Add audio to a movie file. uses sox and ffmpeg. mac/linux

add_audio.sh

#!/bin/bash
###

## USAGE ./add_audio.sh moviefile.mp4 audiofile.mp3
## this will take snippet from audio file and add it to moviefile.
## it will then trim that snippet from audiofile.mp3


DURATION=`ffmpeg -i $1 2>&1 | grep "Duration" | cut -d ' ' -f 4 | sed s/,//`

###
# sox inputfilename.mp3 trimmedfilename.mp3 trim starttime duration
# sox foo.wav trimfoo.wav trim 10 10  # gives you 10-20seconds into foo.wav
# 00:00:19.55  HH:MM:SS.xx
echo "duration = ${DURATION}"


length_seconds=`sox --info -D ${2} | cut -d"." -f1`



sox $2 temp_audio.mp3 trim 0 $DURATION 

length_snip=`sox --info -D temp_audio.mp3 | cut -d"." -f1`


ffmpeg -sameq -i $1 -i temp_audio.mp3 -ab 192k tempout.mp4

# mv tempout.mp4 $1

let "NEWL=${length_seconds}-${length_snip}"
sox $2 ${2}new.mp3 trim $DURATION $NEWL

mv tempout.mp4 $1
mv ${2}new.mp3 $2