ASP.Net Core对USB摄像头进行截图

最近想把之前一个USB摄像头拍照的winform程序迁移到.net 5下,首先找了一下,网上有通过DirectShow.NET读取摄像头的例子,Read Barcode from Webcam Viewer with DirectShow.NET。

这个程序依赖着DirectShow.NET的,虽然它是.net framework版本的。试了一下,迁移到.net 5还是无任何障碍的。但我觉得这些原始api使用起来还是不是很方便,便继续找了一下,找到了一个更加简单的类

    class UsbCamera:IDisposable
    {
        /// Usb camera image size.
        public Size Size { get; private set; }

        /// Start.
        public Action Start { get; private set; }

        /// Stop.
        public Action Stop { get; private set; }

        /// Release resource.
        public Action Release { get; private set; }

        /// Get image.
        /// Immediately after starting, fails because image buffer is not prepared yet.
        public Func GetBitmap { get; private set; }

        /// 
        /// Get available USB camera list.
        /// 
        /// Array of camera name, or if no device found, zero length array.
        public static string[] FindDevices()
        {
            return DirectShow.GetFiltes(DirectShow.DsGuid.CLSID_VideoInputDeviceCategory).ToArray();
        }

        /// 
        /// Get video formats.
        /// 
        public static VideoFormat[] GetVideoFormat(int cameraIndex)
        {
            var filter = DirectShow.CreateFilter(DirectShow.DsGuid.CLSID_VideoInputDeviceCategory, cameraIndex);
            var pin = DirectShow.FindPin(filter, 0, DirectShow.PIN_DIRECTION.PINDIR_OUTPUT);
            return GetVideoOutputFormat(pin);
        }

        /// 
        /// Create USB Camera. If device do not support the size, default size will applied.
        /// 
        /// Camera index in FindDevices() result.
        /// 
        /// Size you want to create. Normally use Size property of VideoFormat in GetVideoFormat() result.
        /// 
        public UsbCamera(int cameraIndex, Size size) : this(cameraIndex, new VideoFormat() { Size = size })
        {
        }

        /// 
        /// Create USB Camera. If device do not support the format, default format will applied.
        /// 
        /// Camera index in FindDevices() result.
        /// 
        /// Normally use GetVideoFormat() result.
        /// You can change TimePerFrame value from Caps.MinFrameInterval to Caps.MaxFrameInterval.
        /// TimePerFrame = 10,000,000 / frame duration. (ex: 333333 in case 30fps).
        /// You can change Size value in case Caps.MaxOutputSize > Caps.MinOutputSize and OutputGranularityX/Y is not zero.
        /// Size = any value from Caps.MinOutputSize to Caps.MaxOutputSize step with OutputGranularityX/Y.
        /// 
        public UsbCamera(int cameraIndex, VideoFormat format)
        {
            var camera_list = FindDevices();
            if (cameraIndex >= camera_list.Length) throw new ArgumentException("USB camera is not available.", "cameraIndex");
            Init(cameraIndex, format);
        }

        private void Init(int index, VideoFormat format)
        {
            //----------------------------------
            // Create Filter Graph
            //----------------------------------
            // +--------------------+  +----------------+  +---------------+
            // |Video Capture Source|→| Sample Grabber |→| Null Renderer |
            // +--------------------+  +----------------+  +---------------+
            //                                 ↓GetBitmap()

            var graph = DirectShow.CreateGraph();

            //----------------------------------
            // VideoCaptureSource
            //----------------------------------
            var vcap_source = CreateVideoCaptureSource(index, format);
            graph.AddFilter(vcap_source, "VideoCapture");

            //------------------------------
            // SampleGrabber
            //------------------------------
            var grabber = CreateSampleGrabber();
            graph.AddFilter(grabber, "SampleGrabber");
            var i_grabber = (DirectShow.ISampleGrabber)grabber;
            i_grabber.SetBufferSamples(true);

            //---------------------------------------------------
            // Null Renderer
            //---------------------------------------------------
            var renderer = DirectShow.CoCreateInstance(DirectShow.DsGuid.CLSID_NullRenderer) as DirectShow.IBaseFilter;
            graph.AddFilter(renderer, "NullRenderer");

            //---------------------------------------------------
            // Create Filter Graph
            //---------------------------------------------------
            var builder = DirectShow.CoCreateInstance(DirectShow.DsGuid.CLSID_CaptureGraphBuilder2) as DirectShow.ICaptureGraphBuilder2;
            builder.SetFiltergraph(graph);
            var pinCategory = DirectShow.DsGuid.PIN_CATEGORY_CAPTURE;
            var mediaType = DirectShow.DsGuid.MEDIATYPE_Video;
            builder.RenderStream(ref pinCategory, ref mediaType, vcap_source, grabber, renderer);

            // SampleGrabber Format.
            {
                var mt = new DirectShow.AM_MEDIA_TYPE();
                i_grabber.GetConnectedMediaType(mt);
                var header = (DirectShow.VIDEOINFOHEADER)Marshal.PtrToStructure(mt.pbFormat, typeof(DirectShow.VIDEOINFOHEADER));
                var width = header.bmiHeader.biWidth;
                var height = header.bmiHeader.biHeight;
                var stride = width * (header.bmiHeader.biBitCount / 8);
                DirectShow.DeleteMediaType(ref mt);

                Size = new Size(width, height);

                // fix screen tearing problem(issure #2)
                // you can use previous method if you swap the comment line below.
                // GetBitmap = () => GetBitmapFromSampleGrabberBuffer(i_grabber, width, height, stride);
                GetBitmap = GetBitmapFromSampleGrabberCallback(i_grabber, width, height, stride);
            }

            // Assign Delegates.
            Start = () => DirectShow.PlayGraph(graph, DirectShow.FILTER_STATE.Running);
            Stop = () => DirectShow.PlayGraph(graph, DirectShow.FILTER_STATE.Stopped);
            Release = () =>
            {
                Stop();

                DirectShow.ReleaseInstance(ref i_grabber);
                DirectShow.ReleaseInstance(ref builder);
                DirectShow.ReleaseInstance(ref graph);
            };

