pa_win_ds.c

一个开源的sip源代码

        goto error;
    }

    memset( stream, 0, sizeof(PaWinDsStream) ); /* initialize all stream variables to 0 */

    if( streamCallback )
    {
        PaUtil_InitializeStreamRepresentation( &stream->streamRepresentation,
                                               &winDsHostApi->callbackStreamInterface, streamCallback, userData );
    }
    else
    {
        PaUtil_InitializeStreamRepresentation( &stream->streamRepresentation,
                                               &winDsHostApi->blockingStreamInterface, streamCallback, userData );
    }
    
    PaUtil_InitializeCpuLoadMeasurer( &stream->cpuLoadMeasurer, sampleRate );


    if( inputParameters )
    {
        /* IMPLEMENT ME - establish which  host formats are available */
        hostInputSampleFormat =
            PaUtil_SelectClosestAvailableFormat( paInt16 /* native formats */, inputParameters->sampleFormat );
    }
	else
	{
		hostInputSampleFormat = 0;
	}

    if( outputParameters )
    {
        /* IMPLEMENT ME - establish which  host formats are available */
        hostOutputSampleFormat =
            PaUtil_SelectClosestAvailableFormat( paInt16 /* native formats */, outputParameters->sampleFormat );
    }
    else
	{
		hostOutputSampleFormat = 0;
	}

    result =  PaUtil_InitializeBufferProcessor( &stream->bufferProcessor,
                    inputChannelCount, inputSampleFormat, hostInputSampleFormat,
                    outputChannelCount, outputSampleFormat, hostOutputSampleFormat,
                    sampleRate, streamFlags, framesPerBuffer,
                    framesPerBuffer, /* ignored in paUtilVariableHostBufferSizePartialUsageAllowed mode. */
                /* This next mode is required because DS can split the host buffer when it wraps around. */
                    paUtilVariableHostBufferSizePartialUsageAllowed,
                    streamCallback, userData );
    if( result != paNoError )
        goto error;


    stream->streamRepresentation.streamInfo.inputLatency =
            PaUtil_GetBufferProcessorInputLatency(&stream->bufferProcessor);   /* FIXME: not initialised anywhere else */
    stream->streamRepresentation.streamInfo.outputLatency =
            PaUtil_GetBufferProcessorOutputLatency(&stream->bufferProcessor);    /* FIXME: not initialised anywhere else */
    stream->streamRepresentation.streamInfo.sampleRate = sampleRate;

    
/* DirectSound specific initialization */ 
    {
        HRESULT          hr;
        int              bytesPerDirectSoundBuffer;
        int              userLatencyFrames;
        int              minLatencyFrames;

        stream->timerID = 0;

    /* Get system minimum latency. */
        minLatencyFrames = PaWinDs_GetMinLatencyFrames( sampleRate );

    /* Let user override latency by passing latency parameter. */
        userLatencyFrames = (suggestedInputLatencyFrames > suggestedOutputLatencyFrames)
                    ? suggestedInputLatencyFrames
                    : suggestedOutputLatencyFrames;
        if( userLatencyFrames > 0 ) minLatencyFrames = userLatencyFrames;

    /* Calculate stream->framesPerDSBuffer depending on framesPerBuffer */
        if( framesPerBuffer == paFramesPerBufferUnspecified )
        {
        /* App support variable framesPerBuffer */
            stream->framesPerDSBuffer = minLatencyFrames;

            stream->streamRepresentation.streamInfo.outputLatency = (double)(minLatencyFrames - 1) / sampleRate;
        }
        else
        {
        /* Round up to number of buffers needed to guarantee that latency. */
            int numUserBuffers = (minLatencyFrames + framesPerBuffer - 1) / framesPerBuffer;
            if( numUserBuffers < 1 ) numUserBuffers = 1;
            numUserBuffers += 1; /* So we have latency worth of buffers ahead of current buffer. */
            stream->framesPerDSBuffer = framesPerBuffer * numUserBuffers;

            stream->streamRepresentation.streamInfo.outputLatency = (double)(framesPerBuffer * (numUserBuffers-1)) / sampleRate;
        }

        {
            /** @todo REVIEW: this calculation seems incorrect to me - rossb. */
            int msecLatency = (int) ((stream->framesPerDSBuffer * MSEC_PER_SECOND) / sampleRate);
            PRINT(("PortAudio on DirectSound - Latency = %d frames, %d msec\n", stream->framesPerDSBuffer, msecLatency ));
        }


