示例#1
0
static int
portaudio_driver_reset_parameters (portaudio_driver_t* driver,
				   jack_nframes_t nframes,
				   jack_nframes_t rate)
{
	if (!jack_power_of_two(nframes)) {
		jack_error("PA: frames must be a power of two "
			 "(64, 512, 1024, ...)");
		return EINVAL;
	}

	Pa_CloseStream(driver->stream);
	return portaudio_driver_set_parameters (driver, nframes, rate);
}
示例#2
0
/** create a new driver instance
 */
static jack_driver_t *
coreaudio_driver_new (char *name,
                      jack_client_t* client,
                      jack_nframes_t frames_per_cycle,
                      jack_nframes_t rate,
                      int capturing,
                      int playing,
                      int chan_in,
                      int chan_out,
                      DitherAlgorithm dither,
                      char* driver_name,AudioDeviceID deviceID)
{
    coreaudio_driver_t *driver;

    JCALog ("coreaudio beta %d driver\n",CAVersion);

    driver = (coreaudio_driver_t *) calloc (1, sizeof (coreaudio_driver_t));

    jack_driver_init ((jack_driver_t *) driver);

    if (!jack_power_of_two(frames_per_cycle)) {
        JCALog (" -p must be a power of two.\n");
        goto error;
    }

    driver->frames_per_cycle = frames_per_cycle;
    driver->device_frame_rate = rate;
    driver->capturing = capturing;
    driver->playing = playing;
    driver->needsChangeBufferSize = FALSE;
    driver->new_bsize = frames_per_cycle;

    driver->attach = (JackDriverAttachFunction) coreaudio_driver_attach;
    driver->detach = (JackDriverDetachFunction) coreaudio_driver_detach;
    driver->read = (JackDriverReadFunction) coreaudio_driver_read;
    driver->write = (JackDriverReadFunction) coreaudio_driver_write;
    driver->null_cycle = (JackDriverNullCycleFunction) coreaudio_driver_null_cycle;
    //driver->bufsize = (JackDriverBufSizeFunction) coreaudio_driver_bufsize;
    driver->start = (JackDriverStartFunction) coreaudio_driver_audio_start;
    driver->stop = (JackDriverStopFunction) coreaudio_driver_audio_stop;
    driver->stream = NULL;

    char deviceName[60];
    bzero(&deviceName[0],sizeof(char)*60);

    if(!driver_name) {
        if (GetDeviceNameFromID(deviceID,deviceName) != noErr) goto error;
    } else {
        strcpy(&deviceName[0],driver_name);
    }

    driver->stream = openAudioInstance((float)rate,frames_per_cycle,chan_in,chan_out,&deviceName[0]);

    if(!driver->stream) goto error;

    driver->client = client;
    driver->period_usecs = (((float)driver->frames_per_cycle) / driver->device_frame_rate) * 1000000.0f;

    setHostData(driver->stream,driver);
    setCycleFun(driver->stream,coreaudio_runCycle);

    driver->incoreaudio = NULL;
    driver->outcoreaudio = NULL;

    driver->playback_nchannels = chan_out;
    driver->capture_nchannels = chan_in;

    strcpy(&driver->driver_name[0],&deviceName[0]);

    jack_init_time();

    return((jack_driver_t *) driver);

error:

    JCALog("Cannot open the coreaudio stream\n");
    free(driver);
    return NULL;
}
示例#3
0
/** create a new driver instance
 */
static jack_driver_t *
portaudio_driver_new (char *name, 
				jack_client_t* client,
				jack_nframes_t frames_per_cycle,
				jack_nframes_t rate,
				int capturing,
				int playing,
				int chan_in, 
				int chan_out,
				DitherAlgorithm dither,
				char* driver_name)
{
	portaudio_driver_t *driver;
	PaError err = paNoError;
	int numDevices;
	int inputDeviceID,outputDeviceID;
	int found;
	
