IMediaParams::FlushEnvelope method (medparam.h)

项目
4/26/2023

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 FlushEnvelope method flushes envelope data for a specified parameter over the specified time range.

Syntax

HRESULT FlushEnvelope(
  [in] DWORD          dwParamIndex,
  [in] REFERENCE_TIME refTimeStart,
  [in] REFERENCE_TIME refTimeEnd
);

Parameters

[in] dwParamIndex

Zero-based index of the parameter, or DWORD_ALLPARAMS to flush envelope data from every parameter.

[in] refTimeStart

Start time of the envelope data to flush.

[in] refTimeEnd

Stop time of the envelope data to flush.

Return value

Returns an HRESULT value. Possible values include the following.

Return code	Description
E_INVALIDARG	Index out of range.
S_OK	Success.

Remarks

If the time span specified by refTimeStart and refTimeEnd overlaps an envelope segment, the entire segment is flushed. On the other hand, if it falls on the boundary of an envelope segment, the entire segment is retained. Thus:

If the start time falls inside an envelope segment, the segment is flushed.
If the end time falls inside an envelope segment, the segment is flushed.
If the start time equals the end time of an envelope segment, the segment is retained.
If the end time equals the start time of an envelope segment, the segment is retained.

To enumerate the parameters supported by this object, along with their index values, use the IMediaParamInfo interface.

Requirements

Requirement	Value
Target Platform	Windows
Header	medparam.h
Library	Dmoguids.lib

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