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Changing the avi mux FPS RRS feed

  • Question

  •   Hello,

     

    It will be possible to change the AVI MUX FPS of video ? For example, capturing, and then before closing the file, can i change the media info with a new FPS?

     

    Thanks in advance,

    Ionut

    Saturday, July 23, 2011 5:15 PM

Answers

  • The fps is autodetected by the avi mux from the timing of the first received frames. To change the fps of an avi file, you just need to hack the righ field in the file header with a hex editor :

    DWORD dwMicroSecPerFrame;

    Refer to the avi file format description, for example here : http://www.alexander-noe.com/video/documentation/avi.pdf
    Michel Roujansky, http://www.roujansky.com
    • Marked as answer by Ionut Cristea Sunday, July 24, 2011 2:56 PM
    Sunday, July 24, 2011 2:55 PM

All replies

  • The fps is autodetected by the avi mux from the timing of the first received frames. To change the fps of an avi file, you just need to hack the righ field in the file header with a hex editor :

    DWORD dwMicroSecPerFrame;

    Refer to the avi file format description, for example here : http://www.alexander-noe.com/video/documentation/avi.pdf
    Michel Roujansky, http://www.roujansky.com
    • Marked as answer by Ionut Cristea Sunday, July 24, 2011 2:56 PM
    Sunday, July 24, 2011 2:55 PM
  •   I've think on that also. Thanks anyway.
    Sunday, July 24, 2011 2:56 PM
  • Ionut Cristea wrote:
    >
    >It will be possible to change the AVI MUX FPS of video ? For example,
    >capturing, and then before closing the file, can i change the media
    >info with a new FPS?
     
    Well, that depends what you want.
     
    Let's say your camera produces 30 frames per second.  In 10 seconds, you
    will capture 300 frames.  For AVI formats, you can change the frame rate in
    the AVI header to 10 frames per second, but now your 300 frames will play
    back in 30 seconds.  That is, you'll get the same movie, but in slow
    motion.
     
    If you want to have your 10 second video play back in 10 seconds but at 10
    frames per second, then you need to have another filter in your graph that
    drops some of the frames.
    --
    Tim Roberts, timr@probo.com
    Providenza & Boekelheide, Inc.
     

    Tim Roberts, DDK MVP Providenza & Boekelheide, Inc.
    Sunday, July 24, 2011 11:45 PM