Unsilence w/ MLT

unsilence.sh

#!/usr/bin/env bash

set -e

if [ "$#" -ne 4 ]; then
    echo "Usage: $0 source-file silencedetect-args speedup-factor output-file"
    echo " E.g.: $0 file.mkv n=-35dB:d=0.25 2.5 file.mlt"
    exit 1;
fi

TIME_REMAP=$(ffmpeg -i "$1" -vn -af silencedetect="$2" -nostats -f null - 2>&1 | awk 'BEGIN {o=i=0;s=0;m='"$3"'} $4 == "silence_start:" {o+=$5-i;i=$5;printf ":%f=%f;",o,i} $4 == "silence_end:" {o+=($5-i)/m;i=$5;printf ":%f=%f;",o,i}')

OUT=$(echo $TIME_REMAP | sed -Ee 's/.+;.//;s/=.+//')

#melt "$1" -consumer xml | sed -E 's|out=".+"|out=":'"$OUT"'"|;s|<producer|<chain|;s|</producer>|<link id="link0"><property name="mlt_service">timeremap</property><property name="pitch">1</property><property name="image_mode">nearest</property><property name="time_map">'"$TIME_REMAP"'</property></link></chain>|' > "$4"
melt -chain "$1" out="$OUT" -link timeremap pitch=1 image_mode=nearest time_map="$TIME_REMAP" -consumer xml:"$4"