	PALog("portaudio driver version : %d\n", kVersion);
	PALog("creating portaudio driver ... %" PRIu32 "|%" PRIu32 "\n",
		frames_per_cycle, rate);

	driver = (portaudio_driver_t *) calloc (1, sizeof (portaudio_driver_t));

	jack_driver_init ((jack_driver_t *) driver);

	if (!jack_power_of_two(frames_per_cycle)) {
		jack_error ("PA: -p must be a power of two.");
		goto error;
	}

	driver->frames_per_cycle = frames_per_cycle;
	driver->frame_rate = rate;
	driver->capturing = capturing;
	driver->playing = playing;

	driver->attach = (JackDriverAttachFunction) portaudio_driver_attach;
	driver->detach = (JackDriverDetachFunction) portaudio_driver_detach;
	driver->read = (JackDriverReadFunction) portaudio_driver_read;
	driver->write = (JackDriverReadFunction) portaudio_driver_write;
	driver->null_cycle = (JackDriverNullCycleFunction) portaudio_driver_null_cycle;
	driver->bufsize = (JackDriverBufSizeFunction) portaudio_driver_bufsize;
	driver->start = (JackDriverStartFunction) portaudio_driver_audio_start;
	driver->stop = (JackDriverStopFunction) portaudio_driver_audio_stop;
	driver->stream = NULL;

#ifdef JACK_USE_MACH_THREADS	
	AudioDeviceID device_id;
	if (driver_name) {
		if (get_device_id_from_uid(driver_name, &device_id) != noErr)
			goto error;
		if (get_device_name_from_id(device_id, driver->driver_name) != noErr)
			goto error;
	} else {
		if (get_device_id_from_num(0, &device_id) != noErr)
			goto error; 
		if (get_device_name_from_id(device_id, driver->driver_name) != noErr)
			goto error;
	}
#endif
       
	err = Pa_Initialize();
	PALog("Pa_Initialize OK \n");
	
	PALog("Driver name required %s\n",driver->driver_name);
	numDevices = Pa_CountDevices();
	
	if( numDevices < 0 ){
		PALog("ERROR: Pa_CountDevices returned 0x%x\n", numDevices);
		err = numDevices;
		goto error;
	}
	
	PALog("Number of devices = %d\n", numDevices);

	if (strcmp(driver->driver_name,"") == 0) {
		found = portaudio_load_default(driver,numDevices,capturing,playing,&inputDeviceID,&outputDeviceID);
		if (!found) {
			PALog("ERROR : default driver has not been found\n");
			err = paHostError;
			goto error;
		}
	}else{
		found = portaudio_load_driver(driver,numDevices,capturing,playing,&inputDeviceID,&outputDeviceID,driver->driver_name);
		if (!found) {
			 PALog("ERROR : driver %s has not been found \n",driver->driver_name);
			 err = paHostError;
			 goto error;
		}
	}

	if (err != paNoError) goto error;
	
	PALog("Pa_GetDefaultOutputDeviceID() %ld\n", (long)Pa_GetDefaultOutputDeviceID());
	PALog("Pa_GetDefaultInputDeviceID() %ld\n",  (long)Pa_GetDefaultInputDeviceID());
	
	PALog("--------------------------------------------------\n");
	PALog("CoreAudio driver %s will be loaded\n", driver->driver_name);
	PALog("inputDeviceID %ld\n",  (long)inputDeviceID);
	PALog("outputDeviceID %ld\n",  (long)outputDeviceID);
	PALog("driver->capture_nchannels %ld\n", driver->capture_nchannels);
	PALog("driver->playback_nchannels %ld\n", driver->playback_nchannels);
	
	PALog("chan_in, chan_out %ld %ld\n",  (long)chan_in,  (long)chan_out);
        
	if (chan_in > 0) 
		driver->capture_nchannels = (driver->capture_nchannels < chan_in) ? driver->capture_nchannels : chan_in;
	
	if (chan_out > 0) 
		driver->playback_nchannels = (driver->playback_nchannels < chan_out) ? driver->playback_nchannels : chan_out;
		
