capvideo.c

虚拟摄像头驱动

**    Context - pointer to the stream extension
**
** Returns: nothing
**
** Side Effects:  none
*/

VOID
STREAMAPI
VideoTimerRoutine(
    PVOID Context
    )
{
    PSTREAMEX                   pStrmEx = ((PSTREAMEX)Context);
    PHW_DEVICE_EXTENSION        pHwDevExt = pStrmEx->pHwDevExt;
    int                         StreamNumber = pStrmEx->pStreamObject->StreamNumber;

    // If we're stopped and the timer is still running, just return.
    // This will stop the timer.

    if (pStrmEx->KSState == KSSTATE_STOP) {
        return;
    }

    // Capture a frame if it's time and we have a buffer

    VideoCaptureRoutine(pStrmEx);

    // Schedule the next timer event
    // Make it run at 2x the requested capture rate (which is in 100nS units)

    StreamClassScheduleTimer (
            pStrmEx->pStreamObject,     // StreamObject
            pHwDevExt,                  // HwDeviceExtension
            (ULONG) (pStrmEx->AvgTimePerFrame / 20), // Microseconds
            VideoTimerRoutine,          // TimerRoutine
            pStrmEx);                   // Context
}


/*
** VideoCaptureRoutine()
**
**    Routine to capture video frames based on a timer.
**
**    Note:  Devices capable of using interrupts should always
**           trigger capture on a VSYNC interrupt, and not use a timer.
**
** Arguments:
**
** Returns: nothing
**
** Side Effects:  none
*/

VOID
STREAMAPI
VideoCaptureRoutine(
    IN PSTREAMEX pStrmEx
    )
{
    PHW_DEVICE_EXTENSION    pHwDevExt = pStrmEx->pHwDevExt;
    int                     StreamNumber = pStrmEx->pStreamObject->StreamNumber;
    PKSSTREAM_HEADER        pDataPacket;
    PKS_FRAME_INFO          pFrameInfo;

    // If we're stopped and the timer is still running, just return.
    // This will stop the timer.

    if (pStrmEx->KSState == KSSTATE_STOP) {
        return;
    }


    // Find out what time it is, if we're using a clock

    if (pStrmEx->hMasterClock ) {
        HW_TIME_CONTEXT TimeContext;

        TimeContext.HwDeviceExtension = pHwDevExt;
        TimeContext.HwStreamObject = pStrmEx->pStreamObject;
        TimeContext.Function = TIME_GET_STREAM_TIME;

        StreamClassQueryMasterClockSync (
                pStrmEx->hMasterClock,
                &TimeContext);

        pStrmEx->QST_StreamTime = TimeContext.Time;
        pStrmEx->QST_Now = TimeContext.SystemTime;

        if (pStrmEx->QST_NextFrame == 0) {
            pStrmEx->QST_NextFrame = pStrmEx->QST_StreamTime + pStrmEx->AvgTimePerFrame;
        }

#ifdef CREATE_A_FLURRY_OF_TIMING_SPEW
        DbgLogTrace(("TestCap: Time=%6d mS at SystemTime=%I64d\n", 
                     (LONG) ((LONGLONG) TimeContext.Time / 10000), 
                     TimeContext.SystemTime));
#endif
    }


    // Only capture in the RUN state

    if (pStrmEx->KSState == KSSTATE_RUN) {

        //
        // Determine if it is time to capture a frame based on
        // how much time has elapsed since capture started.
        // If there isn't a clock available, then capture immediately.
        //

        if ((!pStrmEx->hMasterClock) ||
             (pStrmEx->QST_StreamTime >= pStrmEx->QST_NextFrame)) {

            PHW_STREAM_REQUEST_BLOCK pSrb;

            // Increment the picture count (usually this is VSYNC count)

            pStrmEx->FrameInfo.PictureNumber++;

            //
            // Get the next queue SRB (if any)
            //

            pSrb = VideoQueueRemoveSRB (
                            pHwDevExt,
                            StreamNumber);

            if (pSrb) {

                pDataPacket = pSrb->CommandData.DataBufferArray;
                pFrameInfo = (PKS_FRAME_INFO) (pDataPacket + 1);

                //
                // Call the routine which synthesizes images
                //

