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IWMEncContentAnalyzer::Start

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The Start method starts the process of analyzing content for video optimization.

Syntax

HRESULT Start();

Parameters

This method takes no parameters.

Return Values

If the method succeeds, it returns S_OK. If it fails, it supports the IErrorInfo interface and returns an HRESULT error code.

Remarks

Use the put_SourceGroup method to specify the video content to analyze. Use the Property method to retrieve a value indicating the type of video optimization to apply.

Example Code

// Include libraries.
#include <windows.h>
#include <atlbase.h>
#include <comdef.h>
#include "C:\WMSDK\WMEncSDK9\include\wmencode.h"
#include <conio.h> // for kbhit()

    // Declare variables.
    HRESULT hr;
    IWMEncoder2* pEncoder;
    IWMEncSourceGroupCollection* pSrcGrpColl;
    IWMEncSourceGroup* pSrcGrp;
    IWMEncSource* pSrcVid;
    IWMEncContentAnalyzer* pAnalyze; 

    // Initialize the COM library and retrieve a pointer to an IWMEncoder interface.
    hr = CoInitialize(NULL);
    if ( SUCCEEDED( hr ) )
    {
        hr = CoCreateInstance(CLSID_WMEncoder,
            NULL,
            CLSCTX_INPROC_SERVER,
            IID_IWMEncoder2,
            (void**) &pEncoder);
    }


    // Configure the profile settings for the encoding session.

    // Retrieve the source group collection.
    if ( SUCCEEDED( hr ) )
    {
        hr = pEncoder->get_SourceGroupCollection(&pSrcGrpColl);
    }

    // Add a source group to the collection.
    if ( SUCCEEDED( hr ) )
    {
        hr = pSrcGrpColl->Add(CComBSTR("SG_1"), &pSrcGrp);
    }
    // Add a video source and specify an input file.
    if ( SUCCEEDED( hr ) )
    {
        hr = pSrcGrp->AddSource(WMENC_VIDEO, &pSrcVid);
    }
    if ( SUCCEEDED( hr ) )
    {
        hr = pSrcVid->SetInput(CComBSTR("C:\\InputFile.mpg"));
    }

    // Create an IWMEncContentAnalyzer object.
    if ( SUCCEEDED( hr ) )
    {
        hr = pEncoder->get_ContentAnalyzer(&pAnalyze); 
    }

    // Analyze the first source group.
    if ( SUCCEEDED( hr ) )
    {
        hr = pAnalyze->put_SourceGroup(pSrcGrp); 
    }

    // Start analyzing the video content.
    if ( SUCCEEDED( hr ) )
    {
        hr = pAnalyze->Start();
    }

    // Keep the console window open.
    printf("This pause is required before calling the Property method.");

    // Wait for a key press.
    while(!kbhit())
        _asm nop;

    // Retrieve the value indicating the video optimization to apply.
    CComVariant vResult;
    if ( SUCCEEDED( hr ) )
    {
        hr = pAnalyze->Property(WMENC_VIDEO, 0, CComBSTR("Optimization"), &vResult) ;
    }

    // Stop the content analysis process.
    if ( SUCCEEDED( hr ) )
    {
        hr = pAnalyze->Stop();
    }

    // Release pointers.
    if ( pSrcGrpColl )
    {
        pSrcGrpColl->Release();
        pSrcGrpColl = NULL;
    }
    if ( pSrcVid )
    {
        pSrcVid->Release();
        pSrcVid = NULL;
    }
    if ( pSrcGrp )
    {
        pSrcGrp->Release();
        pSrcGrp = NULL;
    }
    if ( pAnalyze )
    {
        pAnalyze->Release();
        pAnalyze = NULL;
    }
    if ( pEncoder )
    {
        pEncoder->Release();
        pEncoder = NULL;
    }

Requirements

Header: wmencode.h

Library: wmenc.exe

See Also