	PALog("driver->capture_nchannels %ld\n", driver->capture_nchannels);
	PALog("driver->playback_nchannels %ld\n", driver->playback_nchannels);
	
	err = Pa_OpenStream(&driver->stream,
						((capturing && (driver->capture_nchannels > 0)) ? inputDeviceID : paNoDevice),
						((capturing) ? driver->capture_nchannels : 0),             
						paFloat32,	// 32 bit floating point input 
						NULL,
						((playing && (driver->playback_nchannels > 0)) ? outputDeviceID : paNoDevice),
						((playing) ? driver->playback_nchannels : 0),        
						paFloat32,  // 32 bit floating point output 
						NULL,
						rate,
						frames_per_cycle,            // frames per buffer 
						0,              // number of buffers, if zero then use default minimum 
						paClipOff,      // we won't output out of range samples so don't bother clipping them 
						paCallback,
						driver);
	
	if (err != paNoError) goto error;
	
	driver->client = client; 
	driver->period_usecs = (((float) driver->frames_per_cycle) / driver->frame_rate) * 1000000.0f;
	return((jack_driver_t *) driver);

error:

	Pa_Terminate();
	jack_error("An error occured while using the portaudio stream");
	jack_error("Error number: %d", err);
	jack_error("Error message: %s", Pa_GetErrorText(err));
	free(driver);
	return NULL;
}
示例#4
0
/** create a new driver instance
*/
static jack_driver_t *coreaudio_driver_new(char* name,
										   jack_client_t* client,
										   jack_nframes_t nframes,
										   jack_nframes_t samplerate,
										   int capturing,
										   int playing,
										   int inchannels,
										   int outchannels,
										   char* capture_driver_uid,
										   char* playback_driver_uid,
										   jack_nframes_t capture_latency, 
										   jack_nframes_t playback_latency)
{
    coreaudio_driver_t *driver;
	OSStatus err = noErr;
	ComponentResult err1;
    UInt32 outSize;
	UInt32 enableIO;
	AudioStreamBasicDescription srcFormat, dstFormat;
	Float64 sampleRate;
	int in_nChannels = 0;
	int out_nChannels = 0;
	int i;
	
    driver = (coreaudio_driver_t *) calloc(1, sizeof(coreaudio_driver_t));
    jack_driver_init((jack_driver_t *) driver);

    if (!jack_power_of_two(nframes)) {
		jack_error("CA: -p must be a power of two.");
		goto error;
    }

	driver->state = 0;
    driver->frames_per_cycle = nframes;
    driver->frame_rate = samplerate;
    driver->capturing = capturing;
    driver->playing = playing;
	driver->xrun_detected = 0;
	driver->null_cycle = 0;

    driver->attach = (JackDriverAttachFunction) coreaudio_driver_attach;
    driver->detach = (JackDriverDetachFunction) coreaudio_driver_detach;
    driver->read = (JackDriverReadFunction) coreaudio_driver_read;
    driver->write = (JackDriverReadFunction) coreaudio_driver_write;
    driver->null_cycle =
	(JackDriverNullCycleFunction) coreaudio_driver_null_cycle;
    driver->bufsize = (JackDriverBufSizeFunction) coreaudio_driver_bufsize;
    driver->start = (JackDriverStartFunction) coreaudio_driver_audio_start;
    driver->stop = (JackDriverStopFunction) coreaudio_driver_audio_stop;
	driver->capture_frame_latency = capture_latency;
	driver->playback_frame_latency = playback_latency;
	
	// Duplex
    if (strcmp(capture_driver_uid, "") != 0 && strcmp(playback_driver_uid, "") != 0) {
		JCALog("Open duplex \n");
        if (get_device_id_from_uid(playback_driver_uid, &driver->device_id) != noErr) {
            if (get_default_device(&driver->device_id) != noErr) {
				jack_error("Cannot open default device");
				goto error;
			}
		}
		if (get_device_name_from_id(driver->device_id, driver->capture_driver_name) != noErr || get_device_name_from_id(driver->device_id, driver->playback_driver_name) != noErr) {
			jack_error("Cannot get device name from device ID");
			goto error;
		}
		
	// Capture only
	} else if (strcmp(capture_driver_uid, "") != 0) {
		JCALog("Open capture only \n");
		if (get_device_id_from_uid(capture_driver_uid, &driver->device_id) != noErr) {
            if (get_default_input_device(&driver->device_id) != noErr) {
				jack_error("Cannot open default device");
                goto error;
			}
		}
		if (get_device_name_from_id(driver->device_id, driver->capture_driver_name) != noErr) {
			jack_error("Cannot get device name from device ID");
			goto error;
		}
		
