CBaseControlVideo Class

The CBaseControlVideo class implements the IBasicVideo dual interface and controls the video properties of a generic video window. Generally, a CBaseControlVideo object is a video renderer that draws video into a window on the display.

The CBaseControlVideo class supports both properties and methods. Properties are more easily accessible from many Automation controllers (such as the Microsoft® Visual Basic® programming system). However, some operations require applications to be able to change several properties simultaneously; for this reason, methods are provided that enable a number of related properties to be changed.

Many CBaseControlVideo member functions require only that the video renderer be connected to a filter graph. If it is not connected, member functions will return VFW_E_NOT_CONNECTED. Properties set on a video renderer persist between successive connections and disconnections. All applications should ensure that they reset the renderer properties before starting a presentation.

When working with video, the application can select a portion of the video to use. This portion is the source rectangle that the CBaseControlVideo object controls. CBaseControlVideo enables your application to set and retrieve the source rectangle. All the rectangles that CBaseControlVideo uses employ top, left, width, and height rather than top, left, right, and bottom, which is favored in Microsoft Win32® programming. When no source rectangle has been set, the properties of the source rectangle return the full, native video size.

Protected Data Members

Name	Description
m_pFilter	Pointer to an owning media filter.
m_pInterfaceLock	Externally defined critical section.
m_pPin	Control of the media types for connection.

Member Functions

Name	Description
CBaseControlVideo	Constructs a CBaseControlVideo object.
CopyImage	Creates a memory copy of a video image.
GetImageSize	Retrieves video image size information.
SetControlVideoPin	Sets the pin with which this object should synchronize.

Overridable Member Functions

Name	Description
CheckSourceRect	Determines if a source rectangle is valid.
CheckTargetRect	Determines if a target rectangle is valid.
GetSourceRect	Retrieves the current source video rectangle (pure virtual).
GetStaticImage	Returns the current image in a memory buffer (pure virtual).
GetTargetRect	Retrieves the current target video rectangle (pure virtual).
GetVideoFormat	Retrieves the VIDEOINFOHEADER structure containing the video format.
IsDefaultSourceRect	Determines if the renderer is using the default source rectangle (pure virtual).
IsDefaultTargetRect	Determines if the renderer is using the default target rectangle (pure virtual).
OnUpdateRectangles	Called when the source or target rectangle changes.
OnVideoSizeChange	Passes EC_VIDEO_SIZE_CHANGED to the application.
SetDefaultSourceRect	Sets the default source video rectangle (pure virtual).
SetDefaultTargetRect	Sets the default target video rectangle (pure virtual).
SetSourceRect	Sets the current source video rectangle (pure virtual).
SetTargetRect	Sets the current target rectangle (pure virtual).

Implemented IBasicVideo Methods

Name	Description
get_AvgTimePerFrame	Returns an approximate average time per frame.
get_BitErrorRate	Returns an approximate bit error rate.
get_BitRate	Returns an approximate bit rate for the video.
GetCurrentImage	Returns a memory rendering of the current image.
get_DestinationHeight	Retrieves the current destination rectangle's height.
get_DestinationLeft	Retrieves the current destination rectangle's left coordinate.
GetDestinationPosition	Retrieves the current destination position.
get_DestinationTop	Retrieves the current destination rectangle's top coordinate.
get_DestinationWidth	Retrieves the current destination rectangle's width.
get_SourceHeight	Retrieves the current source rectangle's height.
get_SourceLeft	Retrieves the current source rectangle's left coordinate.
GetSourcePosition	Retrieves the current source position.
get_SourceTop	Retrieves the current source rectangle's top coordinate.
get_SourceWidth	Retrieves the current source rectangle's width.
get_VideoHeight	Retrieves the native video height.
GetVideoPaletteEntries	Retrieves a range of palette entries for the video.
GetVideoSize	Retrieves the width and height of the native video.
get_VideoWidth	Retrieves the native video width.
IsUsingDefaultDestination	Determines if the renderer is using the default destination window.
IsUsingDefaultSource	Determines if the renderer is using the default source window.
put_DestinationHeight	Sets the destination rectangle's height.
put_DestinationLeft	Sets the destination rectangle's left coordinate.
put_DestinationTop	Sets the destination rectangle's top coordinate.
put_DestinationWidth	Sets the destination rectangle's width.
put_SourceHeight	Sets the source rectangle's height.
put_SourceLeft	Sets the source rectangle's left coordinate.
put_SourceTop	Sets the source rectangle's top coordinate.
put_SourceWidth	Sets the source rectangle's width.
SetDefaultDestinationPosition	Sets the default destination position again.
SetDefaultSourcePosition	Sets the default source position again.
SetDestinationPosition	Sets the destination rectangle position.
SetSourcePosition	Sets the source rectangle position.

