Nsound::AudioBackendLibao Class Reference

#include <Nsound/AudioBackendLibao.h>

Inheritance diagram for Nsound::AudioBackendLibao:

Public Types
enum	State { BACKEND_NOT_INITIALIZED, BACKEND_READY, BACKEND_ERROR }

Public Member Functions
	AudioBackendLibao (uint32 sample_rate=44100, uint32 channels=1, uint32 bits_per_sample=16)
	~AudioBackendLibao ()
AudioBackendType	getBackendType ()
std::string	getError ()
std::string	getInfo ()
void	initialize ()
void	play (void *data, uint32 n_bytes)
void	scanDevices (AudioPlayback &pb, const AudioStream &test_clip)
void	setOption (const std::string &key, const std::string &value)
	Set libao options. More...
void	shutdown ()
uint32	getBitsPerSample ()
uint32	getChannels ()
uint32	getSampleRate ()
State	getState ()
std::string	getStateString ()
	Returns the backend state. More...

Static Public Member Functions
static std::string	getStateString (const AudioBackend::State &state)
	Returns the backend state string. More...

Protected Attributes
uint32	sample_rate_
uint32	channels_
uint32	bits_per_sample_
State	state_

Private Member Functions
	AudioBackendLibao (const AudioBackendLibao &copy)
AudioBackendLibao &	operator= (const AudioBackendLibao &rhs)

Private Attributes
std::vector< std::string >	options_
std::stringstream	error_buffer_
int32	driver_id_
ao_device *	device_ptr_

Detailed Description

Definition at line 50 of file AudioBackendLibao.h.

Member Enumeration Documentation

enum Nsound::AudioBackend::State

inherited

Enumerator
BACKEND_NOT_INITIALIZED
BACKEND_READY
BACKEND_ERROR

Definition at line 52 of file AudioBackend.h.

    {
        BACKEND_NOT_INITIALIZED,
        BACKEND_READY,
        BACKEND_ERROR,
    };

Constructor & Destructor Documentation

AudioBackendLibao::AudioBackendLibao	(	uint32	sample_rate = 44100,
		uint32	channels = 1,
		uint32	bits_per_sample = 16
	)

Definition at line 75 of file AudioBackendLibao.cc.

References initialize().

    :
    AudioBackend(sample_rate, channels, bits_per_sample),
    options_(),
    error_buffer_(""),
    driver_id_(-1),
    device_ptr_(NULL)
{
    initialize();
};

AudioBackendLibao::~AudioBackendLibao

(

)

Definition at line 90 of file AudioBackendLibao.cc.

References shutdown().

{
    shutdown();
}

Nsound::AudioBackendLibao::AudioBackendLibao ( const AudioBackendLibao &  copy )

inlineprivate

Definition at line 111 of file AudioBackendLibao.h.

        :
        AudioBackend(),
        options_(),
        error_buffer_(""),
        driver_id_(-1),
        device_ptr_(NULL){};

Member Function Documentation

AudioBackendType AudioBackendLibao::getBackendType ( )

virtual

Implements Nsound::AudioBackend.

Definition at line 97 of file AudioBackendLibao.cc.

References Nsound::BACKEND_TYPE_LIBAO.

{
    return BACKEND_TYPE_LIBAO;
}

std::string AudioBackendLibao::getError ( )

virtual

Implements Nsound::AudioBackend.

Definition at line 104 of file AudioBackendLibao.cc.

References error_buffer_.

Referenced by getInfo().

{
    return error_buffer_.str();
}

std::string AudioBackendLibao::getInfo ( )

virtual

Implements Nsound::AudioBackend.

Definition at line 161 of file AudioBackendLibao.cc.

References Nsound::AudioBackend::BACKEND_ERROR, Nsound::AudioBackend::BACKEND_NOT_INITIALIZED, driver_id_, getError(), M_THROW, print_info(), and Nsound::AudioBackend::state_.

{
    #ifndef NSOUND_LIBAO
        state_ = BACKEND_ERROR;
        M_THROW("Nsound::AudioBackendLibao::getInfo():"
            << ": Nsound was not compiled with libao support.\n");
        return;
    #else
        if(state_ == BACKEND_NOT_INITIALIZED)
        {
            return "Nsound::AudioBackendLibao::getInfo(): "
                "Backend not initialized yet";
        }
        else if(state_ == BACKEND_ERROR)
        {
            return getError();
        }

        ao_info * info = ao_driver_info(driver_id_);

        if(info == NULL)
        {
            return "Nsound::AudioBackendLibao::getInfo(): "
                "ao_driver_info() failed";
        }

        return print_info(info);
    #endif
}

void AudioBackendLibao::initialize ( )

virtual

Implements Nsound::AudioBackend.