                ImageSynth (pSrb,
                            IMAGE_XFER_GRAY_INCREASING,
                            pStrmEx->VideoControlMode & KS_VideoControlFlag_FlipHorizontal);

                // Set additional info fields about the data captured such as:
                //   Frames Captured
                //   Frames Dropped
                //   Field Polarity

                pStrmEx->FrameInfo.ExtendedHeaderSize = pFrameInfo->ExtendedHeaderSize;

                *pFrameInfo = pStrmEx->FrameInfo;

                // Init the flags to zero
                pDataPacket->OptionsFlags = 0;

                // Set the discontinuity flag if frames have been previously
                // dropped, and then reset our internal flag

                if (pStrmEx->fDiscontinuity) {
                    pDataPacket->OptionsFlags |= KSSTREAM_HEADER_OPTIONSF_DATADISCONTINUITY;
                    pStrmEx->fDiscontinuity = FALSE;
                }

                //
                // Return the timestamp for the frame
                //
                pDataPacket->PresentationTime.Numerator = 1;
                pDataPacket->PresentationTime.Denominator = 1;
                pDataPacket->Duration = pStrmEx->AvgTimePerFrame;

                //
                // if we have a master clock AND this is the capture stream
                //
                if (pStrmEx->hMasterClock && (StreamNumber == 0)) {

                    pDataPacket->PresentationTime.Time = pStrmEx->QST_StreamTime;
                    pDataPacket->OptionsFlags |=
                        KSSTREAM_HEADER_OPTIONSF_TIMEVALID |
                        KSSTREAM_HEADER_OPTIONSF_DURATIONVALID;
                }
                else {
                    //
                    // no clock or the preview stream, so just mark the time as unknown
                    //
                    pDataPacket->PresentationTime.Time = 0;
                    // clear the timestamp valid flags
                    pDataPacket->OptionsFlags &=
                        ~(KSSTREAM_HEADER_OPTIONSF_TIMEVALID |
                          KSSTREAM_HEADER_OPTIONSF_DURATIONVALID);
                }

                // Every frame we generate is a key frame (aka SplicePoint)
                // Delta frames (B or P) should not set this flag

                pDataPacket->OptionsFlags |= KSSTREAM_HEADER_OPTIONSF_SPLICEPOINT;

                // Output a frame count every 100th frame in Debug mode
                if (pStrmEx->FrameInfo.PictureNumber % 100 == 0) {
                   DbgLogInfo(("TestCap: Picture %u, Stream=%d\n", 
                               (unsigned int)pStrmEx->FrameInfo.PictureNumber, 
                               StreamNumber));
                }

                CompleteStreamSRB (pSrb);

            } // if we have an SRB

            else {

                //
                // No buffer was available when we should have captured one

                // Increment the counter which keeps track of
                // dropped frames

                pStrmEx->FrameInfo.DropCount++;

                // Set the (local) discontinuity flag
                // This will cause the next packet processed to have the
                //   KSSTREAM_HEADER_OPTIONSF_DATADISCONTINUITY flag set.

                pStrmEx->fDiscontinuity = TRUE;

            }

            // Figure out when to capture the next frame
            pStrmEx->QST_NextFrame += pStrmEx->AvgTimePerFrame;

        } // endif time to capture a frame
    } // endif we're running
}


/*
** VideoSetState()
**
**    Sets the current state for a given stream
**
** Arguments:
**
**    pSrb - pointer to the stream request block for properties
**
** Returns:
**
** Side Effects:  none
*/

VOID
STREAMAPI
VideoSetState(
    PHW_STREAM_REQUEST_BLOCK pSrb
    )
{
    PHW_DEVICE_EXTENSION        pHwDevExt = ((PHW_DEVICE_EXTENSION)pSrb->HwDeviceExtension);
    PSTREAMEX                   pStrmEx = (PSTREAMEX)pSrb->StreamObject->HwStreamExtension;
    int                         StreamNumber = pStrmEx->pStreamObject->StreamNumber;
    KSSTATE                     PreviousState;

