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.gif using gap: cutting video frames

Mar 3, 2012, 01:28
Post: #1
.gif using gap: cutting video frames
This is my first time experimenting with gap and I'm trying to make a .gif file using a .wmv file as the source. It needs to be small, about 2 mb or less.

When I first finished the .gif (about 150 frames), the file was much too large. I resized it, used the "optimize" feature, and made it grayscale, but it's still too big.

Now I want to try cutting frames to make the file size smaller. How do I cut every other frame in my .gif?

Alternatively, is there any way to choose the number of frames I want in "extract videorange" (for ex: I want only 10 frames from mark 3:00 to 3:30)?
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Mar 3, 2012, 10:09 (This post was last modified: Mar 3, 2012 10:19 by rich2005.)
Post: #2
RE: .gif using gap: cutting video frames
Sorry this is somewhat off topic, when it comes to video I stop thinking Gimp, this is just for background info.

Assuming you are using windows.

Maybe best to do some pre-processing before importing into gimp-gap

A video can be reduced to frames using ffmpeg (command line but easy) You need to know how to start a command window and navigate to where the video file is located.

ffmpeg -y -r 25 -i <filename>.wmv -r 5 image.%06d.jpg

the first -r is the framerate of the wmv video, the second -r is the output 'framerate' so you could make yours say 12 ( half the video framerate). The outfile shown is jpg but could be png or bmp or...

You do need to know the framerate of the video (you could guess). Several ways but the free video editor Avidemux will tell you.
Where to get ffmpeg, if you don't have it already, the easiest way is to install ImageMagick. This has the advantage that ffmpeg is included with the IM utilities and put on the windows path.

Normally I use linux but some screenshots from a WinXP machine

This has reduced 324 frames down to 66 (every 5-ish)

Selecting a portion of the video.
Avidemux will chop up a video very easily and quickly but it works between 'keyframes' These can be several hundred frames apart in video formats such as wmv. My advice, render the whole clip and select the bits you want.

As an aside you can put those frames back to an animated gif, maybe as a quick test before more thorough processing in GAP, using IM and the command
convert *.jpg <filename>.gif

** now answering questions**
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