IMediaObject::GetInputType

A version of this page is also available for

Windows Embedded CE 6.0 R3

4/8/2010

This method retrieves a preferred media type for a specified input stream.

Syntax

HRESULT GetInputType(
  DWORD dwInputStreamIndex,
  DWORD dwTypeIndex,
  DMO_MEDIA_TYPE* pmt
);

Parameters

• dwInputStreamIndex
  Zero-based index of an input stream on the DMO.

• dwTypeIndex
  Zero-based index on the set of acceptable media types.

• pmt
  [out] Pointer to a DMO_MEDIA_TYPE structure allocated by the caller. The method fills the structure with the media type. The format block might be NULL, in which case the format type GUID is GUID_NULL.

  Note: This parameter is handled differently for Windows and Windows Embedded CE.

Return Value

Returns an HRESULT value. Possible values include the following.

Remarks

Call this method to enumerate an input stream's preferred media types. The DMO assigns each media type an index value in order of preference. The most preferred type has an index of zero. To enumerate all the types, make successive calls while incrementing the type index until the method returns DMO_E_NO_MORE_ITEMS.

If the method succeeds, call MoFreeMediaType to free the format block.

To set the media type, call the IMediaObject::SetInputType method.

Setting the media type on one stream can change another stream's preferred types. In fact, a stream might not have a preferred type until the type is set on another stream. For example, a decoder might not have a preferred output type until the input type is set.

The DMO is not required to update its preferred types dynamically in this fashion. Thus, the types returned by this method are not guaranteed to be valid; they might fail when used in the SetInputType method.

Conversely, the DMO is not guaranteed to enumerate every media type that it supports. To test whether a media type is acceptable, call SetInputType with the DMO_SET_TYPEF_TEST_ONLY flag.

Requirements

See Also

Reference

IMediaObject
IMediaObject::SetInputType
MoFreeMediaType
DMO Error Codes
DMO Error Codes
DMO_MEDIA_TYPE