Definition at line 193 of file AudioBackendLibao.cc.

References Nsound::AudioBackend::BACKEND_ERROR, Nsound::AudioBackend::BACKEND_NOT_INITIALIZED, Nsound::AudioBackend::BACKEND_READY, Nsound::AudioBackend::bits_per_sample_, Nsound::AudioBackend::channels_, device_ptr_, driver_id_, error_buffer_, M_THROW, options_, Nsound::AudioBackend::sample_rate_, and Nsound::AudioBackend::state_.

Referenced by AudioBackendLibao(), and scanDevices().

{
    #ifndef NSOUND_LIBAO
        state_ = BACKEND_ERROR;
        M_THROW("Nsound::AudioBackendLibao::initialize():"
            << ": Nsound was not compiled with libao support.\n");
        return;
    #else

        // Only initialize if the back end has not been initialized yet.
        if(state_ != BACKEND_NOT_INITIALIZED)
        {
            return;
        }

        ao_initialize();

        if(driver_id_ < 0)
        {
            driver_id_ = ao_default_driver_id();
        }

        if(driver_id_ < 0)
        {
            ao_shutdown();

            error_buffer_ << "ao_default_driver_id() failed" << endl;

            state_ = BACKEND_ERROR;

            return;
        }

        // Setup the sample format.
        ao_sample_format format;

        memset(&format, 0, sizeof(ao_sample_format));

        format.bits = bits_per_sample_;
        format.rate = sample_rate_;
        format.channels = channels_;

        #ifdef NSOUND_LITTLE_ENDIAN
            format.byte_format = AO_FMT_LITTLE;
        #else
            format.byte_format = AO_FMT_BIG;
        #endif

        // Need to add config check for the matrix field, for now, just
        // disable.

//~        char matrix[16];
//~        format.matrix = matrix;

//~        switch(channels_)
//~        {
//~            case 1:
//~                sprintf(matrix, "M");
//~                break;

//~            case 2:
//~                sprintf(matrix, "L,R");
//~                break;

//~            default:
//~                error_buffer_
//~                    << "Nsound::AudioBackendLibao::initialize(): "
//~                    << "Don't know how to map "
//~                    << channels_
//~                    << " channels to the ao_sample_format.matrix"
//~                    << endl;

//~               shutdown();
//~               state_ = BACKEND_ERROR;

//~               return;
//~        }

        // Setup any options.

        ao_option * options = NULL;

        uint32 n_options = static_cast<uint32>(options_.size());

        int32 ecode = 0;

        if(n_options >= 2)
        {
            for(uint32 i = 0; i < n_options; i += 2)
            {
                ecode = ao_append_option(
                    &options,
                    options_[i    ].c_str(),
                    options_[i + 1].c_str());

                if(ecode != 1)
                {
                    ao_shutdown();

                    error_buffer_
                        << "Nsound::AudioBackendLibao::initialize():"
                        << __LINE__
                        << ": error appending libao '"
                        << options_[i]
                        << "' : '"
                        << options_[i + 1]
                        << "' device option"
                        << endl;

                    state_ = BACKEND_ERROR;

                    return;
                }
            }
        }

        device_ptr_ = ao_open_live(driver_id_, &format, options);

        ao_free_options(options);

        if(device_ptr_ == NULL)
        {
            ao_shutdown();

            error_buffer_
                << "Nsound::AudioBackendLibao::initialize():"
                << __LINE__
                << ": ao_open_live() failed:"
                << endl;

            switch(errno)
            {
                case AO_ENODRIVER:
                    error_buffer_
                        << "No driver corresponds to driver_id ("
                        << driver_id_
                        << ")"
                        << endl;
                    break;

                case AO_ENOTLIVE:
                    error_buffer_
                        << "This driver is not a live output device"
                        << endl;
                    break;

                case AO_EBADOPTION:
                    error_buffer_
                        << "A valid option key has an invalid value"
                        << endl;
                    break;

                case AO_EOPENDEVICE:
                    error_buffer_
                        << "Cannot open the device (for example, if "
                        << "/dev/dsp cannot be opened for writing)"
                        << endl;
                    break;

                case AO_EFAIL:
                    error_buffer_
                        << "Any other cause of failure"
                        << endl;
                    break;

                default:
                    error_buffer_
                        << "Reason unknown"
                        << endl;
                    break;
            }

            state_ = BACKEND_ERROR;

            return;
        }

        state_ = BACKEND_READY;
    #endif
}

void AudioBackendLibao::play ( void *  data, uint32  n_bytes  )

virtual

Implements Nsound::AudioBackend.

Definition at line 376 of file AudioBackendLibao.cc.

