Bash script to encode videos with ffmpeg to under discord's 8MiB file limit

discordencode.sh

#!/bin/bash
# discordencode - encodes a video file to under 8MiB for Discord
#VF="scale=1280:-2"
usage () {
    echo "Usage: [WEBM=1] [VCODEC=libx264] [ACODEC=aac] [VF=filter] [NOAUDIO=1] [VPRESET=x264-preset] $0 input output.mp4"
}
if [ -z "$1" ]
then
    usage
    exit 1
fi
if [ -z "$2" ]
then
   usage
   exit 1
fi
if [ ! -f "$1" ]; then
    echo "$1 does not exist"
    exit 2
fi
# Bitrate math functions
# Bc and ffprobe are a bit arcane
duration_seconds () {
    ffprobe -i "$1" -show_entries format=duration -v quiet -of csv="p=0"
}

subtract_and_truncate () {
    echo "x = $1; scale = 0; x / 1 - $2" | bc -l
}

divide_floats() {
    echo "scale=2; $1 / $2" | bc
}

audiocodec="aac"
if [[ $WEBM ]] && [ "$WEBM" -eq "1" ]
then
    audiocodec="libopus"
fi
if [[ ! -z $ACODEC ]]
then
    audiocodec="$ACODEC"
	echo "audiocodec! $audiocodec"
fi

audioargs="-c:a $audiocodec -b:a 128k"
audiobits=128
if [[ $NOAUDIO ]] && [ "$NOAUDIO" -eq "1" ]
then
    audioargs="-an"
    audiobits=0
    echo "Using no audio"
fi

if [ -z "$VPRESET" ]
then
    VPRESET=veryslow
fi

encodeparams="-preset $VPRESET -threads 0"
if [[ $WEBM ]] && [ "$WEBM" -eq "1" ]
then
    encodeparams="-cpu-used 3 -row-mt 1"
fi

duration=$(duration_seconds "$1")
echo $1
echo Duration is $duration
kbits=$(subtract_and_truncate $(divide_floats 60630.8 $duration) $audiobits)
echo Video bitrate is $kbits kb/s

videocodec="libx264"
if [[ $WEBM ]] && [ "$WEBM" -eq "1" ]
then
    videocodec="libvpx-vp9"
fi
if [[ ! -z $VCODEC ]]
then
    videocodec="$VCODEC"
	echo "videocodec! $videocodec"
fi

videoargs=""
if [[ ! -z $VF ]]
then
    videoargs="-vf $VF"
	echo "videoargs! $videoargs"
fi

videoformat="mp4"
if [[ $WEBM ]] && [ "$WEBM" -eq "1" ]
then
    videoformat="webm"
fi

# temporary logfile
TMPDIR=$(mktemp -d)
PASSLOGFILE="$TMPDIR/ffmpeg2pass"
set -x
ffmpeg -hide_banner -y -i "$1" -c:v $videocodec -passlogfile $PASSLOGFILE $encodeparams -b:v ${kbits}k $videoargs -pass 1 -an -f $videoformat /dev/null
ffmpeg -hide_banner -i "$1" -c:v $videocodec -passlogfile $PASSLOGFILE $encodeparams -b:v ${kbits}k $videoargs -pass 2 $audioargs "$2"
{ set +x; } 2>/dev/null
# clean tmp
rm -rf "$TMPDIR"

Appreciate you for forking and modifying it for me!