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Freepbx Voicemail Transcription Script: Google Speech API
# sendmail-gcloud
# Original source created by N. Bernaerts:
# modified per:
# modified per:
# current version:
# Notes: This is a script modified from the original to work with a FreePBX Distro PBX so that email notifications sent from
# Asterisk voicemail contain a a speech to text transcription provided by Google Cloud Speech API
# License: There are no explicit license terms on the original script or on the blog post with modifications
# I'm assumig GNU/GPL2+ unless notified otherwise by copyright holder(s)
# Usage: copy this file to /usr/sbin/ set ownership to asterisk:asterisk and make it executable.
# In the [general] section of /etc/asterisk/voicemail.conf set mailcmd=/usr/sbin/sendmail-gcloud
# or in FreePBX 14 GUI go to Settings->Voicemail->Email Config->Mail Command to set this.
# This script also uses dos2unix, ensure it is executable by the asterisk user (chmod 777)
# Requirements:
# Google Cloud services account (paid--free trial available) with Google Speech to Text API enabled
# gcloud cli utility
# gcloud utility must be authenticated. Before doing this, 'su asterisk' so authentication happens in the correct user account
# authenticate with: gcloud auth login
# select project: gcloud config set project <Project ID>
# jq (yum install jq)
# sox with flac
# Version History:
# 2019-02-27 Initial commit by tony722
# set PATH
# save the current directory
pushd .
# create a temporary directory and cd to it
TMPDIR=$(mktemp -d)
# dump the stream to a temporary file
cat >>
# get the boundary
BOUNDARY=$(grep "boundary=" | cut -d'"' -f 2)
# if mail has no boundaries, assume no attachment
if [ "$BOUNDARY" = "" ]
# send the original stream
# cut the original stream into parts
# stream.part - header before the boundary
# stream.part1 - header after the bounday
# stream.part2 - body of the message
# stream.part3 - attachment in base64 (WAV file)
# stream.part4 - footer of the message
awk '/'$BOUNDARY'/{i++}{print > "stream.part"i}'
# cut the attachment into parts
# stream.part3.head - header of attachment
# stream.part3.wav.base64 - wav file of attachment (encoded base64)
sed '7,$d' stream.part3 > stream.part3.wav.head
sed '1,6d' stream.part3 > stream.part3.wav.base64
# convert the base64 file to a wav file
dos2unix -o stream.part3.wav.base64
base64 -di stream.part3.wav.base64 > stream.part3.wav
# convert the wav file to FLAC
sox -G stream.part3.wav --channels=1 --bits=16 --rate=8000 stream.part3.flac
# convert to MP3
sox stream.part3.wav stream.part3-pcm.wav
lame -m m -b 24 stream.part3-pcm.wav stream.part3.mp3
base64 stream.part3.mp3 > stream.part3.mp3.base64
#create mp3 mail part
sed 's/x-[wW][aA][vV]/mpeg/g' stream.part3.wav.head | sed 's/.[wW][aA][vV]/.mp3/g' >
dos2unix -o
unix2dos -o stream.part3.mp3.base64
cat stream.part3.mp3.base64 >>
RESULT=`gcloud ml speech recognize stream.part3.flac --language-code='en-US'`
FILTERED=`echo "$RESULT" | jq -r '.results[].alternatives[].transcript'`
# generate first part of mail body, converting it to LF only
mv stream.part
cat stream.part1 >>
sed '$d' < stream.part2 >>
# beginning of transcription section
echo "" >>
echo "--- Google transcription result ---" >>
# append result of transcription
if [ -z "$FILTERED" ]
echo "(Google was unable to recognize any speech in audio data.)" >>
echo "$FILTERED" >>
# end of message body
tail -1 stream.part2 >>
# add converted attachment
cat >>
# append end of mail body, converting it to LF only
echo "" >> stream.tmp
echo "" >> stream.tmp
cat stream.part4 >> stream.tmp
dos2unix -o stream.tmp
cat stream.tmp >>
# send the mail thru sendmail
cat | sendmail -t
# go back to original directory
# remove all temporary files and temporary directory
rm -Rf $TMPDIR
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