            // Properties.
            Properties = new PropertyItems(vcap_source);
        }

        public void Dispose()
        {
            Release?.Invoke();
        }

        /// Properties user can adjust.
        public PropertyItems Properties { get; private set; }
        public class PropertyItems
        {
            public PropertyItems(DirectShow.IBaseFilter vcap_source)
            {
                // Pan, Tilt, Roll, Zoom, Exposure, Iris, Focus
                this.CameraControl = Enum.GetValues(typeof(DirectShow.CameraControlProperty)).Cast()
                    .Select(item =>
                    {
                        PropertyItems.Property prop = null;
                        try
                        {
                            var cam_ctrl = vcap_source as DirectShow.IAMCameraControl;
                            if (cam_ctrl == null) throw new NotSupportedException("no IAMCameraControl Interface."); // will catched.
                            int min = 0, max = 0, step = 0, def = 0, flags = 0;
                            cam_ctrl.GetRange(item, ref min, ref max, ref step, ref def, ref flags); // COMException if not supports.
                            prop = new Property(min, max, step, def, flags, (flag, value) => cam_ctrl.Set(item, value, (int)flag));
                        }
                        catch (Exception) { prop = new Property(); } // available = false
                        return new { Key = item, Value = prop };
                    }).ToDictionary(x => x.Key, x => x.Value);

                // Brightness, Contrast, Hue, Saturation, Sharpness, Gamma, ColorEnable, WhiteBalance, BacklightCompensation, Gain
                this.VideoProcAmp = Enum.GetValues(typeof(DirectShow.VideoProcAmpProperty)).Cast()
                    .Select(item =>
                    {
                        PropertyItems.Property prop = null;
                        try
                        {
                            var vid_ctrl = vcap_source as DirectShow.IAMVideoProcAmp;
                            if (vid_ctrl == null) throw new NotSupportedException("no IAMVideoProcAmp Interface."); // will catched.
                            int min = 0, max = 0, step = 0, def = 0, flags = 0;
                            vid_ctrl.GetRange(item, ref min, ref max, ref step, ref def, ref flags); // COMException if not supports.
                            prop = new Property(min, max, step, def, flags, (flag, value) => vid_ctrl.Set(item, value, (int)flag));
                        }
                        catch (Exception) { prop = new Property(); } // available = false
                        return new { Key = item, Value = prop };
                    }).ToDictionary(x => x.Key, x => x.Value);
            }

            /// Camera Control properties.
            private Dictionary CameraControl;

            /// Video Processing Amplifier properties.
            private Dictionary VideoProcAmp;

            /// Get CameraControl Property. Check Available before use.
            public Property this[DirectShow.CameraControlProperty item] { get { return CameraControl[item]; } }

            /// Get VideoProcAmp Property. Check Available before use.
            public Property this[DirectShow.VideoProcAmpProperty item] { get { return VideoProcAmp[item]; } }

            public class Property
            {
                public int Min { get; private set; }
                public int Max { get; private set; }
                public int Step { get; private set; }
                public int Default { get; private set; }
                public DirectShow.CameraControlFlags Flags { get; private set; }
                public Action SetValue { get; private set; }
                public bool Available { get; private set; }
                public bool CanAuto { get; private set; }

                public Property()
                {
                    this.SetValue = (flag, value) => { };
                    this.Available = false;
                }

                public Property(int min, int max, int step, int @default, int flags, Action set)
                {
                    this.Min = min;
                    this.Max = max;
                    this.Step = step;
                    this.Default = @default;
                    this.Flags = (DirectShow.CameraControlFlags)flags;
                    this.CanAuto = (Flags & DirectShow.CameraControlFlags.Auto) == DirectShow.CameraControlFlags.Auto;
                    this.SetValue = set;
                    this.Available = true;
                }

                public override string ToString()
                {
                    return string.Format("Available={0}, Min={1}, Max={2}, Step={3}, Default={4}, Flags={5}", Available, Min, Max, Step, Default, Flags);
                }
            }
        }

        private class SampleGrabberCallback : DirectShow.ISampleGrabberCB
        {
            private byte[] Buffer;
            private object BufferLock = new object();

            public Bitmap GetBitmap(int width, int height, int stride)
            {
                var result = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
                if (Buffer == null) return result;

                var bmp_data = result.LockBits(new Rectangle(Point.Empty, result.Size), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
                lock (BufferLock)
                {
                    // copy from last row.
                    for (int y = 0; y < height; y++)
                    {
                        var src_idx = Buffer.Length - (stride * (y + 1));
                        var dst = IntPtr.Add(bmp_data.Scan0, stride * y);
                        Marshal.Copy(Buffer, src_idx, dst, stride);
                    }
                }
                result.UnlockBits(bmp_data);

                return result;
            }

            // called when each sample completed.
            // The data processing thread blocks until the callback method returns. If the callback does not return quickly, it can interfere with playback.
            public int BufferCB(double SampleTime, IntPtr pBuffer, int BufferLen)
            {
                if (Buffer == null || Buffer.Length != BufferLen)
                {
                    Buffer = new byte[BufferLen];
                }

                lock (BufferLock)
                {
                    Marshal.Copy(pBuffer, Buffer, 0, BufferLen);
                }
                return 0;
            }

            // never called.
            public int SampleCB(double SampleTime, DirectShow.IMediaSample pSample)
            {
                throw new NotImplementedException();
            }
        }

        private Func GetBitmapFromSampleGrabberCallback(DirectShow.ISampleGrabber i_grabber, int width, int height, int stride)
        {
            var sampler = new SampleGrabberCallback();
            i_grabber.SetCallback(sampler, 1); // WhichMethodToCallback = BufferCB
            return () => sampler.GetBitmap(width, height, stride);
        }

        /// Get Bitmap from Sample Grabber Current Buffer
        private Bitmap GetBitmapFromSampleGrabberBuffer(DirectShow.ISampleGrabber i_grabber, int width, int height, int stride)
        {
            try
            {
                return GetBitmapFromSampleGrabberBufferMain(i_grabber, width, height, stride);
            }
            catch (COMException ex)
            {
                const uint VFW_E_WRONG_STATE = 0x80040227;
                if ((uint)ex.ErrorCode == VFW_E_WRONG_STATE)
                {
                    // image data is not ready yet. return empty bitmap.
                    return new Bitmap(width, height);
                }

                throw;
            }
        }

        /// Get Bitmap from Sample Grabber Current Buffer
        private Bitmap GetBitmapFromSampleGrabberBufferMain(DirectShow.ISampleGrabber i_grabber, int width, int height, int stride)
        {

            int sz = 0;
            i_grabber.GetCurrentBuffer(ref sz, IntPtr.Zero); // IntPtr.Zeroで呼び出してバッファサイズ取得
            if (sz == 0) return null;

            var ptr = Marshal.AllocCoTaskMem(sz);
            i_grabber.GetCurrentBuffer(ref sz, ptr);

            var data = new byte[sz];
            Marshal.Copy(ptr, data, 0, sz);

            var result = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
            var bmp_data = result.LockBits(new Rectangle(Point.Empty, result.Size), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb);

            for (int y = 0; y < height; y++)
            {
                var src_idx = sz - (stride * (y + 1));
                var dst = IntPtr.Add(bmp_data.Scan0, stride * y);
                Marshal.Copy(data, src_idx, dst, stride);
            }
            result.UnlockBits(bmp_data);
            Marshal.FreeCoTaskMem(ptr);

            return result;
        }


        private DirectShow.IBaseFilter CreateSampleGrabber()
        {
            var filter = DirectShow.CreateFilter(DirectShow.DsGuid.CLSID_SampleGrabber);
            var ismp = filter as DirectShow.ISampleGrabber;

            var mt = new DirectShow.AM_MEDIA_TYPE();
            mt.MajorType = DirectShow.DsGuid.MEDIATYPE_Video;
            mt.SubType = DirectShow.DsGuid.MEDIASUBTYPE_RGB24;
            ismp.SetMediaType(mt);
            return filter;
        }

