Avi image extraction

[Anon]

Hi,
Does anyone know if you can extract an image (like the first image or a random image) from an avi dynamically upon an avi being submitted through a file upload. I want to dynamically extract an image and then resize it so it can be used as a thumbnail for the movie. I've worked some with the GD and some with ImageMagick but I'm not sure if this can be done using those.
Thanks for any help!

[van__]

I would recomend checking out the specs for avi and seeing how it writes it's frame headers and frame blocks. Then I'd unpack('CN',$avi_file) and take a quick looksie at the binary dump so I could see how to parse it for just 1 frame.

...also, you'll probably want to skip say 1/10th of the way through so you actually grab a scene rather than a black frame or opening credit.

[majik-sheff]

This is not a simple thing, and on any platform but windows probably completely impossible. .AVI does not imply a specific format like it once did. There are several different formats, including MPEG, DivX, and others. If you want to be guaranteed a frame grab you'll have to use the win32api function with hooks to the MCI of windows. If you can guarantee the format (meaning you're the only one uploading) then you can do some sort of single frame implementation based upon Microsoft's specs.