IDvdInfo2::GetDVDTextStringAsUnicode method (strmif.h)

Article
07/27/2023

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 GetDVDTextStringAsUnicode method retrieves a DVD text string for a specified language, and returns the text string as a Unicode string.

Syntax

HRESULT GetDVDTextStringAsUnicode(
  [in]  ULONG              ulLangIndex,
  [in]  ULONG              ulStringIndex,
  [out] WCHAR              *pchwBuffer,
  [in]  ULONG              ulMaxBufferSize,
  [out] ULONG              *pulActualSize,
  [out] DVD_TextStringType *pType
);

Parameters

[in] ulLangIndex

Zero-based index of the language. To find the number of text-string languages on the DVD, call IDvdInfo2::GetDVDTextNumberOfLanguages.

[in] ulStringIndex

Zero-based index of the string to retrieve. To find the number of strings for a given language, call IDvdInfo2::GetDVDTextLanguageInfo.

[out] pchwBuffer

Pointer to a buffer that receives the text string. If pchBuffer is NULL, this method returns the size of the string in pulActualSize.

[in] ulMaxBufferSize

Size of the pchBuffer buffer, in WCHARs.

[out] pulActualSize

Receives the actual length of the string in characters, including the terminating NULL.

[out] pType

Receives a member of the DVD_TextStringType enumeration. The value indicates the type of text string, such as movie title or song name. This parameter can also receive values that are not defined in the DVD_TextStringType enumeration.

Return value

Returns one of the following HRESULT values.

Return code	Description
S_OK	Success.
E_FAIL	Unsupported te
E_POINTER	Invalid argument.
E_UNEXPECTED	An unexpected internal error occurred.

Remarks

This method supports text strings that are encoded as Unicode or 7-bit ASCII (ISO/IEC 646). If the text string uses ASCII encoding, the method converts the string to a wide-character string. If the text string uses any other character set, the method returns E_FAIL. In that case, you can call IDvdInfo2::GetDVDTextStringAsNative to retrieve the string as a raw byte array. To find the character set, call IDvdInfo2::GetDVDTextLanguageInfo.

The returned string always includes a terminating NULL. If the buffer is smaller than the length of the DVD text string, the string is truncated. To find the required size of the buffer, call the method once with pchBuffer equal to NULL and ulMaxBufferSize equal to zero. The size is returned in pulActualSize. Then allocate a buffer and call the method again.

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

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