Opencv + recording + udp reading

Hello, this is the situation.

I im trying to do a python application that reads UDP packages.
one message is going to say "start" and the other "stop".

I already know how to read those messages.

Once the start message has arrived i want to record from my webcam, so I'm using opencv to achieve that.

And with the stop message i want to stop and save the .avi file that was recorded from the frames...

I dont know if any of you has any experience in something like this, I´m kinda lost when it comes to Threads and Timers and stuff like that in python..

anyone have some example to record video with opencv with threads?

thank you.

PD: i apologize for my english, is really late and im really tired.