A bash / shell script for splitting videos / movies into several / multiple files using ffmpeg

ffmpeg_split.sh

#!/bin/bash
 
# Created by Håvard Fossli <[email protected]> in 2013
# Derived from Alexis Bezverkhyy <[email protected]> in 2011
# This is free and unencumbered software released into the public domain.
# For more information, please refer to <http://unlicense.org/>
#
# Description
# A bash script for splitting videos into several files using ffmpeg.
#
# Keywords
# Terminal, bash, unix, mac, shell, script, video, movie, split, time interval, multiple files, ffmpeg.
#
# Usefull links when working with ffmpeg
# - https://sites.google.com/site/linuxencoding/ffmpeg-tips
# - http://pvdm.xs4all.nl/wiki/index.php/Convert_an_AVCHD_/_MTS_file_to_MP4_using_ffmpeg
# - http://rodrigopolo.com/ffmpeg/cheats.php
# - http://www.catswhocode.com/blog/19-ffmpeg-commands-for-all-needs
#

# arg1: name of program
function assert_program_exists() {
	command -v $1 >/dev/null 2>&1 || { 
		echo >&2 "You must have $1 installed in order to run this script. Try:"; 
		echo "\$ brew install $1"
		exit 1; 
	}
}

# arg1: duration in format 01:23:45.67
# arg2: offset for group 1 gives hours, 2 gives minutes, 3 gives seconds, 4 gives milliseconds
function parse_duration_info() {
	if [[ $1 ]] && [[ $2 -gt 0 ]] && [[ $2 -lt 5 ]] ; then
		__OFFSET=$2
		__DURATION_PATTERN='\([0-9][0-9]\):\([0-9][0-9]\):\([0-9][0-9]\)\.\([0-9][0-9]\)'
		echo "$1" | sed "s/$__DURATION_PATTERN/\\$__OFFSET/"
	else
		echo "Bad input to parse_duration_info()"
		echo "Givven duration $1"
		echo "Givven offset $2"
		echo "Exiting..."
		exit 1
	fi
}

# arg1: file
function get_video_duration_in_seconds_from_file() {
	if [[ -z "$1" ]] ; then
		echo "Bad input to get_video_duration_in_seconds_from_file()"
		echo "Givven argument: '$1'"
		exit 1
	else
		__FILE=$1
		__DURATION_HMS=$(ffmpeg -i "$__FILE" 2>&1 | grep Duration | grep '\d\d:\d\d:\d\d.\d\d' -o)
		__DURATION_H=$(parse_duration_info "$__DURATION_HMS" 1)
		__DURATION_M=$(parse_duration_info "$__DURATION_HMS" 2)
		__DURATION_S=$(parse_duration_info "$__DURATION_HMS" 3)
		let "__SECONDS = ( __DURATION_H * 60 + __DURATION_M ) * 60 + __DURATION_S"
		echo $__SECONDS
	fi
}

# arg1: path to input file / source
function fallback_out_file_format() {
	if [[ -z "$1" ]] ; then
		echo "Bad input to get_video_duration_in_seconds_from_ffmpeg_info()"
		echo "Input givven $1"
		exit 1
	else
		__FILE_NAME=`rev <<< "$1" | cut -d"." -f2- | rev`
		__FILE_EXT=`rev <<< "$1" | cut -d"." -f1 | rev`
		__OUT_FILE_FORMAT="${__FILE_NAME}-part-%03d.${__FILE_EXT}"	
		echo $__OUT_FILE_FORMAT
		exit 1
	fi	
}

function echo_variables {
	echo 
	echo "### Variables ###"
	echo "- SOURCE $SOURCE"
	echo "- OFFSET $OFFSET"
	echo "- N_FILES $N_FILES"
	echo "- DURATION $DURATION"
	echo "- CHUNK_LEN $CHUNK_LEN"
	echo "- OUT_FILE_FORMAT $OUT_FILE_FORMAT"
	echo 
}

function usage {
	echo "For help and detailed guide type:"
	echo "\$ $0 -h"
}

function detailed_guide {
	echo "
Example: 
\$ $0 input.file chunk-duration output-filename-format