        /// 
        /// Video Capture Sourceフィルタを作成する
        /// 
        private DirectShow.IBaseFilter CreateVideoCaptureSource(int index, VideoFormat format)
        {
            var filter = DirectShow.CreateFilter(DirectShow.DsGuid.CLSID_VideoInputDeviceCategory, index);
            var pin = DirectShow.FindPin(filter, 0, DirectShow.PIN_DIRECTION.PINDIR_OUTPUT);
            SetVideoOutputFormat(pin, format);
            return filter;
        }

        /// 
        /// ビデオキャプチャデバイスの出力形式を選択する。
        /// 
        private static void SetVideoOutputFormat(DirectShow.IPin pin, VideoFormat format)
        {
            var formats = GetVideoOutputFormat(pin);

            for (int i = 0; i < formats.Length; i++)
            {
                var item = formats[i];

                if (item.MajorType != DirectShow.DsGuid.GetNickname(DirectShow.DsGuid.MEDIATYPE_Video)) continue;
                if (string.IsNullOrEmpty(format.SubType) == false && format.SubType != item.SubType) continue;
                if (item.Caps.Guid != DirectShow.DsGuid.FORMAT_VideoInfo) continue;

                if (item.Size.Width == format.Size.Width && item.Size.Height == format.Size.Height)
                {
                    SetVideoOutputFormat(pin, i, format.Size, format.TimePerFrame);
                    return;
                }
            }

            // Not found fixed size, search for variable size.
            for (int i = 0; i < formats.Length; i++)
            {
                var item = formats[i];



                if (item.MajorType != DirectShow.DsGuid.GetNickname(DirectShow.DsGuid.MEDIATYPE_Video)) continue;
                if (string.IsNullOrEmpty(format.SubType) == false && format.SubType != item.SubType) continue;
                if (item.Caps.Guid != DirectShow.DsGuid.FORMAT_VideoInfo) continue;

                if (item.Caps.OutputGranularityX == 0) continue;
                if (item.Caps.OutputGranularityY == 0) continue;

                for (int w = item.Caps.MinOutputSize.cx; w < item.Caps.MaxOutputSize.cx; w += item.Caps.OutputGranularityX)
                {
                    for (int h = item.Caps.MinOutputSize.cy; h < item.Caps.MaxOutputSize.cy; h += item.Caps.OutputGranularityY)
                    {
                        if (w == format.Size.Width && h == format.Size.Height)
                        {
                            SetVideoOutputFormat(pin, i, format.Size, format.TimePerFrame);
                            return;
                        }
                    }
                }
            }

            // Not found, use default size.
            SetVideoOutputFormat(pin, 0, Size.Empty, 0);
        }


        private static VideoFormat[] GetVideoOutputFormat(DirectShow.IPin pin)
        {
            var config = pin as DirectShow.IAMStreamConfig;
            if (config == null)
            {
                throw new InvalidOperationException("no IAMStreamConfig interface.");
            }

            int cap_count = 0, cap_size = 0;
            config.GetNumberOfCapabilities(ref cap_count, ref cap_size);
            if (cap_size != Marshal.SizeOf(typeof(DirectShow.VIDEO_STREAM_CONFIG_CAPS)))
            {
                throw new InvalidOperationException("no VIDEO_STREAM_CONFIG_CAPS.");
            }

            var result = new VideoFormat[cap_count];

            var cap_data = Marshal.AllocHGlobal(cap_size);

            for (int i = 0; i < cap_count; i++)
            {
                var entry = new VideoFormat();

                DirectShow.AM_MEDIA_TYPE mt = null;
                config.GetStreamCaps(i, ref mt, cap_data);
                entry.Caps = PtrToStructure(cap_data);

                entry.MajorType = DirectShow.DsGuid.GetNickname(mt.MajorType);
                entry.SubType = DirectShow.DsGuid.GetNickname(mt.SubType);

                if (mt.FormatType == DirectShow.DsGuid.FORMAT_VideoInfo)
                {
                    var vinfo = PtrToStructure(mt.pbFormat);
                    entry.Size = new Size(vinfo.bmiHeader.biWidth, vinfo.bmiHeader.biHeight);
                    entry.TimePerFrame = vinfo.AvgTimePerFrame;
                }
                else if (mt.FormatType == DirectShow.DsGuid.FORMAT_VideoInfo2)
                {
                    var vinfo = PtrToStructure(mt.pbFormat);
                    entry.Size = new Size(vinfo.bmiHeader.biWidth, vinfo.bmiHeader.biHeight);
                    entry.TimePerFrame = vinfo.AvgTimePerFrame;
                }

                // 解放
                DirectShow.DeleteMediaType(ref mt);

                result[i] = entry;
            }

            // 解放
            Marshal.FreeHGlobal(cap_data);

            return result;
        }

        private static void SetVideoOutputFormat(DirectShow.IPin pin, int index, Size size, long timePerFrame)
        {
            var config = pin as DirectShow.IAMStreamConfig;
            if (config == null)
            {
                throw new InvalidOperationException("no IAMStreamConfig interface.");
            }

            int cap_count = 0, cap_size = 0;
            config.GetNumberOfCapabilities(ref cap_count, ref cap_size);
            if (cap_size != Marshal.SizeOf(typeof(DirectShow.VIDEO_STREAM_CONFIG_CAPS)))
            {
                throw new InvalidOperationException("no VIDEO_STREAM_CONFIG_CAPS.");
            }

            var cap_data = Marshal.AllocHGlobal(cap_size);

