Streaming 2 cameras at home & with FMS

[GuyM142]

Our robot has 2 lifecam cameras and during the last regional we streamed only one of them at any given time and the driver had to switch between them.

Due to long switch times we now stream both of the at once using this code:
http://www.chiefdelphi.com/forums/showthread.php?t=146054

It works well at home streaming both at 360x240, one at 20 fps and one at 15 fps.
I have 2 questions about that:
1. Where can I see how much Mbps the two cameras take?
2. Is there a possibility that this configuration won't work with the FMS at champs?

Thank you!

[Jaci]

The FRC Driver Station's logs will be able to tell you your bandwidth in Mbps (assuming you are using the provided wireless router in the KOP). Clicking the little gear and 'View Log File' will display the logs, the bandwidth is the line labelled "Wifi Mb" (dark blue)

[Greg McKaskle]

That feature of logging has not been implemented. The signal strength and bandwidth were hoped to be calculated by the radio itself and logged over time, but that was actually with a different radio solution, and it is not being used.

The easiest may be to use the Windows Task manager. Open the Networking tab and in View, add the Bytes per Interval column. There may be a better display elsewhere, but that seems to work pretty well.

Greg McKaskle

[Mark McLeod]

Here's a screensteps on measuring bandwidth:
http://wpilib.screenstepslive.com/s/4485/m/24193/l/144992-measuring-bandwidth-usage

Be aware that image compression can easily cause a video stream to jump from 5Mbs to over 7 Mbps on the real playing field.
We always target keeping our combined robot bandwidth under 2Mbs to start with. It can always be increased later after seeing how it behaves on the actual playing field.

The success of image compression in keeping your bandwidth low is very dependent on the complexity of the image.
Images collected at home, pit or practice field can be quite different from the diamond plate, A/V lit, robot cluttered images you'll encounter on the playing field.