Add option to select render device for VAAPI

assets/sunshine.conf

@@ -118,7 +118,11 @@
 # output_name  = \\.\DISPLAY1
 
 # !! Linux only !!
-# Set the display number to stream. I have no idea how they are numbered. They start from 0, usually.
+# Set the display number to stream.
+# You can find them by the following command:
+# xrandr --listmonitors
+# Example output: "0: +HDMI-1 1920/518x1200/324+0+0  HDMI-1"
+#                  ^ <-- You need this.
 # output_name = 0
 
 ###############################################
@@ -222,6 +226,19 @@
 ##########################
 # amd_coder = auto
 
+#################################### VAAPI ###################################
+####### adapter ##########
+# Unlike with `amfvce` and `nvenc`, it doesn't matter if video encoding is done
+# on a different GPU.
+# Run the following commands:
+# 1. ls /dev/dri/renderD*
+#   to find all devices capable of VAAPI
+# 2. vainfo --display drm --device /dev/dri/renderD129 | grep -E "((VAProfileH264High|VAProfileHEVCMain|VAProfileHEVCMain10).*VAEntrypointEncSlice)|Driver version"
+#   Lists the name and capabilities of the device.
+#   To be supported by Sunshine, it needs to have at the very minimum:
+#       VAProfileH264High   : VAEntrypointEncSlice
+# adapter_name = /dev/dri/renderD128
+
 ##############################################
 # Some configurable parameters, are merely toggles for specific features
 # The first occurrence turns it on, the second occurence turns it off, the third occurence turns it on again, etc, etc
@@ -230,4 +247,5 @@
 # To set the initial state of flags -0 and -1 to on, set the following flags:
 # flags = 01
 #
-# See: sunshine --help for all options under the header: flags
+# See: sunshine --help for all options under the header: flags
+adapter_name = /dev/dri/renderD129