Using V4L2 to realize VideoDevice

src/devices/Interop/Unix/Interop.Libraries.cs

@@ -0,0 +1,8 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+internal partial class Interop
+{
+    private const string LibcLibrary = "libc";
+}

src/devices/Interop/Unix/Libc/Interop.ioctl.macros.cs

@@ -0,0 +1,37 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal partial class Interop
+{
+    const int _IOC_NRBITS = 8;
+    const int _IOC_TYPEBITS = 8;
+    const int _IOC_SIZEBITS = 14;
+    const int _IOC_DIRBITS = 2;
+
+    const int _IOC_NRMASK = (1 << _IOC_NRBITS) - 1;
+    const int _IOC_TYPEMASK = (1 << _IOC_TYPEBITS) - 1;
+    const int _IOC_SIZEMASK = (1 << _IOC_SIZEBITS) - 1;
+    const int _IOC_DIRMASK = (1 << _IOC_DIRBITS) - 1;
+
+    const int _IOC_NRSHIFT = 0;
+    const int _IOC_TYPESHIFT = _IOC_NRSHIFT + _IOC_NRBITS;
+    const int _IOC_SIZESHIFT = _IOC_TYPESHIFT + _IOC_TYPEBITS;
+    const int _IOC_DIRSHIFT = _IOC_SIZESHIFT + _IOC_SIZEBITS;
+
+    const int _IOC_NONE = 0;
+    const int _IOC_WRITE = 1;
+    const int _IOC_READ = 2;
+
+    internal static int _IOC(int dir, int type, int nr, int size)
+            => ((dir) << _IOC_DIRSHIFT) | ((type) << _IOC_TYPESHIFT) | ((nr) << _IOC_NRSHIFT) | ((size) << _IOC_SIZESHIFT);
+
+    internal static int _IO(int type, int nr) => _IOC(_IOC_NONE, type, nr, 0);
+    internal static int _IOR(int type, int nr, Type size) => _IOC(_IOC_READ, type, nr, _IOC_TYPECHECK(size));
+    internal static int _IOW(int type, int nr, Type size) => _IOC(_IOC_WRITE, type, nr, _IOC_TYPECHECK(size));
+    internal static int _IOWR(int type, int nr, Type size) => _IOC(_IOC_READ | _IOC_WRITE, type, nr, _IOC_TYPECHECK(size));
+    internal static int _IOC_TYPECHECK(Type t) => Marshal.SizeOf(t);
+}

src/devices/Interop/Unix/Libc/Interop.libc.cs

@@ -0,0 +1,49 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal partial class Interop
+{
+    [DllImport(LibcLibrary, SetLastError = true)]
+    internal static extern int ioctl(int fd, int request, IntPtr argp);
+
+    [DllImport(LibcLibrary, SetLastError = true)]
+    internal static extern int open([MarshalAs(UnmanagedType.LPStr)] string pathname, FileOpenFlags flags);
+
+    [DllImport(LibcLibrary)]
+    internal static extern int close(int fd);
+
+    [DllImport(LibcLibrary, SetLastError = true)]
+    internal static extern IntPtr mmap(IntPtr addr, int length, MemoryMappedProtections prot, MemoryMappedFlags flags, int fd, int offset);
+
+    [DllImport(LibcLibrary)]
+    internal static extern int munmap(IntPtr addr, int length);
+}
+
+internal enum FileOpenFlags
+{
+    O_RDONLY = 0x00,
+    O_RDWR = 0x02,
+    O_NONBLOCK = 0x800,
+    O_SYNC = 0x101000
+}
+
+[Flags]
+internal enum MemoryMappedProtections
+{
+    PROT_NONE = 0x0,
+    PROT_READ = 0x1,
+    PROT_WRITE = 0x2,
+    PROT_EXEC = 0x4
+}
+
+[Flags]
+internal enum MemoryMappedFlags
+{
+    MAP_SHARED = 0x01,
+    MAP_PRIVATE = 0x02,
+    MAP_FIXED = 0x10
+}