  	// Playback only
	} else if (playback_driver_uid != NULL) {
		JCALog("Open playback only \n");
		if (get_device_id_from_uid(playback_driver_uid, &driver->device_id) != noErr) {
            if (get_default_output_device(&driver->device_id) != noErr) {
				jack_error("Cannot open default device");
                goto error;
			}
        }
		if (get_device_name_from_id(driver->device_id, driver->playback_driver_name) != noErr) {
			jack_error("Cannot get device name from device ID");
			goto error;
		}
		
	// Use default driver in duplex mode
	} else {
		JCALog("Open default driver \n");
		if (get_default_device(&driver->device_id) != noErr) {
			jack_error("Cannot open default device");
			goto error;
		}
		if (get_device_name_from_id(driver->device_id, driver->capture_driver_name) != noErr || get_device_name_from_id(driver->device_id, driver->playback_driver_name) != noErr) {
			jack_error("Cannot get device name from device ID");
			goto error;
		}
	}
	
	driver->client = client;
    driver->period_usecs =
		(((float) driver->frames_per_cycle) / driver->frame_rate) *
		1000000.0f;
	
	if (capturing) {
		err = get_total_channels(driver->device_id, &in_nChannels, true);
		if (err != noErr) { 
			jack_error("Cannot get input channel number");
			printError(err);
			goto error;
		} 
	}
	
	if (playing) {
		err = get_total_channels(driver->device_id, &out_nChannels, false);
		if (err != noErr) { 
			jack_error("Cannot get output channel number");
			printError(err);
			goto error;
		} 
	}
	
	if (inchannels > in_nChannels) {
        jack_error("This device hasn't required input channels inchannels = %ld in_nChannels = %ld", inchannels, in_nChannels);
		goto error;
    }
	
	if (outchannels > out_nChannels) {
        jack_error("This device hasn't required output channels outchannels = %ld out_nChannels = %ld", outchannels, out_nChannels);
		goto error;
    }

	if (inchannels == 0) {
		JCALog("Setup max in channels = %ld\n", in_nChannels);
		inchannels = in_nChannels; 
	}
		
	if (outchannels == 0) {
		JCALog("Setup max out channels = %ld\n", out_nChannels);
		outchannels = out_nChannels; 
	}

    // Setting buffer size
    outSize = sizeof(UInt32);
    err = AudioDeviceSetProperty(driver->device_id, NULL, 0, false, kAudioDevicePropertyBufferFrameSize, outSize, &nframes);
    if (err != noErr) {
        jack_error("Cannot set buffer size %ld", nframes);
        printError(err);
		goto error;
    }

	// Set sample rate
	outSize =  sizeof(Float64);
	err = AudioDeviceGetProperty(driver->device_id, 0, kAudioDeviceSectionGlobal, kAudioDevicePropertyNominalSampleRate, &outSize, &sampleRate);
	if (err != noErr) {
		jack_error("Cannot get current sample rate");
		printError(err);
		goto error;
	}

	if (samplerate != (jack_nframes_t)sampleRate) {
		sampleRate = (Float64)samplerate;
		
		// To get SR change notification
		err = AudioDeviceAddPropertyListener(driver->device_id, 0, true, kAudioDevicePropertyNominalSampleRate, sr_notification, driver);
		if (err != noErr) {
			jack_error("Error calling AudioDeviceAddPropertyListener with kAudioDevicePropertyNominalSampleRate");
			printError(err);
			return -1;
		}
		err = AudioDeviceSetProperty(driver->device_id, NULL, 0, kAudioDeviceSectionGlobal, kAudioDevicePropertyNominalSampleRate, outSize, &sampleRate);
		if (err != noErr) {
			jack_error("Cannot set sample rate = %ld", samplerate);
			printError(err);
			return -1;
		}
		
		// Waiting for SR change notification
		int count = 0;
		while (!driver->state && count++ < 100) {
			usleep(100000);
			JCALog("Wait count = %ld\n", count);
		}
		
		// Remove SR change notification
		AudioDeviceRemovePropertyListener(driver->device_id, 0, true, kAudioDevicePropertyNominalSampleRate, sr_notification);
	}

