Monday, May 14, 2012

ffmpeg to create a movie from images

I've switched over to ffmpeg from mencoder. ffmpeg can be obtained from here for mac.

The ffmpeg documentation on creating video slideshows is great.

An example command line for such a use is:

ffmpeg -r 1/.5 -i "0%05d.jpg" -vcodec mjpeg -r 25 drop.avi

Important: if the numbering of your images doesn't start from 1 you should use the -start_number to indicate the first image (from here):
ffmpeg -start_number 2724  -r 1/.075 -i "DSC_%04d.jpg" -vcodec mjpeg -r 25 advair.avi

If there is a break in the file name numbering (eg. you have image01.jpg ... image05.jpg then image08.jpg) ffmpeg will stop at the break and finish the movie. You can use a short bash script to generate a copy of the files numbered as you want them.
ls *.JPG| awk 'BEGIN{ a=0 }{ printf "cp %s image_%04d.jpg\n", $0, a++ }' | bash

You should add options to ls to sort the files as you wish
Here, the first rate command (-r 1/.5) indicates how long each frame should take (here 0.5 of a second) and the second rate command (-r 25) indicates the movie frame rate.

Another example command to compile images into a movie is:
ffmpeg  -i test%06d.png -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an sudoku.mkv

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