DirectShow.NET 替代方案：VisioForge .Net SDK 迁移指南

// 80+ lines of COM interop
var graphBuilder = (IGraphBuilder)new FilterGraph();
var captureGraph = (ICaptureGraphBuilder2)new CaptureGraphBuilder2();
int hr = captureGraph.SetFiltergraph(graphBuilder);
DsError.ThrowExceptionForHR(hr);

// Find video device
var devices = DsDevice.GetDevicesOfCat(FilterCategory.VideoInputDevice);
IBaseFilter sourceFilter;
hr = graphBuilder.AddSourceFilterForMoniker(
    devices[0].Mon, null, devices[0].Name, out sourceFilter);
DsError.ThrowExceptionForHR(hr);

// Render preview
hr = captureGraph.RenderStream(
    PinCategory.Preview, MediaType.Video, sourceFilter, null, null);
DsError.ThrowExceptionForHR(hr);

// Set video window
var videoWindow = (IVideoWindow)graphBuilder;
videoWindow.put_Owner(panelHandle);
videoWindow.put_WindowStyle(WindowStyle.Child | WindowStyle.ClipSiblings);
videoWindow.SetWindowPosition(0, 0, panel.Width, panel.Height);

// Start
var mediaControl = (IMediaControl)graphBuilder;
hr = mediaControl.Run();
DsError.ThrowExceptionForHR(hr);

// Cleanup (must release EVERY COM object)
Marshal.ReleaseComObject(sourceFilter);
Marshal.ReleaseComObject(captureGraph);
Marshal.ReleaseComObject(graphBuilder);

var capture = new VideoCaptureCoreX(videoView);
var devices = await DeviceEnumerator.Shared.VideoSourcesAsync();
capture.Video_Source = new VideoCaptureDeviceSourceSettings(devices[0]);
await capture.StartAsync();

// Cleanup
await capture.StopAsync();
await capture.DisposeAsync();

// Must find H.264 encoder filter, MP4 mux filter, file writer
// Each requires separate COM object management
var graphBuilder = (IGraphBuilder)new FilterGraph();
var captureGraph = (ICaptureGraphBuilder2)new CaptureGraphBuilder2();
captureGraph.SetFiltergraph(graphBuilder);

// Add source
var devices = DsDevice.GetDevicesOfCat(FilterCategory.VideoInputDevice);
IBaseFilter sourceFilter;
graphBuilder.AddSourceFilterForMoniker(
    devices[0].Mon, null, devices[0].Name, out sourceFilter);

// Find and add H.264 encoder (must be installed on system!)
// This varies by system — no guarantee the filter exists
Guid h264Clsid = new Guid("some-encoder-guid");
IBaseFilter encoder = (IBaseFilter)Activator.CreateInstance(
    Type.GetTypeFromCLSID(h264Clsid));
graphBuilder.AddFilter(encoder, "H.264 Encoder");

// Find and add MP4 mux
// Find and add file writer
// Connect source → encoder → mux → writer pins manually
// Each pin connection can fail silently or throw cryptic COM errors

// Configure encoder properties via ICodecAPI or IPropertyBag
// Different for every encoder filter...

var mediaControl = (IMediaControl)graphBuilder;
mediaControl.Run();

// Cleanup: release 5+ COM objects

var capture = new VideoCaptureCoreX(videoView);
var devices = await DeviceEnumerator.Shared.VideoSourcesAsync();
capture.Video_Source = new VideoCaptureDeviceSourceSettings(devices[0]);
capture.Outputs_Add(new MP4Output("recording.mp4"), true);
await capture.StartAsync();

var graphBuilder = (IGraphBuilder)new FilterGraph();
int hr = graphBuilder.RenderFile("video.mp4", null);
DsError.ThrowExceptionForHR(hr);

var videoWindow = (IVideoWindow)graphBuilder;
videoWindow.put_Owner(panelHandle);
videoWindow.put_WindowStyle(WindowStyle.Child);
videoWindow.SetWindowPosition(0, 0, panel.Width, panel.Height);

var mediaControl = (IMediaControl)graphBuilder;
mediaControl.Run();

// Seeking
var mediaSeeking = (IMediaSeeking)graphBuilder;
long position = 50000000; // 5 seconds in 100ns units
mediaSeeking.SetPositions(
    ref position, AMSeekingSeekingFlags.AbsolutePositioning,
    null, AMSeekingSeekingFlags.NoPositioning);

var player = new MediaPlayerCoreX(videoView);
await player.OpenAsync(new Uri("video.mp4"));
await player.PlayAsync();

// Seeking
await player.SeekAsync(TimeSpan.FromSeconds(5));

// Must insert ISampleGrabber into filter graph
var sampleGrabber = (ISampleGrabber)new SampleGrabber();
var mediaType = new AMMediaType();
mediaType.majorType = MediaType.Video;
mediaType.subType = MediaSubType.RGB24;
sampleGrabber.SetMediaType(mediaType);

graphBuilder.AddFilter((IBaseFilter)sampleGrabber, "Grabber");
// Connect pins...
sampleGrabber.SetBufferSamples(true);

// In callback: manually read buffer, create Bitmap from raw bytes
sampleGrabber.GetCurrentBuffer(ref bufferSize, buffer);
// Manual pixel format conversion, stride calculation, etc.

capture.OnVideoFrameBuffer += (s, e) =>
{
    // Frame data available as managed buffer
    // Or convert to SKBitmap/Bitmap directly
    var bitmap = e.Frame.ToBitmap();
    ProcessFrame(bitmap);
};