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CBaseControlVideo::CBaseControlVideo

CBaseControlVideo Class

Constructs a CBaseControlVideo object.

CBaseControlVideo(
  CBaseFilter *pFilter,
  CCritSec *pInterfaceLock,
  TCHAR *pName,
  LPUNKNOWN pUnk,
  HRESULT *phr
  );

Parameters

pFilter

Owning media filter object.

pInterfaceLock

Critical section to use for locking.

pName

Object description.

pUnk

Typical COM ownership.

phr

COM return value.

Return Values

No return value.

Remarks

The object implements the IBasicVideo control interface.

All the interface methods from IBasicVideo that this class implements require that the filter be connected correctly. For this reason, the class is passed a pin with which it should synchronize with. Whenever an interface method is called, the object determines that the pin is still connected.

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CBaseControlVideo::CheckSourceRect

CBaseControlVideo Class

Determines if a source rectangle is valid.

virtual HRESULT CheckSourceRect(
  RECT *pSourceRect
  );

Parameters

pSourceRect

Source rectangle to check.

Return Values

Returns E_INVALIDARG if not valid; otherwise, returns NOERROR (S_OK).

Remarks

This member function checks that the source rectangle requested does not exceed the available source video. The left and top coordinates cannot be negative, and the width and height cannot exceed the right and bottom of the video.

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CBaseControlVideo::CheckTargetRect

CBaseControlVideo Class

Determines if a target rectangle is valid.

virtual HRESULT CheckTargetRect(
  RECT *pTargetRect
  );

Parameters

pTargetRect

Target rectangle to check.

Return Values

Returns E_INVALIDARG if not valid; otherwise, returns NOERROR (S_OK).

Remarks

This member function determines if the target rectangle requested is valid. Because the destination rectangle specifies a position in the logical client of the window, the coordinates can be negative, although the overall width and height cannot be zero or a negative value.

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CBaseControlVideo::CopyImage

CBaseControlVideo Class

Creates a memory copy of an image.

HRESULT CopyImage(
  IMediaSample *pMediaSample,
  VIDEOINFOHEADER *pVideoInfo,
  LONG *pBufferSize,
  BYTE *pVideoImage,
  RECT *pSourceRect
  );

Parameters

pMediaSample

Sample containing the video image.

pVideoInfo

Format representing the video image.

pBufferSize

Size of the output buffer.

pVideoImage

Pointer to the output buffer.

pSourceRect

Source video rectangle.

Return Values

If the pVideoImage parameter is NULL, the pBufferSize parameter is filled in with the number of bytes the output buffer requires to store the image. If the buffer passed in is too small or the member function fails to allocate sufficient memory, the member function returns E_OUTOFMEMORY.

Remarks

The member function retrieves the image from the sample and copies it into the output buffer. The section of video copied into the output buffer reflects the source rectangle that is set through the IBasicVideo interface (although it does not reflect the destination rectangle).

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CBaseControlVideo::get_AvgTimePerFrame

CBaseControlVideo Class

Retrieves the average time per frame.

HRESULT get_AvgTimePerFrame(
  REFTIME *pAvgTimePerFrame
  );

Parameters

pAvgTimePerFrame

Average time per frame.

Return Values

Returns NOERROR if successful or E_OUTOFMEMORY if there is not enough memory available.

Remarks

This member function implements the IBasicVideo::get_AvgTimePerFrame method. It calls the pure virtual CBaseControlVideo::GetVideoFormat member function to retrieve the VIDEOINFOHEADER structure from the derived class.

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CBaseControlVideo::get_BitErrorRate

CBaseControlVideo Class

Returns an approximate bit error rate for the video.

HRESULT get_BitErrorRate(
  long *pBitErrorRate
  );

Parameters

pBitErrorRate

Bit error rate (one error for approximately this many bits).

