IStreamBufferMediaSeeking2::SetRateEx Method

Article
01/07/2009

This topic applies to Windows XP Service Pack 2 only.
The SetRateEx method sets the playback rate, and sets the frame rate for fast-forward play ("trick mode").

Syntax

HRESULT SetRateEx(
  [in]  double dRate,
  [in]  DWORD dwFramesPerSec
);

Parameters

dRate [in]
Playback rate. Valid range is (dRate >= 0.1 || dRate <= -0.1).
dwFramesPerSec [in]
Frames per second for fast-forward play. Cannot be zero. See Remarks for more information.

Return Value

The method returns an HRESULT. Possible values include, but are not limited to, those in the following table.

Return code	Description
S_OK	The method succeeded.

Remarks

At higher frames rates, the Stream Buffer Engine drops delta frames and may skip some key frames. This behavior is determined by the IStreamBufferConfigure2::SetFFTransitionRates method. When the playback rate exceeds the value given in that method's dwMaxNonSkippingRate parameter, the Stream Buffer Engine starts to skip key frames. The number of skipped key frames is determined by the playback rate. To control how many key frames are skipped, use the SetRateEx method:

If the playback rate is less than or equal to dwMaxNonSkippingRate, the dwFramesPerSec parameter is ignored.
If the playback rate exceeds dwMaxNonSkippingRate, the Stream Buffer Engine maintains the frame rate specified in dwFramesPerSec and drops key frames if necessary.

The frame rate is applied to the video stream. If there is no video stream, the method fails. The actual frame rate may vary over short periods of time.

Requirements

Header

Declared in Sbe.h.

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