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About Limiting TrueConf Server to 36 On-Screen Users

August 7, 2015
Alina Krukova

Alina Krukova

36 on 36 multipoint video conferenceOne of the major criteria in choosing a video conferencing solution is the number of on-screen users. Modern customers want to interact with all participants to the conference though it is not always possible or reasonable.

The maximum number of on-screen users in symmetric conferences (where all participants can see and hear each other) in the TrueConf video conferencing systems is 36. Let’s consider the reason for this restriction.

1. Human factor

The element of distraction is an issue in large conferences, where participants can lose track of the conversation due to short latencies and the difference in signal delivery. Sometimes two participants start talking at the same time and when they realize it, they stop talking and after a few seconds, and begin talking again. It is hard to stick to the norms of speech etiquette due to 300-500 ms delays.

Unfortunately, sometimes it is impossible to decrease the latency. If you are struggling with delays, try not to interrupt your interlocutor and express your wish to say something by, e.g. raising your hand in front of the camera. Many video conferencing solutions even offer a special button for this purpose.

With the number of participants exceeding 36 users, the conference will turn into chaos and you will lose control over it. Therefore, it makes sense to appoint one of the users as a moderator (usually the conference host carries out this role) who would allow others to speak by turns. TrueConf users may leverage a special mode called virtual meeting mode, read more about it below.

2. Hardware requirements

Large number of participants of a symmetric video conference in software video conferencing solutions means increased requirements to user’s endpoint, and connected hardware endpoints increase load on server hardware.

In software video conferencing systems, each participant of the conference receives a set of streams. Simultaneous decoding of 16 or more streams represents a significant challenge to the user’s endpoint, even though these streams are of low resolution. It’s easier to decode one 1080p stream than 16 streams each delivering 240p resolution. MCU systems (usually hardware video conferencing systems) don’t have such disadvantages as the server (MCU) overtakes the computing workload.

However, the price per HD port on MCU systems is significantly higher than the price of a modern PC or laptop that would cope with decoding a larger number of streams. And the resolution of the video streams transmitted by MCU is limited to 1080p, while the stream resolution in TrueConf systems can easily reach 4K. Therefore, there is little point in purchasing hardware video conferencing solutions for large conferences.

TrueConf solutions are designed to process a large number of streams. Year by year, we increase the number of on-screen users as PCs and mobile devices become increasingly powerful. Currently, the number of streams is limited to 36 for PCs and to 9 for mobile devices.

3. Bandwidth requirements

The growing number of on-screen participants imposes higher requirements to inbound bandwidth on the video conferencing server or MCU. Widely used Gigabit Ethernet eliminates the bandwidth problem in corporate networks, but not in cloud communication. Therefore, we have limited the number of on-screen participants in the dedicated server solution TrueConf Server to 36 and in the cloud solution TrueConf Online to 9 participants.

It’s worth noting that the bandwidth requirements for SVC-based software solutions (like TrueConf) differ little from requirements for hardware video conferencing systems, so you don’t have to worry that each participant will receive all 36 streams in the original resolution. On the contrary, each participant will receive streams in the resolution he sees on the screen, regardless of his endpoint. Please see the bandwidth requirements for different types of video conferences.

What if I need to interact with a larger number of users?

If you want to conduct video conferences with more than 36 participants, we recommend using a virtual meeting. The maximum number of participants in a virtual meeting is 250 users; 4 participants can simultaneously act as speakers (all other participants can see and hear them) and the rest of the participants act as spectators. The conference owner can designate any user as a speaker in any moment.

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