filter_script usage with ffmpeg and replacing inputs with a file

Question

1. When using ffmpeg -i input1 -i input2 ... -filter_script filter_complex.txt output.mkv I can't seem to get the stream from the filter_complex.txt file to be recognized by ffmpeg. If I add -map [v], then it doesn't recognize the [v] like it would normally and says there's an unconnected output.

2. This is less important, but I haven't found a way to do something like ffmpeg -i inputs.txt ... to avoid the character limit yet, so if you know a way to do that, that would be nice.

Reason: I'm trying to use ffmpeg to overlay many images (~100) onto a video at various points and need to use files so I'm not going over the command line limit of 2k-8k characters in windows.

Answer 1

I found an answer that worked for me. I was trying to use the -map [v] syntax, but it turned out that wasn't necessary and I could just use the filtergraph I made as is. I did use filter_complex_script, which Gyan pointed out is the correct command, but I'm still not quite sure what the difference between the two is after looking through the documentation.

Answer 2

Use -filter_script:v for video.

Ref: https://ffmpeg.org/ffmpeg-all.html#Generic-options

-filter_script[:stream_specifier] filename (output,per-stream)

PS: I just discovered (right now), that you can also use filter_complex_script (:v not needed). -filter_complex_script seems the more advanced approach.