Pin回调DispatchSetFormat

对于每个PIN，都可以有一组回调函数KSPIN_DISPATCH：

typedef struct {
  PFNKSPINIRP  Create;
  PFNKSPINIRP  Close;
  PFNKSPIN  Process;
  PFNKSPINVOID  Reset;
  PFNKSPINSETDATAFORMAT  SetDataFormat;//设置数据流格式
  PFNKSPINSETDEVICESTATE  SetDeviceState;
  PFNKSPIN  Connect;
  PFNKSPINVOID  Disconnect;
  const KSCLOCK_DISPATCH*  Clock;
  const KSALLOCATOR_DISPATCH*  Allocator;
} KSPIN_DISPATCH, *PKSPIN_DISPATCH;

SetDataFormat用于在创建Pin实例时，用于校验之前通过IntersectHandler协商的数据格式是否适用于本KSPIN和与KSDATARANGE相匹配。当动态改变格式时，也会调用此例程。

当动态改变格式时，OldFormat不为空。

比较的参数：

CCapturePin *CapPin = NULL;
if (OldFormat) 
{
    CapPin = reinterpret_cast <CCapturePin *> (Pin->Context);
}

if (IsEqualGUID (Pin->ConnectionFormat->Specifier,VideoInfoSpecifier) 
    &&  Pin->ConnectionFormat->FormatSize >= sizeof (KS_DATAFORMAT_VIDEOINFOHEADER))
{
    PKS_DATAFORMAT_VIDEOINFOHEADER ConnectionFormat = reinterpret_cast <PKS_DATAFORMAT_VIDEOINFOHEADER>(Pin->ConnectionFormat);
    const KS_DATARANGE_VIDEO *VIRange = reinterpret_cast <const KS_DATARANGE_VIDEO *>(DataRange);

    ULONG VideoHeaderSize = KS_SIZE_VIDEOHEADER(&ConnectionFormat->VideoInfoHeader);
    ULONG DataFormatSize = FIELD_OFFSET(KS_DATAFORMAT_VIDEOINFOHEADER, VideoInfoHeader) + VideoHeaderSize;

    if (VideoHeaderSize < ConnectionFormat->VideoInfoHeader.bmiHeader.biSize 
        || DataFormatSize < VideoHeaderSize 
        || DataFormatSize > ConnectionFormat->DataFormat.FormatSize
        ) 
    {
        Status = STATUS_INVALID_PARAMETER;
    }
    else if ((ConnectionFormat->VideoInfoHeader.bmiHeader.biWidth != VIRange -> VideoInfoHeader.bmiHeader.biWidth) 
        ||(ConnectionFormat->VideoInfoHeader.bmiHeader.biHeight != VIRange -> VideoInfoHeader.bmiHeader.biHeight)
        ||(ConnectionFormat->VideoInfoHeader.bmiHeader.biCompression !=VIRange -> VideoInfoHeader.bmiHeader.biCompression) 
        ) 
    {
        Status = STATUS_NO_MATCH;
    } 
    else
    {
        ULONG ImageSize = ConnectionFormat->VideoInfoHeader.bmiHeader.biWidth
            * ConnectionFormat->VideoInfoHeader.bmiHeader.biHeight
            * ConnectionFormat->VideoInfoHeader.bmiHeader.biBitCount/8;

        if (ConnectionFormat->VideoInfoHeader.bmiHeader.biSizeImage <  ImageSize) 
        {
            Status = STATUS_INVALID_PARAMETER;
        } 
        else 
        {
            // We can accept the format. 
            Status = STATUS_SUCCESS;

            //
            // OldFormat is an indication that this is a format change.  
            // Since I do not implement the 
            // KSPROPERTY_CONNECTION_PROPOSEDATAFORMAT, by default, I do 
            // not handle dynamic format changes.
            //
            // If something changes while we're in the stop state, we're 
            // fine to handle it since we haven't "configured the hardware"
            // yet.
            //
            //在相机运行过程中动态修改参数，这里不支持
            if (OldFormat) 
            {
                //
                // If we're in the stop state, we can handle just about any
                // change.  We don't support dynamic format changes. 
                //
                if (Pin -> DeviceState == KSSTATE_STOP) 
                {
                    if (!CapPin ->DumpCaptureVideoInfoHeader())
                    {
                        Status = STATUS_INSUFFICIENT_RESOURCES;
                    }
                } else {
                    //
                    // Because we don't accept dynamic format changes, we
                    // should never get here.  Just being over-protective.
                    //
                    Status = STATUS_INVALID_DEVICE_STATE;
                }
            }
        }
    }
}