus isFullySynced true servers <ip_server> online true min_api_version 1 max_api_version 22 meeting_servers <ip_videoserver>:8188 id 123 hostname <ip_videoserver>:8188 status online servlet_port 8090 last_failure local_meetings_hosted 2
The output of this command contains this information:
Should the remote Carbonio VideoServer be offline or unreachable, the status will be offline instead of online.
The API versions supported by the server (
last failureshows an error message (e.g., Unauthorized request (wrong or missing secret/token) or a generic Runtime Exception) if the last connection attempt to the videoserver was unsuccessful. The message is cleared when the connection is successful.
local_meetings_hostedreports the number of meetings hosted on the current mailbox.
Bandwidth and Codecs#
All the commands must be run as the
The administrator can set the webcam stream quality and the screenshare stream quality specifing the relative bitrate in Kbps. The values must be at least 100 Kbps and can be increased as desired.
Higher values mean more quality but more used bandwidth.
carbonio config global set attribute teamChatWebcamBitrateCap 200 is the command for the webcam stream quality/bandwidth
carbonio config global set attribute teamChatScreenBitrateCap 200 is the command for the screenshare stream qualitybandwidth
By default both the webcam bandwidth and the screen sharing bandwidth are set to 200 Kbps.
By default, the VP8 video codec is used. This is to ensure the best compatibility, as this codec is available in all supported browsers, but other codecs can be enabled:
AV1: carbonio config global set attribute teamChatVideoCodecAV1 true
H264: carbonio config global set attribute teamChatVideoCodecH264 true
H265: carbonio config global set attribute teamChatVideoCodecH265 true
VP8: carbonio config global set attribute teamChatVideoCodecVP8 true
VP9: carbonio config global set attribute teamChatVideoCodecVP9 true
Only one codec can be enabled at the time, so before enabling a new
codec remember to disable the previous one using the same command as the
one in the list above but substituting
To enable the H264 codec run:
carbonio config global set attribute teamChatVideoCodecVP8 false
carbonio config global set attribute teamChatVideoCodecH264 true
The audio codec used by the Carbonio VideoServer is Opus. No other codecs are supported, as Opus is currently the only reliable one available across all supported browsers.
Carbonio VideoServer configuration#
It is possible to allow users to add a custom background to prevent showing the real background behind them, to protect their privacy. This features currently works only with the Chrome browser. To enable the feature, execute the following command
zextras$ carbonio config set global teamVirtualBackgroundEnabled true
Users will see a new button at the bottom of the call that allows them to modify the current background.
The following settings influence the audio experience.
The administrator can set the Opus audio quality by setting the sampling
rate (in Hz) in the
teamChatAudioSamplingRate global attribute.
The available values are:
8000 → represents the narrowband bandwidth
12000 → represents the mediumband bandwidth
16000 → represents the wideband bandwidth (default)
24000 → represents the superwideband bandwidth
48000 → represents the fullband bandwidth
The administrator can optimize the audio sensitivity with these two commands:
carbonio config global set attribute teamChatAudioLevelSensitivity 55
carbonio config global set attribute teamChatAudioSamplingSensitivityInterval 10
The audio level sensitivity defines how much the audio should be normalized between all the audio sources. The value has a range between 0 and 100 where 0 represents the audio muted and 100 the maximum audio level (too loud).
By default the value is set to 55, which is also the value suggested for optimal performances
The audio sampling sensitivity interval defines the interval in seconds used to compute the audio sensitivity level. By default the value is set to 2 seconds, this means that the video server normalizes the audio level considering the audio sources of the last 2 seconds.
The value should be at least 0, but it should be set to 10 seconds to provide the best performances.
Carbonio Chats is disabled by default and can be enabled using two
commands, to be executed as the
zextras user. The first is used to
enable the functionality on the Carbonio infrastructure
zextras$ carbonio prov mc default carbonioFeatureTeamEnabled TRUE
The second is used to enable Chats for a given COS
zextras$ carbonio config set cos default teamChatEnabled true
Recording a Video Meeting#
The owner or moderator of a room can record any meeting and make it available for people to watch it later. A meeting can be recorded only once, meaning that an ongoing recording will be unique for that meeting. In case a recording is interrupted, it can be restarted at a later point. Every user will be notified of the ongoing recording, while any moderator in the room can stop it, even if it was started by another moderator, and save it to a file or to the moderator’s Carbonio Files.
