Changes between Version 12 and Version 13 of StreamingGuide


Ignore:
Timestamp:
Jul 12, 2012, 11:06:10 PM (4 years ago)
Author:
rogerdpack
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • StreamingGuide

    v12 v13  
    4747NB that they also had to adjust the rtbufsize in that example.  I'm also not entirely sure which presets are "best" or what the available options are.  Also note that newer version of ffmpeg may need a different syntax for specifying preset/tune. 
    4848 
    49 == Latency == 
    50 You can decrease latency by specify that I-frames come "more frequently" (or always, in the case of x264's zerolatency), though this can increase frame size/decrease quality, see [http://mewiki.project357.com/wiki/X264_Encoding_Suggestions here] for alternatives. 
     49== Latency/cpu-usage == 
     50 
     51You can decrease latency by specify that I-frames come "more frequently" (or always, in the case of x264's zerolatency), though this can increase frame size/decrease quality, see [http://mewiki.project357.com/wiki/X264_Encoding_Suggestions here] for some alternatives.  To decrease cpu usage required to stream, you could (if capturing from live source) instruct the live source to feed a "smaller stream" (ex: webcam stream 640x480 instead of 1024x1280), or you could set a lower "output quality" setting, or specify a lower output bitrate.  Or try a different output codec, or specify new parameters (for instance, different profile for libx264).  Also specifying $ -threads 0 (the default) instructs the encoder to use all available cpu cores, which can speed up processing.  You could also resize your input first, before transcoding it, so it's not as large.  Applying a smoothing filter like hqdn3d before encoding might help it compress better. 
     52 
     53You could set a "maximum bit rate" or a lower "q rating" (quality level).  If you're able to capture with a pixel format that matches your output format, that might help, since it avoids a conversion.  Using 64-bit instead of 32-bit executables (for those that have a choice) can result in a slight speedup. 
     54 
     55In general the more cpu you use to compress, the better the output image will be, or the large of an image you can handle. 
    5156 
    5257== Streaming a simple RTP audio stream from ffmpeg ==