Changes between Version 58 and Version 59 of StreamingGuide


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Timestamp:
Oct 21, 2013, 11:53:42 PM (3 years ago)
Author:
rogerdpack
Comment:

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  • StreamingGuide

    v58 v59  
    8686NB 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 (-g) 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.  Also if you're using a lossy transport, like UDP, then an i-frame represents "the next change it will have to repair the stream" if there are problems from packet loss. 
    8787 
     88You can also (if capturing from a live source) increase frame rate to decrease latency (which affects throughput and also i-frame frequency, of course). 
     89 
    8890Note 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). 
    8991