FFMPEG image sequence with various durations

Using ffmpeg 2.0 there are a couple of ways to do this:

1. One method is to use file modification times. First set the modification time of the image files so that each image file has a modification time greater than the one before it; the time difference is the duration of the previous image (with 1 second resolution). Then use the image2 demuxer option -ts_from_file 1. For example:

   touch -t 01010000.00 image01.png
   touch -t 01010000.03 image02.png
   touch -t 01010000.08 image03.png
   ...
   ffmpeg -ts_from_file 1 -i image%2d.png -i audio.mp3 -c:a copy -vf fps=25 out.avi
   

2. Another method is to use the concat demuxer, which takes a list of files to concatenate, with optional durations. First create a file listing your images and durations that looks like this:

   ffconcat version 1.0
   file image01.png
   duration 3
   file image02.png
   duration 5
   file image03.png
   

   Then provide this file as input to ffmpeg. For example:

   ffmpeg -i in.ffconcat -i audio.mp3 -c:a copy -vf fps=25 out.avi
   

You may need to duplicate the last file after the final duration. -c:a copy copies the mp3 audio as-is; if you want to convert it to another audio codec then you can specify that instead of copy. You may also want to specify a different video codec with -c:v or a different pixel format with -pix_fmt, such as -c:v libx264 -pix_fmt yuv420p. -vf fps=25 will make the output frame rate 25 fps. If your audio is longer and you want it cut off after the images, use the -shortest option.