I am developing videocall application using RTMFP.
I have encountered a problem that I can't use whole bandwidth of the connection.
I got 4Mbit/512kbit, through VPN but the video is delivered at around 400-600kbps, delivering poor quality.
When I switch to a HSDPA connection, which has potentially lower capabilities, the video looks much, much better. It is achieving up to 1.2Mbit (around maximum needed for my video settings).
I am guessing that Flash is trying to determine some network parameter and makes the limit at some bandwidth. But what parameter is that? How I can tweak the connection to achieve better video quality?
I can use the whole bandwidth (4Mbit) between same peers by using some testing software, like iperf.
I am using Flash 11.4.402.278.
I would be very glad for any hint.
I have figured out that the main difference my connections is the available upload speed.
My VPN has 512up, and HSDPA has 1024up.
I wasn't thinking that it is such a difference, because I was sending only up to 250kb/s, using only 50% of the upload.
To describe problem more briefly:
static video takes around 450kB/s, when video is moving, it can take up to 800kB/s
When I'm connected to the 512kbs upload wire, the receiving video is getting choppy when video is getting higher.
I got bufferTime=0 to ensure minimum latency.
Is there any relationship in available upload and download speed? Does the video receiving client is sending back some sort of info about what he gets?
Can I alter this relationship somehow?