            DirectShow.AM_MEDIA_TYPE mt = null;
            config.GetStreamCaps(index, ref mt, cap_data);
            var cap = PtrToStructure(cap_data);

            if (mt.FormatType == DirectShow.DsGuid.FORMAT_VideoInfo)
            {
                var vinfo = PtrToStructure(mt.pbFormat);
                if (!size.IsEmpty) { vinfo.bmiHeader.biWidth = size.Width; vinfo.bmiHeader.biHeight = size.Height; }
                if (timePerFrame > 0) { vinfo.AvgTimePerFrame = timePerFrame; }
                Marshal.StructureToPtr(vinfo, mt.pbFormat, true);
            }
            else if (mt.FormatType == DirectShow.DsGuid.FORMAT_VideoInfo2)
            {
                var vinfo = PtrToStructure(mt.pbFormat);
                if (!size.IsEmpty) { vinfo.bmiHeader.biWidth = size.Width; vinfo.bmiHeader.biHeight = size.Height; }
                if (timePerFrame > 0) { vinfo.AvgTimePerFrame = timePerFrame; }
                Marshal.StructureToPtr(vinfo, mt.pbFormat, true);
            }

            config.SetFormat(mt);

            if (cap_data != System.IntPtr.Zero) Marshal.FreeHGlobal(cap_data);
            if (mt != null) DirectShow.DeleteMediaType(ref mt);
        }

        private static T PtrToStructure(IntPtr ptr)
        {
            return (T)Marshal.PtrToStructure(ptr, typeof(T));
        }

        public class VideoFormat
        {
            public string MajorType { get; set; }
            public string SubType { get; set; }
            public Size Size { get; set; }
            public long TimePerFrame { get; set; }
            public DirectShow.VIDEO_STREAM_CONFIG_CAPS Caps { get; set; }

            public override string ToString()
            {
                return string.Format("{0}, {1}, {2}, {3}, {4}", MajorType, SubType, Size, TimePerFrame, CapsString());
            }

            private string CapsString()
            {
                var sb = new StringBuilder();
                sb.AppendFormat("{0}, ", DirectShow.DsGuid.GetNickname(Caps.Guid));
                foreach (var info in Caps.GetType().GetFields())
                {
                    sb.AppendFormat("{0}={1}, ", info.Name, info.GetValue(Caps));
                }
                return sb.ToString();
            }
        }


        public static class DirectShow
        {
            #region Function

            public static object CoCreateInstance(Guid clsid)
            {
                return Activator.CreateInstance(Type.GetTypeFromCLSID(clsid));
            }

            public static void ReleaseInstance(ref T com) where T : class
            {
                if (com != null)
                {
                    Marshal.ReleaseComObject(com);
                    com = null;
                }
            }

            public static IGraphBuilder CreateGraph()
            {
                return CoCreateInstance(DsGuid.CLSID_FilterGraph) as IGraphBuilder;
            }

            public static void PlayGraph(IGraphBuilder graph, FILTER_STATE state)
            {
                var mediaControl = graph as IMediaControl;
                if (mediaControl == null) return;

                switch (state)
                {
                    case FILTER_STATE.Paused: mediaControl.Pause(); break;
                    case FILTER_STATE.Stopped: mediaControl.Stop(); break;
                    default: mediaControl.Run(); break;
                }
            }

            public static List GetFiltes(Guid category)
            {
                var result = new List();

                EnumMonikers(category, (moniker, prop) =>
                {
                    object value = null;
                    prop.Read("FriendlyName", ref value, 0);
                    var name = (string)value;

                    result.Add(name);

                    return false; // 継続。
                });

                return result;
            }

            public static IBaseFilter CreateFilter(Guid clsid)
            {
                return CoCreateInstance(clsid) as IBaseFilter;
            }

            public static IBaseFilter CreateFilter(Guid category, int index)
            {
                IBaseFilter result = null;

                int curr_index = 0;
                EnumMonikers(category, (moniker, prop) =>
                {
                    if (index != curr_index++) return false;

                    {
                        object value = null;
                        Guid guid = DirectShow.DsGuid.IID_IBaseFilter;
                        moniker.BindToObject(null, null, ref guid, out value);
                        result = value as IBaseFilter;
                        return true;
                    }
                });

                if (result == null) throw new ArgumentException("can't create filter.");
                return result;
            }

            private static void EnumMonikers(Guid category, Func func)
            {
                IEnumMoniker enumerator = null;
                ICreateDevEnum device = null;

                try
                {
                    device = (ICreateDevEnum)Activator.CreateInstance(Type.GetTypeFromCLSID(DsGuid.CLSID_SystemDeviceEnum));
                    device.CreateClassEnumerator(ref category, ref enumerator, 0);

                    if (enumerator == null) return;

                    var monikers = new IMoniker[1];
                    var fetched = IntPtr.Zero;

                    while (enumerator.Next(monikers.Length, monikers, fetched) == 0)
                    {
                        var moniker = monikers[0];

                        object value = null;
                        Guid guid = DsGuid.IID_IPropertyBag;
                        moniker.BindToStorage(null, null, ref guid, out value);
                        var prop = (IPropertyBag)value;

                        try
                        {
                            var rc = func(moniker, prop);
                            if (rc == true) break;
                        }
                        finally
                        {
                            Marshal.ReleaseComObject(prop);
                            if (moniker != null) Marshal.ReleaseComObject(moniker);
                        }
                    }
                }
                finally
                {
                    if (enumerator != null) Marshal.ReleaseComObject(enumerator);
                    if (device != null) Marshal.ReleaseComObject(device);
                }
            }

            public static IPin FindPin(IBaseFilter filter, string name)
            {
                var result = EnumPins(filter, (info) =>
                {
                    return (info.achName == name);
                });

                if (result == null) throw new ArgumentException("can't fild pin.");
                return result;
            }
            public static IPin FindPin(IBaseFilter filter, int index, PIN_DIRECTION direction)
            {
                int curr_index = 0;
                var result = EnumPins(filter, (info) =>
                {
                    if (info.dir != direction) return false;

                    return (index == curr_index++);
                });

                if (result == null) throw new ArgumentException("can't fild pin.");
                return result;
            }

            private static IPin EnumPins(IBaseFilter filter, Func func)
            {
                IEnumPins pins = null;
                IPin ipin = null;

                try
                {
                    filter.EnumPins(ref pins);

                    int fetched = 0;
                    while (pins.Next(1, ref ipin, ref fetched) == 0)
                    {
                        if (fetched == 0) break;

