Changes between Version 52 and Version 53 of StreamingGuide


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Timestamp:
Nov 26, 2012, 9:00:28 PM (3 years ago)
Author:
rogerdpack
Comment:

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  • StreamingGuide

    v52 v53  
    7676You will also want to try and decrease latency at the server side, for instance [http://www.wowza.com/forums/content.php?81-How-to-achieve-the-lowest-latency-from-capture-to-playback wowza] hints. 
    7777 
    78 Also setting  -probesize and -analyzeduration to low values may help your stream start up more quickly (it uses these to scan for "streams" in certain muxers, like ts, where some can appears "later", and also to estimate the duration, which, for live streams, the latter you don't need anyway). 
     78Also setting -probesize and -analyzeduration to low values may help your stream start up more quickly (it uses these to scan for "streams" in certain muxers, like ts, where some can appears "later", and also to estimate the duration, which, for live streams, the latter you don't need anyway). 
    7979 
    8080Reducing cacheing at the client side can help, too, for instance mplayer has a "-nocache" option, other players may similarly has some type of pre-playback buffering that is occurring. 
     
    8686Note 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). 
    8787 
    88 There is also an option -fflags nobuffer which is said to [http://ffmpeg.org/ffmpeg.html#Format-AVOptions reduce latency]. 
    89  
    90 Also note that by default, ffplay introduces a latency of its own, so if you use it for testing (see troubleshooting section) it may need some of these parameters, as well.  Also useful is mplayer with its -nocache for testing latency.   
     88There is also an option -fflags nobuffer which might[http://ffmpeg.org/ffmpeg.html#Format-AVOptions reduce latency]. 
     89 
     90=== testing latency === 
     91 
     92By default, ffplay introduces a small latency of its own, so if you use it for testing (see troubleshooting section) it may need some of these parameters, as well.  NB that ffplay has somewhat poor video output, though, so don't base quality levels on that.  Also some settings mentioned above like "probesize" might help it start more quickly. 
     93 
     94Also useful is mplayer with its -nocache for testing latency (or -benchmark).  
     95 
     96Using the SDL out is also said to view frames with minimal latency: "ffmpeg ... -f sdl -"    
     97 
     98=== see also === 
    9199 
    92100[http://stackoverflow.com/a/12085571/32453 Here] is a list of some other ideas to try (make sure you're using VBR, etc.)