#! /bin/sh

if [ -z "$1" ]; then
   echo "Usage: [vcodec=s] [vbitrate=n] [vscale=s] [abitrate=n] [ascale=s] $0 input.avi"
   exit 1
fi

if [ -z "$vcodec" ]; then
   vcodec=x264
else
   vcodec="$vcodec"
fi

if [ -z "$vbitrate" ]; then
   vbitrate=2200
else
   vbitrate="$vbitrate"
fi

if [ -n "$vscale" ]; then
   vscale="-Z $vscale"
fi

if [ -z "$abitrate" ]; then
   abitrate=320
else
   abitrate="$abitrate"
fi

if [ -n "$ascale" ]; then
   ascale="-s $ascale"
fi

if [ "$vcodec" = x264 ]; then
   vopts="--bitrate=$vbitrate"

elif [ "$vcodec" = x264-hq ]; then
   vopts="--bitrate=$vbitrate --8x8dct --ref=2 --bframes=3 --b-pyramid --weightb"

elif [ "$vcodec" = x264-vhq ]; then
   vopts="--bitrate=$vbitrate --8x8dct --ref=5 --bframes=3 --b-pyramid --weightb --partitions=all --me=umh"

else
   echo "Unknown video codec $vcodec; known codecs are x264[-[v]hq]" >&2
   exit 1
fi

if [ -z "$pass" ]; then
   pass=1
else
   pass="$pass"
fi

# Video
transcode -i "$1" -x auto,null -y yuv4mpeg,null -k -u 50 $vscale $ascale -o _tmp.y4m || exit 1

if [ "$pass" -eq 1 ]; then
   x264 $vopts --progress -o _tmp.mkv           _tmp.y4m || exit 1

elif [ "$pass" -eq 2 ]; then
   x264 $vopts --progress -o /dev/null --pass=1 _tmp.y4m &&
   x264 $vopts --progress -o _tmp.mkv  --pass=2 _tmp.y4m || exit 1

elif [ "$pass" -eq 3 ]; then
   x264 $vopts --progress -o /dev/null --pass=1 _tmp.y4m &&
   x264 $vopts --progress -o /dev/null --pass=3 _tmp.y4m &&
   x264 $vopts --progress -o _tmp.mkv  --pass=3 _tmp.y4m || exit 1
                                       # pass=3 is not a typo!

else
   echo "Can only do 1, 2 or 3 passes." >&2
   exit 1
fi

# Audio
transcode -i "$1" -x null,auto -y null,ogg -g 0x0 -b "$abitrate" -m _tmp.ogg &&

exec mkvmerge -o output.mkv -A _tmp.mkv _tmp.ogg