Sample Code
Windows Driver Samples/ AVStream filter-centric simulated capture sample driver (Avssamp)/ C++/ capture.cpp/
/************************************************************************** AVStream Filter-Centric Sample Copyright (c) 1999 - 2001, Microsoft Corporation File: capture.cpp Abstract: This file contains the capture pin implementation for all capture pins on the sample filter. History: created 5/31/01 **************************************************************************/ #include "avssamp.h" /************************************************************************** PAGED CODE **************************************************************************/ #ifdef ALLOC_PRAGMA #pragma code_seg("PAGE") #endif // ALLOC_PRAGMA CCapturePin:: CCapturePin ( IN PKSPIN Pin ) : m_Pin (Pin), m_State (KSSTATE_STOP) /*++ Routine Description: Construct a new capture pin. Find out the filter associated with this pin and stash a pointer to our parent filter. Arguments: Pin - The AVStream pin object being created. Return Value: None --*/ { PAGED_CODE(); PKSFILTER ParentFilter = KsPinGetParentFilter (Pin); m_ParentFilter = reinterpret_cast <CCaptureFilter *> ( ParentFilter -> Context ); } /*************************************************/ NTSTATUS CCapturePin:: SetState ( IN KSSTATE ToState, IN KSSTATE FromState ) /*++ Routine Description: Called when the pin is transitioning state. This is a bridge from DispatchSetState in the context of the capture pin. The function itself performs basic clock handling (things that all the derived pins would use) and then calls the appropriate method in the derived class. Arguments: FromState - The state the pin is transitioning away from ToState - The state the pin is transitioning towards Return Value: Success / Failure of state transition. --*/ { PAGED_CODE(); NTSTATUS Status = STATUS_SUCCESS; switch (ToState) { case KSSTATE_STOP: // // Reset the dropped frame counter. // m_DroppedFrames = 0; m_FrameNumber = 0; // // On a transition to stop, the clock will be released. // if (m_Clock) { m_Clock -> Release (); m_Clock = NULL; } Status = Stop (FromState); break; case KSSTATE_ACQUIRE: // // On a transition to acqiure (from stop), the pin queries for // its assigned clock. This can be done either here or at the // transition to pause. // if (FromState == KSSTATE_STOP) { Status = KsPinGetReferenceClockInterface ( m_Pin, &m_Clock ); if (!NT_SUCCESS (Status)) { m_Clock = NULL; } } Status = Acquire (FromState); break; case KSSTATE_PAUSE: Status = Pause (FromState); break; case KSSTATE_RUN: Status = Run (FromState); break; } if (NT_SUCCESS (Status)) { m_State = ToState; } return Status; } /************************************************************************** LOCKED CODE **************************************************************************/ #ifdef ALLOC_PRAGMA #pragma code_seg() #endif // ALLOC_PRAGMA ULONG CCapturePin:: QueryFrameDrop ( ) /*++ Routine Description: Return the number of frames which have been dropped on this pin. Arguments: None Return Value: The number of frames which have been dropped on this pin. --*/ { return m_DroppedFrames; } /*************************************************/ void CCapturePin:: NotifyDrops ( IN ULONG VidDrop, IN ULONG AudDrop ) /*++ Routine Description: Stash the number of dropped frames on each pin in this pin to allow this data to be incorporated into any synthesis. Arguments: VidDrop - Number of video frames that have been dropped AudDrop - Number of audio frames that have been dropped Return Value: None --*/ { m_NotifyVidDrop = VidDrop; m_NotifyAudDrop = AudDrop; }
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