src/devices/Interop/Unix/Libc/Interop.videodev2.cs

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+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+internal enum VideoSettings : int
+{
+    VIDIOC_QUERYCAP = -2140645888,
+    VIDIOC_ENUM_FMT = -1069525502,
+    VIDIOC_CROPCAP = -1070836166,
+    VIDIOC_G_CROP = -1072409029,
+    VIDIOC_S_CROP = 1075074620,
+    VIDIOC_G_FMT = -1060350460,
+    VIDIOC_S_FMT = -1060350459,
+    VIDIOC_REQBUFS = -1072409080,
+    VIDIOC_QUERYBUF = -1069263351,
+    VIDIOC_STREAMON = 1074026002,
+    VIDIOC_STREAMOFF = 1074026003,
+    VIDIOC_QBUF = -1069263345,
+    VIDIOC_DQBUF = -1069263343,
+    VIDIOC_ENUM_FRAMESIZES = -1070836150,
+    VIDIOC_G_CTRL = -1073195493,
+    VIDIOC_S_CTRL = -1073195492,
+    VIDIOC_QUERYCTRL = -1069263324,
+}
+
+/// <summary>
+/// videodev2.h Request Definition
+/// </summary>
+internal class RawVideoSettings
+{
+    public static int VIDIOC_QUERYCAP = Interop._IOR('V', 0, typeof(v4l2_capability));
+    public static int VIDIOC_ENUM_FMT = Interop._IOWR('V', 2, typeof(v4l2_fmtdesc));
+    public static int VIDIOC_G_FMT = Interop._IOWR('V', 4, typeof(v4l2_format));
+    public static int VIDIOC_S_FMT = Interop._IOWR('V', 5, typeof(v4l2_format));
+    public static int VIDIOC_REQBUFS = Interop._IOWR('V', 8, typeof(v4l2_requestbuffers));
+    public static int VIDIOC_QUERYBUF = Interop._IOWR('V', 9, typeof(v4l2_buffer));
+    public static int VIDIOC_OVERLAY = Interop._IOW('V', 14, typeof(int));
+    public static int VIDIOC_QBUF = Interop._IOWR('V', 15, typeof(v4l2_buffer));
+    public static int VIDIOC_DQBUF = Interop._IOWR('V', 17, typeof(v4l2_buffer));
+    public static int VIDIOC_STREAMON = Interop._IOW('V', 18, typeof(int));
+    public static int VIDIOC_STREAMOFF = Interop._IOW('V', 19, typeof(int));
+    public static int VIDIOC_G_CTRL = Interop._IOWR('V', 27, typeof(v4l2_control));
+    public static int VIDIOC_S_CTRL = Interop._IOWR('V', 28, typeof(v4l2_control));
+    public static int VIDIOC_QUERYCTRL = Interop._IOWR('V', 36, typeof(v4l2_queryctrl));
+    public static int VIDIOC_G_INPUT = Interop._IOR('V', 38, typeof(int));
+    public static int VIDIOC_S_INPUT = Interop._IOWR('V', 39, typeof(int));
+    public static int VIDIOC_G_OUTPUT = Interop._IOR('V', 46, typeof(int));
+    public static int VIDIOC_S_OUTPUT = Interop._IOWR('V', 47, typeof(int));
+    public static int VIDIOC_CROPCAP = Interop._IOWR('V', 58, typeof(v4l2_cropcap));
+    public static int VIDIOC_G_CROP = Interop._IOWR('V', 59, typeof(v4l2_crop));
+    public static int VIDIOC_S_CROP = Interop._IOW('V', 60, typeof(v4l2_crop));
+    public static int VIDIOC_TRY_FMT = Interop._IOWR('V', 64, typeof(v4l2_format));
+    public static int VIDIOC_G_PRIORITY = Interop._IOR('V', 67, typeof(uint));
+    public static int VIDIOC_S_PRIORITY = Interop._IOW('V', 68, typeof(uint));
+    public static int VIDIOC_ENUM_FRAMESIZES = Interop._IOWR('V', 74, typeof(v4l2_frmsizeenum));
+    public static int VIDIOC_PREPARE_BUF = Interop._IOWR('V', 93, typeof(v4l2_buffer));
+}