A CLI wrapper app to fix the Non-monotonous DTS in media file using ffmpeg

fix-nm-dts-av.sh

#!/bin/bash

# Check the number of arguments

if [ $# -ne 1 ]; then
  echo "Error: No arguments provided"
  exit 1
fi

display_help_menu() {
  echo "Fix the Non-monotonous DTS in media file"
  echo "Usage:"
  echo "  ${0##*/} <input> <output> <video_tbn> <audio_hz>"
  echo "Arguments:"
  echo "  input         input video file path"
  echo "  output        output video file path"
  echo "  video_tbn     video timebase number [12800 tbn]"
  echo "  audio_hz      audio sample rate [44100 Hz]"
}

get_timestamped_filename() {
  file=$(basename $1)
  file_basename="${file%.*}"
  file_extension="${file##*.}"
  echo "$file_basename-$(date +%Y%m%d%H%M%S).$file_extension"
}

# Loop through the arguments
for arg in "$@"; do
  # Check if the argument is -h or --help
  case $arg in
    -h|--help)
      display_help_menu
      exit 0
      ;;
  esac
done

if [ $# -ne 1 ]; then
  display_help_menu
  exit 1
fi

# Assign the arguments to variables
input=$1
output=$2
video_tbn=$3
audio_hz=$4

# Set to default value of arguments if missing

if [[ ! -f $input ]]; then
  echo "Invalid 'input' file: $input"
  exit 2
fi

if [ -z "$output" ]; then
  echo "Warning: Missing 'output' file"
  output=$(get_timestamped_filename $input)
  echo "Set output file to '$output' by default"
fi

if [ -z "$video_tbn" ]; then
  echo "Warning: Missing 'video_tbn' value"
  video_tbn=12800
  echo "Set video timebase number to $video_tbn tbn by default"
fi

if [ -z "$audio_hz" ]; then
  echo "Warning: Missing 'audio_hz' value"
  audio_hz=44100
  echo "Set audio sample rate to $audio_hz Hz by default"
fi


# Check the format of the arguments

if [[ ! $video_tbn =~ ^[0-9]+$ ]]; then
  echo "Invalid 'video_tbn' value: $video_tbn"
  exit 2
fi

if [[ ! $audio_hz =~ ^[0-9]+$ ]]; then
  echo "Invalid 'audio_hz' value: $audio_hz"
  exit 2
fi

echo "Probe streams (before)"
ffprobe -hide_banner -i $input

output_filename=$(basename $output)
output_extension="${output_filename##*.}"

temp_file="$(date +%Y%m%d%H%M%S)-$output_filename"

echo "Fix video timebase number"
ffmpeg -hide_banner -i $input -c:v libx264 -c:a copy -pix_fmt yuv420p -video_track_timescale $video_tbn $temp_file


echo "Fix audio sample rate"
ffmpeg -hide_banner -i $temp_file -acodec aac -vcodec copy -ar $audio_hz $output

rm $temp_file

echo "Probe streams (after)"
ffprobe -hide_banner -i $input