Using ffmpeg in Docker to add srt subtitle files to mp4 files

ffmpeg_add_srt.sh

#!/usr/bin/env bash
#
# Using ffmpeg in Docker to add srt subtitle files to mp4 files
#
# https://mutsinzi.com/add-srt-subtitles-to-quicktime/
# https://hub.docker.com/r/jrottenberg/ffmpeg

# Given the following directory structure:
# .
# ├── in
# │   ├── Subs
# │   │   └── French.fre.srt
# │   └── video.mp4
# └── out

docker run --rm \
  -v "$(pwd)/in:/tmp/workdir/in" \
  -v "$(pwd)/out:/tmp/workdir/out" \
  jrottenberg/ffmpeg \
    -i in/video.mp4 -i in/Subs/French.fre.srt -c:v copy -c:a copy \
    -c:s mov_text -metadata:s:s:0 language=fre out/video.mp4