real-time-audio-transcription

Read wav audio files and get their audio chunks transcribed by Google Speech API in real time.

This program takes an audio file as an input and uses Google Speech API to output a text transcription. The audio file is read in real time (bitrate is taken from the .wav header information), and synchronized transcription requests are made to Google's server over the nodejs-speech NPM package.

Requirements

Node.js

version 5 and above should work

A Google Speech API enabled project

The GOOGLE_APPLICATION_CREDENTIALS must be properly set and point to a valid service account file.

If you need to get service account, you need to :

• Create or select a project
• Enable the Cloud Speech API for that project
• Create a service account
• Download a private key as JSON

And then set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the file path of the JSON file that contains your service account key. More info here : https://cloud.google.com/nodejs/

Installation

git clone https://github.com/phsultan/real-time-audio-transcription.git
cd real-time-audio-transcription
npm install

Usage

Usage: node readAndTranscribe.js [options] [filename]

  finename                   Audio file to transcribe, a WAV container. If not
                             present, audio is read from standard input.

Options:
  -l, --lang                 Transcription language code, e.g. : en-US, fr-FR.
                             Defaults to en-US.

  -s, --silence              Frames with energy under this value will be considered
                             to be silent. Defaults to 100 (purely arbitrary !).

  -e, --eof                  The maximum number of tries to consider that the
                             end of file (EOF) has been reached. Useful if you run
                             this program to transcribe a file that is being
                             continuously fed with new audio data. Defaults to 4.

  -m, --minaudio             The minimum acceptable duration of speech to trigger
                             a recognition request. More audio data will be collected
                             if we're under this value before issuing a recognition
                             request. Defaults to 2 seconds.

  -M, --maxaudio             The maximum acceptable duration of speech to trigger
                             a recognition request. If we don't detect any silence
                             and the audio buffer is about to exceed this value,
                             then we force a recognition request to Google.
                             Defaults to 10 seconds.

  -d, --debug                Run in debug mode.

  -h, --help                 Show this help message.

Examples

Read content from a local audio file /tmp/audio-content.wav, get a Spanish transcription :

$ node readAndTranscribe.js /tmp/audio-content.wav --lang=en-ES

Read content from a URL, transcribe with default options (US English transcription) :

$ curl -s -X GET 'http://mydomain.com/audio-content.wav' | node readAndTranscribe.js