playback.cpp
[Das dieser Seite zugeordnete Feature DirectShow ist ein Legacyfeature. Es wurde von MediaPlayer, IMFMediaEngine und Audio/Video Capture in Media Foundation abgelöst. Diese Features wurden für Windows 10 und Windows 11 optimiert. Microsoft empfiehlt dringend, dass neuer Code mediaPlayer, IMFMediaEngine und Audio/Video Capture in Media Foundation anstelle von DirectShow verwendet, wenn möglich. Microsoft schlägt vor, dass vorhandener Code, der die Legacy-APIs verwendet, so umgeschrieben wird, dass nach Möglichkeit die neuen APIs verwendet werden.]
Dieses Thema enthält Code für das Tutorial Audio/VideoWiedergabe in DirectShow.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) Microsoft Corporation. All rights reserved.
#include <new>
#include <windows.h>
#include <dshow.h>
#include "playback.h"
#include "video.h"
DShowPlayer::DShowPlayer(HWND hwnd) :
m_state(STATE_NO_GRAPH),
m_hwnd(hwnd),
m_pGraph(NULL),
m_pControl(NULL),
m_pEvent(NULL),
m_pVideo(NULL)
{
}
DShowPlayer::~DShowPlayer()
{
TearDownGraph();
}
// Open a media file for playback.
HRESULT DShowPlayer::OpenFile(PCWSTR pszFileName)
{
IBaseFilter *pSource = NULL;
// Create a new filter graph. (This also closes the old one, if any.)
HRESULT hr = InitializeGraph();
if (FAILED(hr))
{
goto done;
}
// Add the source filter to the graph.
hr = m_pGraph->AddSourceFilter(pszFileName, NULL, &pSource);
if (FAILED(hr))
{
goto done;
}
// Try to render the streams.
hr = RenderStreams(pSource);
done:
if (FAILED(hr))
{
TearDownGraph();
}
SafeRelease(&pSource);
return hr;
}
// Respond to a graph event.
//
// The owning window should call this method when it receives the window
// message that the application specified when it called SetEventWindow.
//
// Caution: Do not tear down the graph from inside the callback.
HRESULT DShowPlayer::HandleGraphEvent(GraphEventFN pfnOnGraphEvent)
{
if (!m_pEvent)
{
return E_UNEXPECTED;
}
long evCode = 0;
LONG_PTR param1 = 0, param2 = 0;
HRESULT hr = S_OK;
// Get the events from the queue.
while (SUCCEEDED(m_pEvent->GetEvent(&evCode, ¶m1, ¶m2, 0)))
{
// Invoke the callback.
pfnOnGraphEvent(m_hwnd, evCode, param1, param2);
// Free the event data.
hr = m_pEvent->FreeEventParams(evCode, param1, param2);
if (FAILED(hr))
{
break;
}
}
return hr;
}
HRESULT DShowPlayer::Play()
{
if (m_state != STATE_PAUSED && m_state != STATE_STOPPED)
{
return VFW_E_WRONG_STATE;
}
HRESULT hr = m_pControl->Run();
if (SUCCEEDED(hr))
{
m_state = STATE_RUNNING;
}
return hr;
}
HRESULT DShowPlayer::Pause()
{
if (m_state != STATE_RUNNING)
{
return VFW_E_WRONG_STATE;
}
HRESULT hr = m_pControl->Pause();
if (SUCCEEDED(hr))
{
m_state = STATE_PAUSED;
}
return hr;
}
HRESULT DShowPlayer::Stop()
{
if (m_state != STATE_RUNNING && m_state != STATE_PAUSED)
{
return VFW_E_WRONG_STATE;
}
HRESULT hr = m_pControl->Stop();
if (SUCCEEDED(hr))
{
m_state = STATE_STOPPED;
}
return hr;
}
// EVR/VMR functionality
BOOL DShowPlayer::HasVideo() const
{
return (m_pVideo && m_pVideo->HasVideo());
}
// Sets the destination rectangle for the video.
HRESULT DShowPlayer::UpdateVideoWindow(const LPRECT prc)
{
if (m_pVideo)
{
return m_pVideo->UpdateVideoWindow(m_hwnd, prc);
}
else
{
return S_OK;
}
}
// Repaints the video. Call this method when the application receives WM_PAINT.
HRESULT DShowPlayer::Repaint(HDC hdc)
{
if (m_pVideo)
{
return m_pVideo->Repaint(m_hwnd, hdc);
}
else
{
return S_OK;
}
}
// Notifies the video renderer that the display mode changed.
