IDvdControl2::PlayBackwards method (strmif.h)

Article
02/22/2024

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 PlayBackwards method plays backward at the specified speed from the current location.

Syntax

HRESULT PlayBackwards(
  [in]  double  dSpeed,
  [in]  DWORD   dwFlags,
  [out] IDvdCmd **ppCmd
);

Parameters

[in] dSpeed

Value that specifies the speed of backward play. This value is a multiplier, where 1.0 is the authored speed. So, a value of 2.5 plays backward at two and one-half times the authored speed, while a value of 0.5 plays backward at half the authored speed. The actual speed of playback depends on the video decoder's capabilities and might differ from the specified rate. For reverse play, audio is muted and no subpicture is displayed. Any speed below 0.00001 is converted to 0.00001.

[in] dwFlags

Bitwise OR of one or more flags from the DVD_CMD_FLAGS enumeration, specifying how to synchronize the command.

[out] ppCmd

Receives a pointer to an IDvdCmd object that can be used to synchronize DVD commands. The caller must release the interface. This parameter can be NULL. For more information, see Synchronizing DVD Commands.

Return value

Returns one of the following values.

Return code	Description
S_OK	Success.
VFW_E_DVD_OPERATION_INHIBITED	UOP control prohibits the operation.

Remarks

This method is demonstrated in the DVDSample application in CDvdCore::Rewind.

The following table shows the Annex J command name to which this method name corresponds, and the domains in which this method is valid.

Annex J Command Name	Valid Domains
Backward_Scan	DVD_DOMAIN_VideoManagerMenu DVD_DOMAIN_VideoTitleSetMenu DVD_DOMAIN_Title

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	strmif.h (include Dshow.h)
Library	Strmiids.lib