Live Video - BW usage peaks when there is no movement in the cam

Hey everybody,

I was testing somethings today and I came across a ¿strange? issue:

- Live Stream (Audio and Video, low resolution...less than 100Kbps).

- The quality of the cam is set to 0 and the bandwidth is set to some value around 150Kbps.

- FPS around 10 and KFI interval around 5

- I've seen this happen to red5 and other media servers as well, and I've seen this happen in commercial products like Adobe Connect (so it's not likely it's because of my crappy test code, he).

- Local LAN dedicated server, so no hw or bw issues.

The stream goes smoothly and the bw usage goes like expected, but if the speaker stands still and stop talking (or if you point the webcam to the wall) the bw starts peaking to almost double the amount it's supposed to.

Has anybody experienced this behavior before?

If I set the bandwidth to 0 and the quality to some value like 80 then the bw does not peak when there is no movement.

Thanks in advance,

Ignacio