    // AUHAL
    ComponentDescription cd = {kAudioUnitType_Output, kAudioUnitSubType_HALOutput, kAudioUnitManufacturer_Apple, 0, 0};
    Component HALOutput = FindNextComponent(NULL, &cd);

    err1 = OpenAComponent(HALOutput, &driver->au_hal);
    if (err1 != noErr) {
		jack_error("Error calling OpenAComponent");
        printError(err1);
        goto error;
	}

    err1 = AudioUnitInitialize(driver->au_hal);
    if (err1 != noErr) {
		jack_error("Cannot initialize AUHAL unit");
		printError(err1);
        goto error;
	}

 	// Start I/O
	enableIO = 1;
	if (capturing && inchannels > 0) {
		JCALog("Setup AUHAL input\n");
        err1 = AudioUnitSetProperty(driver->au_hal, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &enableIO, sizeof(enableIO));
        if (err1 != noErr) {
            jack_error("Error calling AudioUnitSetProperty - kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input");
            printError(err1);
            goto error;
        }
    }
	
	if (playing && outchannels > 0) {
		JCALog("Setup AUHAL output\n");
		err1 = AudioUnitSetProperty(driver->au_hal, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &enableIO, sizeof(enableIO));
		if (err1 != noErr) {
			jack_error("Error calling AudioUnitSetProperty - kAudioOutputUnitProperty_EnableIO,kAudioUnitScope_Output");
			printError(err1);
			goto error;
		}
	}
	
	// Setup up choosen device, in both input and output cases
	err1 = AudioUnitSetProperty(driver->au_hal, kAudioOutputUnitProperty_CurrentDevice, kAudioUnitScope_Global, 0, &driver->device_id, sizeof(AudioDeviceID));
	if (err1 != noErr) {
		jack_error("Error calling AudioUnitSetProperty - kAudioOutputUnitProperty_CurrentDevice");
		printError(err1);
		goto error;
	}

	// Set buffer size
	if (capturing && inchannels > 0) {
		err1 = AudioUnitSetProperty(driver->au_hal, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 1, (UInt32*)&nframes, sizeof(UInt32));
		if (err1 != noErr) {
			jack_error("Error calling AudioUnitSetProperty - kAudioUnitProperty_MaximumFramesPerSlice");
			printError(err1);
			goto error;
		}
	}
	
	if (playing && outchannels > 0) {
		err1 = AudioUnitSetProperty(driver->au_hal, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Global, 0, (UInt32*)&nframes, sizeof(UInt32));
		if (err1 != noErr) {
			jack_error("Error calling AudioUnitSetProperty - kAudioUnitProperty_MaximumFramesPerSlice");
			printError(err1);
			goto error;
		}
	}

	// Setup channel map
	if (capturing && inchannels > 0 && inchannels < in_nChannels) {
        SInt32 chanArr[in_nChannels];
        for (i = 0; i < in_nChannels; i++) {
            chanArr[i] = -1;
        }
        for (i = 0; i < inchannels; i++) {
            chanArr[i] = i;
        }
        AudioUnitSetProperty(driver->au_hal, kAudioOutputUnitProperty_ChannelMap , kAudioUnitScope_Input, 1, chanArr, sizeof(SInt32) * in_nChannels);
        if (err1 != noErr) {
            jack_error("Error calling AudioUnitSetProperty - kAudioOutputUnitProperty_ChannelMap 1");
            printError(err1);
        }
    }

    if (playing && outchannels > 0 && outchannels < out_nChannels) {
        SInt32 chanArr[out_nChannels];
        for (i = 0;	i < out_nChannels; i++) {
            chanArr[i] = -1;
        }
        for (i = 0; i < outchannels; i++) {
            chanArr[i] = i;
        }
        err1 = AudioUnitSetProperty(driver->au_hal, kAudioOutputUnitProperty_ChannelMap, kAudioUnitScope_Output, 0, chanArr, sizeof(SInt32) * out_nChannels);
        if (err1 != noErr) {
            jack_error("Error calling AudioUnitSetProperty - kAudioOutputUnitProperty_ChannelMap 0");
            printError(err1);
        }
    }

