ffmpeg to show images for different durations in a video:
(command taken from example on this page)
ffmpeg -f concat -i input.txt -vsync vfr -pix_fmt yuv420p output.mp4
input.txt roughly looks like:
file '/path/to/im1.png' duration 123 file '/path/to/im2.png' duration 234 file '/path/to/im3.png' duration 235 file '/path/to/im4.png' duration 400 file '/path/to/im4.png'
The resulting file has trouble playing back in
Movies and TV (windows), and
VLC. On a hunch, I ran the file through
ffmpeg again to see I could ‘fix’ the output file (command used:
ffmpeg -i in.mp4 out.mp4).
out.mp4 was much larger than
in.mp4 (around an order of magnitude), but played smoothly, showed progress correctly, and was able to seek properly. What could be the reason for this?