Rhino Speech-to-Intent
C Quick Start

Platforms

• Linux (x86_64)
• macOS (x86_64, arm64)
• Windows (x86_64)
• BeagleBone
• NVIDIA Jetson Nano
• Raspberry Pi (Zero, 2, 3, 4)

Requirements

• C99-compatible compiler
• CMake (3.4+)
• For Windows Only: MinGW is required to build the demo

Picovoice Account & AccessKey

Signup or Login to Picovoice Console to get your AccessKey. Make sure to keep your AccessKey secret.

Setup

1. Clone the repository:

git clone --recurse-submodules https://github.com/Picovoice/rhino.git

Usage

1. Include the public header files (picovoice.h and pv_rhino.h) .
2. Link the project to an appropriate precompiled library for the target platform and load it.
3. Download a language model .
4. Download a context file based on the desired language and the target platform.
5. Construct the Rhino object:

static const char* ACCESS_KEY = "${ACCESS_KEY}";

const char *model_file_path = "${MODEL_FILE_PATH}";
const char *context_file_path = "${CONTEXT_FILE_PATH}";
const float sensitivity = 0.5f;

pv_rhino_t *rhino;

const pv_status_t status = pv_rhino_init(
    model_file_path,
    context_file_path,
    &sensitivity,
    true,
    &rhino);

if (status != PV_STATUS_SUCCESS) {
    // add error handling code
}

6. Pass in frames of audio to the pv_rhino_process function:

extern const int16_t *get_next_audio_frame(void);

while (true) {
    const int16_t *pcm = get_next_audio_frame();

    bool is_finalized;
    pv_status_t status = pv_rhino_process(rhino, pcm, &is_finalized);
    if (status != PV_STATUS_SUCCESS) {
        // add error handling code
    }

    if (is_finalized) {
        bool is_understood;
        status = pv_rhino_is_understood(rhino, &is_understood);
        if (status != PV_STATUS_SUCCESS) {
            // add error handling code
        }

        if (is_understood) {
            const char *intent;
            int num_slots;
            const char **slots;
            const char **values;
            status = pv_rhino_get_intent(
                rhino,
                &intent,
                &num_slots,
                &slots,
                &values);
            if (status != PV_STATUS_SUCCESS) {
                // add error handling code
            }

            // add code to take action based on inferred intent and slot values

            pv_rhino_free_slots_and_values(rhino, slots, values);
        } else {
            // add code to handle unsupported commands
        }

        pv_rhino_reset(rhino);
    }
}

7. Release resources explicitly when done with Rhino:

pv_rhino_delete(rhino);

Custom Contexts

Create custom context using the Picovoice Console . Download the custom context file (.rhn) and create an instance of Rhino using the custom context model.

Non-English Languages

Use the corresponding model file (.pv) to detect non-English wake words. The model files for all supported languages are available on the Rhino GitHub repository .

Demo

For the Rhino C SDK, we offer demo applications that demonstrate how to use the Speech-to-Intent engine on real-time audio streams (i.e. microphone input) and audio files.

Setup

1. Clone the repository:

git clone --recurse-submodules https://github.com/Picovoice/rhino.git

2. Build the microphone demo:

cd rhino
cmake -S demo/c/. -B demo/c/build && cmake --build demo/c/build --target rhino_demo_mic

Usage

To see the usage options for the demo:

./demo/c/build/rhino_demo_mic

Ensure you have a working microphone connected to your system and run the following command to infer intent from spoken commands:

./demo/c/build/rhino_demo_mic \
-l lib/${PLATFORM}/${ARCH}/libpv_rhino.so \
-m lib/common/rhino_params.pv \
-c resources/contexts/${PLATFORM}/smart_lighting_${PLATFORM}.rhn \
-d ${AUDIO_DEVICE_INDEX} \
-a ${ACCESS_KEY}

For more information on our Rhino demos for C, head over to our GitHub repository .

Resources