#!/bin/bash

set -e

die() {
    echo $1
    exit 1
}

[ $# = 0 ] && die 'No input file name.'

fname="$1"
output="$1.mp4"
bitrate=11000k

if [ -f "$output" ] ; then
    printf 'Output file exists: %s. Override? [yN] ' "$output"
    read answer
    case "$answer" in
        [yY]) ;;
        *) exit 0;;
    esac
fi

vcodec_opts="-preset medium -level 4.1 -r 25 -b:v $bitrate -bt $bitrate -s hd1080 -aspect 16:9"

ffmpeg -v warning -i "$fname"\
    -vcodec libx264 $vcodec_opts\
    -an\
    -pass 1\
    -f mp4 -y /dev/null

ffmpeg -v warning -i "$fname"\
    -vcodec libx264 $vcodec_opts\
    -acodec libmp3lame -ab 256k\
    -pass 2\
    -y "$output"