video-encode.sh

#!/usr/bin/env bash

set -o nounset   # abort on unbound variable
set -o pipefail  # don't hide errors within pipes

# Define usage function
usage() {
  cat <<EOF
Usage: $(basename "${BASH_SOURCE[0]}") [-k|--keep] [--recursive] [--force] [--dry-run] INPUT_DIR [OUTPUT_DIR]

Batch re-encodes video files with x265

Available options:

-h, --help      Print this help and exit
-k, --keep      Keeps the original files
--recursive     Searches for files recursively
--dry-run       Performs a dry run withour chaging files
--force         Skip checking the target format
--downscale     Downscale to 1280x720 is size is larger
EOF
  exit
}

# Function to handle Ctrl-C
interrupt_handler() {
  echo "Ctrl-C caught. Terminating loop on next iteration."
  stop_loop=true
}

print_file_stats() {
  local file=$1
  local output=$2

  size_before=$(stat -c%s "$file")
  count_total=$((count_total + 1))
  size_before_total=$((size_before + size_before_total))
  size_after=$size_before

  if [ "$DRY_RUN" != true ]; then
    size_after=$(stat -c%s "$output")
  fi

  size_after_total=$((size_after + size_after_total))
  reduction_ratio=$(bc -l <<< "scale=2; ($size_before - $size_after) / $size_before")
  printf "# number: %d\tsize before: %s\tsize after: %s\treduction: %s\tfilename: %s\n" "$count_total" "$size_before" "$size_after" "$reduction_ratio" "$file"
}

# Function to process single file
process_file() {
  local file=$1

  codec=$(ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1 "$file")

  # Get the base filename without extension
  filename=$(basename -- "$file")
  directory=$(dirname "$file")
  filename="${filename%.*}"

  # Set the output directory to the file directory
  OUTPUT_DIR="$directory"

  if [[ ("$file" == *_x265.mp4) || ("$file" == *_x265.mkv) ]]; then
    echo "Skipping [filename] $file"
    return
  fi
  
  if [[ ($codec == "hevc") ]]; then
    if [[ ("$FORCE" == true) ]]; then
      echo "Force converting $file"
    else
      echo "Skipping [codec] $file"
      return
    fi
  fi

  # Determine the output file extension
  if [[ "$file" == *.mkv ]]; then
    output_ext=".mkv"
  else
    output_ext=".mp4"
  fi

  # Set the output file name and path
  output="$OUTPUT_DIR/${filename}_x265${output_ext}"

  options=(-c:v libx265 -crf 28 -preset medium -c:a aac)
  
  if $DOWNSCALE; then
    # options=("${options[@]}" "-vf" "scale=1280:720:force_original_aspect_ratio=decrease,pad=1280:720:-1:-1:color=black")
    options=("${options[@]}" "-vf" "scale='if(gt(iw,1280),min(1280,iw),iw)':'if(gt(ih,720),min(720,ih),ih)'")
  fi

  exit_code=0
  # Re-encode the video file using FFmpeg
  if [ "$DRY_RUN" = true ]; then
    echo "> ffmpeg -nostdin -i $file ${options[*]} $output"
  else
    ffmpeg -nostdin -i "$file" "${options[@]}" "$output"
    exit_code=$?
  fi

  # Check if the re-encoding process was successful
  if [ $exit_code -eq 0 ]; then

    print_file_stats "$file" "$output"

    # Delete the failed attempt if it exists
    if ! $KEEP; then
      if [ "$DRY_RUN" = true ]; then
        echo "> rm -f $file"
      else
        rm -f "$file"
      fi
    fi
  else
    # Delete the failed output
    if [ "$DRY_RUN" = true ]; then
      echo "> rm -f $output"
    else
      rm -f "$output"
    fi
  fi
}

# Parse command line arguments
KEEP=false
DRY_RUN=false
FORCE=false
RECURSIVE=false
DOWNSCALE=false
INPUT_DIR=""
OUTPUT_DIR=""
size_before_total=0
size_after_total=0
count_total=0
stop_loop=false

while [[ $# -gt 0 ]]; do
  key="$1"

  case $key in
    -h|--help)
      usage
      ;;
    -k|--keep)
      KEEP=true
      shift
      ;;
    --dry-run)
      DRY_RUN=true
      shift
      ;;
    --force)
      FORCE=true
      shift
      ;;
    --recursive)
      RECURSIVE=true
      shift
      ;;
    --downscale)
      DOWNSCALE=true
      shift
      ;;
    *)
      if [ -z "$INPUT_DIR" ]; then
        INPUT_DIR="$1"
      elif [ -z "$OUTPUT_DIR" ]; then
        OUTPUT_DIR="$1"
      else
        usage
      fi
      shift
      ;;
  esac
done

if [ -z "$INPUT_DIR" ]; then
  usage
fi

if [ "$RECURSIVE" = true ]; then
  find_options=()
else
  find_options=(-maxdepth 1)
fi

# Set the interrupt handler
trap interrupt_handler SIGINT

# Loop through all video files in the input directory
while IFS= read -r -d '' file; do
  if "$stop_loop"; then
    break
  fi
  process_file "$file"
done < <(find "$INPUT_DIR" "${find_options[@]}" -type f \( -iname "*.flv" -o -iname "*.wmv" -o -iname "*.mpg" -o -iname "*.mpeg" -o -iname "*.avi" -o -iname "*.mkv" -o -iname "*.mp4" \) ! -name "*_x265.mp4" ! -name "*_x265.mkv" -print0)

if [ $size_before_total -gt 0 ]; then
  reduction_ratio_total=$(bc -l <<< "scale=2; ($size_before_total - $size_after_total) / $size_before_total")
  printf "# totals: count %d\tsize before: %s\tsize after: %s\treduction: %s\n" "$count_total" "$size_before_total" "$size_after_total" "$reduction_ratio_total"
fi