        /* ------------------ OUTPUT */
        if( outputParameters )
        {
            /*
            PaDeviceInfo *deviceInfo = hostApi->deviceInfos[ outputParameters->device ];
            DBUG(("PaHost_OpenStream: deviceID = 0x%x\n", outputParameters->device));
            */
            
            bytesPerDirectSoundBuffer = stream->framesPerDSBuffer * outputParameters->channelCount * sizeof(short);
            if( bytesPerDirectSoundBuffer < DSBSIZE_MIN )
            {
                result = paBufferTooSmall;
                goto error;
            }
            else if( bytesPerDirectSoundBuffer > DSBSIZE_MAX )
            {
                result = paBufferTooBig;
                goto error;
            }


            hr = paWinDsDSoundEntryPoints.DirectSoundCreate( winDsHostApi->winDsDeviceInfos[outputParameters->device].lpGUID,
                        &stream->pDirectSound, NULL );
            if( hr != DS_OK )
            {
                ERR_RPT(("PortAudio: DirectSoundCreate() failed!\n"));
                result = paUnanticipatedHostError;
                PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr );
                goto error;
            }
            hr = InitOutputBuffer( stream,
                                       (unsigned long) (sampleRate + 0.5),
                                       (WORD)outputParameters->channelCount, bytesPerDirectSoundBuffer );
            DBUG(("InitOutputBuffer() returns %x\n", hr));
            if( hr != DS_OK )
            {
                result = paUnanticipatedHostError;
                PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr );
                goto error;
            }
            /* Calculate value used in latency calculation to avoid real-time divides. */
            stream->secondsPerHostByte = 1.0 /
                (stream->bufferProcessor.bytesPerHostOutputSample *
                outputChannelCount * sampleRate);
        }

        /* ------------------ INPUT */
        if( inputParameters )
        {
            /*
            PaDeviceInfo *deviceInfo = hostApi->deviceInfos[ inputParameters->device ];
            DBUG(("PaHost_OpenStream: deviceID = 0x%x\n", inputParameters->device));
            */
            
            bytesPerDirectSoundBuffer = stream->framesPerDSBuffer * inputParameters->channelCount * sizeof(short);
            if( bytesPerDirectSoundBuffer < DSBSIZE_MIN )
            {
                result = paBufferTooSmall;
                goto error;
            }
            else if( bytesPerDirectSoundBuffer > DSBSIZE_MAX )
            {
                result = paBufferTooBig;
                goto error;
            }

            hr = paWinDsDSoundEntryPoints.DirectSoundCaptureCreate( winDsHostApi->winDsDeviceInfos[inputParameters->device].lpGUID,
                        &stream->pDirectSoundCapture,   NULL );
            if( hr != DS_OK )
            {
                ERR_RPT(("PortAudio: DirectSoundCaptureCreate() failed!\n"));
                result = paUnanticipatedHostError;
                PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr );
                goto error;
            }
            hr = InitInputBuffer( stream,
                                      (unsigned long) (sampleRate + 0.5),
                                      (WORD)inputParameters->channelCount, bytesPerDirectSoundBuffer );
            DBUG(("InitInputBuffer() returns %x\n", hr));
            if( hr != DS_OK )
            {
                ERR_RPT(("PortAudio: DSW_InitInputBuffer() returns %x\n", hr));
                result = paUnanticipatedHostError;
                PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr );
                goto error;
            }
        }

    }

    *s = (PaStream*)stream;

    return result;

error:
    if( stream )
        PaUtil_FreeMemory( stream );

