Changes between Version 56 and Version 57 of StreamingGuide

Oct 21, 2013, 9:41:34 PM (3 years ago)

mention difference i-frames make in connection speed


  • StreamingGuide

    v56 v57  
    8484You might get less latency by using one of the "point to point" protocols described in this document, at well. You'd lose the benefit of having a server, of course. 
     86NB that if you are sending to UDP or what not, that a client may have to wait until the next i-frame to be able to start receiving the stream, so the GOP setting (-i) i-frame interval will have an effect on how quickly they can connect.  Setting it to a lower number means it will use more bandwidth, but clients will be able to connectmore quickly (the default for x264 is 250--so for 30 fps that means an i-frame only once every 10 seconds or so).  So it's a tradeoff if you adjust it.  This does not affect actual latency (just connection time) since the client can still display frames very quickly after and once it has received its first i-frame. 
    8688Note also that using dshow's "rtbufsize" has the unfortunate side effect of allowing frames to "buffer" while it is waiting on encoding of previous frames, or waiting for them to be sent on the wire.  This means that if you use a higher value at all, it can cause/introduce added latency if it ever gets used (but if used, can be helpful for other aspects, like transmitting more frames overall). 
    235237If you are forced to use udp (for instance you need to broadcast to a multicast port for whatever reason) then you may be able to avoid the packet loss by (sending less data or sending the same frames over and over again so they have a higher chance of being received). 
     239See also the section on i-frames in [#Latency]. 
    237241== External links ==