Handy ffmpeg helpers

ffmpeg_helpers.bash

vid_get_scale() {
  raw_path="$1"
  long_dim="$2"
  if [[ -z "${raw_path}" || -z "${long_dim}" ]]; then
    echo "Usage: vid_get_scale RAW_PATH LONG_DIMENSION"
  else
    vid_meta="$( \
      ffprobe \
        -hide_banner \
        -v quiet \
        -print_format json \
        -select_streams v:0 \
        -show_streams \
        "${raw_path}" )"
    read -r -d '' select_filter <<-'EOF'
	if (
	  [.streams[0].side_data_list[0].rotation] |
	  inside([-90, 90]))
	then ("-2:" + $ARGS.positional[0])
	else ($ARGS.positional[0] + ":-2")
	end
	EOF
    echo "${vid_meta}" | \
    jq \
      --raw-output \
      --monochrome-output \
      --join-output \
      --args \
      "${select_filter}" \
      "${long_dim}"
  fi
}

vid_resize() {
  raw_path="$1"
  long_dim="$2"
  if [[ -z "${raw_path}" || -z "${long_dim}" ]]; then
    echo "Usage: vid_resize RAW_PATH LONG_DIMENSION"
  else
    scale_arg="$(vid_get_scale "${raw_path}" "${long_dim}")"
    output_ext="$(echo "${raw_path}" | grep -Eo '[^.]+$')"
    output_base="$(basename "${raw_path}" ".${output_ext}")"
    output_path="${output_base}-smaller.${output_ext}"
    ffmpeg \
      -y \
      -i "${raw_path}" \
      -vf "scale=${scale_arg}" \
      "${output_path}"
  fi
}

vid_make_gif() {
  raw_path="$1"
  long_dim="$2"
  frame_rate="$3"
  pause_len="$4"
  if [[ -z "${raw_path}" || -z "${long_dim}" || -z "${frame_rate}" ]]; then
    echo "Usage: vid_make_gif RAW_PATH LONG_DIMENSION FRAME_RATE [PAUSE_LENGTH]"
  else
    scale_arg="$(vid_get_scale "${raw_path}" "${long_dim}")"
    if [[ -z "${pause_len}" ]]; then
      pause_filter=''
    else
      pause_filter="tpad=stop_mode=clone:stop_duration=${pause_len},"
    fi
    source_ext="$(echo "${raw_path}" | grep -Eo '[^.]+$')"
    output_base="$(basename "${raw_path}" "${source_ext}")"
    output_path="${output_base}gif"
    ffmpeg \
      -y \
      -i "${raw_path}" \
      -filter_complex \
        "[0:v] fps=${frame_rate},scale=${scale_arg},${pause_filter}split [a][b];[a] palettegen [p];[b][p] paletteuse" \
      "${output_path}"
  fi
}