superstar_v2/Services/MediaServicePrimary.cs

using DirectShowLib;
using System;
using System.Runtime.InteropServices;

namespace DualScreenDemo.Services
{
    public class MediaServicePrimary
    {
        IGraphBuilder graphBuilder;
        IBaseFilter sourceFilter;
        IBaseFilter lavSplitter;
        IBaseFilter lavVideoDecoder;
        IBaseFilter videoRenderer;
        IVideoWindow videoWindow;
        IMediaControl mediaControl;


        public MediaServicePrimary(){}

        public int Run()
        {
            if (mediaControl != null)
                return mediaControl.Run();
            else
                return 0;
        }
        public int Stop()
        {
            if (mediaControl != null)
                return mediaControl.Stop();
            else
                return 0;

        }
        public int Pause()
        {
            if (mediaControl != null)
                return mediaControl.Pause();
            else
                return 0;
        }
        public void VideoPlayerFormClosing()
        {
            if (videoWindow != null)
            {
                videoWindow.put_Visible(OABool.False);
                videoWindow.put_Owner(IntPtr.Zero);
                Marshal.ReleaseComObject(videoWindow);
                videoWindow = null;
            }
        }

        public void StopAndReleaseResources()
        {
            if (mediaControl != null)
            {
                mediaControl.Stop();
                SafeRelease(ref mediaControl);
            }
            SafeRelease(ref videoWindow);
            SafeRelease(ref videoRenderer);
            SafeRelease(ref sourceFilter);
            SafeRelease(ref lavVideoDecoder);
            SafeRelease(ref lavSplitter);
            SafeRelease(ref graphBuilder);
        }

        public void RenderMediaFile(string filePath, nint Handle, int Width, int Height)
        {
            StopAndReleaseResources();
            if (videoWindow != null) videoWindow.put_Visible(OABool.False);

            int hr;
            graphBuilder = (IGraphBuilder)new FilterGraph();
            if (graphBuilder == null)
                throw new Exception("Failed to create FilterGraph for primary monitor.");

            graphBuilder.AddSourceFilter(filePath, "Source", out sourceFilter);
            try
            {
                lavSplitter = AddFilterByClsid(graphBuilder, "LAV Splitter", Clsid.LAVSplitter);
                lavVideoDecoder = AddFilterByClsid(graphBuilder, "LAV Video Decoder", Clsid.LAVVideoDecoder);
                videoRenderer = AddFilterByClsid(graphBuilder, "Primary Video Renderer", Clsid.VideoRenderer);
                hr = graphBuilder.AddFilter(videoRenderer, "Primary Video Renderer");
                DsError.ThrowExceptionForHR(hr);

                mediaControl = (IMediaControl)graphBuilder;
                if (mediaControl == null)
                {
                    Console.WriteLine("Failed to get Media Control for primary monitor.");
                    return;
                }
                hr = ConnectFilters(graphBuilder, sourceFilter, "Output", lavSplitter, "Input");
                DsError.ThrowExceptionForHR(hr);
                hr = ConnectFilters(graphBuilder, lavSplitter, "Video", lavVideoDecoder, "Input");
                DsError.ThrowExceptionForHR(hr);
                hr = ConnectFilters(graphBuilder, lavVideoDecoder, "Output", videoRenderer, "VMR Input0");
                DsError.ThrowExceptionForHR(hr);

                try
                {

                    IVideoWindow videoWindow = (IVideoWindow)videoRenderer;
                    videoWindow.put_Owner(Handle);
                    videoWindow.put_WindowStyle(WindowStyle.Child | WindowStyle.ClipChildren);

                    // ⬅ 左上角對齊（固定從 0,0 開始）
                    videoWindow.SetWindowPosition(0, 0, Width, Height);

                    videoWindow.put_Visible(OABool.True);

                    // Console.WriteLine("Video window configured successfully.");
                }
                catch (Exception ex)
                {
                    Console.WriteLine(String.Format("Error syncing to primary monitor: {0}", ex.Message));
                    MessageBox.Show(String.Format("Error syncing to primary monitor: {0}", ex.Message));
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error initializing graph builder for primary monitor: " + ex.Message);
            }
        }
        private static IBaseFilter AddFilterByClsid(IGraphBuilder graphBuilder, string name, Guid clsid)
        {
            try
            {
                // 获取 CLSID 对应的类型
                Type filterType = Type.GetTypeFromCLSID(clsid);
                //Console.WriteLine($"Attempting to create filter of type: {filterType.FullName}");

                // 创建实例
                object filterObject = Activator.CreateInstance(filterType);

                // 尝试转换为 IBaseFilter
                IBaseFilter filter = filterObject as IBaseFilter;

                if (filter == null)
                {
                    // 如果转换失败，使用 IUnknown 获取并转换为 IBaseFilter
                    IntPtr comObjectPointer = Marshal.GetIUnknownForObject(filterObject);
                    filter = (IBaseFilter)Marshal.GetObjectForIUnknown(comObjectPointer);
                    // Console.WriteLine($"Successfully converted COM object to IBaseFilter via IUnknown.");
                }
                else
                {
                    // Console.WriteLine($"Successfully created IBaseFilter directly.");
                }

                // 添加过滤器到图形构建器
                int hr = graphBuilder.AddFilter(filter, name);
                if (hr != 0)
                {
                    // Console.WriteLine($"Failed to add filter {name} with CLSID {clsid}, HRESULT: {hr}");
                }

                DsError.ThrowExceptionForHR(hr);
                // Console.WriteLine($"Successfully added filter {name} with CLSID {clsid}");
                return filter;
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Exception in AddFilterByClsid: {ex.Message}");
                throw; // Rethrow the exception to handle it further up the call stack
            }
        }
        private int ConnectFilters(IGraphBuilder graphBuilder, IBaseFilter sourceFilter, string sourcePinName, IBaseFilter destFilter, string destPinName)
        {
            IPin outPin = FindPin(sourceFilter, sourcePinName);
            IPin inPin = FindPin(destFilter, destPinName);
            if (outPin == null || inPin == null)
            {
                Console.WriteLine(String.Format("Cannot find pins: {0} or {1}", sourcePinName, destPinName));
                return -1;
            }
            int hr = graphBuilder.Connect(outPin, inPin);
            return hr;
        }
        private IPin FindPin(IBaseFilter filter, string pinName)
        {
            IEnumPins enumPins;
            IPin[] pins = new IPin[1];

            filter.EnumPins(out enumPins);
            enumPins.Reset();

            while (enumPins.Next(1, pins, IntPtr.Zero) == 0)
            {
                PinInfo pinInfo;
                pins[0].QueryPinInfo(out pinInfo);
                Console.WriteLine(pinInfo);

                if (pinInfo.name == pinName)
                {
                    return pins[0];
                }
            }
            return null;
        }
        private void SafeRelease<T>(ref T comObject) where T : class
        {
            if (comObject != null)
            {
                Marshal.ReleaseComObject(comObject);
                comObject = null;
            }
        }
    }
}