IDMOVideoOutputOptimizations::GetCurrentSampleRequirements method (mediaobj.h)
[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 GetCurrentSampleRequirements method retrieves the optimization features required to process the next sample, given the features already agreed to by the application.
Syntax
HRESULT GetCurrentSampleRequirements(
ULONG ulOutputStreamIndex,
DWORD *pdwRequestedFeatures
);
Parameters
ulOutputStreamIndex
Zero-based index of an output stream on the DMO.
pdwRequestedFeatures
Pointer to a variable that receives the required features. The returned value is a bitwise combination of zero or more flags from the DMO_VIDEO_OUTPUT_STREAM_FLAGS enumeration.
Return value
Returns an HRESULT value. Possible values include those in the following table.
| Return code | Description |
|---|---|
|
Invalid stream index |
|
NULL pointer argument |
|
Success |
Remarks
After an application calls the IDMOVideoOutputOptimizations::SetOperationMode method, it must provide all the features it has agreed to. However, the DMO might not require every feature on every sample. This method enables the DMO to waive an agreed-upon feature for one sample.
Before processing a sample, the application can call this method. If the DMO does not require a given feature in order to process the next sample, it omits the corresponding flag from the pdwRequestedFeatures parameter. For the next sample only, the application can ignore the feature. The results of this method are valid only for the next call to the IMediaObject::ProcessOutput method.
The DMO will return only the flags that were agreed to in the SetOperationMode method. In other words, you cannot dynamically enable new features with this method.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Windows |
| Header | mediaobj.h (include Dmo.h) |
| Library | Dmoguids.lib |