Video conferencing is great when everything works and everyone can see and hear each other! It can also be a pain when things do not work as expected. To be better prepared to troubleshoot a poor quality video conference, there's a few things you'd be well to understand.
Video and audio streams
In a multi-party conference call, a separate video stream and audio stream is sent and received over the internet from each participant to every other participant. By default...
- a call of 2 participants will have a total of 4 video streams (1 sent and 1 received for each participant)
- a call of 3 participants will have a total of 9 video streams (1 sent and 2 received for each participant)
- a call of 4 participants will have a total of 16 video streams (1 sent and 3 received for each participant)
- a call of 5 participants will have a total of 25 video streams (1 sent and 4 received for each participant)
- a call of 10 participants will have a total of 100 video streams (1 sent and 9 received for each participant)
- a call of 30 participants will have a total of 900 video streams (1 sent and 29 received for each participant)
Streams require/consume internet bandwidth
Each video stream and audio stream requires an amount of bandwith (data being received and sent over the participant's internet connection).
- Hi-quality video streams use significantly more bandwidth than low-quality video streams
- With each additional conference participant, more internet bandwidth will be consumed on each participant's internet connection.
- The internet connection of each conference participant will have a finite capacity and will have only sufficient bandwidth to cope with a given number of video streams. Some participants with high capacity connections will cope with many streams, whilst those with low capacity connections will cope with less.
- Conference participants are likely to have different internet connection capacities. Those with fast-fibre or 5G mobile connections will cope very well with multiple streams (lots of exchanged data), whilst those with older connections or 3G mobile may struggle with more than a few.
The conference server attempts to optimise the conference experience for all participants in the call. It constantly monitors the network connection of each individual participant, and automatically modifies video streams to each individual.
- If the conference server detects the bandwidth of a participant is nearing capacity (and will therefore be unable to cope with additional streams), it may reduce the quantity and quality of the video streams being sent to the participant.
- If the conference server detects a participant has a very low capacity bandwidth, it may cut all video to and from that participant, and steam only the audio. For a call, it is better to hear and not see, than to see and not hear.
- In the case of a low capacity connection, the participant will hear the audio of other participants, but will not see their video streams. Instead, the participant will see a blank video placeholder for each of the other participants, showing only their names or initials. Note: the participant will still see their own video, as no bandwidth is required to display video from the device camear directly on the device.
- Other participants will not see the video streams of such participants with low internet bandwidth. Instead, they will see a blank video placeholder that displays their name or initials.
- In a confernce, participants may be presented with a mixture of the high quality video streams from other participants that have a good internet connection, and blank video placeholders for those with a poor internet connection.
- Where participant connections have insufficient bandwith, or server resources are stretched, the conference server may also dynamically reduce the number of video streams being sent, instead prioritising the video streams of those who have spoken most recently. The streams of others, perhaps quieter participants will be cut and replaced with blank video placeholders. In such cases, the conference view will change as different participants speak.
When joining a conference, each participant must give permission to their browser (Chrome, Edge, Firefox, Safari, etc) to use the device's camera and microphone. If permission is not given, the browser is not able to share video or audio streams.
Modern laptops, computers, phones and tablets often have more than one camera and microphone. Whilst the conference service attempts to choose an appropriate camera and microphone, conference participants are advised to go to settings in the conference screen and select the desired camera and microphone. See our Webinar Room user guide for more information.
If the correct camera and microphone are not set, the participant's video and audio streams will not be shared.
Do I have sufficient bandwidth at my device?
The amount of available bandwidth will be determined by the capacity of the connection supplied by the internet provider, minus any bandwidth being consumed by other users on the same network (eg others playing video games, streaming movies or on video calls).
- Available bandwith of 3 mb/s will just about cope with a conference of 3 or 4 participants. With more participants, expect streams to be cut.
- A dedicated bandwith connection of 80 mb/s (ie no other users on the network) will cope well with a conference of 20+ participants. However, if other participants have a slower connection, video streams may still be cut.
Have I given permission to my browser (Chrome, Edge, Firefox, Safari, etc) to access my device's camera and microphone?
If not, no video or audio will be streamed. See our Permissions help guide for more information.
Have I set the conference service to know which camera and microphone to use?
Modern devices often have more than one camera and microphone. Use the settings tool to ensure the conference service knows which camera and microphone to use. See our Webinar Room user guide for more information.
Do I have proxy settings issues?
Schools and corporate networks often have a proxy that polices the network. Proxies often block the exchange of data with unknown services. Proxies will need to be configured to allow exchange of data with our conferencing servers. See our user guide for more information.