Info:
- input file may be any kind of file reconginzed by ffmpeg
- chunk duration must be in seconds
- output filename format must be printf-like, for example myvideo-part-%04d.avi
- if no output filename format is given, it will be computed
  automatically from input filename

Flags: 
-s	Path to video source (string)

-o	Path to output file with format (string)
	Format must be printf-like, for example ./path/video-part-%03d.avi

-c	Chunk length in seconds (integer)

-v	Takes no arguments
	Will be Verbose

-a	Takes no arguments
	Will remove audiostream

-p	Takes no arguments
	Will play sound on done

-i	Offset for file format (integer)

-h	Takes no arguments
	Help - detailed guide

-d	Takes no arguments
	Dry-run (no actual writing)
	"
}

# Allow to be terminated with ctrl + c
trap "exit" INT

# Assert ffmpeg is installed
assert_program_exists "ffmpeg"

# Set variables and default values
typeset -i CHUNK_LEN
CHUNK_LEN=60
SOURCE=''
OUT_FILE_FORMAT=''
REMOVE_AUDIO_STREAM=false
VERBOSE=false
PLAY_SOUND=false
DRY_RUN=false
FILE_OFFSET='1'
OFFSET='0'
HELP=false

# Grab input arguments
while getopts “s:o:c:vapi:hd” OPTION
do
     case $OPTION in
         s) SOURCE=$(echo "$OPTARG" | sed 's/ /\\ /g' ) ;;
         o)	OUT_FILE_FORMAT=$(echo "$OPTARG" | sed 's/ /\\ /g' ) ;;
         c)	CHUNK_LEN="$OPTARG" ;;
         v)	VERBOSE=true ;;
         a)	REMOVE_AUDIO_STREAM=true ;;
         p)	PLAY_SOUND=true ;;
         i)	FILE_OFFSET=$OPTARG ;;
         h)	HELP=true ;;
         d)	DRY_RUN=true ;;
         ?)	usage
			exit 1
			;;
     esac
done

if $HELP ; then
	detailed_guide
	exit 1
fi

if [[ -z $SOURCE ]] ; then
	echo "Invalid source"
    usage
    exit 1
fi
 
if [ -z "$OUT_FILE_FORMAT" ] ; then
	OUT_FILE_FORMAT=$(fallback_out_file_format $SOURCE)
fi

FFMPEG_INFO=$(ffmpeg -i "$__FILE" 2>&1)
DURATION=$(get_video_duration_in_seconds_from_file $SOURCE)
let 'N_FILES = (DURATION - 1) / CHUNK_LEN + 1'

if $VERBOSE ; then
	echo_variables
fi

if [ "$DURATION" = '0' ] ; then
	echo "Invalid input video"
	usage
	exit 1
fi

if [ "$CHUNK_LEN" = "0" ] ; then
	usage
	exit 2
fi
 
while [[ $OFFSET -lt $DURATION ]] ; do

	OUT_FILE=$(printf "$OUT_FILE_FORMAT" "$FILE_OFFSET")
	FFMPEG_PARAMETERS="-i $SOURCE -ss $OFFSET -t $CHUNK_LEN"

	if $REMOVE_AUDIO_STREAM ; then
		FFMPEG_PARAMETERS+=" -vcodec copy -an $OUT_FILE"
	else
		FFMPEG_PARAMETERS+=" -vcodec copy -acodec copy $OUT_FILE"
	fi	

	echo "### Writing file $FILE_OFFSET of $N_FILES to $OUT_FILE ###"

	if $DRY_RUN ; then	
		echo "Would call ffmpeg $FFMPEG_PARAMETERS"
	else
		ffmpeg $FFMPEG_PARAMETERS
	fi

	let "FILE_OFFSET = FILE_OFFSET + 1"
	let "OFFSET = OFFSET + CHUNK_LEN"
	
	echo 
done

if $PLAY_SOUND ; then
	# & means async
	say "Done! ." &
fi