Concatenate MP4 files and inject 360 metadata. Similar to concat-mp4.py, but depends on https://github.com/google/spatial-media

ffcat.sh

#!/usr/bin/env bash

# Usage: ffcat <output> <input> [input ...]

set -euo pipefail

# Prints the contents of a concat file for ffmpeg.
function catfile() {
  local inputs=($@)
  local input
  for input in "${inputs[@]}" ; do
    # TODO: Escape embedded ' characters.
    printf "file '%s'\n" "$(readlink -f $input)"
  done
}

function main() {
  if [[ $# < 2 ]] ; then
    echo "Usage: $0 <output> <input> [input ...]" >&2
    exit 2
  fi
  local output="$1"
  shift
  local inputs=($@)

  local tempdir
  tempdir="$(mktemp -d 'ffcat.XXXXXXXXXX')"
  echo "Writing to temp dir: $tempdir"
  local tempfile="$tempdir/cat.mp4"

  catfile "${inputs[@]}"
  echo "Concatenating files"
  ffmpeg -f concat -safe 0 -i <(catfile "${inputs[@]}") -c copy "$tempfile"
  echo "Injecting 360 metadata"
  python3 "$HOME/dls/git/spatial-media/spatialmedia" -i "$tempfile" "$output"
  rm -r "$tempdir"
  echo "Done"
}

main "$@"