1 files changed, 129 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.Nvdec.FFmpeg/Native/FFmpegApi.cs b/src/Ryujinx.Graphics.Nvdec.FFmpeg/Native/FFmpegApi.cs
new file mode 100644
index 00000000..d173a412
--- /dev/null
+++ b/src/Ryujinx.Graphics.Nvdec.FFmpeg/Native/FFmpegApi.cs
@@ -0,0 +1,129 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Graphics.Nvdec.FFmpeg.Native
+{
+    static partial class FFmpegApi
+    {
+        public const string AvCodecLibraryName = "avcodec";
+        public const string AvUtilLibraryName = "avutil";
+
+        private static readonly Dictionary<string, (int, int)> _librariesWhitelist = new Dictionary<string, (int, int)>
+        {
+            { AvCodecLibraryName, (58, 59) },
+            { AvUtilLibraryName, (56, 57) }
+        };
+
+        private static string FormatLibraryNameForCurrentOs(string libraryName, int version)
+        {
+            if (OperatingSystem.IsWindows())
+            {
+                return $"{libraryName}-{version}.dll";
+            }
+            else if (OperatingSystem.IsLinux())
+            {
+                return $"lib{libraryName}.so.{version}";
+            }
+            else if (OperatingSystem.IsMacOS())
+            {
+                return $"lib{libraryName}.{version}.dylib";
+            }
+            else
+            {
+                throw new NotImplementedException($"Unsupported OS for FFmpeg: {RuntimeInformation.RuntimeIdentifier}");
+            }
+        }
+
+
+        private static bool TryLoadWhitelistedLibrary(string libraryName, Assembly assembly, DllImportSearchPath? searchPath, out IntPtr handle)
+        {
+            handle = IntPtr.Zero;
+
+            if (_librariesWhitelist.TryGetValue(libraryName, out var value))
+            {
+                (int minVersion, int maxVersion) = value;
+
+                for (int version = maxVersion; version >= minVersion; version--)
+                {
+                    if (NativeLibrary.TryLoad(FormatLibraryNameForCurrentOs(libraryName, version), assembly, searchPath, out handle))
+                    {
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+
+        static FFmpegApi()
+        {
+            NativeLibrary.SetDllImportResolver(typeof(FFmpegApi).Assembly, (name, assembly, path) =>
+            {
+                IntPtr handle;
+
+                if (name == AvUtilLibraryName && TryLoadWhitelistedLibrary(AvUtilLibraryName, assembly, path, out handle))
+                {
+                    return handle;
+                }
+                else if (name == AvCodecLibraryName && TryLoadWhitelistedLibrary(AvCodecLibraryName, assembly, path, out handle))
+                {
+                    return handle;
+                }
+
+                return IntPtr.Zero;
+            });
+        }
+
+        public unsafe delegate void av_log_set_callback_callback(void* a0, AVLog level, [MarshalAs(UnmanagedType.LPUTF8Str)] string a2, byte* a3);
+
+        [LibraryImport(AvUtilLibraryName)]
+        internal static unsafe partial AVFrame* av_frame_alloc();
+
+        [LibraryImport(AvUtilLibraryName)]
+        internal static unsafe partial void av_frame_unref(AVFrame* frame);
+
+        [LibraryImport(AvUtilLibraryName)]
+        internal static unsafe partial void av_free(AVFrame* frame);
+
+        [LibraryImport(AvUtilLibraryName)]
+        internal static unsafe partial void av_log_set_level(AVLog level);
+
+        [LibraryImport(AvUtilLibraryName)]
+        internal static unsafe partial void av_log_set_callback(av_log_set_callback_callback callback);
+
+        [LibraryImport(AvUtilLibraryName)]
+        internal static unsafe partial AVLog av_log_get_level();
+
+        [LibraryImport(AvUtilLibraryName)]
+        internal static unsafe partial void av_log_format_line(void* ptr, AVLog level, [MarshalAs(UnmanagedType.LPUTF8Str)] string fmt, byte* vl, byte* line, int lineSize, int* printPrefix);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial AVCodec* avcodec_find_decoder(AVCodecID id);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial AVCodecContext* avcodec_alloc_context3(AVCodec* codec);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial int avcodec_open2(AVCodecContext* avctx, AVCodec* codec, void **options);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial int avcodec_close(AVCodecContext* avctx);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial void avcodec_free_context(AVCodecContext** avctx);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial AVPacket* av_packet_alloc();
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial void av_packet_unref(AVPacket* pkt);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial void av_packet_free(AVPacket** pkt);
+
+        [LibraryImport(AvCodecLibraryName)]
+        internal static unsafe partial int avcodec_version();
+    }
+}