On Thursday 17 March 2011 08:45 AM, Venkatraman S wrote: > > Can someone explain how video streaming works - i am mainly interested in > how the server works when you click along the timeline of the video. Does > the server span threads/processes to fetch the frame from a specified moment > - how is the load sharing(/scalability) achieved! Do these need custom-OS > for efficient file traversals?
What? What do you want to know? None of your assumptions are correct. The idea is that the video is distributed using HTTP or RTSP and then the media is UDP multicast or unicast using RTP. In the case of youtube I think there is no RTP at all. At any rate read the relevant RFCs. But you don't seem to be interested in the low level protocol semantics. You want to know what happens at the programming/network /CPU usage level. It is like this(I think, not sure). When the user seeks to a particular offset in the video, the MPEG frames at that file offset are sent. That is all. No multithreading, no multiple connections. Just one connection. MPEG as a protocol encodes video in B, P and I frames. Read the MPEG spec. Actually video streaming is fairly straight forward if you consider only the higher level protocol. Just like reading from a disk except that the download happens on demand rather than all at one stroke. For smooth playback you will want to have a few future frames download apriori. Of course there is more than what meets the eye but this should do for the moment. -Girish _______________________________________________ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
