IMFASFContentInfo::ParseHeader method (wmcontainer.h)

Article
10/13/2021

Parses the information in an ASF header and uses that information to set values in the ContentInfo object. You can pass the entire header in a single buffer or send it in several pieces.

Syntax

HRESULT ParseHeader(
  [in] IMFMediaBuffer *pIHeaderBuffer,
  [in] QWORD          cbOffsetWithinHeader
);

Parameters

[in] pIHeaderBuffer

Pointer to the IMFMediaBuffer interface of a buffer object containing some or all of the header. The buffer must contain at least 30 bytes, which is the size of the Header Object, not including the objects contained in the Header Object (that is, everything up to and including the Reserved2 field in the Header Object).

[in] cbOffsetWithinHeader

Offset, in bytes, of the first byte in the buffer relative to the beginning of the header.

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 header is completely parsed and validated.
MF_E_ASF_INVALIDDATA	The input buffer does not contain valid ASF data.
MF_E_BUFFERTOOSMALL	The input buffer is too small.
MF_S_ASF_PARSEINPROGRESS	The method succeeded, but the header passed was incomplete. This is the successful return code for all calls but the last one when passing the header in pieces.

Remarks

If you pass the header in pieces, the ContentInfo object will keep references to the buffer objects until the entire header is parsed. Therefore, do not write over the buffers passed into this method.

The start of the Header object has the following layout in memory:

Field Name	Size in bytes
Object ID	16
Object Size	8
Number of Header Objects	4
Reserved1	1
Reserved2	1

The first call to ParseHeader reads everything up to and including Rerserved2, so it requires a minimum of 30 bytes. (Note that the IMFASFContentInfo::GetHeaderSize method reads only the Object ID and Object Size fields, so that method requires a minimum of 24 bytes.)

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Target Platform	Windows
Header	wmcontainer.h
Library	Mfuuid.lib