#!/bin/bash

# Copyright (C) 2008 Sebastian Kemper (sebastian_ml @ gmx net)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# This script converts video files in batch mode to iPod (tm) compatible
# MP4s.

VERSION="1.0.9"

# History:

# 1.0.4: - Fixed a typo in comments
#        - Start version history
#        - Change FAAC_ENCOPTS comment
#        - Introduce $MFPS for accurate FPS
#        - Add '-noskip -mc 0' to mencoder calls
#        - Add check for frame rates greater than 30
#        - Add lock file
#        - Exit on error
#        - Set keyint/keyint_min
#        - Add note regarding MP4Box and file names
#        - Write down requirements
# 1.0.5: - Small change to comments
#        - Use myidentify instead of midentify; now input pixel aspect
#          ratio doesn't have to be 1:1 anymore
#        - Function c; unset variables containing essential file
#          properties and continue
#        - Protect mplayer from input while extracting audio
#          (-nolirc -noconsolecontrols etc.)
#        - Remove AVI requirement; now any file is possible as input
#        - Add VFOPTS variable
# 1.0.6: - Remove '-noskip -mc 0' again
#        - Change "Usage: ..." info
#        - Add rough sketch about what the script does and what it can't
#          do
#        - Add note about iPod (tm) import
#        - Print target bitrate and bpp
#        - Unset LC_ALL and set LC_NUMERIC to POSIX to make sure we get
#          dot instead of comma as decimal separator as bc expects a dot
# 1.0.7: - Add a little enhancement to function c; ability to return to
#          the n-th eclosing loop
#        - Fix two funtion c calls returning to the wrong loops
# 1.0.8: - Remove myidentify log when skipping file
#        - Use rm -f
#        - Add possibility to add options to mencoder calls through
#          $MENCODER_OPTS
# 1.0.9. - In case aspect ratio is not set simply assume Width:Height
#        - Add -endpos .1 to myidentify to prevent playback of audio
#          files; thanks to Reimar Doeffinger for the tip
#        - Check $VFOPTS for cropping. If detected calculate new aspect
#          ratio so we get a proper output resolution

# Notes:

# The script can process multiple input files. For every file the script
# tries to calculate a fitting output resolution. If one is found the
# file gets converted to H264 video/AAC LC audio and finally wrapped up
# in a MP4 container. The only video filter applied throughout the
# process is mencoder's "scale" filter (unless the user wants other
# filters prepended; read on for more info).

# This script can't do framerate conversion. Neither can it handle
# variable framerates. Another thing it can't do is select between
# available audio/video tracks.

# There are different ways to import the resulting files onto your iPod
# (tm). For instance you can use amarok or gtkpod. Or you could try
# iTunes (tm). It may be necessary to run MP4Box -ipod <MP4> before
# iTunes (tm) accepts the file for transfer. Feedback welcome.

# Feedback and fixes are _always_ welcome. Use email address at the top.

# You can specify video filter options on a per file basis. To do that
# simply put _one_ line of options in a file named like the input file
# with the suffix .vf (e.g. input.avi.vf for input.avi). This file has
# to be in the same directory as the input file. These options will then
# be prepended to the preset options (scale=x:y,harddup). This is useful
# for cropping etc.
# Example: crop=716:576:2:0

# MP4Box is a great tool but it has its issues. For instance it can't
# handle file names very well. So in case MP4Box segfaults try renaming
# the input file like this:
# a) make the file name shorter
# b) make sure the file name consists only of ASCII characters

# Make sure you have enough space left in your ${TMP_DIR} and
# ${WORK_DIR}!

# Requirements:

# - coreutils (everyone should have those anyway)
# - bc (for floating point calculations)
# - findutils (script needs 'xargs')
# - faac (audio encoder)
# - mplayer
# - mencoder (with x264 support)
# - aacgain (to ReplayGain the audio, you should at least use v1.7.0)
# - MP4Box (part of gpac, v0.4.4 or later required)

# Configuration:                                                       #

# Options can be set in the script itself or (preferably) in a file in
# the user's home directory, namely ~/.avi2mp4.conf.

