Quote:
Originally Posted by jhersh
It looks like what they really said is no to UDP... can you make it work over TCP?
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Sure, but we think that a lot of the slowness was caused by TCP. For example, if a frame of the video being transmitted gets screwed up, it's not that big of a deal using UDP, especially if you have a high framerate. You can just drop the frame and wait for the next one (no big deal if you're getting a good 20 of them every second - the user will barely notice). If we use TCP and the same thing happens to a packet, the receive() function stops the entire program execution, sends a request to resend the packet, and waits for the packet to get sent again, all for just one frame (or even just one part of a frame). You're making the entire system, which could be better spending its time just displaying the next frame(s), wait on just one frame instead of moving on.
We're also aware that some of the latency is being caused by the Classmate not being enough to keep up with the cRIO, but TCP doesn't help in this respect.