    return result;
}


/************************************************************************************
 * Determine how much space can be safely written to in DS buffer.
 * Detect underflows and overflows.
 * Does not allow writing into safety gap maintained by DirectSound.
 */
static HRESULT QueryOutputSpace( PaWinDsStream *stream, long *bytesEmpty )
{
    HRESULT hr;
    DWORD   playCursor;
    DWORD   writeCursor;
    long    numBytesEmpty;
    long    playWriteGap;
    // Query to see how much room is in buffer.
    hr = IDirectSoundBuffer_GetCurrentPosition( stream->pDirectSoundOutputBuffer,
            &playCursor, &writeCursor );
    if( hr != DS_OK )
    {
        return hr;
    }
    // Determine size of gap between playIndex and WriteIndex that we cannot write into.
    playWriteGap = writeCursor - playCursor;
    if( playWriteGap < 0 ) playWriteGap += stream->outputBufferSizeBytes; // unwrap
    /* DirectSound doesn't have a large enough playCursor so we cannot detect wrap-around. */
    /* Attempt to detect playCursor wrap-around and correct it. */
    if( stream->outputIsRunning && (stream->perfCounterTicksPerBuffer.QuadPart != 0) )
    {
        /* How much time has elapsed since last check. */
        LARGE_INTEGER   currentTime;
        LARGE_INTEGER   elapsedTime;
        long            bytesPlayed;
        long            bytesExpected;
        long            buffersWrapped;
        QueryPerformanceCounter( &currentTime );
        elapsedTime.QuadPart = currentTime.QuadPart - stream->previousPlayTime.QuadPart;
        stream->previousPlayTime = currentTime;
        /* How many bytes does DirectSound say have been played. */
        bytesPlayed = playCursor - stream->previousPlayCursor;
        if( bytesPlayed < 0 ) bytesPlayed += stream->outputBufferSizeBytes; // unwrap
        stream->previousPlayCursor = playCursor;
        /* Calculate how many bytes we would have expected to been played by now. */
        bytesExpected = (long) ((elapsedTime.QuadPart * stream->outputBufferSizeBytes) / stream->perfCounterTicksPerBuffer.QuadPart);
        buffersWrapped = (bytesExpected - bytesPlayed) / stream->outputBufferSizeBytes;
        if( buffersWrapped > 0 )
        {
            playCursor += (buffersWrapped * stream->outputBufferSizeBytes);
            bytesPlayed += (buffersWrapped * stream->outputBufferSizeBytes);
        }
        /* Maintain frame output cursor. */
        stream->framesPlayed += (bytesPlayed / stream->bytesPerOutputFrame);
    }
    numBytesEmpty = playCursor - stream->outputBufferWriteOffsetBytes;
    if( numBytesEmpty < 0 ) numBytesEmpty += stream->outputBufferSizeBytes; // unwrap offset
    /* Have we underflowed? */
    if( numBytesEmpty > (stream->outputBufferSizeBytes - playWriteGap) )
    {
        if( stream->outputIsRunning )
        {
            stream->outputUnderflowCount += 1;
        }
        stream->outputBufferWriteOffsetBytes = writeCursor;
        numBytesEmpty = stream->outputBufferSizeBytes - playWriteGap;
    }
    *bytesEmpty = numBytesEmpty;
    return hr;
}

/***********************************************************************************/
static PaError Pa_TimeSlice( PaWinDsStream *stream )
{
    PaError           result = 0;   /* FIXME: this should be declared int and this function should also return that type (same as stream callback return type)*/
    long              numFrames = 0;
    long              bytesEmpty = 0;
    long              bytesFilled = 0;
    long              bytesToXfer = 0;
    long              framesToXfer = 0;
    long              numInFramesReady = 0;
    long              numOutFramesReady = 0;
    long              bytesProcessed;
    HRESULT           hresult;
    double            outputLatency = 0;
    PaStreamCallbackTimeInfo timeInfo = {0,0,0}; /** @todo implement inputBufferAdcTime */
    
/* Input */
    LPBYTE            lpInBuf1 = NULL;
    LPBYTE            lpInBuf2 = NULL;
    DWORD             dwInSize1 = 0;
    DWORD             dwInSize2 = 0;
/* Output */
    LPBYTE            lpOutBuf1 = NULL;
    LPBYTE            lpOutBuf2 = NULL;
    DWORD             dwOutSize1 = 0;
    DWORD             dwOutSize2 = 0;

    /* How much input data is available? */
    if( stream->bufferProcessor.inputChannelCount > 0 )
    {
        HRESULT hr;
        DWORD capturePos;
        DWORD readPos;
        long  filled = 0;
        // Query to see how much data is in buffer.
        // We don't need the capture position but sometimes DirectSound doesn't handle NULLS correctly
        // so let's pass a pointer just to be safe.
        hr = IDirectSoundCaptureBuffer_GetCurrentPosition( stream->pDirectSoundInputBuffer, &capturePos, &readPos );
        if( hr == DS_OK )
        {
            filled = readPos - stream->readOffset;
            if( filled < 0 ) filled += stream->inputSize; // unwrap offset
            bytesFilled = filled;
        }
            // FIXME: what happens if IDirectSoundCaptureBuffer_GetCurrentPosition fails?

        framesToXfer = numInFramesReady = bytesFilled / stream->bytesPerInputFrame;
        outputLatency = ((double)bytesFilled) * stream->secondsPerHostByte;

        /** @todo Check for overflow */
    }

    /* How much output room is available? */
    if( stream->bufferProcessor.outputChannelCount > 0 )
    {
        UINT previousUnderflowCount = stream->outputUnderflowCount;
        QueryOutputSpace( stream, &bytesEmpty );
        framesToXfer = numOutFramesReady = bytesEmpty / stream->bytesPerOutputFrame;

        /* Check for underflow */
        if( stream->outputUnderflowCount != previousUnderflowCount )
            stream->callbackFlags |= paOutputUnderflow;
    }

    if( (numInFramesReady > 0) && (numOutFramesReady > 0) )
    {
        framesToXfer = (n