Detect DTMF tones

This sample app demostrates how to use audio APIs to detect DTMF tones during an active voice call. Note that only Rx direction is supported currently.

1. Get the AudioFactory instance

auto &audioFactory = AudioFactory::getInstance();

2. Get the AudioManager instance and check for audio subsystem readiness

std::promise<ServiceStatus> prom{};
// Get AudioManager instance
audioManager = audioFactory.getAudioManager([&prom](ServiceStatus serviceStatus) {
    prom.set_value(serviceStatus);
});
if (!audioManager) {
    std::cout << "Failed to get AudioManager instance" << std::endl;
    return;
}

// Check if audio subsystem is ready
// If audio subsystem is not ready, wait for it to be ready
ServiceStatus managerStatus = audioManager->getServiceStatus();
if (managerStatus != ServiceStatus::SERVICE_AVAILABLE) {
    std::cout << "\nAudio subsystem is not ready, Please wait ..." << std::endl;
    managerStatus = prom.get_future().get();
}

// Check the service status again
if (managerStatus == ServiceStatus::SERVICE_AVAILABLE) {
    std::cout << "Audio Subsytem is Ready << std::endl;
} else {
    std::cout << "ERROR - Unable to initialize audio subsystem" << std::endl;
    return;
}

3. Exit the application, if SDK is unable to initialize audio subsystem

if(isReady) {
    std::cout << " *** Audio subsystem is ready *** " << std::endl;
} else {
    std::cout << " *** ERROR - Unable to initialize audio subsystem " << std::endl;
    return 1;
}

4. Create an audio stream (to be associated with a voice call session)

// Callback which provides response to createStream
void createStreamCallback(std::shared_ptr<IAudioStream> &stream, ErrorCode error) {
    if (error != ErrorCode::SUCCESS) {
        std::cout << "createStream() failed with error" << static_cast<int>(error) << std::endl;
        return;
    }
    std::cout << "createStream() succeeded." << std::endl;
    audioVoiceStream = std::dynamic_pointer_cast<IAudioVoiceStream>(stream);
}

StreamConfig config;
config.type = StreamType::VOICE_CALL;
config.slotId = DEFAULT_SLOT_ID;
config.sampleRate = 16000;
config.format = AudioFormat::PCM_16BIT_SIGNED;
config.channelTypeMask = ChannelType::LEFT;
config.deviceTypes.emplace_back(DeviceType::DEVICE_TYPE_SPEAKER);

status = audioManager->createStream(config, createStreamCallback);

5. Start the voice call session

// Callback which provides response to startAudio
void startAudioCallback(ErrorCode error)
{
    if (error != ErrorCode::SUCCESS) {
        std::cout << "startAudio() failed with error " << static_cast<int>(error) << std::endl;
        return;
    }
    std::cout << "startAudio() succeeded." << std::endl;
}

status = audioVoiceStream->startAudio(startAudioCallback);

6. Register a listener to get notifications on DTMF tone detection

// Callback which provides response to registerListener
void registerListenerCallback(ErrorCode error)
{
    if (error != ErrorCode::SUCCESS) {
        std::cout << "registerListener() failed with error " << static_cast<int>(error)
                            << std::endl;
        return;
    }
    std::cout << "registerListener() succeeded." << std::endl;
}

// Instantiate MyVoiceListener
auto myDtmfToneListener = std::make_shared<MyVoiceListener>();

// Register the listener
status = audioVoiceStream->registerListener(myDtmfToneListener, registerListenerCallback);

7. De-register the listener to stop getting the notifications

status = audioVoiceStream->deRegisterListener(myDtmfToneListener);

8. Stop the voice call session

// Callback which provides response to stopAudio
void stopAudioCallback(ErrorCode error)
{
    if (error != ErrorCode::SUCCESS) {
        std::cout << "stopAudio() failed with error " << static_cast<int>(error) << std::endl;
        return;
    }
    std::cout << "stopAudio() succeeded." << std::endl;
}

status = audioVoiceStream->stopAudio(stopAudioCallback);

9. Dispose the audio stream associated with the voice call session

// Implement a response callback method to get the request status
void deleteStreamCallback(ErrorCode error) {
    if (error != ErrorCode::SUCCESS) {
        std::cout << "deleteStream() failed with error" << static_cast<int>(error) << std::endl;
        return;
    }
    std::cout << "deleteStream() succeeded." << std::endl;
    audioVoiceStream->reset();
}

status = audioManager->deleteStream(std::dynamic_pointer_cast<IAudioStream>(audioVoiceStream),
                                deleteStreamCallback);