    //
    // For each stream, the following states are used:
    //
    // Stop:    Absolute minimum resources are used.  No outstanding IRPs.
    // Acquire: KS only state that has no DirectShow correpondence
    //          Acquire needed resources.
    // Pause:   Getting ready to run.  Allocate needed resources so that
    //          the eventual transition to Run is as fast as possible.
    //          Read SRBs will be queued at either the Stream class
    //          or in your driver (depending on when you send "ReadyForNext")
    //          and whether you're using the Stream class for synchronization
    // Run:     Streaming.
    //
    // Moving to Stop to Run always transitions through Pause.
    //
    // But since a client app could crash unexpectedly, drivers should handle
    // the situation of having outstanding IRPs cancelled and open streams
    // being closed WHILE THEY ARE STREAMING!
    //
    // Note that it is quite possible to transition repeatedly between states:
    // Stop -> Pause -> Stop -> Pause -> Run -> Pause -> Run -> Pause -> Stop
    //

    //
    // Remember the state we're transitioning away from
    //

    PreviousState = pStrmEx->KSState;

    //
    // Set the new state
    //

    pStrmEx->KSState = pSrb->CommandData.StreamState;

    switch (pSrb->CommandData.StreamState)

    {
    case KSSTATE_STOP:

        //
        // The stream class will cancel all outstanding IRPs for us
        // (but only if it is maintaining the queue ie. using Stream Class synchronization)
        // Since Testcap is not using Stream Class synchronization, we must clear the queue here

        VideoQueueCancelAllSRBs (pStrmEx);

        DbgLogInfo(("TestCap: STATE Stopped, Stream=%d\n", StreamNumber));
        break;

    case KSSTATE_ACQUIRE:

        //
        // This is a KS only state, that has no correspondence in DirectShow
        //
        DbgLogInfo(("TestCap: STATE Acquire, Stream=%d\n", StreamNumber));
        break;

    case KSSTATE_PAUSE:

        //
        // On a transition to pause from acquire or stop, start our timer running.
        //

        if (PreviousState == KSSTATE_ACQUIRE || PreviousState == KSSTATE_STOP) {

            // Zero the frame counters
            pStrmEx->FrameInfo.PictureNumber = 0;
            pStrmEx->FrameInfo.DropCount = 0;
            pStrmEx->FrameInfo.dwFrameFlags = 0;

            // Setup the next timer callback(s)
            VideoTimerRoutine(pStrmEx);
        }
        DbgLogInfo(("TestCap: STATE Pause, Stream=%d\n", StreamNumber));
        break;

    case KSSTATE_RUN:

        //
        // Begin Streaming.
        //

        // Reset the discontinuity flag

        pStrmEx->fDiscontinuity = FALSE;

        // Setting the NextFrame time to zero will cause the value to be
        // reset from the stream time

        pStrmEx->QST_NextFrame = 0;

        DbgLogInfo(("TestCap: STATE Run, Stream=%d\n", StreamNumber));
        break;

    } // end switch (pSrb->CommandData.StreamState)
}

/*
** VideoGetState()
**
**    Gets the current state of the requested stream
**
** Arguments:
**
**    pSrb - pointer to the stream request block for properties
**
** Returns:
**
** Side Effects:  none
*/

VOID
STREAMAPI
VideoGetState(
    PHW_STREAM_REQUEST_BLOCK pSrb
    )
{
    PSTREAMEX               pStrmEx = (PSTREAMEX)pSrb->StreamObject->HwStreamExtension;

    pSrb->CommandData.StreamState = pStrmEx->KSState;
    pSrb->ActualBytesTransferred = sizeof (KSSTATE);

    // A very odd rule:
    // When transitioning from stop to pause, DShow tries to preroll
    // the graph.  Capture sources can't preroll, and indicate this
    // by returning VFW_S_CANT_CUE in user mode.  To indicate this
    // condition from drivers, they must return STATUS_NO_DATA_DETECTED

    if (pStrmEx->KSState == KSSTATE_PAUSE) {
       pSrb->Status = STATUS_NO_DATA_DETECTED;
    }
}


/*
** VideoStreamGetConnectionProperty()
**
**    Gets the properties for a stream
**
** Arguments:
**
**    pSrb - pointer to the stream request block for properties
**
** Returns:
**
** Side Effects:  none
*/

