Looping over certain files recursively which creating a directory inside each directory

Question

I wrote a simple bash script to convert video files. When run, it first makes output directory and then iterates over all .mp4 files, converts them and puts the result to output directory.

mkdir output && for f in *.mp4; do echo $f; \
ffmpeg -loglevel warning -i $f -vf scale=1280:-2,fps=25 output/$f; done

I'd like to add to the script one feature: looping in all the sub-directories (but no the current directory itself), creating 'output` directory and executing conversion.

I managed to find all files meeting given criterion in all sub-directories by using this code:

for d in */; do
  for f in "$d"/*.mp4; do
    echo "$d"
    file="${f##*/}"
    echo "$file"
  done
done

The script prints the following, which is correct.

1/
01.mp4
2/
02.mp4

However, that's all I was able to do.

Answer 1

You can use find to search directories recursively.

$ find -mindepth 2 -type f ! -path '*/output/*' -name '*.mp4' \
  -exec bash -c 'mkdir -p "${1%/*}/output"; ffmpeg -loglevel warning -i "$1" -vf scale=1280:-2,fps=25 "${1%/*}/output/${1##*/}"' _ {} \;

Or a for loop with globstar:

#!/bin/bash

shopt -s globstar nullglob

for i in **/*.mp4; do
    if [[ $i != */output/* ]]; then
        mkdir -p "${i%/*}/output"
        ffmpeg -loglevel warning -i "$i" -vf scale=1280:-2,fps=25 "${i%/*}/output/${i##*/}"
    fi
done