                        var info = new PIN_INFO();
                        try
                        {
                            ipin.QueryPinInfo(info);
                            var rc = func(info);
                            if (rc) return ipin;
                        }
                        finally
                        {
                            if (info.pFilter != null) Marshal.ReleaseComObject(info.pFilter);
                        }
                    }
                }
                catch
                {
                    if (ipin != null) Marshal.ReleaseComObject(ipin);
                    throw;
                }
                finally
                {
                    if (pins != null) Marshal.ReleaseComObject(pins);
                }

                return null;
            }

            public static void ConnectFilter(IGraphBuilder graph, IBaseFilter out_flt, int out_no, IBaseFilter in_flt, int in_no)
            {
                var out_pin = FindPin(out_flt, out_no, PIN_DIRECTION.PINDIR_OUTPUT);
                var inp_pin = FindPin(in_flt, in_no, PIN_DIRECTION.PINDIR_INPUT);
                graph.Connect(out_pin, inp_pin);
            }

            public static void DeleteMediaType(ref AM_MEDIA_TYPE mt)
            {
                if (mt.lSampleSize != 0) Marshal.FreeCoTaskMem(mt.pbFormat);
                if (mt.pUnk != IntPtr.Zero) Marshal.FreeCoTaskMem(mt.pUnk);
                mt = null;
            }

            #endregion


            #region Interface

            [ComVisible(true), ComImport(), Guid("56a8689f-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IFilterGraph
            {
                int AddFilter([In] IBaseFilter pFilter, [In, MarshalAs(UnmanagedType.LPWStr)] string pName);
                int RemoveFilter([In] IBaseFilter pFilter);
                int EnumFilters([In, Out] ref IEnumFilters ppEnum);
                int FindFilterByName([In, MarshalAs(UnmanagedType.LPWStr)] string pName, [In, Out] ref IBaseFilter ppFilter);
                int ConnectDirect([In] IPin ppinOut, [In] IPin ppinIn, [In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int Reconnect([In] IPin ppin);
                int Disconnect([In] IPin ppin);
                int SetDefaultSyncSource();
            }

            [ComVisible(true), ComImport(), Guid("56a868a9-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IGraphBuilder : IFilterGraph
            {
                int Connect([In] IPin ppinOut, [In] IPin ppinIn);
                int Render([In] IPin ppinOut);
                int RenderFile([In, MarshalAs(UnmanagedType.LPWStr)] string lpcwstrFile, [In, MarshalAs(UnmanagedType.LPWStr)] string lpcwstrPlayList);
                int AddSourceFilter([In, MarshalAs(UnmanagedType.LPWStr)] string lpcwstrFileName, [In, MarshalAs(UnmanagedType.LPWStr)] string lpcwstrFilterName, [In, Out] ref IBaseFilter ppFilter);
                int SetLogFile(IntPtr hFile);
                int Abort();
                int ShouldOperationContinue();
            }

            [ComVisible(true), ComImport(), Guid("56a868b1-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsDual)]
            public interface IMediaControl
            {
                int Run();
                int Pause();
                int Stop();
                int GetState(int msTimeout, out int pfs);
                int RenderFile(string strFilename);
                int AddSourceFilter([In] string strFilename, [In, Out, MarshalAs(UnmanagedType.IDispatch)] ref object ppUnk);
                int get_FilterCollection([In, Out, MarshalAs(UnmanagedType.IDispatch)] ref object ppUnk);
                int get_RegFilterCollection([In, Out, MarshalAs(UnmanagedType.IDispatch)] ref object ppUnk);
                int StopWhenReady();
            }

            [ComVisible(true), ComImport(), Guid("93E5A4E0-2D50-11d2-ABFA-00A0C9C6E38D"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface ICaptureGraphBuilder2
            {
                int SetFiltergraph([In] IGraphBuilder pfg);
                int GetFiltergraph([In, Out] ref IGraphBuilder ppfg);
                int SetOutputFileName([In] ref Guid pType, [In, MarshalAs(UnmanagedType.LPWStr)] string lpstrFile, [In, Out] ref IBaseFilter ppbf, [In, Out] ref IFileSinkFilter ppSink);
                int FindInterface([In] ref Guid pCategory, [In] ref Guid pType, [In] IBaseFilter pbf, [In] IntPtr riid, [In, Out, MarshalAs(UnmanagedType.IUnknown)] ref object ppint);
                int RenderStream([In] ref Guid pCategory, [In] ref Guid pType, [In, MarshalAs(UnmanagedType.IUnknown)] object pSource, [In] IBaseFilter pfCompressor, [In] IBaseFilter pfRenderer);
                int ControlStream([In] ref Guid pCategory, [In] ref Guid pType, [In] IBaseFilter pFilter, [In] IntPtr pstart, [In] IntPtr pstop, [In] short wStartCookie, [In] short wStopCookie);
                int AllocCapFile([In, MarshalAs(UnmanagedType.LPWStr)] string lpstrFile, [In] long dwlSize);
                int CopyCaptureFile([In, MarshalAs(UnmanagedType.LPWStr)] string lpwstrOld, [In, MarshalAs(UnmanagedType.LPWStr)] string lpwstrNew, [In] int fAllowEscAbort, [In] IAMCopyCaptureFileProgress pFilter);
                int FindPin([In] object pSource, [In] int pindir, [In] ref Guid pCategory, [In] ref Guid pType, [In, MarshalAs(UnmanagedType.Bool)] bool fUnconnected, [In] int num, [Out] out IntPtr ppPin);
            }

            [ComVisible(true), ComImport(), Guid("a2104830-7c70-11cf-8bce-00aa00a3f1a6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IFileSinkFilter
            {
                int SetFileName([In, MarshalAs(UnmanagedType.LPWStr)] string pszFileName, [In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int GetCurFile([In, Out, MarshalAs(UnmanagedType.LPWStr)] ref string pszFileName, [Out, MarshalAs(UnmanagedType.LPStruct)] out AM_MEDIA_TYPE pmt);
            }

            [ComVisible(true), ComImport(), Guid("670d1d20-a068-11d0-b3f0-00aa003761c5"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IAMCopyCaptureFileProgress
            {
                int Progress(int iProgress);
            }


            [ComVisible(true), ComImport(), Guid("C6E13370-30AC-11d0-A18C-00A0C9118956"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IAMCameraControl
            {
                int GetRange([In] CameraControlProperty Property, [In, Out] ref int pMin, [In, Out] ref int pMax, [In, Out] ref int pSteppingDelta, [In, Out] ref int pDefault, [In, Out] ref int pCapsFlag);
                int Set([In] CameraControlProperty Property, [In] int lValue, [In] int Flags);
                int Get([In] CameraControlProperty Property, [In, Out] ref int lValue, [In, Out] ref int Flags);
            }


            [ComVisible(true), ComImport(), Guid("C6E13360-30AC-11d0-A18C-00A0C9118956"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IAMVideoProcAmp
            {
                int GetRange([In] VideoProcAmpProperty Property, [In, Out] ref int pMin, [In, Out] ref int pMax, [In, Out] ref int pSteppingDelta, [In, Out] ref int pDefault, [In, Out] ref int pCapsFlag);
                int Set([In] VideoProcAmpProperty Property, [In] int lValue, [In] int Flags);
                int Get([In] VideoProcAmpProperty Property, [In, Out] ref int lValue, [In, Out] ref int Flags);
            }


