Changing the avi mux FPS

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

Answer 1

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

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Michel Roujansky, http://www.roujansky.com

Answer 2

  I've think on that also. Thanks anyway.

Answer 3

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, [e-mail]

Providenza & Boekelheide, Inc.

 

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Tim Roberts, DDK MVP Providenza & Boekelheide, Inc.