Return Values

Returns NOERROR if successful or E_OUTOFMEMORY if there is not enough memory available.

Remarks

This member function implements the IBasicVideo::get_BitErrorRate method. It calls the pure virtual CBaseControlVideo::GetVideoFormat to retrieve the VIDEOINFOHEADER structure from the derived class.

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CBaseControlVideo::get_BitRate

CBaseControlVideo Class

Returns an approximate bit rate for the video.

HRESULT get_BitRate(
  long *pBitRate
  );

Parameters

pBitRate

Bit rate in bits per second.

Return Values

Returns NOERROR if successful or E_OUTOFMEMORY not enough memory is available.

Remarks

This member function implements the IBasicVideo::get_BitRate method. It calls the pure virtual CBaseControlVideo::GetVideoFormat to retrieve the VIDEOINFOHEADER structure from the derived class.

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CBaseControlVideo::GetCurrentImage

CBaseControlVideo Class

Returns a copy of the current image at the renderer.

HRESULT GetCurrentImage(
  long *pBufferSize,
  long *pVideoImage
  );

Parameters

pBufferSize

Size of the output buffer.

pVideoImage

Pointer to the output buffer for the image.

Return Values

Returns an HRESULT value.

Remarks

This member function retrieves the image from the sample and copies it into the output buffer. The section of video copied into the output buffer reflects the source rectangle set through the IBasicVideo interface. It does not reflect the destination rectangle.

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CBaseControlVideo::get_DestinationHeight

CBaseControlVideo Class

Retrieves the current destination rectangle height.

HRESULT get_DestinationHeight(
  long *pDestinationHeight
  );

Parameters

pDestinationHeight

Holds the destination height.

Return Values

Returns an HRESULT value.

Remarks

This member function implements the IBasicVideo::get_DestinationHeight method.

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where it will be played. The destination rectangle is relative to the client area of the window that it is playing in. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::get_DestinationLeft

CBaseControlVideo Class

Retrieves the left coordinate of the current destination rectangle.

HRESULT get_DestinationLeft(
  long *pDestinationLeft
  );

Parameters

pDestinationLeft

Contains the left coordinate of the destination rectangle.

Return Values

Returns an HRESULT value.

Remarks

This member function implements the IBasicVideo::get_DestinationLeft method.

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::GetDestinationPosition

CBaseControlVideo Class

Retrieves the destination rectangle.

HRESULT GetDestinationPosition(
  long *pLeft,
  long *pTop,
  long *pWidth,
  long *pHeight
  );

Parameters

pLeft

Contains the left coordinate.

pTop

Contains the top coordinate.

pWidth

Contains the width.

pHeight

Contains the height.

Return Values

Returns an HRESULT value.

Remarks

This member function can be used in place of separate calls to the CBaseControlVideo::get_DestinationLeft, CBaseControlVideo::get_DestinationTop, CBaseControlVideo::get_DestinationWidth, and CBaseControlVideo::get_DestinationHeight member functions. An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::get_DestinationTop

CBaseControlVideo Class

Retrieves the top coordinate of the current destination rectangle.

HRESULT get_DestinationTop(
  long *pDestinationTop
  );

Parameters

pDestinationTop

Contains the top coordinate of the destination rectangle.

Return Values

Returns an HRESULT value.

Remarks

This member function implements the IBasicVideo::get_DestinationTop method.

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::get_DestinationWidth

CBaseControlVideo Class

Retrieves the width of the current destination rectangle.

HRESULT get_DestinationWidth(
  long *pDestinationWidth
  );

Parameters

pDestinationWidth

Contains the destination width.

Return Values

Returns an HRESULT value.

Remarks

This member function implements the IBasicVideo::get_DestinationWidth method.

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::GetImageSize

CBaseControlVideo Class

Retrieves video image size information.

HRESULT GetImageSize(
  VIDEOINFOHEADER *pVideoInfo,
  long *pBufferSize,
  RECT *pSourceRect
  );

Parameters

pVideoInfo

Contains a pointer to a VIDEOINFOHEADER structure to be filled in.

pBufferSize

Size of the video buffer.

pSourceRect

Rectangle dimensions of the source video.

Return Values

Returns an HRESULT value.

