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Activity Forums Compression Techniques encoding live stream

  • encoding live stream

    Posted by Peter Sram on March 28, 2011 at 3:07 pm

    Hello I’m facing troubles when encoding live streams. I would like to stream from IP cam (rtsp h264 1600×1200) to websites via rtmp. So I am using some rtmp server (crtmpserver exactly) which can handle rtsp2rtmp. But I need to encode the stream to several other streams (smaller, resolution, smaller bitrate) to allow user to choose desired quality. So I’m taking the output rtmp stream from the server and trzing to encode it and push back to server.
    Everything is working when I simply do “-vcodec copy -acodec copy”, but everytime i try to downscale resolution or change bitrate, the output is very weird.
    When something is moving, sometimes it has a pixelate ghost (trace) – and sometimes it looks like the picture is going back the start of the ghost (trace) and back to normal again (this frame jump occurs multiple times), after that it continues. This occurs very often.

    I’m using command:

    ffmpeg -i rtmp://localhost/live/cam1_original -f flv -vcodec libx264 -an -vpre ultrafast -s vga tcp://localhost:6666

    I tried a lot of parameters (vpre, threads, r, re, b, bufsize, rtbufsize, etc..) But every time the same, sometimes little better, sometimes worse.

    Could it be because of that the server is virtual?

    Can you help me with better parameters, please?

    Thak you very much

    Peter Sram replied 15 years, 3 months ago 2 Members · 3 Replies
  • 3 Replies
  • Richard Tolley

    May 25, 2011 at 12:49 pm

    Hi

    Is there any chance of sharing your configuration of crtmpserver?

    I’m about to try and do exactly the same thing.

    If I have any success creating the other streams I will gladly post back.

    Regards

    Rich

  • Peter Sram

    May 25, 2011 at 1:32 pm

    Hi,
    no problem, but I’m still facing the problems that I described… so maybe I can help you and you can help me… But I didn’t change a lot of the example configuration file 🙂 I have only uncommented one of the external streams and changed to fit my needs (if I remember it exactly)
    conf file: 2398_crtmpserver.lua.zip
    But maybe you will not have such a problems like me.

  • Peter Sram

    June 3, 2011 at 6:05 am

    Any progress?

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