Usage question: How many Video feeds can I have running in my meeting room at once?
Answer: Let’s consider a working example around the bandwidth utilization of six Video cameras in a single meeting room consisting of one host and five participants. This working example may be that a of an interactive management meeting or of a college classroom where multiple students interact in a small group session using their webcams. From an examination of this example, you will be able to calculate video camera utilization parameters for other meetings whether they be larger or smaller ones.
To help illustrate what I mean, see this picture from our Connect 9.1 Release Notes
Each of our six webcam-wielding clients is connected to the server and will receive five video streams from the server (N-1).
Lets calculate first the number of streams outbound: 6 x 5 = 30
Lets also consider the 6 publishing streams from each client to the Connect server for a total of 36 total streams to support the Connect Video pods.
Now lets calculate the amount of bandwidth used by each stream; here you have power to decide how much bandwidth is to be used by each stream as there are many variables that Adobe Connect puts in your control:
In your meeting room, as a host, click Meeting > Preferences:
Under Meeting > Preferences, there are two important options that you are going to adjust – Bandwidth and Video:
The size of the video streams commensurate with each webcam instance will depend on how you configure these settings.
Following our example, if you go with the settings that I have depicted in the screen captures above to support the 6 Video feeds in a single meeting: DSL Bandwith and Standard Video quality = 213 kbps per stream:
36 streams x 213 = 7668 kbps or 8 Mbps for the 6 separate cameras.
There are other variables to consider as well. Building on our example, let’s say you also want to use VoIP:
DSL VoIP = 22 kbs x 36 = 792 kbs or 1Mbps (rounded up) additional bandwidth needed.
There are other ways to optimize: the video streams are always larger when clients use the Flashplayer in a browser rather than using the Connect Meeting addin. The Connect addin uses the ON2 codec and is far more economical when it comes to bandwidth utilization. For each client running without the Connect addin it is prudent to plan for an additional 50% for each of their Video streams. To avoid this additional bandwidth consumption, send out a link with the Adobe Connect Addin prior to your meeting and encourage clients to install it. It is a small modified version of the Flashplayer:
Another variable to consider that when the Video instance sizes are smaller, Connect adjusts to a lower publishing resolution to save some bandwidth. Unless you are sure the clients have the addin, the final planning number for our 12 webcam meeting is:
300 kbps for each stream (assuming that the addin will not be ubiquitous) x 36 stream = 11 Mbps + 1 Mbps for VoIP = 12Mbps.
Presenting a PowerPoint or a PDF that is uploaded to the Meeting room does not add to the overhead. Chat, Notes and Whiteboards are also insignificant with reference to bandwidth impact.
To drill home the point and procedure, let’s try the same exercise with 12 concurrent interactive collaborating Video feeds:
- Each of our 12 clients is connected to the server and will receive 11 video streams from the server (N-1).
- Lets calculate first the number of streams outbound: 12 x 11 = 132
- Lets also consider the 12 publishing streams from each client to the Connect server for a total of 144 total streams to support the Connect Video feeds.
- Following this larger example, if you go with the settings that I depicted previously in the screen captures above to support the 12 Video feeds in a single meeting: DSL Bandwith and Standard Video quality = 213 kbps per stream:
- 144 streams x 213 = 30672 kbps or 31 Mbps (rounded up) for the 12 separate cameras.
- DSL VoIP = 22 kbps x 144 = 3168 kbs or 3Mbps additional bandwidth needed.
- 300 kbps for each stream (assuming that the addin will not be ubiquitous) x 144 stream = 43Mbps + 3 Mbps for VoIP = 46Mbps.
Hopefully these exercises help with your planning for large successful meetings. There are other variables to consider such as Screen-Sharing and we will touch on those in a subsequent blog article. Consider, for example that when you are pushing the limits of your network, audio is usually given QoS priority over video.
Note: These examples assume that each client has a separate connection with the server and the Connect Edge servers are not remote to consolidate streams; they are not geographically distributed; they are collocated with the origin servers as is commonly the case so that each of the 12 attendees are receiving 11 subscribed streams from the data center (N-1).
Note also: Regardless of how many cameras you have active, the Connect addin will use one TCP connection over port 1935 (and encrypted on 443) that carries all the streams.