FFMPEG : custom sequence input images

Question

I created a video from a set of images.

The command look like:

ffmpeg -i bg.jpeg -i img_%d.png -filter_complex overlay=5:H-h-5[b]-shortest testvid.mp         


        

Answer 1

You can use the concat demuxer with the custom sequence.

First, create a text file:

file 'img_0.png'
file 'img_1.png'
file 'img_1.png'
file 'img_2.png'
file 'img_1.png'
file 'img5.png'
file 'img_4.png'

Then run

ffmpeg -i bg.jpeg -f concat -r 25 -i list.txt -filter_complex "overlay=5:H-h-5" -shortest out.mp4

Edit: For PNG and most other image formats, r should be expressly specified to initialize a duration for each image entry in the list.

Answer 2

I just had the same issue, and if you have the need to generate image list as a part of program execution, then consider adding a duration <sec> string after every file <path> line, which will make the filter infer DTS. Like below:

file 'img.00000020.png'
duration 0.03333
file 'img.00000021.png'
duration 0.03333
...

For the case of offline conversion of a bunch of images, inline globbing worked just fine (so yes - DTS errors come from concat filter), but the following bash command can provide a list for the dry run:

for i in img.*.png; do echo file \'$i\'; echo duration 0.03333; done > list.txt