CTransformFilter

最新推荐文章于 2016-08-04 20:15:13 发布

zhubaoFORWARD

最新推荐文章于 2016-08-04 20:15:13 发布

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CC 4.0 BY-SA版权

文章标签： styles filter output object input function

本文链接：https://blog.youkuaiyun.com/zhubaoFORWARD/article/details/1439886

本文详细介绍了DirectShow中CTransformFilter类的功能与使用方法，包括修改窗口样式、构造函数参数说明及成员变量的作用。此外，还深入探讨了该类的主要方法，如FindPin、StartStreaming等。

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修改窗口风格 of the CWindow object.

BOOL ModifyStyle(
   DWORD dwRemove,
   DWORD dwAdd,
   UINT nFlags = 0
) throw();

dwRemove
[in] Specifies the window styles to be removed during style modification.
dwAdd
[in] Specifies the window styles to be added during style modification.
nFlags
[in] Window-positioning flags. For a list of possible values, see the SetWindowPos function in the Platform SDK.
Return Value
TRUE if the window styles are modified; otherwise, FALSE.

例： m_VideoWindow.ModifyStyle(0, WS_CLIPCHILDREN);

////////////////////////////////////////////////////////////////
CTransformFilter(
    TCHAR *pObjectName,
    LPUNKNOWN lpUnk,
    CLSID clsid
);

pObjectName

String containing the debug name of the filter. For more information, see CBaseObject.

lpUnk

Pointer to the owner of this object. If the object is aggregated, pass a pointer to the aggregating object's IUnknown interface. Otherwise, set this parameter to NULL.

clsid

Class identifier of the filter.
/////
1。CTransformFilter::m_bQualityChanged
2。CTransformFilter::m_bEOSDelivered指出filter是否发送 an end-of-stream通告
3。CTransformFilter::m_bSampleSkipped指出 whether the most recent sample was dropped. If the Receive method drops a sample, it sets the value to TRUE.
4。CTransformFilter::Transform
转换 an input sample 产生 an output sample.
5。CTransformFilter::GetPinCount返回filter上pin的个数
6。CTransformFilter::GetPin得到一个pin
8。CTransformFilter::FindPin返回一个带有指定标示符的pin
    HRESULT FindPin   (
                           LPCWSTR Id,//标示pin的字符串
                           IPin **ppPin
                     );

ppPin

Address of a variable that receives a pointer to the pin's IPin interface. 失败，则 *ppPin is set to NULL
Value                      Description
S_OK                        成功
E_OUTOFMEMORY               Insufficient memory.
E_POINTER                   空指针
VFW_E_NOT_FOUND             Could not find a pin with this identifier.
9。CTransformFilter::StartStreaming当filter的状态是暂停时调用StartStreaming
10。CTransformFilter::CheckConnect测定pin的连接是否是适当的
11。CTransformFilter::BreakConnect从连接状态释放pin
12。CTransformFilter::CompleteConnect 完成a pin connection
13。CTransformFilter::InitializeOutputSample 找回 a new output sample并把它初始化
14。CTransformFilter::Receive
    The Receive method receives a media sample, processes it, and delivers an output sample to the downstream filter.
15。CTransformFilter::AlterQuality
    The AlterQuality method notifies the filter that a quality change is requested
16。CTransformFilter::EndOfStream
     The EndOfStream method notifies the filter that no additional data is expected from the input pin.