IMFPMediaPlayerCallback::OnMediaPlayerEvent method (mfplay.h)

Articolo
12/05/2018

[The feature associated with this page, MFPlay, is a legacy feature. It has been superseded by MediaPlayer and IMFMediaEngine. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer and IMFMediaEngine instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

Called by the MFPlay player object to notify the application of a playback event.

Syntax

void OnMediaPlayerEvent(
  [in] MFP_EVENT_HEADER *pEventHeader
);

Parameters

[in] pEventHeader

Pointer to an MFP_EVENT_HEADER structure that contains information about the event.

Return value

None

Remarks

The specific type of playback event is given in the eEventType member of the MFP_EVENT_HEADER structure. This structure contains information that is common to all of the event types. Some event types use extended structures. A set of macros is defined for casting the pEventHeader pointer to the correct structure type. For more information, see MFP_EVENT_TYPE.

It is safe to call IMFPMediaPlayer and IMFPMediaItem methods inside the OnMediaPlayer method. MFPlay is guaranteed not to reenter the OnMediaPlayer method. That is, calls to OnMediaPlayer are serialized, and the method will not be invoked again from inside OnMediaPlayer.

Examples

The following code shows how to cast the pEventHeader parameter to the correct structure type and pass the structure pointer to a handler function. The handler functions are declared at the start of the example. The application would need to provide implementations for these functions. Note that you do not have to handle every event. For example, if your application never calls IMFPMediaPlayer::SetRate, you would not need to handle the MFP_EVENT_TYPE_RATE_SET event. In that case, simply omit MFP_EVENT_TYPE_RATE_SET from the switch statement.

// Declarations of MFPlay event handler functions.

void OnPlay(MFP_PLAY_EVENT *pEvent);
void OnPause(MFP_PAUSE_EVENT *pEvent);
void OnStop(MFP_STOP_EVENT *pEvent);
void OnPositionSet(MFP_POSITION_SET_EVENT *pEvent);
void OnRateSet(MFP_RATE_SET_EVENT *pEvent);
void OnMediaItemCreated(MFP_MEDIAITEM_CREATED_EVENT *pEvent);
void OnMediaItemSet(MFP_MEDIAITEM_SET_EVENT *pEvent);
void OnFrameStep(MFP_FRAME_STEP_EVENT *pEvent);
void OnMediaItemCleared(MFP_MEDIAITEM_CLEARED_EVENT *pEvent);
void OnMFEvent(MFP_MF_EVENT *pEvent); 
void OnError(MFP_ERROR_EVENT *pEvent);
void OnPlaybackEnded(MFP_PLAYBACK_ENDED_EVENT *pEvent);
void OnAquireUserCredential(MFP_ACQUIRE_USER_CREDENTIAL_EVENT *pEvent);

// Implementation of IMFPMediaPlayerCallback::OnMediaPlayerEvent
void STDMETHODCALLTYPE PlayerCallback::OnMediaPlayerEvent(MFP_EVENT_HEADER * pEventHeader)
{
    switch (pEventHeader->eEventType)
    {
    case MFP_EVENT_TYPE_PLAY: 
        OnPlay(MFP_GET_PLAY_EVENT(pEventHeader));
        break;

    case MFP_EVENT_TYPE_PAUSE: 
        OnPause(MFP_GET_PAUSE_EVENT(pEventHeader));
        break;

    case MFP_EVENT_TYPE_STOP: 
        OnStop(MFP_GET_STOP_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_POSITION_SET: 
        OnPositionSet(MFP_GET_POSITION_SET_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_RATE_SET: 
        OnRateSet(MFP_GET_RATE_SET_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_MEDIAITEM_CREATED: 
        OnMediaItemCreated(MFP_GET_MEDIAITEM_CREATED_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_MEDIAITEM_SET: 
        OnMediaItemSet(MFP_GET_MEDIAITEM_SET_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_FRAME_STEP: 
        OnFrameStep(MFP_GET_FRAME_STEP_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_MEDIAITEM_CLEARED: 
        OnMediaItemCleared(MFP_GET_MEDIAITEM_CLEARED_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_MF: 
        OnMFEvent(MFP_GET_MF_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_ERROR: 
        OnError(MFP_GET_ERROR_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_PLAYBACK_ENDED: 
        OnPlaybackEnded(MFP_GET_PLAYBACK_ENDED_EVENT(pEventHeader)); 
        break;

    case MFP_EVENT_TYPE_ACQUIRE_USER_CREDENTIAL: 
        OnAquireUserCredential(MFP_GET_ACQUIRE_USER_CREDENTIAL_EVENT(pEventHeader)); 
        break;
    }
}

Requirements

Requirement	Value
Minimum supported client	Windows 7 [desktop apps only]
Minimum supported server	Windows Server 2008 R2 [desktop apps only]
Target Platform	Windows
Header	mfplay.h

Condividi tramite