Script mixing Janus .mjr audio files (videocall recordings)

merge_audio.sh

#!/bin/bash

JANUS_BIN=/usr/bin/janus-pp-rec
FFMPEG_BIN=/usr/bin/ffmpeg

FFMPEG_VER=$($FFMPEG_BIN -version | sed -n "s/ffmpeg version \([-0-9.]*\).*/\1/p;")
MIN_VER="4.3"
NORMALIZE_FILTERS=""


vercomp () {
    if [[ $1 == $2 ]]
    then
        return 0
    fi
    local IFS=.
    local i ver1=($1) ver2=($2)
    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
    do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++))
    do
        if [[ -z ${ver2[i]} ]]
        then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]}))
        then
            return 1
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]}))
        then
            return 2
        fi
    done
    return 0
}

vercomp $FFMPEG_VER $MIN_VER
if [ $? -eq 2 ]
then
  echo "FFmpeg min version required $MIN_VER"
  exit
fi

vercomp $FFMPEG_VER "5.0"
cmp=$?
if [ $cmp -eq 1 ] || [ $cmp -eq 0 ]
then
  NORMALIZE_FILTERS=":normalize=0,dynaudnorm"
fi


file1=$1
file2=$2
out1=${file1%.mjr}.opus
out2=${file2%.mjr}.opus
if [ -z "$3" ]
then
  out3=OUTPUT.opus
else
  out3=$3
fi

start1=`$JANUS_BIN --extended-json $file1 | jq ".u"`
start2=`$JANUS_BIN --extended-json $file2 | jq ".u"`
delay=$((($start1-$start2)/1000))

if [ $delay -lt 0 ]
then
  delay1=0
  delay2=${delay#-}
else
  delay1=$delay
  delay2=0
fi

$JANUS_BIN $file1 $out1
$JANUS_BIN $file2 $out2

$FFMPEG_BIN -i $out1 -i $out2  -filter_complex "[0:a] adelay=$delay1:all=1, asetpts=N/SR/TB [mic0]; [1:a] adelay=$delay2:all=1, asetpts=N/SR/TB [mic1]; [mic0][mic1] amix=inputs=2$NORMALIZE_FILTERS" $out3
rm -f $out1 $out2