Remarks

This member function is a helper function used for creating memory image renderings of DIB images. It is called from the base class implementation of CBaseControlVideo::GetCurrentImage when a null pVideoImage parameter is passed to that member function. As a result, this member function constructs and returns a VIDEOINFOHEADER structure, using the information in pBufferSize and pSourceRect.

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CBaseControlVideo::get_SourceHeight

CBaseControlVideo Class

Retrieves the height of the current source rectangle.

HRESULT get_SourceHeight(
  long *pSourceHeight
  );

Parameters

pSourceHeight

Contains the height of the source rectangle.

Return Values

Returns an HRESULT value.

Remarks

This member function implements the IBasicVideo::get_SourceHeight method.

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::get_SourceLeft

CBaseControlVideo Class

Retrieves the left coordinate of the current source rectangle.

HRESULT get_SourceLeft(
  long *pSourceLeft
  );

Parameters

pSourceLeft

Holds the left coordinate of the current source rectangle.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::GetSourcePosition

CBaseControlVideo Class

Retrieves the source rectangle in one atomic operation.

HRESULT GetSourcePosition(
  long *pLeft,
  long *pTop,
  long *pWidth,
  long *pHeight
  );

Parameters

pLeft

Contains the left coordinate.

pTop

Contains the top coordinate.

pWidth

Contains the width.

pHeight

Contains the height.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::GetSourceRect

CBaseControlVideo Class

Returns the source rectangle. This is an internal method.

virtual HRESULT GetSourceRect(
  RECT *pSourceRect
  ) PURE;

Parameters

pSourceRect

Contains the retrieved source rectangle.

Return Values

Returns an HRESULT value.

Remarks

This member function must be overridden in the derived class to return the source rectangle held by the video renderer. It is called from the following CBaseControlVideo member functions.

• CBaseControlVideo::GetSourcePosition
• CBaseControlVideo::put_SourceLeft
• CBaseControlVideo::get_SourceLeft
• CBaseControlVideo::put_SourceWidth
• CBaseControlVideo::get_SourceWidth
• CBaseControlVideo::put_SourceTop
• CBaseControlVideo::get_SourceTop
• CBaseControlVideo::put_SourceHeight
• CBaseControlVideo::get_SourceHeight

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

// Return the current source rectangle

HRESULT CVideoText::GetSourceRect(RECT *pSourceRect)
{
    ASSERT(pSourceRect);
    m_pRenderer->m_DrawImage.GetSourceRect(pSourceRect);
    return NOERROR;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object.

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CBaseControlVideo::get_SourceTop

CBaseControlVideo Class

Retrieves the top coordinate of the current source rectangle.

HRESULT get_SourceTop(
  long *pSourceTop
  );

Parameters

pSourceTop

Contains the top coordinate of the source rectangle.

Return Values

Returns an HRESULT value.

Remarks

This member function implements the IBasicVideo::get_SourceTop method.

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::get_SourceWidth

CBaseControlVideo Class

Retrieves the width of the current source rectangle.

HRESULT get_SourceWidth(
  long *pSourceWidth
  );

Parameters

pSourceWidth

Contains the width of the current source rectangle.

Return Values

Returns an HRESULT value.

Remarks

This member function implements the IBasicVideo::get_SourceWidth method.

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

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CBaseControlVideo::GetStaticImage

CBaseControlVideo Class

Pure virtual method that derived classes override.

virtual HRESULT GetStaticImage(
  long *pBufferSize,
  long *pDIBImage
  ) PURE;

Parameters

pBufferSize

Size of the output buffer.

pDIBImage

Pointer to output buffer.

Return Values

Returns an HRESULT value.

Remarks

Through the IBasicVideo interface, an application can request that it be given a copy of the current image in a memory buffer (some renderers can return E_NOTIMPL to this if they do not support it). The derived class determines how to retrieve the image. When the application calls CBaseControlVideo::GetStaticImage, it calls this pure virtual method that the derived class should override to implement it. This is also called by the CBaseControlVideo::GetCurrentImage member function.

The class provides a helper member function, CBaseControlVideo::CopyImage, that can be given a sample that contains an image, and the member function will copy the relevant section of it (based on the current source rectangle) into the output buffer supplied by the application.