            [ComVisible(true), ComImport(), Guid("6A2E0670-28E4-11D0-A18C-00A0C9118956"), System.Security.SuppressUnmanagedCodeSecurity, InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IAMVideoControl
            {
                int GetCaps([In] IPin pPin, [Out] out int pCapsFlags);
                int SetMode([In] IPin pPin, [In] int Mode);
                int GetMode([In] IPin pPin, [Out] out int Mode);
                int GetCurrentActualFrameRate([In] IPin pPin, [Out] out long ActualFrameRate);
                int GetMaxAvailableFrameRate([In] IPin pPin, [In] int iIndex, [In] Size Dimensions, [Out] out long MaxAvailableFrameRate);
                int GetFrameRateList([In] IPin pPin, [In] int iIndex, [In] Size Dimensions, [Out] out int ListSize, [Out] out IntPtr FrameRates);
            }

            [ComVisible(true), ComImport(), Guid("56a86895-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IBaseFilter
            {
                // Inherits IPersist
                int GetClassID([Out] out Guid pClassID);

                // Inherits IMediaControl
                int Stop();
                int Pause();
                int Run(long tStart);
                int GetState(int dwMilliSecsTimeout, [In, Out] ref int filtState);
                int SetSyncSource([In] IReferenceClock pClock);
                int GetSyncSource([In, Out] ref IReferenceClock pClock);

                // -----
                int EnumPins([In, Out] ref IEnumPins ppEnum);
                int FindPin([In, MarshalAs(UnmanagedType.LPWStr)] string Id, [In, Out] ref IPin ppPin);
                int QueryFilterInfo([Out] FILTER_INFO pInfo);
                int JoinFilterGraph([In] IFilterGraph pGraph, [In, MarshalAs(UnmanagedType.LPWStr)] string pName);
                int QueryVendorInfo([In, Out, MarshalAs(UnmanagedType.LPWStr)] ref string pVendorInfo);
            }


            [ComVisible(true), ComImport(), Guid("56a86893-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IEnumFilters
            {
                int Next([In] int cFilters, [In, Out] ref IBaseFilter ppFilter, [In, Out] ref int pcFetched);
                int Skip([In] int cFilters);
                void Reset();
                void Clone([In, Out] ref IEnumFilters ppEnum);
            }

            [ComVisible(true), ComImport(), Guid("C6E13340-30AC-11d0-A18C-00A0C9118956"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IAMStreamConfig
            {
                int SetFormat([In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int GetFormat([In, Out, MarshalAs(UnmanagedType.LPStruct)] ref AM_MEDIA_TYPE ppmt);
                int GetNumberOfCapabilities(ref int piCount, ref int piSize);
                int GetStreamCaps(int iIndex, [In, Out, MarshalAs(UnmanagedType.LPStruct)] ref AM_MEDIA_TYPE ppmt, IntPtr pSCC);
            }

            [ComVisible(true), ComImport(), Guid("56a8689a-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IMediaSample
            {
                int GetPointer(ref IntPtr ppBuffer);
                int GetSize();
                int GetTime(ref long pTimeStart, ref long pTimeEnd);
                int SetTime([In, MarshalAs(UnmanagedType.LPStruct)] UInt64 pTimeStart, [In, MarshalAs(UnmanagedType.LPStruct)] UInt64 pTimeEnd);
                int IsSyncPoint();
                int SetSyncPoint([In, MarshalAs(UnmanagedType.Bool)] bool bIsSyncPoint);
                int IsPreroll();
                int SetPreroll([In, MarshalAs(UnmanagedType.Bool)] bool bIsPreroll);
                int GetActualDataLength();
                int SetActualDataLength(int len);
                int GetMediaType([In, Out, MarshalAs(UnmanagedType.LPStruct)] ref AM_MEDIA_TYPE ppMediaType);
                int SetMediaType([In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pMediaType);
                int IsDiscontinuity();
                int SetDiscontinuity([In, MarshalAs(UnmanagedType.Bool)] bool bDiscontinuity);
                int GetMediaTime(ref long pTimeStart, ref long pTimeEnd);
                int SetMediaTime([In, MarshalAs(UnmanagedType.LPStruct)] UInt64 pTimeStart, [In, MarshalAs(UnmanagedType.LPStruct)] UInt64 pTimeEnd);
            }

            [ComVisible(true), ComImport(), Guid("89c31040-846b-11ce-97d3-00aa0055595a"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IEnumMediaTypes
            {
                int Next([In] int cMediaTypes, [In, Out, MarshalAs(UnmanagedType.LPStruct)] ref AM_MEDIA_TYPE ppMediaTypes, [In, Out] ref int pcFetched);
                int Skip([In] int cMediaTypes);
                int Reset();
                int Clone([In, Out] ref IEnumMediaTypes ppEnum);
            }

            [ComVisible(true), ComImport(), Guid("56a86891-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IPin
            {
                int Connect([In] IPin pReceivePin, [In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int ReceiveConnection([In] IPin pReceivePin, [In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int Disconnect();
                int ConnectedTo([In, Out] ref IPin ppPin);
                int ConnectionMediaType([Out, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int QueryPinInfo([Out] PIN_INFO pInfo);
                int QueryDirection(ref PIN_DIRECTION pPinDir);
                int QueryId([In, Out, MarshalAs(UnmanagedType.LPWStr)] ref string Id);
                int QueryAccept([In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int EnumMediaTypes([In, Out] ref IEnumMediaTypes ppEnum);
                int QueryInternalConnections(IntPtr apPin, [In, Out] ref int nPin);
                int EndOfStream();
                int BeginFlush();
                int EndFlush();
                int NewSegment(long tStart, long tStop, double dRate);
            }

            [ComVisible(true), ComImport(), Guid("56a86892-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IEnumPins
            {
                int Next([In] int cPins, [In, Out] ref IPin ppPins, [In, Out] ref int pcFetched);
                int Skip([In] int cPins);
                void Reset();
                void Clone([In, Out] ref IEnumPins ppEnum);
            }

            [ComVisible(true), ComImport(), Guid("56a86897-0ad4-11ce-b03a-0020af0ba770"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IReferenceClock
            {
                int GetTime(ref long pTime);
                int AdviseTime(long baseTime, long streamTime, IntPtr hEvent, ref int pdwAdviseCookie);
                int AdvisePeriodic(long startTime, long periodTime, IntPtr hSemaphore, ref int pdwAdviseCookie);
                int Unadvise(int dwAdviseCookie);
            }

