Ignore bogus refresh rates just to be on the safe side

app/build.gradle

@@ -11,8 +11,8 @@ android {
         minSdkVersion 16
         targetSdkVersion 27
 
-        versionName "5.6.4"
-        versionCode = 143
+        versionName "5.6.5"
+        versionCode = 145
     }
 
     flavorDimensions "root"
@@ -54,6 +54,38 @@ android {
             applicationIdSuffix ".debug"
         }
         release {
+            // To whomever is releasing/using an APK in release mode with
+            // Moonlight's official application ID, please stop. I see every
+            // single one of your crashes in my Play Console and it makes
+            // Moonlight's reliability look worse and makes it more difficult
+            // to distinguish real crashes from your crashy VR app. Seriously,
+            // 44 of the *same* native crash in 72 hours and a few each of
+            // several other crashes.
+            //
+            // This is technically not your fault. I would have hoped Google
+            // would validate the signature of the APK before attributing
+            // the crash to it. I asked their Play Store support about this
+            // and they said they don't and don't have plans to, so that sucks.
+            //
+            // In any case, it's bad form to release an APK using someone
+            // else's application ID. There is no legitimate reason, that
+            // anyone would need to comment out the following line, except me
+            // when I release an official signed Moonlight build. If you feel
+            // like doing so would solve something, I can tell you it will not.
+            // You can't upgrade an app while retaining data without having the
+            // same signature as the official version. Nor can you post it on
+            // the Play Store, since that application ID is already taken.
+            // Reputable APK hosting websites similarly validate the signature
+            // is consistent with the Play Store and won't allow an APK that
+            // isn't signed the same as the original.
+            //
+            // I wish any and all people using Moonlight as the basis of other
+            // cool projects the best of luck with their efforts. All I ask
+            // is to please change the applicationId before you publish.
+            //
+            // TL;DR: Leave the following line alone!
+            applicationIdSuffix ".unofficial"
+
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt')
         }

app/src/main/java/com/limelight/Game.java

@@ -304,7 +304,40 @@ public class Game extends Activity implements SurfaceHolder.Callback,
             // If we're using OSC, always set at least gamepad 1.
             gamepadMask |= 1;
         }
-        
+
+        // Set to the optimal mode for streaming
+        float displayRefreshRate = prepareDisplayForRendering();
+        LimeLog.info("Display refresh rate: "+displayRefreshRate);
+
+        // HACK: Despite many efforts to ensure low latency consistent frame
+        // delivery, the best non-lossy mechanism is to buffer 1 extra frame
+        // in the output pipeline. Android does some buffering on its end
+        // in SurfaceFlinger and it's difficult (impossible?) to inspect
+        // the precise state of the buffer queue to the screen after we
+        // release a frame for rendering.
+        //
+        // Since buffering a frame adds latency and we are primarily a
+        // latency-optimized client, rather than one designed for picture-perfect
+        // accuracy, we will synthetically induce a negative pressure on the display
+        // output pipeline by driving the decoder input pipeline under the speed
+        // that the display can refresh. This ensures a constant negative pressure
+        // to keep latency down but does induce a periodic frame loss. However, this
+        // periodic frame loss is *way* less than what we'd already get in Marshmallow's
+        // display pipeline where frames are dropped outside of our control if they land
+        // on the same V-sync.
+        //
+        // Hopefully, we can get rid of this once someone comes up with a better way
+        // to track the state of the pipeline and time frames.
+        int roundedRefreshRate = Math.round(displayRefreshRate);
+        if (roundedRefreshRate <= 49) {
+            // Let's avoid clearly bogus refresh rates
+            roundedRefreshRate = 60;
+        }
+        if (!prefConfig.disableFrameDrop && prefConfig.fps >= roundedRefreshRate) {
+            prefConfig.fps = roundedRefreshRate - 1;
+            LimeLog.info("Adjusting FPS target for screen to "+prefConfig.fps);
+        }
+
         StreamConfiguration config = new StreamConfiguration.Builder()
                 .setResolution(prefConfig.width, prefConfig.height)
                 .setRefreshRate(prefConfig.fps)
@@ -318,6 +351,7 @@ public class Game extends Activity implements SurfaceHolder.Callback,
                 .setHevcSupported(decoderRenderer.isHevcSupported())
                 .setEnableHdr(willStreamHdr)
                 .setAttachedGamepadMask(gamepadMask)
+                .setClientRefreshRateX100((int)(displayRefreshRate * 100))
                 .setAudioConfiguration(prefConfig.enable51Surround ?
                         MoonBridge.AUDIO_CONFIGURATION_51_SURROUND :
                         MoonBridge.AUDIO_CONFIGURATION_STEREO)
@@ -330,9 +364,6 @@ public class Game extends Activity implements SurfaceHolder.Callback,
         InputManager inputManager = (InputManager) getSystemService(Context.INPUT_SERVICE);
         inputManager.registerInputDeviceListener(controllerHandler, null);
 