//
// Call this method when the application receives WM_DISPLAYCHANGE.
HRESULT DShowPlayer::DisplayModeChanged()
{
if (m_pVideo)
{
return m_pVideo->DisplayModeChanged();
}
else
{
return S_OK;
}
}
// Graph building
// Create a new filter graph.
HRESULT DShowPlayer::InitializeGraph()
{
TearDownGraph();
// Create the Filter Graph Manager.
HRESULT hr = CoCreateInstance(CLSID_FilterGraph, NULL,
CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&m_pGraph));
if (FAILED(hr))
{
goto done;
}
hr = m_pGraph->QueryInterface(IID_PPV_ARGS(&m_pControl));
if (FAILED(hr))
{
goto done;
}
hr = m_pGraph->QueryInterface(IID_PPV_ARGS(&m_pEvent));
if (FAILED(hr))
{
goto done;
}
// Set up event notification.
hr = m_pEvent->SetNotifyWindow((OAHWND)m_hwnd, WM_GRAPH_EVENT, NULL);
if (FAILED(hr))
{
goto done;
}
m_state = STATE_STOPPED;
done:
return hr;
}
void DShowPlayer::TearDownGraph()
{
// Stop sending event messages
if (m_pEvent)
{
m_pEvent->SetNotifyWindow((OAHWND)NULL, NULL, NULL);
}
SafeRelease(&m_pGraph);
SafeRelease(&m_pControl);
SafeRelease(&m_pEvent);
delete m_pVideo;
m_pVideo = NULL;
m_state = STATE_NO_GRAPH;
}
HRESULT DShowPlayer::CreateVideoRenderer()
{
HRESULT hr = E_FAIL;
enum { Try_EVR, Try_VMR9, Try_VMR7 };
for (DWORD i = Try_EVR; i <= Try_VMR7; i++)
{
switch (i)
{
case Try_EVR:
m_pVideo = new (std::nothrow) CEVR();
break;
case Try_VMR9:
m_pVideo = new (std::nothrow) CVMR9();
break;
case Try_VMR7:
m_pVideo = new (std::nothrow) CVMR7();
break;
}
if (m_pVideo == NULL)
{
hr = E_OUTOFMEMORY;
break;
}
hr = m_pVideo->AddToGraph(m_pGraph, m_hwnd);
if (SUCCEEDED(hr))
{
break;
}
delete m_pVideo;
m_pVideo = NULL;
}
return hr;
}
// Render the streams from a source filter.
HRESULT DShowPlayer::RenderStreams(IBaseFilter *pSource)
{
BOOL bRenderedAnyPin = FALSE;
IFilterGraph2 *pGraph2 = NULL;
IEnumPins *pEnum = NULL;
IBaseFilter *pAudioRenderer = NULL;
HRESULT hr = m_pGraph->QueryInterface(IID_PPV_ARGS(&pGraph2));
if (FAILED(hr))
{
goto done;
}
// Add the video renderer to the graph
hr = CreateVideoRenderer();
if (FAILED(hr))
{
goto done;
}
// Add the DSound Renderer to the graph.
hr = AddFilterByCLSID(m_pGraph, CLSID_DSoundRender,
&pAudioRenderer, L"Audio Renderer");
if (FAILED(hr))
{
goto done;
}
// Enumerate the pins on the source filter.
hr = pSource->EnumPins(&pEnum);
if (FAILED(hr))
{
goto done;
}
// Loop through all the pins
IPin *pPin;
while (S_OK == pEnum->Next(1, &pPin, NULL))
{
// Try to render this pin.
// It's OK if we fail some pins, if at least one pin renders.
HRESULT hr2 = pGraph2->RenderEx(pPin, AM_RENDEREX_RENDERTOEXISTINGRENDERERS, NULL);
pPin->Release();
if (SUCCEEDED(hr2))
{
bRenderedAnyPin = TRUE;
}
}
hr = m_pVideo->FinalizeGraph(m_pGraph);
if (FAILED(hr))
{
goto done;
}
// Remove the audio renderer, if not used.
BOOL bRemoved;
hr = RemoveUnconnectedRenderer(m_pGraph, pAudioRenderer, &bRemoved);
done:
SafeRelease(&pEnum);
SafeRelease(&pAudioRenderer);
SafeRelease(&pGraph2);
// If we succeeded to this point, make sure we rendered at least one
// stream.
if (SUCCEEDED(hr))
{
if (!bRenderedAnyPin)
{
hr = VFW_E_CANNOT_RENDER;
}
}
return hr;
}
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