References Nsound::AudioBackend::BACKEND_ERROR, Nsound::AudioBackend::BACKEND_READY, device_ptr_, error_buffer_, M_THROW, and Nsound::AudioBackend::state_.

{
    #ifndef NSOUND_LIBAO
        state_ = BACKEND_ERROR;
        M_THROW("Nsound::AudioBackendLibao::play():"
            << ": Nsound was not compiled with libao support.\n");
        return;
    #else

        if(state_ != BACKEND_READY)
        {
            return;
        }

        if(n_bytes == 0)
        {
            return;
        }

        if(data == NULL)
        {
            error_buffer_
                << "AudioBackendLibao::play():"
                << __LINE__
                << ": data == NULL"
                << endl;

            state_ = BACKEND_ERROR;

            return;
        }

        int32 ecode = 0;

        ecode = ao_play(
            device_ptr_,
            reinterpret_cast<char *>(data),
            n_bytes);

        if(ecode == 0)
        {
            state_ = BACKEND_ERROR;

            ao_close(device_ptr_);
            ao_shutdown();

            error_buffer_
                << "AudioBackendLibao::play():"
                << __LINE__
                << ": ao_play() failed"
                << endl;

            return;
        }

    #endif
}

void AudioBackendLibao::scanDevices ( AudioPlayback &  pb, const AudioStream &  test_clip  )

virtual

Implements Nsound::AudioBackend.

Definition at line 467 of file AudioBackendLibao.cc.

References driver_id_, driver_types, initialize(), N_DRIVER_TYPES, Nsound::AudioPlayback::play(), and shutdown().

{
    for(uint32 i = 0; i < N_DRIVER_TYPES; ++i)
    {
        int32 id = ao_driver_id(driver_types[i].c_str());

        if(id >= 0)
        {
            shutdown();
            driver_id_ = id;
            initialize();

            cout << "Libao: found driver '"
                 << driver_types[i].c_str()
                 << "', id = "
                 << id
                 << "\nPLAYBACK STARTING ...";
            cout.flush();

            pb.play(test_clip);

            cout << " STOPPED\n";
            cout.flush();

            shutdown();
        }
    }
}

void AudioBackendLibao::setOption ( const std::string &  key, const std::string &  value  )

virtual

Set libao options.

Available options:

Key	Value
"driver"	"alsa", "arts", "axis", "esd", "irix", "macosx", "nas", "oss", "pulse", "roar", "sndio", "sun", "wmm"

Each libao driver has specific options. Please read the labao documentation for the options here.

Implements Nsound::AudioBackend.

Definition at line 498 of file AudioBackendLibao.cc.

References Nsound::AudioBackend::BACKEND_ERROR, driver_id_, integer(), lower(), M_THROW, options_, and Nsound::AudioBackend::state_.

{
    #ifndef NSOUND_LIBAO
        state_ = BACKEND_ERROR;
        M_THROW("Nsound::AudioBackendLibao::setOption():"
            << ": Nsound was not compiled with libao support.\n");
        return;
    #else

        std::string k = lower(key);

        // Special handeling if key == "id"
        if(k == "id")
        {
            int32 id = integer(value, &state_);
            if(id >= 0) driver_id_ = id;
        }
        else
        if(k == "driver")
        {
            int32 id = ao_driver_id(value.c_str());

            cerr << "key = 'driver', value = '"
                 << value.c_str()
                 << "', id = "
                 << id
                 << "\n";
            cerr.flush();

            if(id >= 0)
            {
                driver_id_ = id;
            }
            else
            {
                state_ = BACKEND_ERROR;
                M_THROW("Nsound::AudioBackendLibao::setOption():"
                    << ": failed to select driver '"
                    << value
                    << "'\n");
                return;
            }
        }
        else
        {
            options_.push_back(key);
            options_.push_back(value);
        }
    #endif
}

void AudioBackendLibao::shutdown ( )

virtual

Implements Nsound::AudioBackend.

Definition at line 551 of file AudioBackendLibao.cc.

References Nsound::AudioBackend::BACKEND_ERROR, Nsound::AudioBackend::BACKEND_NOT_INITIALIZED, device_ptr_, driver_id_, M_THROW, and Nsound::AudioBackend::state_.

Referenced by scanDevices(), and ~AudioBackendLibao().

{
    #ifndef NSOUND_LIBAO
        state_ = BACKEND_ERROR;
        M_THROW("Nsound::AudioBackendLibao::shutdown():"
            << ": Nsound was not compiled with libao support.\n");
        return;
    #else
        if(device_ptr_ != NULL)
        {
            ao_close(device_ptr_);
            device_ptr_ = NULL;
            driver_id_ = -1;
        }

        ao_shutdown();
        state_ = BACKEND_NOT_INITIALIZED;
    #endif
}

AudioBackendLibao& Nsound::AudioBackendLibao::operator= ( const AudioBackendLibao &  rhs )

inlineprivate

Definition at line 119 of file AudioBackendLibao.h.

