Playback on voice paths

This sample app demonstrates how to use the audio APIs for compressed audio format playback on voice paths.

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. Create an audio playback session with voice path direction

StreamConfig config;

config.type = StreamType::PLAY;
config.slotId = DEFAULT_SLOT_ID;
config.sampleRate = SAMPLE_RATE;
config.format = AudioFormat::AMRWB_PLUS;

// here both channel selected, this can be selected according to requirement
config.channelTypeMask = (ChannelType::LEFT | ChannelType::RIGHT);

// Since the voice path is selected, we don't need to provide any device
// Voice path direction TX is for Voice uplink while direction RX is for Voice downlink
config.voicePaths.emplace_back(Direction::TX);

// Passing Decoder Specific Configuration, refer header file for more details.
AmrwbpParams amrParams{};
if (config.format == AudioFormat::AMRWB_PLUS) {
    amrParams.bitWidth = 16;
    amrParams.frameFormat = AmrwbpFrameFormat::FILE_STORAGE_FORMAT;
    config.formatParams = &amrParams;
} else {
    config.formatParams = nullptr;
}

std::promise<bool> p;
auto status = audioManager->createStream(config,
    [&p,this](std::shared_ptr<IAudioStream> &audioStream, ErrorCode error) {
        if (error == ErrorCode::SUCCESS) {
            audioPlayStream_ = std::dynamic_pointer_cast<IAudioPlayStream>(audioStream);
            p.set_value(true);
        } else {
            p.set_value(false);
            std::cout << "failed to Create a stream" <<std::endl;
        }
    });
if (status == Status::SUCCESS) {
    std::cout << "Request to create stream sent" << std::endl;
} else {
    std::cout << "Request to create stream failed"  << std::endl;
}

if (p.get_future().get()) {
    std::cout<< "Audio Play Stream is Created" << std::endl;
}

4. Allocate stream buffers for playback operation

// Get an audio buffer (we can get more than one)
auto streamBuffer = audioPlayStream->getStreamBuffer();
if (streamBuffer != nullptr) {
    // Setting the size that is to be written to stream as the 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
    size = streamBuffer->getMinSize();
    if (size == 0) {
        size =  streamBuffer->getMaxSize();
    }
    streamBuffer->setDataSize(size);
} else {
    std::cout << "Failed to get Stream Buffer " << std::endl;
}

5. Start write operation for playback to start

// We need an active voice session to play on voice paths.
// Callback which provides response to write operation.
void writeCallback(std::shared_ptr<IStreamBuffer> buffer, uint32_t bytes, ErrorCode error)
{
    if (error != ErrorCode::SUCCESS) {
        std::cout << "write() returned with error " << static_cast<int>(error) << std::endl;
        // Application needs to resend the Bitstream buffer from leftover position if bytes
        // consumed are not equal to requested number of bytes to be written.
        pipeLineEmpty_ = false;
    }
    buffer->reset();
    return;
}

// Indication Received only when callback returns with error that bytes written
// are not equal to bytes requested to write. It notifies that pipeline is ready
// to accept new buffer to write
void onReadyForWrite() {
    pipeLineEmpty_ = true;
}

// Write desired data into the buffer, the bytes sent as 0x1 for example purpose only.
// First write starts Playback Session.
memset(streamBuffer->getRawBuffer(),0x1,size);

auto status = audioPlayStream->write(streamBuffer, writeCallback);
if (status != telux::common::Status::SUCCESS) {
    std::cout << "write() failed with error" << static_cast<int>(status) << std::endl;
} else {
    std::cout << "Request to write to stream sent" << std::endl;
}

6.1 Stop playback operation(STOP_AFTER_PLAY : Stops after playing pending buffers in pipeline)

std::promise<bool> p;
auto status = audioPlayStream_->stopAudio(StopType::STOP_AFTER_PLAY, [&p](ErrorCode error) {
    if (error == ErrorCode::SUCCESS) {
        p.set_value(true);
    } else {
        p.set_value(false);
        std::cout << "Failed to stop after playing buffers" << std::endl;
    }
});
if (status == Status::SUCCESS) {
    std::cout << "Request to stop playback after pending buffers Sent" << std::endl;
} else {
    std::cout << "Request to stop playback after pending buffers failed" << std::endl;
}
if (p.get_future().get()) {
    std::cout << "Pending buffers played successful !!" << std::endl;
}

6.2 Stop playback operation(FORCE_STOP : Stops immediately, all buffers in pipeline are flushed)

std::promise<bool> p;
    auto status = audioPlayStream_->stopAudio(
        StopType::FORCE_STOP, [&p](telux::common::ErrorCode error) {
        if (error == telux::common::ErrorCode::SUCCESS) {
            p.set_value(true);
        } else {
            p.set_value(false);
            std::cout << "Failed to force stop" << std::endl;
        }
        });
    if(status == telux::common::Status::SUCCESS){
        std::cout << "Request to force stop Sent" << std::endl;
    } else {
        std::cout << "Request to force stop failed" << std::endl;
    }
    if (p.get_future().get()) {
            std::cout << "Force Stop successful !!" << std::endl;
    }

7. Dispose the audio stream, once end of operation is reached

std::promise<bool> p;
Status status = audioManager-> deleteStream(
audioPlayStream_, [&p,this](ErrorCode error) {
    if (error == ErrorCode::SUCCESS) {
        p.set_value(true);
    } else {
        p.set_value(false);
        std::cout << "Failed to delete a stream" << std::endl;
    }
});
if (status == Status::SUCCESS) {
    std::cout << "Request to delete stream sent" << std::endl;
} else {
    std::cout << "Request to delete stream failed"  << std::endl;
}
if (p.get_future().get()) {
    audioPlayStream_= nullptr;
    std::cout << "Audio Play Stream is Deleted" << std::endl;
}