Optimize CUDA support to avoid roundtrip to CPU memory

app/app.pro

@@ -88,6 +88,11 @@ unix:!macx {
             PKGCONFIG += libdrm
             CONFIG += libdrm
         }
+
+        packagesExist(ffnvcodec) {
+            PKGCONFIG += ffnvcodec
+            CONFIG += cuda
+        }
     }
 
     packagesExist(wayland-client) {
@@ -196,7 +201,6 @@ ffmpeg {
     SOURCES += \
         streaming/video/ffmpeg.cpp \
         streaming/video/ffmpeg-renderers/sdlvid.cpp \
-        streaming/video/ffmpeg-renderers/cuda.cpp \
         streaming/video/ffmpeg-renderers/pacer/pacer.cpp \
         streaming/video/ffmpeg-renderers/pacer/nullthreadedvsyncsource.cpp
 
@@ -204,7 +208,6 @@ ffmpeg {
         streaming/video/ffmpeg.h \
         streaming/video/ffmpeg-renderers/renderer.h \
         streaming/video/ffmpeg-renderers/sdlvid.h \
-        streaming/video/ffmpeg-renderers/cuda.h \
         streaming/video/ffmpeg-renderers/pacer/pacer.h \
         streaming/video/ffmpeg-renderers/pacer/nullthreadedvsyncsource.h
 }
@@ -261,6 +264,13 @@ libdrm {
         LIBS += -ldl
     }
 }
+cuda {
+    message(CUDA support enabled)
+
+    DEFINES += HAVE_CUDA
+    SOURCES += streaming/video/ffmpeg-renderers/cuda.cpp
+    HEADERS += streaming/video/ffmpeg-renderers/cuda.h
+}
 config_EGL {
     message(EGL renderer selected)