Elphel 333, Theora and FPS

2005-04-11
2013-06-03
  • Nobody/Anonymous

    From  Theora_I_spec: 
    "Theora I currently supports progressive video data of arbitrary dimensions at a
    constant frame rate in one of several Y 0CbCr color spaces."

    But FPS in Elphel cameras can change during streaming (for example if exposure has been changed).  It is  problem or not?

    alexlp

     
    • Andrey Filippov

      Andrey Filippov - 2005-04-11

      To my understanding the frame rate should be constant and we will have to restart the stream if it changes (i.e. because of the exposure goes above the initial frame period).

      Andrey

       
    • Phil

      Phil - 2005-04-19

      Is it possible to have a rolling quality setting? So the quality would drop if the scene becomes complex & thus keep the same bandwidth?  Now I'm looking at the film we made this weekend & there are points were the frame rate slowed a bit when under trees with big crowds. There used to be a quality button on the control panel so perhaps there would be a way to trigger this function if bandwidth reached a set number?

       
      • Andrey Filippov

        Andrey Filippov - 2005-04-19

        Phil,

        I'm sure this can be done even in the 313 camera with JPEG - I had something similar in the very first version of quasi-streaming (creating a long quicktime file on the fly) - I was adjusting quality between frames to keep the frame size approximately the same.

        But have you tried all the steramers (if frame drops occur in the camera - it happens in the streamer software)? What about one made by Spectr?

        Andrey

         
    • Phil

      Phil - 2005-04-20

      I tried the Spectr streamer via windows & it seems the same. I think we will need soon a 2nd camera. Would the 333 solve any of the issues for me?  I think most of the issues are bandwidth related with the 313 set at 70% it can be producing 40kb images out in the fields & 250kb images in the trees with many supporters & flags etc!  There were no real skips (apart from the worst spots) but you can tell frames are being dropped as the speed sometimes increases under the trees!  If the camera could just pump out 150kb (or lower) images I think there would be no problems. It was dark & misty so perhaps with more light it will get better?  I will try next time a slightly smaller image & a fixed 20fps frame rate.

      regards Phil

      PS Some More 313 70% images!
      http://www.tacx-video.com/images/HD2005/Amstel

       
      • Andrey Filippov

        Andrey Filippov - 2005-04-20

        HI Phil,

        I'm nead Moscow, connection is far from good so it will take me some time to view your images :-(
        If the frames dropping is about the same with different streamers I suspect the problem to still be on the PC side.

        Andrey

         

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