# Directory for temporary files. Files created there will be deleted.
# Example:
# TMP_DIR="${HOME}/rip/tmp"

TMP_DIR=""

# The directory where the resulting MP4 files will be put.
# Example:
# WORK_DIR="${HOME}/rip"

WORK_DIR=""

# The video bitrate you want your videos to have.
# Example:
# BITRATE="500"

BITRATE=""

# Your choice for minimum bpp. That's "bits per pixel".
# bpp = ( video_bitrate * 1000 ) / ( fps * width * height )
# Sane range is 0.15 - 0.25 (I guess). Higher BPP usually means higher
# quality but this is just a rule of thumb and by no means guaranteed.
# Anyway, for batch encoding this is a good ruler.
# Example:
# MIN_BPP="0.19"

MIN_BPP=""

# faac encoding options. Leaving this empty lets faac use its default
# settings. At the moment this means VBR at a quality level of 100 which
# usually results in a bitrate of 120 kbit/s.
# Example:
# FAAC_ENCOPTS="-q 80"

FAAC_ENCOPTS=""

# x264 encoding options. "nocabac" and "level_idc=30" will be preset.
# Same goes for "keyint" and "keyint_min".
# Example:
# X264_ENCOPTS="frameref=3:turbo=1:partitions=all:mixed_refs=1:fast_pskip=0:threads=auto"
# Check the mencoder man page for more options if you like.

X264_ENCOPTS=""

# Extra options to pass to mencoder. For example I like to use the
# following:
# MENCODER_OPTS="-sws 1"
# The default scaler of mencoder is bicubic and it sharpens the image
# which in turn decreases compressibility of the picture. So while
# scaling down it so happens that using a bilinear scaler helps improve
# the quality of the encoded video.

MENCODER_OPTS=""

# End of configuration                                                 #

function e {
if [ ${ERROR} != 0 ]
then
	echo
	echo "An error occurred. Check program output. Exiting."
	exit 1
fi
}

function c {
unset -v ID_DEMUXER ID_VIDEO_WIDTH ID_VIDEO_HEIGHT ID_VIDEO_FPS ID_VIDEO_ASPECT \
VFOPTS ID_AUDIO_CODEC ID_AUDIO_NCH
continue ${1}
}

function myidentify {
mplayer -endpos .1 -vo null -ao null -frames 1 -identify "${1}" 2>/dev/null |
        sed -ne '/^ID_/ {
                          s/[]()|&;<>`'"'"'\\!$" []/\\&/g;p
                        }'
}

function remlog {
rm -f "${TMP_DIR}"/"${BASENAME}"_myidentify.log
}

AVI2MP4=`basename "${0}"`
echo "${AVI2MP4} v${VERSION}"

[[ -f ~/.avi2mp4.conf ]] && source ~/.avi2mp4.conf

unset -v VFOPTS LC_ALL
export LC_NUMERIC="POSIX"

for i in bc xargs faac mplayer mencoder aacgain MP4Box
do
	if ! [ -x "`which ${i} 2>/dev/null`" ]
	then
		echo
		echo "${i} is missing. Exiting."
		exit 1
	fi
done

for i in WORK_DIR TMP_DIR BITRATE MIN_BPP
do
	eval j=\$${i}
	if [ -z ${j} ]
	then
		echo
		echo "${i} is not set. Exiting."
		exit 1
	fi
done

for i in WORK_DIR TMP_DIR
do
	eval j=\$${i}
	if ! [ -d "${j}" ]
	then
		echo
		echo "${i} does not exist or is not a directory. Exiting."
		exit 1
	fi
	if ! [ -w "${j}" ]
	then
		echo
		echo "${i} is not writable. Exiting."
		exit 1
	fi
done

if [ ${#} = 0 ]
then
	echo
	echo "Usage: ${AVI2MP4} <file> [<another file>] ..."
	exit 0
fi

if [ ${X264_ENCOPTS} ]
then
	X264_ENCOPTS=:${X264_ENCOPTS}
fi

for i in "${@}"
do

	BASENAME=`basename "${i}" | sed 's/\(.*\)\.[a-z,0-9]*/\1/'`
	FILENAME=`basename "${i}"`
	DIRNAME=`dirname "${i}"`

	echo
	echo -e "File:\t\t\t${FILENAME}"
	echo

	if ! [ -e "${i}" ]
	then
		echo "Input file does not exist. Skipping."
		c
	fi

	if [ -e "${WORK_DIR}"/"${BASENAME}".mp4 ]
	then
		echo "File already converted to MP4. Skipping."
		c
	fi

	if [ -e "${TMP_DIR}"/"${BASENAME}".lock ]
	then
		echo "Conversion of input file already underway. If this is not the case"
		echo "remove the stale lock file and run this script again. Skipping."
		c
	fi