Regardless if the recording is terminated by the person who started it or not, a copy of the recording will always be saved in the Carbonio Files account of who started the recording.
This functionality is provided by a specific package, called
carbonio-videoserver-recorder, that must be installed together
carbonio-videoserver. On a Multi-Server, this means that the
package must be installed on each node on which
carbonio-videoserver is installed.
All the instructions below must be executed on every node on
carbonio-videoserver is installed, unless differently
# apt install carbonio-videoserver-recorder
# yum install carbonio-videoserver-recorder
The package installs a service that needs to be associated with the Carbonio VideoServer instance, a task that needs to be executed from the CLI on a Node which installs the Mailstore & Provisioning Role, using a command that differ depending if you already installed and configured the Carbonio VideoServer or not.
If you already installed Carbonio VideoServer, execute this command on the Node featuring the Mailstore & Provisioning Role
zextras$ carbonio chats video-server update-servlet example.com:8188 8090
Here, replace example.com with the domain name or IP on which the Carbonio VideoServer is installed, 8188 the Carbonio VideoServer port, and 8090 (which is the default value) with the servlet port that will be used only for recording.
The value of the servlet port (8090) must
match the one defined in file
the Node installing the Video Server Role.
If you did not yet install Carbonio VideoServer, you can execute the following command on the Node installing the Mailstore & Provisioning Role, which configures at the same time both the Carbonio VideoServer and the recording servlet.
zextras$ carbonio chats video-server add example.com port 8188 servlet_port 8090 secret A_SECRET_PASSWORD
Replace example.com with the actual domain name or IP, 8188
and 8090 with the ports associated with the Carbonio VideoServer and the
recorder, respectively, and A_SECRET_PASSWORD with the value
of the variable
api_secret in file
/etc/janus/janus.jcfg on the Node installing the Video
Server Role, for example:
api_secret = "+xpghXktjPGGRIs7Y7ryoeBvW9ReS8RQ"
In both cases, edit the file
nat_1_1_mapping and write the public IP
address of Carbonio as the value for that variable, for
nat_1_1_mapping = "220.127.116.11".
Configure Carbonio VideoServer Recording#
To complete the setup, you need to execute a few commands as the
zextras user on the node with the Mailstore & Provisioning
Role. First, make sure that the functionality is enabled on the
infrastructure at COS level.
zextras$ carbonio config set cos attribute teamChatEnabled true
You need then to enable the actual recording on the rooms.
zextras$ carbonio config set global teamVideoServerRecordingEnabled true
Finally, allow all users to start a recording.
zextras$ carbonio config set global teamMeetingRecordingEnabled true
In this command, the policy allows every user to record a meeting. It is however possible to enforce this policy at user or COS level, to allow only selected users or members of a COS to record meetings.
Carbonio VideoServer Scaling#
Multiple Carbonio VideoServer can be run on the same infrastructure.
To add a new Carbonio VideoServer to the configuration, run the Carbonio VideoServer installer on a
new server and follow the instructions - the installer will provide
the required commands (
carbonio chats video-server add with the
appropriate parameters) needed to add the server to the infrastructure
once packages are installed.
To remove a Carbonio VideoServer from the configuration, use the
video-server remove command from any mailbox server - this will
remove the appropriate entries from the Zextras Config (manual package
removal on the video server is required).
When using multiple video servers, meetings are instanced on any of the available instances.
The CLI command to manage Carbonio VideoServer installations is :command`carbonio team` with the sub-command
video-serverand the parameters add and remove.
zextras$ carbonio chats video-server add *videoserver.example.com* [param VALUE[,VALUE]]
zextras$ carbonio chats video-server remove *videoserver.example.com* [param VALUE[,VALUE]]
Modify or Move a Carbonio VideoServer Installation#
To reconfigure an existing Carbonio VideoServer instance, simply use the various commands previously mentioned in this Section, then restart the Carbonio VideoServer service.
If you prefer to move the Carbonio VideoServer to a different Node, or need to do so
because for example the current Node must be decommissioned, you first
need to remove the Carbonio VideoServer instance: as the
zextras user run
zextras$ carbonio chats videoserver remove video.example.com
Here, video.example.com is the name of the Carbonio VideoServer instance, that you
can retrieve as the
hostname in the output of
zextras$ carbonio chats clusterstatus
Once done, remove the package
# apt remove service-discover-agent carbonio-videoserver
# dnf remove service-discover-agent carbonio-videoserver