IMediaObjectInPlace::Process method (mediaobj.h)

Article
4/26/2023

[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 Process method processes a block of data. The application supplies a pointer to a block of input data. The DMO processes the data in place.

Syntax

HRESULT Process(
  [in]      ULONG          ulSize,
  [in, out] BYTE           *pData,
  [in]      REFERENCE_TIME refTimeStart,
  [in]      DWORD          dwFlags
);

Parameters

[in] ulSize

Size of the data, in bytes.

[in, out] pData

Pointer to a buffer of size ulSize. On input, the buffer holds the input data. If the method returns successfully, the buffer contains the output data.

[in] refTimeStart

Start time of the data.

[in] dwFlags

Either DMO_INPLACE_NORMAL or DMO_INPLACE_ZERO. See Remarks for more information.

Return value

Returns an HRESULT value. Possible values include those in the following table.

Return code	Description
E_FAIL	Failure
S_FALSE	Success. There is still data to process.
S_OK	Success. There is no remaining data to process.

Remarks

If the method fails, the buffer might contain garbage. The application should not use the contents of the buffer.

The DMO might produce output data beyond the length of the input data. This is called an effect tail. For example, a reverb effect continues after the input reaches silence. If the DMO has an effect tail, this method returns S_FALSE.

While the application has input data for processing, call the Process method with the dwFlags parameter set to DMO_INPLACE_NORMAL. If the last such call returns S_FALSE, call Process again, this time with a zeroed input buffer and the DMO_INPLACE_ZERO flag. The DMO will now fill the zeroed buffer with the effect tail. Continue calling Process in this way until the return value is S_OK, indicating that the DMO has finished processing the effect tail.

If the DMO has no effect tail, this method returns S_TRUE or an error code.

Requirements

Requirement	Value
Target Platform	Windows
Header	mediaobj.h (include Dmo.h)
Library	Dmoguids.lib

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