Audio capture session

Audio Manager API Sample Reference for audio capture session

This Section demonstrates how to use the Audio Manager API for audio capture session.

1. Get the AudioFactory instance

auto &audioFactory = audioFactory::getInstance();

2. Get the AudioManager object 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 object" << 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. Create an Audio Stream (Audio Capture Session)

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

//Create an Audio Stream (Audio Capture Session)
StreamConfig config;
config.type = StreamType::CAPTURE;
config.sampleRate = 48000;
config.format = AudioFormat::PCM_16BIT_SIGNED;
config.channelTypeMask = ChannelType::LEFT;
config.deviceTypes.emplace_back(DeviceType::DEVICE_TYPE_SPEAKER);
status = audioManager->createStream(config, createStreamCallback);

4. Allocate Stream Buffers for Capture Operation

// Get an audio buffer (can get more than one)
auto streamBuffer = audioCaptureStream->getStreamBuffer();
if(streamBuffer != nullptr) {
    // Setting the bytesToRead (bytes to be read from stream) as minimum size
    // required by stream. In any case if size returned is 0, using the Maximum Buffer
    // Size, any buffer size between min and max can be used
    bytesToRead = streamBuffer->getMinSize();
    if(bytesToRead == 0) {
        bytesToRead = streamBuffer->getMaxSize();
    }
} else {
    std::cout << "Failed to get Stream Buffer " << std::endl;
    return EXIT_FAILURE;
}

5. Start read operation for the capture to Start

//Callback which provides response to read operation
void readCallback(std::shared_ptr<IStreamBuffer> buffer, ErrorCode error)
{
    uint32_t bytesWrittenToFile = 0;
    if (error != ErrorCode::SUCCESS) {
        std::cout << "read() returned with error " << static_cast<int>(error) << std::endl;
    } else {
        uint32_t size = buffer->getDataSize();
        std::cout << "Successfully read " << size << " bytes" << std::endl;
    }
    buffer->reset();
    return;
}
//Read from Capture
//First read starts Capture Session.
auto status = audioCaptureStream->read(streamBuffer, bytesToRead, readCallback);
if(status != telux::common::Status::SUCCESS) {
    std::cout << "read() failed with error" << static_cast<int>(status) << std::endl;
} else {
    std::cout << "Request to read stream sent" << std::endl;
}

6. Delete an Audio Stream (Audio Capture Session), once required bytes captured

//Callback which provides response to deleteStream
void deleteStreamCallback(ErrorCode error) {
    if (error != ErrorCode::SUCCESS) {
        std::cout << "deleteStream() returned with error " << static_cast<int>(error)
                    << std::endl;
        return;
    }
    std::cout << "deleteStream() succeeded." << std::endl;
    audioCaptureStream.reset();
}
//Delete an Audio Stream (Audio Capture Session), once reached end of operation.
Status  status = audioManager->deleteStream(
           std::dynamic_pointer_cast<IAudioStream>(audioCaptureStream), deleteStreamCallback);
if (status != Status::SUCCESS) {
    std::cout << "deleteStream failed with error" << static_cast<int>(status) << std::endl;
}