A shell wrapper for `ffmpeg` command to compress video files to mp4 with h264 codec.

tomp4.sh

#!/bin/bash/

# Shell wrapper for converting to mp4 with h264 codec with sensible defaults optimized for small file size.


while getopts ":h" opt; do
  case $opt in
    h)
      echo "Usage: 'tomp4 INPUT OUTPUT SCALE_FACTOR'" >&2
      echo "Only INPUT is required, just hit enter for default values when prompted." >&2
      exit 1
      ;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      exit 1
      ;;
  esac
done

if [ -z $1 ]; then
  echo "Which file do you want to convert?"
  echo "usage: 'tomp4 INPUT OUTPUT SCALE_FACTOR'"
  echo "Only INPUT is required, for others you can just hit enter for default values when prompted."
  exit 1
fi

###### helper functions

floatToInt() {
  printf "%.0f\n" "$@"
}

nearestEven() {
  if (( $1 % 2 == 0 )); then
    echo $1
  else
    echo $(( $1 + 1 ))
  fi
}

just_compress() {
  echo '*************************'
  echo '*** Just compressing. ***'
  echo '*************************'
  ffmpeg -i $1 -c:v libx264 -preset slow -crf 22 -c:a copy -r 30 $2
}

resize_and_compress() {
  echo '******************************'
  echo '*** Scaling & compressing. ***'
  echo '******************************'
  ffmpeg -i $1 -c:v libx264 -preset slow -crf 22 -c:a copy -vf scale=$3 -r 30 $2
}

scale() {
  FACTOR=$1
  INPUT=$2
  OUTPUT=$3

  ORIGINAL_WIDTH=`mediainfo --language=raw --inform="Video;%Width%" $INPUT`
  TARGET_WIDTH=$(floatToInt $(bc <<< $ORIGINAL_WIDTH*$FACTOR ))

  DIMENSIONS="$(nearestEven $TARGET_WIDTH):-2"

  resize_and_compress $INPUT $OUTPUT $DIMENSIONS
}

target_width() {
  WIDTH=$1
  INPUT=$2
  OUTPUT=$3

  DIMENSIONS="$(nearestEven $WIDTH):-2"

  resize_and_compress $INPUT $OUTPUT $DIMENSIONS
}

target_height() {
  HEIGHT=$1
  INPUT=$2
  OUTPUT=$3

  DIMENSIONS="-2:$(nearestEven $HEIGHT)"

  resize_and_compress $INPUT $OUTPUT $DIMENSIONS
}

###### processing input params

INPUT=$1

if [ -z $2 ]; then
  echo "Output file name (defaults to [orignal_file_name]_scaled.mp4)"
  read OUTPUT

  [[ $OUTPUT ]] && OUTPUT="$OUTPUT.mp4" || OUTPUT="[$INPUT]_scaled.mp4"
else
  OUTPUT="$2.mp4"
fi

if [ -z $3 ]; then
  echo "Choose scaling option: by a factor (f), specific output width (w) or height (h)"
  read SCALING_OPTION
  case $SCALING_OPTION in
    "f")
      echo "Enter scaling factor (e.g. '.5' for 2x smaller, '2' for 2x larger)"
      read SCALING_FACTOR
      if [ -z $SCALING_FACTOR ]; then
        just_compress $INPUT $OUTPUT
      else
        scale $SCALING_FACTOR $INPUT $OUTPUT
      fi
      ;;
    "w")
      echo "Enter target width in pixels"
      read TARGET_WIDTH
      if [ -z $TARGET_WIDTH ]; then
        just_compress $INPUT $OUTPUT
      else
        target_width $TARGET_WIDTH $INPUT $OUTPUT
      fi
      ;;
    "h")
      echo "Enter target height in pixels"
      read TARGET_HEIGHT
      if [ -z $TARGET_HEIGHT ]; then
        just_compress $INPUT $OUTPUT
      else
        target_height $TARGET_HEIGHT $INPUT $OUTPUT
      fi
      ;;
    *)
      just_compress $INPUT $OUTPUT
      exit 0
      ;;
  esac
else
  scale $3 $INPUT $OUTPUT
fi