Enable VideoToolbox AV1 decode

This decoder differs from others provided by VideoToolbox in that it lacks any software fallback. To achieve consistent behavior with other VideoToolbox decoders, this PR implemented additional checking on the server to simulate the software fallback provided by VideoToolbox.

The current fallback checking mechanism is a temporary solution. In the long term, it should be replaced with a more capable hardware capability checking system.

1 files changed, 85 insertions, 0 deletions

diff --git a/MediaBrowser.MediaEncoding/Encoder/ApplePlatformHelper.cs b/MediaBrowser.MediaEncoding/Encoder/ApplePlatformHelper.cs
new file mode 100644
index 000000000..ea2289bd7
--- /dev/null
+++ b/MediaBrowser.MediaEncoding/Encoder/ApplePlatformHelper.cs
@@ -0,0 +1,85 @@
+#pragma warning disable CA1031
+
+using System;
+using System.Linq;
+using System.Runtime.InteropServices;
+using Microsoft.Extensions.Logging;
+
+namespace MediaBrowser.MediaEncoding.Encoder;
+
+/// <summary>
+/// Helper class for Apple platform specific operations.
+/// </summary>
+public static class ApplePlatformHelper
+{
+    private static readonly string[] _av1DecodeBlacklistedCpuClass = ["M1", "M2"];
+
+    private static string GetSysctlValue(string name)
+    {
+        IntPtr length = IntPtr.Zero;
+        // Get length of the value
+        int osStatus = SysctlByName(name, IntPtr.Zero, ref length, IntPtr.Zero, 0);
+
+        if (osStatus != 0)
+        {
+            throw new NotSupportedException($"Failed to get sysctl value for {name} with error {osStatus}");
+        }
+
+        IntPtr buffer = Marshal.AllocHGlobal(length.ToInt32());
+        try
+        {
+            osStatus = SysctlByName(name, buffer, ref length, IntPtr.Zero, 0);
+            if (osStatus != 0)
+            {
+                throw new NotSupportedException($"Failed to get sysctl value for {name} with error {osStatus}");
+            }
+
+            return Marshal.PtrToStringAnsi(buffer) ?? string.Empty;
+        }
+        finally
+        {
+            Marshal.FreeHGlobal(buffer);
+        }
+    }
+
+    private static int SysctlByName(string name, IntPtr oldp, ref IntPtr oldlenp, IntPtr newp, uint newlen)
+    {
+        return NativeMethods.SysctlByName(System.Text.Encoding.ASCII.GetBytes(name), oldp, ref oldlenp, newp, newlen);
+    }
+
+    /// <summary>
+    /// Check if the current system has hardware acceleration for AV1 decoding.
+    /// </summary>
+    /// <param name="logger">The logger used for error logging.</param>
+    /// <returns>Boolean indicates the hwaccel support.</returns>
+    public static bool HasAv1HardwareAccel(ILogger logger)
+    {
+        if (!RuntimeInformation.OSArchitecture.Equals(Architecture.Arm64))
+        {
+            return false;
+        }
+
+        try
+        {
+            string cpuBrandString = GetSysctlValue("machdep.cpu.brand_string");
+            return !_av1DecodeBlacklistedCpuClass.Any(blacklistedCpuClass => cpuBrandString.Contains(blacklistedCpuClass, StringComparison.OrdinalIgnoreCase));
+        }
+        catch (NotSupportedException e)
+        {
+            logger.LogError("Error getting CPU brand string: {Message}", e.Message);
+        }
+        catch (Exception e)
+        {
+            logger.LogError("Unknown error occured: {Exception}", e);
+        }
+
+        return false;
+    }
+
+    private static class NativeMethods
+    {
+        [DllImport("libc", EntryPoint = "sysctlbyname", SetLastError = true)]
+        [DefaultDllImportSearchPaths(DllImportSearchPath.SafeDirectories)]
+        internal static extern int SysctlByName(byte[] name, IntPtr oldp, ref IntPtr oldlenp, IntPtr newp, uint newlen);
+    }
+}