IWMEncAudienceObj::put_VideoBufferSize

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The put_VideoBufferSize method specifies the maximum size of the video buffer.

Syntax

HRESULT put_VideoBufferSize(
  short  iRenderSiteIndex,
  long  lBS
);

Parameters

iRenderSiteIndex

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

lBS

[in]  long that indicates the size of the video buffer, in milliseconds. Set this value to -1 to use the client's default buffer size.

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

The buffer size is only relevant to constant bit rate (CBR) content.

Example Code

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

    HRESULT hr;
    IWMEncProfile2* pPro2;
    IWMEncAudienceObj* pAudnc;
    long lAudCount;
    int i;

    // Initialize the COM library and retrieve a pointer to an IWMEncProfile2 interface.
    hr = CoInitialize(NULL);

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

    // Verify profile settings immediately as they are set.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->put_ValidateMode(VARIANT_TRUE);
    }

    // Provide a name and description.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->put_ProfileName(CComBSTR("Sample MBR Profile"));
    }
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->put_ProfileDescription(CComBSTR("A video profile with three audiences"));
    }

    // Specify video content.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->put_ContentType(16);
    }

    // Specify constant bit rate (CBR) mode.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->put_VBRMode(WMENC_VIDEO, 0, WMENC_PVM_NONE);
    }

    // Add audiences for 200, 400, and 600 Kbps.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->AddAudience(200000, &pAudnc);
    }
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->AddAudience(400000, &pAudnc);
    }
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->AddAudience(600000, &pAudnc);
    }
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->get_AudienceCount(&lAudCount);
    }

    // Create an audience object then loop through all of the audiences
    // in the current profile, making the same changes to each audience.
    for (i = 0; i < lAudCount; i++)
    {
        if ( SUCCEEDED( hr ) )
        {
            hr = pPro2->get_Audience(i, &pAudnc);
        }
        // The Windows Media 9 codec is used by default, but you can change
        // it as follows. Be sure to make this change for each audience.
        if ( SUCCEEDED( hr ) )
        {
            hr = pAudnc->put_VideoCodec(0, 2);
        }

        // Make the video output size match the input size by setting height and width to 0.
        if ( SUCCEEDED( hr ) )
        {
            hr = pAudnc->put_VideoHeight(0, 0);
        }
        if ( SUCCEEDED( hr ) )
        {
            hr = pAudnc->put_VideoWidth(0, 0);
        }

        // Change the buffer size to 5 seconds. By default, the end user's default setting is used.
        if ( SUCCEEDED( hr ) )
        {
            hr = pAudnc->put_VideoBufferSize(0, 5000);
        }
    }

    // Change the video image sharpness for the first audience only.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->get_Audience(0, &pAudnc);
    }
    if ( SUCCEEDED( hr ) )
    {
        hr = pAudnc->put_VideoImageSharpness(0, 70);
    }

    // Validate the settings to make sure the profile has no errors.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->Validate();
    }

    // Save the profile to a .prx file.
    if ( SUCCEEDED( hr ) )
    {
        hr = pPro2->SaveToFile(CComBSTR("C:\\Program Files\\Windows Media Components\\Encoder\\Profiles\\CPPprofile.prx"));
    }

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

Requirements

Header: wmencode.h

Library: wmenc.exe

See Also