	// Setup stream converters
  	srcFormat.mSampleRate = samplerate;
	srcFormat.mFormatID = kAudioFormatLinearPCM;
	srcFormat.mFormatFlags = kAudioFormatFlagsNativeFloatPacked | kLinearPCMFormatFlagIsNonInterleaved;
	srcFormat.mBytesPerPacket = sizeof(float);
	srcFormat.mFramesPerPacket = 1;
	srcFormat.mBytesPerFrame = sizeof(float);
	srcFormat.mChannelsPerFrame = outchannels;
	srcFormat.mBitsPerChannel = 32;

	err1 = AudioUnitSetProperty(driver->au_hal, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &srcFormat, sizeof(AudioStreamBasicDescription));
	if (err1 != noErr) {
		jack_error("Error calling AudioUnitSetProperty - kAudioUnitProperty_StreamFormat kAudioUnitScope_Input");
		printError(err1);
	}

	dstFormat.mSampleRate = samplerate;
	dstFormat.mFormatID = kAudioFormatLinearPCM;
	dstFormat.mFormatFlags = kAudioFormatFlagsNativeFloatPacked | kLinearPCMFormatFlagIsNonInterleaved;
	dstFormat.mBytesPerPacket = sizeof(float);
	dstFormat.mFramesPerPacket = 1;
	dstFormat.mBytesPerFrame = sizeof(float);
	dstFormat.mChannelsPerFrame = inchannels;
	dstFormat.mBitsPerChannel = 32;

	err1 = AudioUnitSetProperty(driver->au_hal, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, &dstFormat, sizeof(AudioStreamBasicDescription));
	if (err1 != noErr) {
		jack_error("Error calling AudioUnitSetProperty - kAudioUnitProperty_StreamFormat kAudioUnitScope_Output");
		printError(err1);
	}

	// Setup callbacks
    if (inchannels > 0 && outchannels == 0) {
        AURenderCallbackStruct output;
        output.inputProc = render_input;
        output.inputProcRefCon = driver;
    	err1 = AudioUnitSetProperty(driver->au_hal, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, 0, &output, sizeof(output));
        if (err1 != noErr) {
            jack_error("Error calling  AudioUnitSetProperty - kAudioUnitProperty_SetRenderCallback 1");
            printError(err1);
            goto error;
        }
    } else {
        AURenderCallbackStruct output;
        output.inputProc = render;
        output.inputProcRefCon = driver;
        err1 = AudioUnitSetProperty(driver->au_hal, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &output, sizeof(output));
        if (err1 != noErr) {
            jack_error("Error calling AudioUnitSetProperty - kAudioUnitProperty_SetRenderCallback 0");
            printError(err1);
            goto error;
        }
    }

	if (capturing && inchannels > 0) {
		driver->input_list = (AudioBufferList*)malloc(sizeof(UInt32) + inchannels * sizeof(AudioBuffer));
		if (driver->input_list == 0)
			goto error;
		driver->input_list->mNumberBuffers = inchannels;
		
		// Prepare buffers
		for (i = 0; i < driver->capture_nchannels; i++) {
			driver->input_list->mBuffers[i].mNumberChannels = 1;
			driver->input_list->mBuffers[i].mDataByteSize = nframes * sizeof(float);
		}
	}

	err = AudioDeviceAddPropertyListener(driver->device_id, 0, true, kAudioDeviceProcessorOverload, notification, driver);
    if (err != noErr) {
		jack_error("Error calling AudioDeviceAddPropertyListener with kAudioDeviceProcessorOverload");
        goto error;
	}
		
	err = AudioDeviceAddPropertyListener(driver->device_id, 0, true, kAudioDevicePropertyNominalSampleRate, notification, driver);
    if (err != noErr) {
        jack_error("Error calling AudioDeviceAddPropertyListener with kAudioDevicePropertyNominalSampleRate");
        goto error;
    }
 
	driver->playback_nchannels = outchannels;
    driver->capture_nchannels = inchannels;
	return ((jack_driver_t *) driver);

  error:
	AudioUnitUninitialize(driver->au_hal);
	CloseComponent(driver->au_hal);
    jack_error("Cannot open the coreaudio driver");
    free(driver);
    return NULL;
}