Automatic Speech Recognition with NVidia NeMo

ASR with NeMo

This example demonstrates how to use the NeMo to perform ASR (Automatic Speech Recognition) in Label Studio.

Use this model if you want to transcribe and fix your audio data.

Labeling interface

This example works with the Label Studio’s pre-built Audio Transcription template (available under Audio Processing > Audio Transcription).

<View>
  <Audio name="audio" value="$audio" zoom="true" hotkey="ctrl+enter" />
  <Header value="Provide Transcription" />
  <TextArea name="transcription" toName="audio"
            rows="4" editable="true" maxSubmissions="1" />
</View>

But you can use any other labeling interface that combines <Audio> and <TextArea> elements.

Warning: If you use files hosted in Label Studio (e.g. audio files directly uploaded via import dialog), you must provide the LABEL_STUDIO_URL and LABEL_STUDIO_API_KEY environment variables to the ML backend. For more information about finding your Label Studio API key, see our documentation.

Running with Docker (recommended)

Start the Machine Learning backend on http://localhost:9090 with the prebuilt image:

docker-compose up

Validate that backend is running:

$ curl http://localhost:9090/
{"status":"UP"}

Create a project in Label Studio. Then from the Model page in the project settings, connect the model. The default URL is http://localhost:9090.

Building from source (advanced)

To build the ML backend from source, you have to clone the repository and build the Docker image:

docker-compose build

Running without Docker (advanced)

To run the ML backend without Docker, you have to clone the repository and install all dependencies using pip:

python -m venv ml-backend
source ml-backend/bin/activate
pip install -r requirements.txt

Then you can start the ML backend:

label-studio-ml start ./nemo_asr

Configuration

Parameters can be set in docker-compose.yml before running the container.

The following common parameters are available:

MODEL_NAME - Specify the model name for the ASR. (QuartzNet15x5Base-En by default)
BASIC_AUTH_USER - Specify the basic auth user for the model server
BASIC_AUTH_PASS - Specify the basic auth password for the model server
LOG_LEVEL - Set the log level for the model server
WORKERS - Specify the number of workers for the model server
THREADS - Specify the number of threads for the model server
LABEL_STUDIO_HOST: The host of the Label Studio instance. Default is http://localhost:8080.
LABEL_STUDIO_API_KEY: The API key for the Label Studio instance.

Customization

The ML backend can be customized by adding your own models and logic inside ./nemo_asr/model.py.