First part of my question:
I read on the ffmpeg documentation (
section 3.2 How do I encode single pictures into movies?) the following:
To encode single pictures into movies, run the command:
ffmpeg -f image2 -i img%d.jpg movie.mpg
Notice that `%d' is replaced by the image number: img%03d.jpg means the sequence img001.jpg, img002.jpg, etc...
My question is: Who is doing the translation between
img001.jpg, img002.jpg, etc? Is it the shell or ffmpeg?
I would like to ask ffmpeg to encode a sequence of images into a video. However, my sequences often start with an index different from 1, (e.g. we can call it
start_index) and end on an index that we can call
end_index. Moreover, the sequence uses increments of value
img_0025.png, img_0030.png, img_0035.png, ... img_0100.png
start_index was 25,
end_index was 100, and
increment was 5.
I would like feed an image sequence like the above to ffmpeg without having to rename the sequence first. The documentation explains how to do this with symbolic links, but I was wondering if there is a way to avoid them altogether, maybe using advanced globbing on zsh.