The following example from the video renderer sample, SampVid, demonstrates an implementation of this member function in a derived class. In this example, m_pRenderer holds an object of a class derived from CBaseVideoRenderer.

// Return a copy of the current image in the video renderer

HRESULT CVideoText::GetStaticImage(long *pBufferSize,long *pDIBImage)
{
    // Get any sample the renderer may be holding

    IMediaSample *pMediaSample = m_pRenderer->GetCurrentSample();
    if (pMediaSample == NULL) {
        return E_UNEXPECTED;
    }

    // Call the base class helper method to do the work

    HRESULT hr = CopyImage(pMediaSample,          // Buffer containing image
                           &m_pRenderer->m_mtIn,                // Type representing bitmap
                           pBufferSize,                                     // Size of buffer for DIB
                           (BYTE*) pDIBImage);                   // Data buffer for output

    pMediaSample->Release();
    return hr;
}

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CBaseControlVideo::GetTargetRect

CBaseControlVideo Class

Returns the destination rectangle. This is an internal helper member function.

virtual HRESULT GetTargetRect(
  RECT *pTargetRect
  ) PURE;

Parameters

pTargetRect

Contains the destination rectangle.

Return Values

Returns an HRESULT value.

Remarks

This member function must be overridden in the derived class to return the target rectangle held by the video renderer. It is called from the following CBaseControlVideo member functions.

• CBaseControlVideo::GetDestinationPosition
• CBaseControlVideo::put_DestinationLeft
• CBaseControlVideo::get_DestinationLeft
• CBaseControlVideo::put_DestinationWidth
• CBaseControlVideo::get_DestinationWidth
• CBaseControlVideo::put_DestinationTop
• CBaseControlVideo::get_DestinationTop
• CBaseControlVideo::put_DestinationHeight
• CBaseControlVideo::get_DestinationHeight

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

// Return the current destination rectangle

HRESULT CVideoText::GetTargetRect(RECT *pTargetRect)
{
    ASSERT(pTargetRect);
    m_pRenderer->m_DrawImage.GetTargetRect(pTargetRect);
    return NOERROR;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object.

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CBaseControlVideo::GetVideoFormat

CBaseControlVideo Class

Retrieves a video sample that represents the current video format.

virtual VIDEOINFOHEADER * GetVideoFormat( ) PURE;

Return Values

Returns a pointer to a VIDEOINFOHEADER structure that contains the current video format.

Remarks

To return and check certain information through IBasicVideo, the object must know the current video format. It gets this information by calling this pure virtual method that derived classes must override. This member function is called by the following CBaseControlVideo member functions.

• CBaseControlVideo::OnVideoSizeChange
• CBaseControlVideo::get_AvgTimePerFrame
• CBaseControlVideo::get_BitRate
• CBaseControlVideo::get_BitErrorRate
• CBaseControlVideo::get_VideoWidth
• CBaseControlVideo::get_VideoHeight
• CBaseControlVideo::GetVideoPaletteEntries
• CBaseControlVideo::GetVideoSize

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CBaseControlVideo::get_VideoHeight

CBaseControlVideo Class

Retrieves the height of the native video.

HRESULT get_VideoHeight(
  long *pVideoHeight
  );

Parameters

pVideoHeight

Contains the height of the native video, in pixels.

Return Values

Returns NOERROR if successful or E_OUTOFMEMORY if there is not enough memory available.

Remarks

This member function implements the IBasicVideo::get_VideoHeight method. It calls the pure virtual CBaseControlVideo::GetVideoFormat to retrieve the VIDEOINFOHEADER structure from the derived class.

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CBaseControlVideo::GetVideoPaletteEntries

CBaseControlVideo Class

Retrieves a range of palette entries for the video.

HRESULT GetVideoPaletteEntries(
  long StartIndex,
  long Entries,
  long *pRetrieved,
  long *pPalette
  );

Parameters

StartIndex

Zero-based start palette entry.

Entries

Number of entries required.

pRetrieved

Number of colors obtained.

pPalette

Pointer to output buffer for colors.

Return Values

Returns NOERROR if successful, VFW_E_NO_PALETTE_AVAILABLE if the video samples has no color palette, E_OUTOFMEMORY if there is not enough memory available, E_INVALIDARG if StartIndex is invalid, or S_FALSE if there are no colors in the palette.