	# Get properties of file
	myidentify "${i}" > "${TMP_DIR}"/"${BASENAME}"_myidentify.log
	source "${TMP_DIR}"/"${BASENAME}"_myidentify.log
	
	for j in ID_DEMUXER ID_VIDEO_WIDTH ID_VIDEO_HEIGHT ID_VIDEO_FPS ID_VIDEO_ASPECT \
	ID_AUDIO_CODEC ID_AUDIO_NCH
	do
        	eval k=\$${j}
        	if ! [ ${k} ]
		then
			echo "Input file not recognized as a valid media file. Skipping."
			remlog
			c 2
		fi
	done

	for j in ID_VIDEO_WIDTH ID_VIDEO_HEIGHT ID_VIDEO_FPS ID_AUDIO_NCH
	do
		eval k=\$${j}
		IS_NULL=`echo "${k}==0" | bc -l`
		if [ ${IS_NULL} = 1 ]
		then
			echo "Input file properties invalid. Skipping."
			remlog
			c 2
		fi
	done

        if [ `echo "${ID_VIDEO_ASPECT}==0" | bc -l` = 1 ]
        then
                echo "Video aspect not set. Assuming Width:Height."
                echo
                ID_VIDEO_ASPECT=`echo "${ID_VIDEO_WIDTH}/${ID_VIDEO_HEIGHT}" | bc -l | xargs printf "%1.4f\n"`
        fi

        [[ -f "${i}".vf ]] && VFOPTS=`head -n1 "${i}".vf`
        if [ ${VFOPTS} ]
        then
                VFOPTS=${VFOPTS},
        fi

	# If we find crop=w:h:x:y in $VFOPTS let's get w and h and figure out
	# the new aspect ratio:
	CW=`echo ${VFOPTS} | sed 's/[a-z,:=0-9]*crop=//' | sed 's/:[a-z,:=0-9]*//g'`
	CH=`echo ${VFOPTS} | sed 's/[a-z,:=0-9]*crop=//' | sed "s/${CW}://" | sed 's/:[a-z,:=0-9]*//g'`
	if [ ${CW} ] || [ ${CH} ]
	then
		if ! [ ${CW} ]
		then
			CW=${ID_VIDEO_WIDTH}
		fi
		if ! [ ${CH} ]
		then
			CH=${ID_VIDEO_HEIGHT}
		fi
		ID_VIDEO_ASPECT=`echo "(${CW}*${ID_VIDEO_ASPECT}*${ID_VIDEO_HEIGHT})/(${CH}*${ID_VIDEO_WIDTH})" | bc -l | xargs printf "%1.4f\n"`
	fi


	echo -e "Dimension:\t\t${ID_VIDEO_WIDTH}x${ID_VIDEO_HEIGHT}"
	echo -e "FPS:\t\t\t${ID_VIDEO_FPS}"
	echo -e "Aspect:\t\t\t${ID_VIDEO_ASPECT}"
	echo

	if [ `echo "${ID_VIDEO_FPS}>30" | bc -l` = 1 ]
	then
		echo "Input framerate is greater than 30. iPod's (tm) can only"
		echo "handle up to 30 frames per second. This script can't handle"
		echo "framerate conversion. Skipping."
		remlog
		c
	fi

	for ((OUT_HORIZ=640; OUT_HORIZ>=240; OUT_HORIZ-=16))
	do
		MULTIPLIER=`echo "${OUT_HORIZ}/(${ID_VIDEO_ASPECT}*16)" | bc -l | xargs printf "%1.0f\n"`

		OUT_VERT=`echo "16*${MULTIPLIER}" | bc -l`

		OUT_BPP=`echo "scale=4;((${BITRATE}*1000)/(${ID_VIDEO_FPS}*${OUT_HORIZ}*${OUT_VERT}))" | bc -l | xargs printf "%1.4f\n"`
		LEGIT=`echo "${OUT_BPP}>=${MIN_BPP}" | bc -l`

		if [ ${LEGIT} = 1 ]
		then
			break
		fi
	done

	if [ ${LEGIT} = 0 ]
	then
		echo "No valid output dimension found. Skipping."
		remlog
		c
	fi

	echo -e "Output dimension:\t${OUT_HORIZ}x${OUT_VERT}"
	echo -e "Target video bitrate:\t${BITRATE} kbit/s"
	echo -e "Target bits per pixel:\t${OUT_BPP}"
	echo

	echo "Creating lock file:"
	touch "${TMP_DIR}"/"${BASENAME}".lock
	ERROR=${?}
	e
	echo "${TMP_DIR}/${BASENAME}.lock"
	echo "Lock file created."
	echo

