gistfile1.sh

#!/usr/local/bin/bash

INPUT="$1"
OUTPUT="$2"
VIDEO_CODEC="mpeg2video"
VIDEO_FPS=`mkvinfo $1 | grep -A 10 'Codec ID: V_MPEG4' | grep -w fps | awk '{print $6}' | cut -d'(' -f2`

mkvinfo $INPUT | grep -qE 'Codec ID.*DTS'

if [ $? -eq 0 ]; then
AUDIO_CODEC="ac3"
AUDIO_BITRATE="-ab 640k"
AUDIO_FREQ="-ar 48000"
AUDIO_CHANNELS="-ac 6"
else
AUDIO_CODEC="copy"
AUDIO_BITRATE=""
AUDIO_FREQ=""
AUDIO_CHANNELS=""
fi

FORMAT="dvd"

ffmpeg -threads 8 -i "${INPUT}" -vcodec ${VIDEO_CODEC} -r ${VIDEO_FPS} -sameq -acodec $AUDIO_CODEC $AUDIO_BITRATE $AUDIO_FREQ $AUDIO_CHANNELS -scodec copy -f ${FORMAT} - > "${OUTPUT}" 2>/dev/null