IWMDRMTranscryptor::Seek method (wmsdkidl.h)

Article
4/26/2023

[The feature associated with this page, Windows Media Format 11 SDK, is a legacy feature. It has been superseded by Source Reader and Sink Writer. Source Reader and Sink Writer have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Source Reader and Sink Writer instead of Windows Media Format 11 SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

[Seek is available for use in the operating systems specified in the Requirements section. It may be altered or unavailable in subsequent versions. Instead, use Microsoft PlayReady. ]

The Seek method sets the DRM transcryptor to read from the specified point in the data stream of the loaded file. Subsequent Read calls generate data beginning at that point.

Syntax

HRESULT Seek(
  [in] QWORD hnsTime
);

Parameters

[in] hnsTime

Seek time in 100-nanosecond units.

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.
NS_E_INVALID_REQUEST	There is no file loaded in the transcryptor.

Remarks

This method is asynchronous. It returns immediately, but processing is not complete until a WMT_TRANSCRYPTOR_SEEKED message is sent to the IWMStatusCallback::OnStatus callback method.

If the seek operation fails, no message is sent.

The first successful call to Seek causes the transcryptor to read the ASF header for the content. All subsequent Seek calls change the reading location in the data section, but do not generate a header or an ASF Data Object (the ASF object that contains top-level information about the data section).

To convert the entire file, call Seek with a presentation time of 0.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only],Windows Media Format 9.5 SDK
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	wmsdkidl.h (include Wmsdk.h)
Library	WMStubDRM.lib

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