IMediaSeeking::SetPositions (Compact 2013)

Artigo
01/31/2017

3/26/2014

This method sets current and stop positions and applies flags to both.

Syntax

HRESULT SetPositions(
  LONGLONG* pCurrent,
  DWORD dwCurrentFlags,
  LONGLONG* pStop,
  DWORD dwStopFlags
);

Parameters

pCurrent
[in, out] Start position if stopped, or position from which to continue if paused.

dwCurrentFlags
[in] When seeking, one of these flags must be set to indicate the type of seek. The flags passed to this method should include one positioning value and (optionally) any of the nonpositioning values.
- AM_SEEKING_NoPositioning
  No change in positioning.
- AM_SEEKING_AbsolutePositioning
  Position supplied is absolute.
- AM_SEEKING_RelativePositioning
  Position supplied is relative to the current position.
- AM_SEEKING_IncrementalPositioning
  This flag only applies to the dwStopFlags. The pCurrent parameter must be set to a valid position.
- AM_SEEKING_PositioningBitsMask
  Mask flag; determine if seeking is required by performing a bitwise AND of the four flags listed above and this mask.
  
  If the resulting value is nonzero, some form of seeking is required.
  
  Check the value of the last two bits to determine which of the above flags are set.
- AM_SEEKING_SeekToKeyFrame
  Seek to the nearest key frame (not as accurate but quicker).
- AM_SEEKING_ReturnTime
  Return the media time equivalents for pCurrent and pStop (overwriting these values with the returned values).
- AM_SEEKING_Segment
  At the end of the segment call EC_ENDOFSEGMENT instead of EndOfStream.
- AM_SEEKING_NoFlush
  Do not flush.

pStop
[in, out] Position in the stream at which to quit.

dwStopFlags
[in] Stop position seeking options to be applied. These are the same as listed for dwCurrentFlags.

Return Value

Returns an HRESULT value. The following table shows some of the possible return values.

Value	Description
NOERROR	Method succeeded.
E_INVALIDARG	One or more parameters is out of range.
E_POINTER	pCurrent is NULL and the corresponding dwCurrentFlags is not set to AM_SEEKING_NoPositioning. pStop is NULL and the corresponding dwStopFlags is not set to AM_SEEKING_NoPositioning. pStop is relative to pCurrent and pCurrent is not set to a valid start position.

NOERROR

Method succeeded.

E_INVALIDARG

One or more parameters is out of range.

E_POINTER

pCurrent is NULL and the corresponding dwCurrentFlags is not set to AM_SEEKING_NoPositioning.

pStop is NULL and the corresponding dwStopFlags is not set to AM_SEEKING_NoPositioning.

pStop is relative to pCurrent and pCurrent is not set to a valid start position.

Remarks

This method supports server-side playlist streaming over HTTP and Microsoft media server.

Example

The following code fragment checks for the type of seeking required.

switch ( dwFlags & AM_SEEKING_PositioningBitsMask )
{
  case AM_SEEKING_IncrementalPositioning:
    // Check this is on a stop time
    // Get Current, add this delta, apply result as new stop time
    break;
  case AM_SEEKING_RelativePositioning:
    // ...
    break;
  case AM_SEEKING_AbsolutePositioning:
    // ...
    break;
  case AM_SEEKING_NoPositioning:
    // Nothing to do.
    break;
}

Requirements

Header	dshow.h
Library	Strmiids.lib

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