            [ComVisible(true), ComImport(), Guid("29840822-5B84-11D0-BD3B-00A0C911CE86"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface ICreateDevEnum
            {
                int CreateClassEnumerator([In] ref Guid pType, [In, Out] ref System.Runtime.InteropServices.ComTypes.IEnumMoniker ppEnumMoniker, [In] int dwFlags);
            }

            [ComVisible(true), ComImport(), Guid("55272A00-42CB-11CE-8135-00AA004BB851"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface IPropertyBag
            {
                int Read([MarshalAs(UnmanagedType.LPWStr)] string PropName, ref object Var, int ErrorLog);
                int Write(string PropName, ref object Var);
            }

            [ComVisible(true), ComImport(), Guid("6B652FFF-11FE-4fce-92AD-0266B5D7C78F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface ISampleGrabber
            {
                int SetOneShot([In, MarshalAs(UnmanagedType.Bool)] bool OneShot);
                int SetMediaType([In, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int GetConnectedMediaType([Out, MarshalAs(UnmanagedType.LPStruct)] AM_MEDIA_TYPE pmt);
                int SetBufferSamples([In, MarshalAs(UnmanagedType.Bool)] bool BufferThem);
                int GetCurrentBuffer(ref int pBufferSize, IntPtr pBuffer);
                int GetCurrentSample(IntPtr ppSample);
                int SetCallback(ISampleGrabberCB pCallback, int WhichMethodToCallback);
            }

            [ComVisible(true), ComImport(), Guid("0579154A-2B53-4994-B0D0-E773148EFF85"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
            public interface ISampleGrabberCB
            {
                [PreserveSig()]
                int SampleCB(double SampleTime, IMediaSample pSample);
                [PreserveSig()]
                int BufferCB(double SampleTime, IntPtr pBuffer, int BufferLen);
            }

            #endregion


            #region Structure

            [Serializable]
            [StructLayout(LayoutKind.Sequential), ComVisible(false)]
            public class AM_MEDIA_TYPE
            {
                public Guid MajorType;
                public Guid SubType;
                [MarshalAs(UnmanagedType.Bool)]
                public bool bFixedSizeSamples;
                [MarshalAs(UnmanagedType.Bool)]
                public bool bTemporalCompression;
                public uint lSampleSize;
                public Guid FormatType;
                public IntPtr pUnk;
                public uint cbFormat;
                public IntPtr pbFormat;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode), ComVisible(false)]
            public class FILTER_INFO
            {
                [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
                public string achName;
                [MarshalAs(UnmanagedType.IUnknown)]
                public object pGraph;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode), ComVisible(false)]
            public class PIN_INFO
            {
                public IBaseFilter pFilter;
                public PIN_DIRECTION dir;
                [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 128)]
                public string achName;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential, Pack = 8), ComVisible(false)]
            public struct VIDEO_STREAM_CONFIG_CAPS
            {
                public Guid Guid;
                public uint VideoStandard;
                public SIZE InputSize;
                public SIZE MinCroppingSize;
                public SIZE MaxCroppingSize;
                public int CropGranularityX;
                public int CropGranularityY;
                public int CropAlignX;
                public int CropAlignY;
                public SIZE MinOutputSize;
                public SIZE MaxOutputSize;
                public int OutputGranularityX;
                public int OutputGranularityY;
                public int StretchTapsX;
                public int StretchTapsY;
                public int ShrinkTapsX;
                public int ShrinkTapsY;
                public long MinFrameInterval;
                public long MaxFrameInterval;
                public int MinBitsPerSecond;
                public int MaxBitsPerSecond;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential), ComVisible(false)]
            public struct VIDEOINFOHEADER
            {
                public RECT SrcRect;
                public RECT TrgRect;
                public int BitRate;
                public int BitErrorRate;
                public long AvgTimePerFrame;
                public BITMAPINFOHEADER bmiHeader;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential), ComVisible(false)]
            public struct VIDEOINFOHEADER2
            {
                public RECT SrcRect;
                public RECT TrgRect;
                public int BitRate;
                public int BitErrorRate;
                public long AvgTimePerFrame;
                public int InterlaceFlags;
                public int CopyProtectFlags;
                public int PictAspectRatioX;
                public int PictAspectRatioY;
                public int ControlFlags; // or Reserved1
                public int Reserved2;
                public BITMAPINFOHEADER bmiHeader;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential, Pack = 2), ComVisible(false)]
            public struct BITMAPINFOHEADER
            {
                public int biSize;
                public int biWidth;
                public int biHeight;
                public short biPlanes;
                public short biBitCount;
                public int biCompression;
                public int biSizeImage;
                public int biXPelsPerMeter;
                public int biYPelsPerMeter;
                public int biClrUsed;
                public int biClrImportant;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential), ComVisible(false)]
            public struct WAVEFORMATEX
            {
                public ushort wFormatTag;
                public ushort nChannels;
                public uint nSamplesPerSec;
                public uint nAvgBytesPerSec;
                public short nBlockAlign;
                public short wBitsPerSample;
                public short cbSize;
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential, Pack = 8), ComVisible(false)]
            public struct SIZE
            {
                public int cx;
                public int cy;
                public override string ToString() { return string.Format("{{{0}, {1}}}", cx, cy); } // for debugging.
            }

            [Serializable]
            [StructLayout(LayoutKind.Sequential), ComVisible(false)]
            public struct RECT
            {
                public int Left;
                public int Top;
                public int Right;
                public int Bottom;
                public override string ToString() { return string.Format("{{{0}, {1}, {2}, {3}}}", Left, Top, Right, Bottom); } // for debugging.
            }
            #endregion


            #region Enum

            [ComVisible(false)]
            public enum PIN_DIRECTION
            {
                PINDIR_INPUT = 0,
                PINDIR_OUTPUT = 1,
            }

            [ComVisible(false)]
            public enum FILTER_STATE : int
            {
                Stopped = 0,
                Paused = 1,
                Running = 2,
            }

            [ComVisible(false)]
            public enum CameraControlProperty
            {
                Pan = 0,
                Tilt = 1,
                Roll = 2,
                Zoom = 3,
                Exposure = 4,
                Iris = 5,
                Focus = 6,
            }

            [ComVisible(false), Flags()]
            public enum CameraControlFlags
            {
                Auto = 0x0001,
                Manual = 0x0002,
            }

            [ComVisible(false)]
            public enum VideoProcAmpProperty
            {
                Brightness = 0,
                Contrast = 1,
                Hue = 2,
                Saturation = 3,
                Sharpness = 4,
                Gamma = 5,
                ColorEnable = 6,
                WhiteBalance = 7,
                BacklightCompensation = 8,
                Gain = 9
            }