	# Mencoder likes accurate FPS
	if [ ${ID_VIDEO_FPS} = 23.976 ]
	then
		MFPS='24000/1001'
	elif [ ${ID_VIDEO_FPS} = 29.970 ]
	then
		MFPS='30000/1001'
	else
		MFPS=${ID_VIDEO_FPS}
	fi

	# Set keyint/keyint_min according to ID_VIDEO_FPS
	KEYINT_MIN=`echo "${ID_VIDEO_FPS}" | xargs printf "%1.0f\n"`
	KEYINT=`echo "${ID_VIDEO_FPS}*10" | bc -l | xargs printf "%1.0f\n"`

	echo "MEncoder 1st pass:"
	echo
	mencoder "${i}" -oac copy -ovc x264 -vf ${VFOPTS}scale=${OUT_HORIZ}:${OUT_VERT},harddup -ofps ${MFPS} -x264encopts \
	pass=1:bitrate=${BITRATE}:keyint=${KEYINT}:keyint_min=${KEYINT_MIN}:nocabac:level_idc=30${X264_ENCOPTS} \
	-o /dev/null -passlogfile "${TMP_DIR}"/"${BASENAME}"_mencoder.log ${MENCODER_OPTS}
	ERROR=${?}
	e

	echo
	echo "MEncoder 2nd pass:"
	echo
	mencoder "${i}" -oac copy -ovc x264 -vf ${VFOPTS}scale=${OUT_HORIZ}:${OUT_VERT},harddup -ofps ${MFPS} -x264encopts \
	pass=2:bitrate=${BITRATE}:keyint=${KEYINT}:keyint_min=${KEYINT_MIN}:nocabac:level_idc=30${X264_ENCOPTS} \
	-o "${TMP_DIR}"/"${BASENAME}"_mencoder.avi -passlogfile "${TMP_DIR}"/"${BASENAME}"_mencoder.log ${MENCODER_OPTS}
	ERROR=${?}
	e

	echo
	echo "Extracting audio:"
	echo
	mplayer "${TMP_DIR}"/"${BASENAME}"_mencoder.avi -vc null -vo null -ao \
	pcm:fast:file="${TMP_DIR}"/"${BASENAME}"_mplayer.wav -noconsolecontrols \
	-nolirc -nojoystick -nomouseinput
	ERROR=${?}
	e

	echo
	echo "Encoding audio:"
	echo
	faac -o "${TMP_DIR}"/"${BASENAME}"_faac.m4a ${FAAC_ENCOPTS} "${TMP_DIR}"/"${BASENAME}"_mplayer.wav
	ERROR=${?}
	e

	echo
	echo "Applying ReplayGain:"
	echo
	aacgain -r -k "${TMP_DIR}"/"${BASENAME}"_faac.m4a
	ERROR=${?}
	e

	echo
	echo "Extracting raw x264 bitstream from video:"
	echo
	MP4Box -aviraw video "${TMP_DIR}"/"${BASENAME}"_mencoder.avi
	ERROR=${?}
	e

	echo
	echo "Muxing:"
	echo
	MP4Box -itags name="${BASENAME}" -new -add "${TMP_DIR}"/"${BASENAME}"_faac.m4a \
	-add "${TMP_DIR}"/"${BASENAME}"_mencoder_video.h264:fps=${ID_VIDEO_FPS} -tmp "${TMP_DIR}" \
	"${WORK_DIR}"/"${BASENAME}".mp4
	ERROR=${?}
	e

	echo
	echo "Cleaning up."
	rm -f "${TMP_DIR}"/"${BASENAME}"_mencoder.log "${TMP_DIR}"/"${BASENAME}"_mencoder.avi \
	"${TMP_DIR}"/"${BASENAME}"_mplayer.wav "${TMP_DIR}"/"${BASENAME}"_faac.m4a \
	"${TMP_DIR}"/"${BASENAME}"_mencoder_video.h264 "${TMP_DIR}"/"${BASENAME}".lock \
	"${TMP_DIR}"/"${BASENAME}"_myidentify.log
	ERROR=${?}
	e

	echo "Encoding ${BASENAME}.mp4 finished."

	c

done