IDVB_NIT::GetRecordDescriptorByTag Method

Article
01/07/2009

This topic applies to Update Rollup 2 for Microsoft Windows XP Media Center Edition 2005 and later.
The GetRecordDescriptorByTag method searches a record in the NIT for a descriptor with a specified descriptor tag.

Syntax

HRESULT GetRecordDescriptorByTag(
  [in]   DWORD dwRecordIndex,
  [in]   BYTE bTag,
  [in]   DWORD *pdwCookie,
  [out]  IGenericDescriptor **ppDescriptor
);

Parameters

dwRecordIndex [in]
Specifies the record number, indexed from zero. Call the IDVB_NIT::GetCountOfRecords method to get the number of records in the NIT.
bTag [in]
Specifies the descriptor tag for which to search.
pdwCookie [in]
Pointer to a variable that specifies the start position in the descriptor list. This parameter is optional. If the value of pdwCookie is NULL, the search starts from the first descriptor in the list. Otherwise, the search starts from the position given in pdwCookie. When the method returns, the pdwCookie parameter contains the position of the next matching descriptor, if any. You can use this parameter to iterate through the descriptor list, looking for every instance of a particular descriptor tag.
ppDescriptor [out]
Address of a variable that receives an IGenericDescriptor interface pointer. Use this interface to retrieve the information in the descriptor. The caller must release the interface.

Return Value

The method returns an HRESULT. Possible values include those in the following table.

Return code	Description
MPEG2_E_OUT_OF_BOUNDS	Index out of bounds.
MPEG2_E_NOT_PRESENT	The specified tag was not found.
MPEG2_S_MORE_DATA_AVAILABLE	The record contains at least one more descriptor with this tag.
MPEG2_S_NO_MORE_DATA_AVAILABLE	The record does not contain any more descriptors with this tag.
S_OK	The method succeeded.

Remarks

If the value of pdwCookie is not NULL, the method returns either MPEG2_S_NO_MORE_DATA_AVAILABLE or MPEG2_S_MORE_DATA_AVAILABLE to indicate whether the record contains additional tags that match the search criteria.

Requirements

Header

Declared in Dvbsiparser.h.

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