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IAMVideoCompression::get_WindowSize method (strmif.h)

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[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The get_WindowSize method retrieves the number of frames over which the compressor will maintain the average data rate.

For example, assuming a data rate of 100K/sec and a frame rate of 10 frames per second, if the window size is 1, then every frame will be 10K or less. If the window size is 5, then every five consecutive frames will average 10K per frame, but individual frames may exceed this size.

The default window size is 1.

Syntax

HRESULT get_WindowSize(
  [out] DWORDLONG *pWindowSize
);

Parameters

[out] pWindowSize

Pointer to a variable that receives the window size, expressed as a number of frames.

Return value

Returns an HRESULT value. Possible values include the following.

Return code Description
S_OK
 Success.
E_NOTIMPL
 Not implemented.
E_POINTER
 NULL pointer argument.

Requirements

Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header strmif.h (include Dshow.h)
Library Strmiids.lib

See also

Error and Success Codes

IAMVideoCompression Interface

IAMVideoCompression::put_WindowSize