Remarks

This member function returns the current palette of the video as an array allocated by the user. To remain consistent, use the members in the Win32 PALETTEENTRY structure to return the colors, rather than the members in the RGBQUAD structure (although the parameter is a LONG). The memory is allocated by the caller, so simply copy each in turn. Determine that the number of entries requested and the start position offset are both valid. If the number of entries evaluates to zero, return an S_FALSE code.

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CBaseControlVideo::GetVideoSize

CBaseControlVideo Class

Retrieves the native video's width and height.

HRESULT GetVideoSize(
  long *pWidth,
  long *pHeight
  );

Parameters

pWidth

Contains the video width.

pHeight

Contains the video height.

Return Values

Returns an HRESULT value.

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CBaseControlVideo::get_VideoWidth

CBaseControlVideo Class

Retrieves the width of the native video.

HRESULT get_VideoWidth(
  long *pVideoWidth
  );

Parameters

pVideoWidth

Contains the width of the native video, in pixels.

Return Values

Returns NOERROR if successful or E_OUTOFMEMORY if there is not enough memory available.

Remarks

This member function implements the IBasicVideo::get_VideoWidth method. It calls the pure virtual CBaseControlVideo::GetVideoFormat to retrieve the VIDEOINFOHEADER structure from the derived class.

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CBaseControlVideo::IsDefaultSourceRect

CBaseControlVideo Class

Determines if the renderer is using the default source rectangle (pure virtual).

virtual HRESULT IsDefaultSourceRect(void) PURE;

Return Values

Returns an HRESULT value.

Remarks

This member function must be implemented in the derived class. It is called by the CBaseControlVideo::IsUsingDefaultSource member function.

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

// Return S_OK if using the default source otherwise S_FALSE

HRESULT CVideoText::IsDefaultSourceRect()
{
    RECT SourceRect;

    VIDEOINFO *pVideoInfo = (VIDEOINFO *) m_pRenderer->m_mtIn.Format();
    BITMAPINFOHEADER *pHeader = HEADER(pVideoInfo);
    m_pRenderer->m_DrawImage.GetSourceRect(&SourceRect);

    // Check the coordinates that match the video dimensions

    if (SourceRect.left != 0 || SourceRect.top != 0 ||
            SourceRect.right != pHeader->biWidth ||
                SourceRect.bottom != pHeader->biHeight) {
                    return S_FALSE;
    }
    return S_OK;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object. The m_mtIn data member, also defined in the derived class, holds a CMediaType object with the media type of the input pin.

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CBaseControlVideo::IsDefaultTargetRect

CBaseControlVideo Class

Determines if the renderer is using the default target rectangle (pure virtual).

virtual HRESULT IsDefaultTargetRect(void) PURE;

Return Values

Returns an HRESULT value.

Remarks

This member function must be implemented in the derived class. It is called by the CBaseControlVideo::IsUsingDefaultDestination member function.

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

// Return S_OK if using the default target; otherwise S_FALSE

HRESULT CVideoText::IsDefaultTargetRect()
{
    RECT TargetRect;

    VIDEOINFO *pVideoInfo = (VIDEOINFO *) m_pRenderer->m_mtIn.Format();
    BITMAPINFOHEADER *pHeader = HEADER(pVideoInfo);
    m_pRenderer->m_DrawImage.GetTargetRect(&TargetRect);

    // Check the destination that matches the initial client area

    if (TargetRect.left != 0 || TargetRect.top != 0 ||
            TargetRect.right != m_Size.cx ||
                TargetRect.bottom != m_Size.cy) {
                    return S_FALSE;
    }
    return S_OK;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object. The m_mtIn data member, also defined in the derived class, holds a CMediaType object with media type of the input pin.

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CBaseControlVideo::IsUsingDefaultSource

CBaseControlVideo Class

Determines if the renderer is using the default source window.

virtual HRESULT IsUsingDefaultSource(void);

Return Values

Returns an HRESULT value.

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CBaseControlVideo::IsUsingDefaultDestination

CBaseControlVideo Class

Determines if the renderer is using the default destination window.

virtual HRESULT IsUsingDefaultDestination(void);

Return Values

Returns an HRESULT value. Returns S_OK if using the default destination; otherwise, returns S_FALSE.

