7mb/s, Will it be an Issue?

[Wzup4021]

Does anybody believe the bandwidth limit will be much of an issue? What kind of visual feed resolution/refresh rate should we be able to get after factoring in the control signals.

[Steven Donow]

I don't know of any people having issues with it last season. There's a recommended frame rate for camera transmission which is more than adequate.

However, at some events last year(mainly early weeks), there were instances where the required framerate/compression rate was smaller/different than the FIRST recommended.

[Al Skierkiewicz]

To give you a reference, DTV with multiple MPEG streams, with up to 10 channel audio and data services is limited to 19.1Mb/s. We are broadcasting one 720P HD channel with 8 channels of audio and 2 SAP audio, plus three 640I channels with english and spanish channels plus some data services in our 19.1 stream. So 7 Mb/s should give you no problem. However, if you use a high resolution video with high refresh rate, MPEG4 cameras will eat up a lot of bandwidth. Keep to the recommendations and should have no bandwidth problems.

[Tom Line]

Also, please try to size your use for your actual need. No one needs to see the goals in 720p video with no compression. In the past the FTA's have had to require teams to play with all video streams and cameras turned off because some teams were using far, far too much bandwidth (for no good reason). Use common sense and minimize your usage.

[Joe Ross]

Have you read the FMS White Paper? It includes suggested camera settings. The Control System documentation has instruction for measuring your bandwidth usage.

[magnets]

7 mb/s is not an issue. It's the latency that comes with running near above 4 mb/s, and the fact that you don't always get 7 mb/s, and no matter what FIRST says, having an alliance partner using two cameras WILL lower your availible bandwidth

[vScourge]

For those with past experience, what was the (even estimated) lowest bandwidth you observed? We talking 5 mb/s or < 1 mb/s, etc?

Similarly, what kind of latency should we plan for, worst-case?

[matthewdenny]

How does this compare to previous years? Has it always been 7Mbps, and this is just the first time it has been explicitly stated, or is this a change?

[Joe Ross]

Originally Posted by matthewdenny

How does this compare to previous years? Has it always been 7Mbps, and this is just the first time it has been explicitly stated, or is this a change?

The same as last year. Last year was the first year of an explicit bandwidth limit.

[thmeans06]

Hey FIRST... Gigabit Technology... Just Sayin.

[yash101]

I did a bandwidth test and found that streaming from two cameras with 38% compression, 640, 480, 600 KB/s were following through the network, which equals to 4.8 mbps. That means that the 7 mbps might a problem of you are using two cameras. We used an M1013 and M1011 for this test

[apalrd]

Originally Posted by thmeans06

Hey FIRST... Gigabit Technology... Just Sayin.

The issue is 802.11 WiFi, gigabit would not change anything there. They are already running 802.11N and cannot use more than 1 channel due to the number of fields running at the Championship.

If you honestly need more than 7 mb/s you are doing something wrong.

[Conor Ryan]

Originally Posted by Joe Ross

Have you read the FMS White Paper? It includes suggested camera settings. The Control System documentation has instruction for measuring your bandwidth usage.

There is even more documentation:
http://wpilib.screenstepslive.com/s/...andwidth-usage
(I suggest the second version where you use WireShark)

Think about the driver psychology before the programming, it might be a good idea to put some sort of display on the robot. Like what boom done did.

[Aroki]

Originally Posted by DevenStonow

I don't know of any people having issues with it last season. There's a recommended frame rate for camera transmission which is more than adequate.

However, at some events last year(mainly early weeks), there were instances where the required framerate/compression rate was smaller/different than the FIRST recommended.

At the Buckeye regional we had issues, but it was likely us streaming at a resolution that was to high or them having a lower framerate/compression rate. We ended up just removing the camera.