Cloud Speech API gRPC samples for Java

This is a sample repo for accessing the Google Cloud Speech API with gRPC client library.

Prerequisites

Enable the Speech API

If you have not already done so, enable the Google Cloud Speech API for your project. You must be whitelisted to do this.

Download and install Java and Maven

Install Java7 or higher.

This sample uses the Apache Maven build system. Before getting started, be sure to download and install it. When you use Maven as described here, it will automatically download the needed client libraries.

Set Up to Authenticate With Your Project's Credentials

The example uses a service account for OAuth2 authentication. So next, set up to authenticate with the Speech API using your project's service account credentials.

Visit the Cloud Console, and navigate to: API Manager > Credentials > Create credentials > Service account key > New service account. Create a new service account, and download the json credentials file.

Then, set the GOOGLE_APPLICATION_CREDENTIALS environment variable to point to your downloaded service account credentials before running this example:

export GOOGLE_APPLICATION_CREDENTIALS=/path/to/your/credentials-key.json

If you do not do this, you will see an error that looks something like this when you run the example scripts: WARNING: RPC failed: Status{code=PERMISSION_DENIED, description=Request had insufficient authentication scopes., cause=null}. See the Cloud Platform Auth Guide for more information.

Build the application

Then, build the program:

$ mvn package

or

$ mvn compile
$ mvn assembly:single

Run the clients

These programs return the transcription of the audio file you provided. Please note that the audio file must be in RAW format. You can use sox (available, e.g. via http://sox.sourceforge.net/ or homebrew) to convert audio files to raw format.

Run the non-streaming client

You can run the batch client like this:

$ bin/speech-sample-nonstreaming.sh --host=speech.googleapis.com --port=443 \
--file=<audio file path> --sampling=<sample rate>

Try a streaming rate of 16000 and the included sample audio file, as follows:

$ bin/speech-sample-nonstreaming.sh --host=speech.googleapis.com --port=443 \
--file=resources/audio.raw --sampling=16000

Run the streaming client

You can run the streaming client as follows:

$ bin/speech-sample-streaming.sh --host=speech.googleapis.com --port=443 \
--file=resources/audio.raw --sampling=16000