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CBaseControlVideo::OnUpdateRectangles

CBaseControlVideo Class

Called when either the source or destination rectangle changes.

virtual HRESULT OnUpdateRectangles( );

Return Values

Returns an HRESULT value.

---

CBaseControlVideo::OnVideoSizeChange

CBaseControlVideo Class

Passes an EC_VIDEO_SIZE_CHANGED message to the filter graph manager.

virtual HRESULT OnVideoSizeChange( );

Return Values

Returns an HRESULT value.

Remarks

A video renderer should call this member function each time the video size is changed; this will typically be called once after initial connection. If the renderer can support dynamic format changes (from 320x240 to 160x120), it should also call it after each change.

---

CBaseControlVideo::put_DestinationHeight

CBaseControlVideo Class

Sets the destination rectangle height.

HRESULT put_DestinationHeight(
  long DestinationHeight
  );

Parameters

DestinationHeight

New destination height.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::put_DestinationLeft

CBaseControlVideo Class

Sets the left coordinate of the destination rectangle.

HRESULT put_DestinationLeft(
  long DestinationLeft
  );

Parameters

DestinationLeft

New left coordinate of destination rectangle.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::put_DestinationTop

CBaseControlVideo Class

Sets the top coordinate of the destination rectangle.

HRESULT put_DestinationTop(
  long DestinationTop
  );

Parameters

DestinationTop

New top coordinate of the destination rectangle.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::put_DestinationWidth

CBaseControlVideo Class

Sets the width of the destination rectangle.

HRESULT put_DestinationWidth(
  long DestinationWidth
  );

Parameters

DestinationWidth

New destination width.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::put_SourceHeight

CBaseControlVideo Class

Sets the source rectangle height.

HRESULT put_SourceHeight(
  long SourceHeight
  );

Parameters

SourceHeight

Contains the source height.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::put_SourceLeft

CBaseControlVideo Class

Sets the source rectangle left coordinate.

HRESULT put_SourceLeft(
  long SourceLeft
  );

Parameters

SourceLeft

New left coordinate of the source rectangle.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::put_SourceTop

CBaseControlVideo Class

Sets the top coordinate of the source rectangle.

HRESULT put_SourceTop(
  long SourceTop
  );

Parameters

SourceTop

New top coordinate of the source rectangle.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::put_SourceWidth

CBaseControlVideo Class

Sets the width of the source rectangle.

HRESULT put_SourceWidth(
  long SourceWidth
  );

Parameters

SourceWidth

New width of the source rectangle.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::SetControlVideoPin

CBaseControlVideo Class

Sets the pin used by the filter.

void SetControlVideoPin(
  CBasePin *pPin
  );

Parameters

pPin

Pin with which the interface is synchronized.

Return Values

No return value.

Remarks

The interface can be called only when the filter has been connected successfully. The object is passed through this method to the pin with which it is synchronized; in most cases it will determine if the pin is connected when it has an interface method called and will return VFW_E_NOT_CONNECTED if it fails.

---

CBaseControlVideo::SetDefaultDestinationPosition

CBaseControlVideo Class

Sets the renderer back to using the default destination position (typically the entire window client area).

HRESULT SetDefaultDestinationPosition( );

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::SetDefaultSourcePosition

CBaseControlVideo Class

Sets the renderer back to using the default source position (typically all the native video).

HRESULT SetDefaultSourcePosition( );

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::SetDefaultSourceRect

CBaseControlVideo Class

Sets the default source video rectangle (pure virtual). This in an internal member function that gets called when the source rectangle is reset.

virtual HRESULT SetDefaultSourceRect( ) PURE;

Return Values

Returns an HRESULT value.

Remarks

Derived classes should override this to reset the source rectangle. It is called from CBaseControlVideo::SetDefaultSourcePosition.

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

// This is called when we reset the default source rectangle

HRESULT CVideoText::SetDefaultSourceRect()
{
    VIDEOINFO *pVideoInfo = (VIDEOINFO *) m_pRenderer->m_mtIn.Format();
    BITMAPINFOHEADER *pHeader = HEADER(pVideoInfo);
    RECT SourceRect = {0,0,pHeader->biWidth,pHeader->biHeight};
    m_pRenderer->m_DrawImage.SetSourceRect(&SourceRect);
    return NOERROR;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object. The m_mtIn data member, also defined in the derived class, holds a CMediaType object with media type of the input pin.

