vid4rb

#!/bin/bash
#
# vid4rb
#
# REQUIREMENTS:
# Mplayer & Mencoder

# This script encodes video for playback on Rockboxed players.  It
# automatically detects and applies good crop values.  It automatically
# scales the video to a suitable size.  It detects the audio type in the
# source video and transcodes it only if necessary.  There are options
# to make sample encodes (tests), to specify output directory, to
# disable autocropping and to choose higher quality encoding.
# Run the script with no options or arguments for some short
# instructions & read the comments at the end of the script.

SCREENW=320

function usage ()
{
printf "\n\tEdit the script and change the value of SCREENW to the width
\tof your player's screen.
\n\tScreen Sizes WxH of various Rockbox Supported Players:\n
\tiPod Video, Gigabeat, Fuze+\t\t\t320x240
\tiriver H300, iPod Color/Photo & Sansa e200\t220x176
\tiPod Nano\t\t\t\t\t176x132
\tiAudio X5 / M5 and iriver H10 20GB / H120     160x128
\tiPod Mini 1G / 2G\t\t\t\t138x110
\tiriver H10 5/6GB\t\t\t\t128x128
\tSansa c200\t\t\t\t\t132x80
\n\nUSAGE:\n\t$(basename "$0") -o <full path to output dire\
ctory> [videofile1 videofile2 videofile3...]
\tIf -o is not used then new files are written to input directories.\n
\t-t encode 120 second test sample
\t-f # set fps to # (defaults to 25)
\t-c disable crop detection and cropping (useful for short clips)
\t-q Higher quality - Video at 400 kbs & Audio at 160 kbs\n
\tConverted movies have old extension removed and are saved as
\t<movie>_rb.mpeg or <movie>_sample_rb.mpeg\n\n"
}

function checkaudio ()
{
    AUD=$(mplayer -noconfig all -frames 0 -vo null -ao null -channels 8 \
    -identify "$MOVIE" 2>/dev/null |awk -F "ID_" '{print $2}'|sort -u|\
    sed '/^$/d' |grep -ci -e AUDIO_CODEC=mpg123 -e AUDIO_RATE=44100)
}

function cropdetect ()
{
    CROP="1"
    TOTAL_LOOPS="10"

    A=0
    while [ "$A" -lt "$TOTAL_LOOPS" ] ; do
    A="$(( $A + 1 ))"
    SKIP_SECS="$(( 30 * $A ))"

    mplayer "$MOVIE" -ss $SKIP_SECS \
    -frames 20 -vo md5sum -nosound -nocache \
    -vf cropdetect=20:16 2>&1 > mplayer.log < /dev/null

    CROP[$A]=`awk -F 'crop=' '/crop/ {print $2}' < mplayer.log |\
    awk -F ')' '{print $1}' | tail -n 1`

done
    rm md5sums mplayer.log


    B=0
    while [ "$B" -lt "$TOTAL_LOOPS" ] ; do
    B="$(( $B + 1 ))"

    C=0
    while [ "$C" -lt "$TOTAL_LOOPS" ] ; do
    C="$(( $C + 1 ))"

if [ "${CROP[$B]}" == "${CROP[$C]}" ] ; then
    COUNT_CROP[$B]="$(( ${COUNT_CROP[$B]} + 1 ))"
fi
done
done

    HIGHEST_COUNT=0

    D=0
    while [ "$D" -lt "$TOTAL_LOOPS" ] ; do
    D="$(( $D + 1 ))"

if [ "${COUNT_CROP[$D]}" -gt "$HIGHEST_COUNT" ] ; then
    HIGHEST_COUNT="${COUNT_CROP[$D]}"
    GREATEST="$D"
fi
done

    CROP="crop=${CROP[$GREATEST]}"
    echo -e "$CROP"

}

while getopts 'co:qtF' OPTION
do
    case $OPTION in
    c)  cflag=1
        ;;
    f)  fflag=1
        fval=$OPTARG
        ;;
    o)  oflag=1
        oval=$OPTARG
        ;;
    q)  qflag=1
        ;;
    t)  tflag=1
        ;;
    esac
done
shift $(($OPTIND-1))

if [ $# -lt 1 ]; then
    usage
    exit 1
fi

printf "\n\tMovies to be converted are:\n"
printf "\n\t\t%s" "$@"

let CORES=$(cat /proc/cpuinfo | grep processor | wc -l)

for MOVIE in "$@" ; do

if [ $oflag ]; then
    VIDOUT=$(echo ${MOVIE%.*}| sed 's,.*/,,')
    VIDOUT="$oval"/"$VIDOUT"
    else
    VIDOUT="${MOVIE%.*}"
fi

if [ $tflag ]; then
    SAMPLE=" -ss 120 -endpos 120"
    EXTN=_sample_rb.mpeg
    else
    EXTN=_rb.mpeg
fi

if [ $qflag ]; then
    TRANSCODE="-af resample=44100:0:0:volnorm=2,volume=2 -oac mp3lame \
-lameopts cbr:preset=160"
    VBITRATE="vbitrate=400"
    else
    TRANSCODE="-af resample=44100:0:0:volnorm=2,volume=2 -oac mp3lame \
-lameopts cbr:preset=96"
    VBITRATE="vbitrate=224"
fi

# if audio is already mp1/2/3 at 44.1 then keep it, otherwise transcode.
checkaudio
if  [ $AUD -eq 2 ]; then
    AUDIO="-oac copy"
    else
    AUDIO=$TRANSCODE
fi

printf "\n\n\tConverting $(basename "$MOVIE")\n\t
Calculating Cropping, Scaling, Audio...wait\n\n"

if [ -z $cflag ]; then
# Run cropdetect, discard all the crap, get the crop value
    CROP="-vf crop=$(cropdetect| awk -F 'crop=' '/crop/ {print $2}')"
    echo $CROP
    else
    CROP=""
fi

# Do the encoding
mencoder "$MOVIE"$SAMPLE \
-of mpeg -ofps ${fval:-25} $CROP -vf scale=$SCREENW:-2 \
-ovc lavc -lavcopts vcodec=mpeg2video:vmax_b_frames=4:$VBITRATE:threads=$CORES -mc 0 -noskip \
-alang en $AUDIO \
-o "$VIDOUT"$EXTN
done

# Cropping
#
# The autocrop will often cause a failure if the video is much shorter
# than 5 minutes.  Use -c to disable the autocropping.

# Audio
#
# Rockbox's MPEGplayer can play video with mp1, mp2 or mp3 audio, but it
# can only play audio with a sample rate of 44.1 KHz.  It's quite common
# to find mp3 audio at 48 KHz in video clips.  This script detects if
# audio is mp1/mp2/mp3 at 44.1. If so then the audio is retained. If not
# then it is transcoded.

# Quality
#
# Default settings are video bitrate at 224 and audio at 96.
# Use -q to switch this to video at 400 and audio at 160.
# If the existing audio is already mp1/mp2/mp3 at 44.1 then it will not
# be transcoded even when the -q option is used, only the video bitrate
# will be increased. This prevents loss of audio quality where possible.
#
# Both picture quality and file size increase a lot when raising video
# bitrate to 400.  Above 400 you don't really see any quality
# improvement on tiny screens, only bigger files.