DoProcessOutput in the Sample Video DSP Plug-in
[The feature associated with this page, Windows Media Player SDK, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of Windows Media Player SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
Because a video DSP plug-in typically supports several video formats, it is convenient to separate the processing implementation code into a separate function for each format. This means that the implementation of DoProcessOutput for video DSP plug-ins is relatively simple.
The implementation in the sample plug-in first tests whether the user has enabled the plug-in. If the plug-in is disabled, the code copies the data provided in the input buffer to the output buffer without changing it, as the following code demonstrates:
// Test whether the plug-in has been disabled by the user.
if (!m_bEnabled)
{
// Just copy the data without changing it. You should
// also do any necessary format conversion here.
memcpy(pbOutputData, pbInputData, m_dwBufferSize);
*cbBytesProcessed = m_dwBufferSize;
return S_OK;
}
If the plug-in is enabled, the code simply performs a series of checks on the input media type subtype member to determine the current video format. When a match is found, the code calls the appropriate processing function.
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