---

CBaseControlVideo::SetDefaultTargetRect

CBaseControlVideo Class

Sets the default target video rectangle (pure virtual). This is an internal member function that gets called when the source rectangle is reset.

virtual HRESULT SetDefaultTargetRect( ) PURE;

Return Values

Returns an HRESULT value.

Remarks

Derived classes should override this to reset the destination video rectangle. It is called from the CBaseControlVideo::SetDefaultDestinationPosition member function.

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

// This is called when we reset the default target rectangle

HRESULT CVideoText::SetDefaultTargetRect()
{
    VIDEOINFO *pVideoInfo = (VIDEOINFO *) m_pRenderer->m_mtIn.Format();
    BITMAPINFOHEADER *pHeader = HEADER(pVideoInfo);
    RECT TargetRect = {0,0,m_Size.cx,m_Size.cy};
    m_pRenderer->m_DrawImage.SetTargetRect(&TargetRect);
    return NOERROR;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object. The m_mtIn data member, also defined in the derived class, holds a CMediaType object with the media type of the input pin.

---

CBaseControlVideo::SetDestinationPosition

CBaseControlVideo Class

Sets the destination rectangle for the video.

HRESULT SetDestinationPosition(
  long Left,
  long Top,
  long Width,
  long Height
  );

Parameters

Left

New left coordinate.

Top

New top coordinate.

Width

New width.

Height

New height.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::SetSourcePosition

CBaseControlVideo Class

Sets a new source position for the video.

HRESULT SetSourcePosition(
  long Left,
  long Top,
  long Width,
  long Height
  );

Parameters

Left

New left coordinate.

Top

New top coordinate.

Width

New width.

Height

New height.

Return Values

Returns an HRESULT value.

Remarks

An application can change the source and destination rectangles for the video through the IBasicVideo interface. The source rectangle affects which section of the native video source will appear on the display; the destination rectangle affects where the video will appear when played. The destination rectangle is relative to the client area of the window in which it is playing. The upper-left corner of the window is coordinate (0,0).

---

CBaseControlVideo::SetSourceRect

CBaseControlVideo Class

Sets the current source video rectangle (pure virtual). This is an internal member function that gets called when the source rectangle changes.

virtual HRESULT SetSourceRect(
  RECT *pSourceRect
  ) PURE;

Parameters

pSourceRect

Contains the source rectangle.

Return Values

Returns an HRESULT value.

Remarks

Derived classes should override this member function to know when the source rectangle changes. It is called from the following member functions.

• CBaseControlVideo::SetSourcePosition
• CBaseControlVideo::put_SourceLeft
• CBaseControlVideo::put_SourceWidth
• CBaseControlVideo::put_SourceTop
• CBaseControlVideo::put_SourceHeight

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

HRESULT CVideoText::SetSourceRect(RECT *pSourceRect)
{
    m_pRenderer->m_DrawImage.SetSourceRect(pSourceRect);
    return NOERROR;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object.

---

CBaseControlVideo::SetTargetRect

CBaseControlVideo Class

Sets the current target rectangle (pure virtual). This is an internal member function that gets called when the destination rectangle changes.

virtual HRESULT SetTargetRect(
  RECT *pTargetRect
  ) PURE;

Parameters

pTargetRect

Contains the destination rectangle.

Return Values

Returns an HRESULT value.

Remarks

Derived classes should override this to know when the destination rectangle changes. It is called from the following member functions.

• CBaseControlVideo::SetDestinationPosition
• CBaseControlVideo::put_DestinationLeft
• CBaseControlVideo::put_DestinationWidth
• CBaseControlVideo::put_DestinationTop
• CBaseControlVideo::put_DestinationHeight

The following example from the video renderer sample, SampVid, demonstrates an implementation of this function in a derived class.

HRESULT CVideoText::SetTargetRect(RECT *pTargetRect)
{
    m_pRenderer->m_DrawImage.SetTargetRect(pTargetRect);
    return NOERROR;
}

In this example, CVideoText is a class derived from CBaseControlVideo, m_pRenderer holds an object of a class derived from CBaseVideoRenderer, and the m_DrawImage data member, defined in the derived class, holds a CDrawImage object.

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