Converts any video to h264 and any audio tracks to AAC, maintins original bitrate. If video is an old xvid/divx that has packed bitstream it will fix that first. Validates the output file (correct codecs and within SECONDS_FUDGE duration or it is rejected) prior to deleting the original. If your ffmpeg doesn't have libfdk compiled in, just chang…

convert.sh

#!/bin/bash
# This will transcode the file given as an argument into h264/aac. It is designed to be used automatically (triggered by inotify or systemd.path) 
# so it is very strict on the output. It checks that the output is valid, an that it is the same duration as the input, if it is correct it will 
# delete the original. 
# If your ffmpeg is not compiled with libfdk_aac, you can change the libfdk_aac to "aac" and use ffmpeg's encoder which is almost as good as libfdk.

# SECONDS_FUDGE is the number of seconds plus or minus that the transcoded video has to be within duration from the original or we reject it
SECONDS_FUDGE=${SECONDS_FUDGE:-15} # 15 seconds is not too bad if we're mainly doing films. 

function checkPacked() {
# Older divx/xvid codecs use a terrible non-standard technique that put extra stuff in a frame
# We dont want to transcode without fixing this first
if [ ! -f "$1" ]; then
	echo "File not found"
	exit 3
fi
info=$(mediainfo "$1")
if echo "$info" | grep -q 'Packed bitstream'; then
	filename=$(basename "$1")
	extension="${filename##*.}"
	filename="${filename%.*}"
	tmpn="$filename_tmp.$extension"
	ffmpeg -v quiet -i "$1" -codec copy -bsf:v mpeg4_unpack_bframes "$tmpn"
	if [ -f "$tmpn" ]; then
		rm "$1"
		mv "$tmpn" "$1"
		echo "$1 - packed bitstream detected and corrected."
	else
		echo "$1 was packed, but conversion failed!"
	fi
fi
}

function removeTempFiles() {
	base=$(basename "$1")
	noext="${base%.*}*"
	rm -rf "/tmp/convert/$noext*"
	cnt=$(ls /tmp/convert/ | wc -l)
	if [ "$cnt" == "0" ]; then
		rmdir /tmp/convert
	fi
}

fpath=$1
if [ ! -f "$fpath" ]; then
	echo "File not found!"
	exit 1
fi
info=$(mediainfo "$fpath")
firstDuration=$(ffmpeg -i "$fpath" 2>&1 | grep Duration | awk '{print $2}' | tr -d ,)
if echo "$info" | grep -Eq '^Format[ ]+: AAC$'; then
	if echo "$info" | grep -Eq '^Codec ID[ ]+: avc1$'; then
		echo "$fpath already h264/aac"
		exit 0
	fi
fi

checkPacked "$fpath"
echo "Beginning transcode of $fpath"
if echo "$fpath" | grep -Eq '\/'; then
	DIR="${fpath%/*}"
else
	DIR="./"
fi
file="${fpath##*/}"
fpath2="/tmp/convert/$file"
mkdir -p /tmp/convert/
cp "$fpath" "$fpath2"
ffmpeg -i "$fpath2" -v quiet  -c:v libx264 -c:a libfdk_aac $2 -map 0 "${fpath2%.*}.mp4"
if [ ! -f "${fpath2%.*}.mp4" ]; then
	echo "MP4 wasn't generated!"
	exit 1
else
	if [ "$EUID" == "0" ]; then
    # if we're running as root that probably means we want to chown the files afterwards
    chown "${MEDIA_OWNER:-mdm}:${MEDIA_GROUP:-82}" "${fpath2%.*}.mp4"
fi
file2="${fpath2%.*}.mp4"
info=$(mediainfo "$file2")
if echo "$info" | grep -Eq '^Format[ ]+: AAC$'; then
	if echo "$info" | grep -Eq '^Codec ID[ ]+: avc1$'; then
		echo "Validating $file2..."
		secondDuration=$(ffmpeg -i "$file2" 2>&1 | grep Duration | awk '{print $2}' | tr -d ,)
            # convert to unixtime so we can cheat and determine the difference in seconds
            SEC1=`date +%s -d ${firstDuration}`
            SEC2=`date +%s -d ${secondDuration}`
            DIFFSEC=`expr ${SEC1} - ${SEC2}`
            # some videos appear to be a few seconds different in duration, but otherwise encoded correctly.
            # we can adjust SECONDS_FUDGE to tighten this check
            if [ "$DIFFSEC" -gt "$(echo -$SECONDS_FUDGE | bc)" ]; then
            	if [ "${DIFFSEC}" -lt "${SECONDS_FUDGE}" ]; then
            		echo "$fpath -> ${fpath%.*}.mp4 transcode verified successful, removing $fpath "
            		rm "$fpath"
            		mv "${fpath2%.*}.mp4" "$DIR"
            		removeTempFiles $fpath
            		exit 0
            	fi
            fi
            echo "Transcode has a $DIFFSEC seconds difference between the original's duration! REJECT!"
            removeTempFiles $fpath
            exit 4
        fi
    fi

    echo "MP4 generated, but it is not h264/aac ??"
    removeTempFiles $fpath
    exit 2
fi