From c20daa8867b9ea4736691c05caa993a459f71446 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Tue, 5 Nov 2019 18:36:43 -0800
Subject: [PATCH] Add compatibility checks for HEVC Main10 in VT backend

---
 app/app.pro                                |  2 +-
 app/streaming/video/ffmpeg-renderers/vt.mm | 47 ++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/app/app.pro b/app/app.pro
index e9e7cd2e..74412d93 100644
--- a/app/app.pro
+++ b/app/app.pro
@@ -114,7 +114,7 @@ win32:!winrt {
 }
 macx {
     LIBS += -lssl -lcrypto -lavcodec.58 -lavutil.56 -lopus -framework SDL2 -framework SDL2_ttf
-    LIBS += -lobjc -framework VideoToolbox -framework AVFoundation -framework CoreVideo -framework CoreGraphics -framework CoreMedia -framework AppKit
+    LIBS += -lobjc -framework VideoToolbox -framework AVFoundation -framework CoreVideo -framework CoreGraphics -framework CoreMedia -framework AppKit -framework Metal
 
     # For libsoundio
     LIBS += -framework CoreAudio -framework AudioUnit
diff --git a/app/streaming/video/ffmpeg-renderers/vt.mm b/app/streaming/video/ffmpeg-renderers/vt.mm
index ce7490d9..d955ecb6 100644
--- a/app/streaming/video/ffmpeg-renderers/vt.mm
+++ b/app/streaming/video/ffmpeg-renderers/vt.mm
@@ -14,6 +14,7 @@
 #import <VideoToolbox/VideoToolbox.h>
 #import <AVFoundation/AVFoundation.h>
 #import <dispatch/dispatch.h>
+#import <Metal/Metal.h>
 
 class VTRenderer : public IFFmpegRenderer
 {
@@ -234,6 +235,52 @@ public:
                                 "No HW accelerated HEVC decode via VT");
                     return false;
                 }
+
+                // HEVC Main10 requires more extensive checks because there's no
+                // simple API to check for Main10 hardware decoding, and if we don't
+                // have it, we'll silently get software decoding with horrible performance.
+                if (params->videoFormat == VIDEO_FORMAT_H265_MAIN10) {
+                #if __MAC_OS_X_VERSION_MAX_ALLOWED >= 101400
+                    if (__builtin_available(macOS 10.14, *)) {
+                        id<MTLDevice> device = MTLCreateSystemDefaultDevice();
+                        if (device == nullptr) {
+                            SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                                        "Unable to get default Metal device");
+                            return false;
+                        }
+
+                        // Exclude all GPUs earlier than macOSGPUFamily2
+                        // https://developer.apple.com/documentation/metal/mtlfeatureset/mtlfeatureset_macos_gpufamily2_v1
+                        if ([device supportsFeatureSet:MTLFeatureSet_macOS_GPUFamily2_v1]) {
+                            if ([device.name containsString:@"Intel"]) {
+                                // 500-series Intel GPUs are Skylake and don't support Main10 hardware decoding
+                                if ([device.name containsString:@" 5"]) {
+                                    SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                                                "No HEVC Main10 support on Skylake iGPU");
+                                    return false;
+                                }
+                            }
+                            else if ([device.name containsString:@"AMD"]) {
+                                // FirePro D, M200, and M300 series GPUs don't support Main10 hardware decoding
+                                if ([device.name containsString:@"FirePro D"] ||
+                                        [device.name containsString:@" M2"] ||
+                                        [device.name containsString:@" M3"]) {
+                                    SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                                                "No HEVC Main10 support on AMD GPUs until Polaris");
+                                    return false;
+                                }
+                            }
+                        }
+                    }
+                    else
+            #endif
+                    {
+                        // Fail closed for HEVC Main10 if we're not on 10.14+
+                        SDL_LogWarn(SDL_LOG_CATEGORY_APPLICATION,
+                                    "No HEVC Main10 support on < macOS 10.14");
+                        return false;
+                    }
+                }
             }
             else
     #endif