            #endregion


            #region Guid

            public static class DsGuid
            {
                // MediaType
                public static readonly Guid MEDIATYPE_Video = new Guid("{73646976-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIATYPE_Audio = new Guid("{73647561-0000-0010-8000-00AA00389B71}");

                // SubType
                public static readonly Guid MEDIASUBTYPE_None = new Guid("{E436EB8E-524F-11CE-9F53-0020AF0BA770}");
                public static readonly Guid MEDIASUBTYPE_YUYV = new Guid("{56595559-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_IYUV = new Guid("{56555949-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_YVU9 = new Guid("{39555659-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_YUY2 = new Guid("{32595559-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_YVYU = new Guid("{55595659-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_UYVY = new Guid("{59565955-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_MJPG = new Guid("{47504A4D-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_RGB565 = new Guid("{E436EB7B-524F-11CE-9F53-0020AF0BA770}");
                public static readonly Guid MEDIASUBTYPE_RGB555 = new Guid("{E436EB7C-524F-11CE-9F53-0020AF0BA770}");
                public static readonly Guid MEDIASUBTYPE_RGB24 = new Guid("{E436EB7D-524F-11CE-9F53-0020AF0BA770}");
                public static readonly Guid MEDIASUBTYPE_RGB32 = new Guid("{E436EB7E-524F-11CE-9F53-0020AF0BA770}");
                public static readonly Guid MEDIASUBTYPE_ARGB32 = new Guid("{773C9AC0-3274-11D0-B724-00AA006C1A01}");
                public static readonly Guid MEDIASUBTYPE_PCM = new Guid("{00000001-0000-0010-8000-00AA00389B71}");
                public static readonly Guid MEDIASUBTYPE_WAVE = new Guid("{E436EB8B-524F-11CE-9F53-0020AF0BA770}");

                // FormatType
                public static readonly Guid FORMAT_None = new Guid("{0F6417D6-C318-11D0-A43F-00A0C9223196}");
                public static readonly Guid FORMAT_VideoInfo = new Guid("{05589F80-C356-11CE-BF01-00AA0055595A}");
                public static readonly Guid FORMAT_VideoInfo2 = new Guid("{F72A76A0-EB0A-11d0-ACE4-0000C0CC16BA}");
                public static readonly Guid FORMAT_WaveFormatEx = new Guid("{05589F81-C356-11CE-BF01-00AA0055595A}");

                // CLSID
                public static readonly Guid CLSID_AudioInputDeviceCategory = new Guid("{33D9A762-90C8-11d0-BD43-00A0C911CE86}");
                public static readonly Guid CLSID_AudioRendererCategory = new Guid("{E0F158E1-CB04-11d0-BD4E-00A0C911CE86}");
                public static readonly Guid CLSID_VideoInputDeviceCategory = new Guid("{860BB310-5D01-11d0-BD3B-00A0C911CE86}");
                public static readonly Guid CLSID_VideoCompressorCategory = new Guid("{33D9A760-90C8-11d0-BD43-00A0C911CE86}");

                public static readonly Guid CLSID_NullRenderer = new Guid("{C1F400A4-3F08-11D3-9F0B-006008039E37}");
                public static readonly Guid CLSID_SampleGrabber = new Guid("{C1F400A0-3F08-11D3-9F0B-006008039E37}");

                public static readonly Guid CLSID_FilterGraph = new Guid("{E436EBB3-524F-11CE-9F53-0020AF0BA770}");
                public static readonly Guid CLSID_SystemDeviceEnum = new Guid("{62BE5D10-60EB-11d0-BD3B-00A0C911CE86}");
                public static readonly Guid CLSID_CaptureGraphBuilder2 = new Guid("{BF87B6E1-8C27-11d0-B3F0-00AA003761C5}");

                public static readonly Guid IID_IPropertyBag = new Guid("{55272A00-42CB-11CE-8135-00AA004BB851}");
                public static readonly Guid IID_IBaseFilter = new Guid("{56a86895-0ad4-11ce-b03a-0020af0ba770}");
                public static readonly Guid IID_IAMStreamConfig = new Guid("{C6E13340-30AC-11d0-A18C-00A0C9118956}");

                public static readonly Guid PIN_CATEGORY_CAPTURE = new Guid("{fb6c4281-0353-11d1-905f-0000c0cc16ba}");
                public static readonly Guid PIN_CATEGORY_PREVIEW = new Guid("{fb6c4282-0353-11d1-905f-0000c0cc16ba}");
                public static readonly Guid PIN_CATEGORY_STILL = new Guid("{fb6c428a-0353-11d1-905f-0000c0cc16ba}");

                private static Dictionary NicknameCache = null;

                public static string GetNickname(Guid guid)
                {
                    if (NicknameCache == null)
                    {
                        NicknameCache = typeof(DsGuid).GetFields(System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public)
                            .Where(x => x.FieldType == typeof(Guid))
                            .ToDictionary(x => (Guid)x.GetValue(null), x => x.Name);
                    }

                    if (NicknameCache.ContainsKey(guid))
                    {
                        var name = NicknameCache[guid];
                        var elem = name.Split('_');

                        if (elem.Length >= 2)
                        {
                            var text = string.Join("_", elem.Skip(1).ToArray());
                            return string.Format("[{0}]", text);
                        }
                        else
                        {
                            return name;
                        }
                    }

                    return guid.ToString();
                }
            }
            #endregion
        }
    }

使用非常简单: 

    //获取所有的摄像头
    string[] devices = UsbCamera.FindDevices();

    //获取摄像头支持的分辨率
    int cameraIndex = 0;
    UsbCamera.VideoFormat[] formats = UsbCamera.GetVideoFormat(cameraIndex);
    for (int i = 0; i < formats.Length; i++)
        Console.WriteLine("{0}:{1}", i, formats[i]);

    // create usb camera and start.
    using var camera = new UsbCamera(cameraIndex, formats[0]);
    camera.Start();

    //第一次截图不延迟的话,会出现黑屏
    await Task.Delay(100);
    var bmp = camera.GetBitmap();
    bmp.Save(@$"r:\test.jpg");

这个代码本身也是封装了direct show,但它只封装了摄像头相关的部分,只有1k多行,可以直接嵌入到项目中。 另外,这个截图本身不依赖于STA线程的,可以非常方便的封装成一个远程usb拍照的功能的,也可以供web使用。 如果不太要求效果的话,做个远程的摄像头也是可以的。

以上就是这篇文章的全部内容了,希望本文的内容对大家的学习或者工作具有一定的参考学习价值,谢谢大家对脚本之家的支持。如果你想了解更多相关内容请查看下面相关链接

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