VOID
STREAMAPI
VideoStreamGetConnectionProperty(
    PHW_STREAM_REQUEST_BLOCK pSrb
    )
{
    PSTREAMEX pStrmEx = (PSTREAMEX)pSrb->StreamObject->HwStreamExtension;
    PSTREAM_PROPERTY_DESCRIPTOR pSPD = pSrb->CommandData.PropertyInfo;
    ULONG Id = pSPD->Property->Id;              // index of the property
    int  streamNumber = (int)pSrb->StreamObject->StreamNumber;

	KdPrint(("VideoStreamGetConnectionProperty\n"));

    switch (Id) {
        // This property describes the allocator requirements for the stream
        case KSPROPERTY_CONNECTION_ALLOCATORFRAMING:
        {
            PKSALLOCATOR_FRAMING Framing =
                (PKSALLOCATOR_FRAMING) pSPD->PropertyInfo;
            Framing->RequirementsFlags =
                KSALLOCATOR_REQUIREMENTF_SYSTEM_MEMORY |
                KSALLOCATOR_REQUIREMENTF_INPLACE_MODIFIER |
                KSALLOCATOR_REQUIREMENTF_PREFERENCES_ONLY;
            Framing->PoolType = PagedPool;
            Framing->FileAlignment = 0; // FILE_LONG_ALIGNMENT???;
            Framing->Reserved = 0;
            pSrb->ActualBytesTransferred = sizeof (KSALLOCATOR_FRAMING);

            switch (streamNumber) {
                case STREAM_Capture:
                case STREAM_Preview:
                    Framing->Frames = 2;
                    Framing->FrameSize =
                        pStrmEx->pVideoInfoHeader->bmiHeader.biSizeImage;
                    break;

                default:
                    pSrb->Status = STATUS_INVALID_PARAMETER;
                    break;
            }
            break;
        }

        default:
            TRAP;
            break;
    }
}

/*
** VideoStreamGetDroppedFramesProperty()
**
**    Gets dynamic information about the progress of the capture process.
**
** Arguments:
**
**    pSrb - pointer to the stream request block for properties
**
** Returns:
**
** Side Effects:  none
*/

VOID
STREAMAPI
VideoStreamGetDroppedFramesProperty(
    PHW_STREAM_REQUEST_BLOCK pSrb
    )
{
    PSTREAMEX pStrmEx = (PSTREAMEX)pSrb->StreamObject->HwStreamExtension;
    PSTREAM_PROPERTY_DESCRIPTOR pSPD = pSrb->CommandData.PropertyInfo;
    ULONG Id = pSPD->Property->Id;              // index of the property

	KdPrint(("VideoStreamGetDroppedFramesProperty\n"));
    switch (Id) {

    case KSPROPERTY_DROPPEDFRAMES_CURRENT:
        {
            PKSPROPERTY_DROPPEDFRAMES_CURRENT_S pDroppedFrames =
                (PKSPROPERTY_DROPPEDFRAMES_CURRENT_S) pSPD->PropertyInfo;

            pDroppedFrames->PictureNumber = pStrmEx->FrameInfo.PictureNumber;
            pDroppedFrames->DropCount = pStrmEx->FrameInfo.DropCount;
            pDroppedFrames->AverageFrameSize = pStrmEx->pVideoInfoHeader->bmiHeader.biSizeImage;

            pSrb->ActualBytesTransferred = sizeof (KSPROPERTY_DROPPEDFRAMES_CURRENT_S);
        }
        break;

    default:
        TRAP;
        break;
    }
}

//==========================================================================;
//                   Clock Handling Routines
//==========================================================================;


/*
** VideoIndicateMasterClock ()
**
**    If this stream is not being used as the master clock, this function
**      is used to provide us with a handle to the clock to use when
**      requesting the current stream time.
**
** Arguments:
**
**    pSrb - pointer to the stream request block for properties
**
** Returns:
**
** Side Effects:  none
*/

VOID
STREAMAPI
VideoIndicateMasterClock(
    PHW_STREAM_REQUEST_BLOCK pSrb
    )
{
    PSTREAMEX pStrmEx = (PSTREAMEX)pSrb->StreamObject->HwStreamExtension;

    pStrmEx->hMasterClock = pSrb->CommandData.MasterClockHandle;
}