IWMEncAudienceObj::put_VideoBitrate

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The put_VideoBitrate method specifies the bit rate of the video stream in the current audience.

Syntax

HRESULT put_VideoBitrate(
  short  iRenderSiteIndex,
  long  lBitrate
);

Parameters

iRenderSiteIndex

[in]  short containing the audience stream index. Because an audience can only contain one stream of each type, iRenderSiteIndex must be zero.

lBitrate

[in]  long that indicates the video bit rate, in bits per second (bps).

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

If you are working with a profile that uses a constant bit rate (CBR) mode with the full frames (uncompressed) video codec, changing the bit rate has no effect.

Example Code

// Include libraries.
#include <windows.h>
#include <atlbase.h>
#include <comdef.h>
#include "C:\WMSDK\WMEncSDK9\include\wmencode.h"

    // Declare variables.
    HRESULT hr;
    IWMEncoder* pEncoder;
    IWMEncProfileCollection* pProColl;
    IWMEncProfile* pPro;

    IWMEncProfile2* pPro2;
    IWMEncAudienceObj* pAudnc;

    // 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_IWMEncoder,
            (void**) &pEncoder);
    }

    // Retrieve a specific profile.
    if ( SUCCEEDED( hr ) )
    {
        hr = pEncoder->get_ProfileCollection(&pProColl);
    }
    if ( SUCCEEDED( hr ) )
    {
        hr = pProColl->Item(11, &pPro);
    }

    if ( SUCCEEDED( hr ) )
    {
        hr = CoCreateInstance(CLSID_WMEncProfile2,
            NULL,
            CLSCTX_INPROC_SERVER,
            IID_IWMEncProfile2,
            (void**) &pPro2);
    }

    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->LoadFromIWMProfile(pPro);
    }

    // Retrieve the first audience in the profile.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->get_Audience(0, &pAudnc);
    }

    // Specify the video bit rate for the first stream.
    long lVidBRate = 600000; // 600 Kbps.
    if ( SUCCEEDED( hr ) )
    {
        hr = pAudnc->put_VideoBitrate(0, lVidBRate);
    }

    // Release pointers.
    if ( pAudnc )
    {
        pAudnc->Release();
        pAudnc = NULL;
    }
    if ( pPro2 )
    {
        pPro2->Release();
        pPro2 = NULL;
    }

Requirements

Header: wmencode.h

Library: wmenc.exe

See Also