{return *this;};

uint32 Nsound::AudioBackend::getBitsPerSample ( )

inlineinherited

Definition at line 77 of file AudioBackend.h.

References Nsound::AudioBackend::bits_per_sample_.

Referenced by Nsound::AudioPlayback::getBitsPerSample().

{return bits_per_sample_;};

uint32 Nsound::AudioBackend::getChannels ( )

inlineinherited

Definition at line 80 of file AudioBackend.h.

References Nsound::AudioBackend::channels_.

Referenced by Nsound::AudioPlayback::getChannels(), and play_int().

{return channels_;};

uint32 Nsound::AudioBackend::getSampleRate ( )

inlineinherited

Definition at line 91 of file AudioBackend.h.

References Nsound::AudioBackend::sample_rate_.

Referenced by Nsound::AudioPlayback::getSampleRate().

{return sample_rate_;};

State Nsound::AudioBackend::getState ( )

inlineinherited

Definition at line 94 of file AudioBackend.h.

References Nsound::AudioBackend::state_.

Referenced by Nsound::AudioPlayback::getState(), Nsound::AudioPlayback::initialize(), Nsound::AudioPlayback::scanDevices(), and Nsound::AudioPlayback::setOption().

{return state_;};

std::string AudioBackend::getStateString ( )

inherited

Returns the backend state.

Definition at line 43 of file AudioBackend.cc.

References Nsound::AudioBackend::state_, and state_strings.

Referenced by Nsound::AudioPlayback::getStateString().

{
    return state_strings[state_];
}

std::string AudioBackend::getStateString ( const AudioBackend::State &  state )

staticinherited

Returns the backend state string.

Definition at line 51 of file AudioBackend.cc.

References Nsound::AudioBackend::BACKEND_ERROR, Nsound::AudioBackend::BACKEND_NOT_INITIALIZED, and state_strings.

{
    if( state >= BACKEND_NOT_INITIALIZED &&
        state <= BACKEND_ERROR)
    {
        return state_strings[state];
    }

    return "Unknown Backend State";
}

Member Data Documentation

std::vector< std::string > Nsound::AudioBackendLibao::options_

private

Definition at line 119 of file AudioBackendLibao.h.

Referenced by initialize(), and setOption().

std::stringstream Nsound::AudioBackendLibao::error_buffer_

private

Definition at line 122 of file AudioBackendLibao.h.

Referenced by getError(), initialize(), and play().

int32 Nsound::AudioBackendLibao::driver_id_

private

Definition at line 124 of file AudioBackendLibao.h.

Referenced by getInfo(), initialize(), scanDevices(), setOption(), and shutdown().

ao_device* Nsound::AudioBackendLibao::device_ptr_

private

Definition at line 125 of file AudioBackendLibao.h.

Referenced by initialize(), play(), and shutdown().

uint32 Nsound::AudioBackend::sample_rate_

protectedinherited

Definition at line 127 of file AudioBackend.h.

Referenced by Nsound::AudioBackend::getSampleRate(), initialize(), and Nsound::AudioBackendLibportaudio::initialize().

uint32 Nsound::AudioBackend::channels_

protectedinherited

Definition at line 128 of file AudioBackend.h.

Referenced by Nsound::AudioBackend::getChannels(), initialize(), and Nsound::AudioBackendLibportaudio::initialize().

uint32 Nsound::AudioBackend::bits_per_sample_

protectedinherited

Definition at line 129 of file AudioBackend.h.

Referenced by Nsound::AudioBackend::getBitsPerSample(), initialize(), and Nsound::AudioBackendLibportaudio::initialize().

State Nsound::AudioBackend::state_

protectedinherited

Definition at line 130 of file AudioBackend.h.

Referenced by getInfo(), Nsound::AudioBackendLibportaudio::getInfo(), Nsound::AudioBackend::getState(), Nsound::AudioBackend::getStateString(), initialize(), Nsound::AudioBackendLibportaudio::initialize(), play(), Nsound::AudioBackendLibportaudio::play(), setOption(), Nsound::AudioBackendLibportaudio::setOption(), shutdown(), Nsound::AudioBackendLibportaudio::shutdown(), and Nsound::AudioBackendLibportaudio::~AudioBackendLibportaudio().

---

The documentation for this class was generated from the following files:

• Nsound/AudioBackendLibao.h
• Nsound/AudioBackendLibao.cc