-        // Set to the optimal mode for streaming
-        prepareDisplayForRendering();
-
         // Initialize touch contexts
         for (int i = 0; i < touchContextMap.length; i++) {
             touchContextMap[i] = new TouchContext(conn, i,
@@ -407,9 +438,10 @@ public class Game extends Activity implements SurfaceHolder.Callback,
         }
     }
 
-    private void prepareDisplayForRendering() {
+    private float prepareDisplayForRendering() {
         Display display = getWindowManager().getDefaultDisplay();
         WindowManager.LayoutParams windowLayoutParams = getWindow().getAttributes();
+        float displayRefreshRate;
 
         // On M, we can explicitly set the optimal display mode
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
@@ -447,6 +479,7 @@ public class Game extends Activity implements SurfaceHolder.Callback,
             LimeLog.info("Selected display mode: "+bestMode.getPhysicalWidth()+"x"+
                     bestMode.getPhysicalHeight()+"x"+bestMode.getRefreshRate());
             windowLayoutParams.preferredDisplayModeId = bestMode.getModeId();
+            displayRefreshRate = bestMode.getRefreshRate();
         }
         // On L, we can at least tell the OS that we want 60 Hz
         else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
@@ -459,6 +492,12 @@ public class Game extends Activity implements SurfaceHolder.Callback,
             }
             LimeLog.info("Selected refresh rate: "+bestRefreshRate);
             windowLayoutParams.preferredRefreshRate = bestRefreshRate;
+            displayRefreshRate = bestRefreshRate;
+        }
+        else {
+            // Otherwise, the active display refresh rate is just
+            // whatever is currently in use.
+            displayRefreshRate = display.getRefreshRate();
         }
 
         // Apply the display mode change
@@ -494,6 +533,8 @@ public class Game extends Activity implements SurfaceHolder.Callback,
             // Set the surface to scale based on the aspect ratio of the stream
             streamView.setDesiredAspectRatio((double)prefConfig.width / (double)prefConfig.height);
         }
+
+        return displayRefreshRate;
     }
 
     @SuppressLint("InlinedApi")

app/src/main/java/com/limelight/binding/video/MediaCodecDecoderRenderer.java

@@ -410,7 +410,7 @@ public class MediaCodecDecoderRenderer extends VideoDecoderRenderer {
                             }
 
                             // Render the last buffer
-                            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && prefs.disableFrameDrop) {
+                            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                                 // Use a PTS that will cause this frame to never be dropped if frame dropping
                                 // is disabled
                                 videoDecoder.releaseOutputBuffer(lastIndex, 0);

app/src/main/java/com/limelight/binding/video/MediaCodecHelper.java

@@ -153,27 +153,51 @@ public class MediaCodecHelper {
 		// Qualcomm is currently the only decoders in this group.
 	}
 
-	private static boolean isLowEndSnapdragonRenderer(String glRenderer) {
+	private static String getAdrenoVersionString(String glRenderer) {
 		glRenderer = glRenderer.toLowerCase().trim();
 
 		if (!glRenderer.contains("adreno")) {
-			return false;
+			return null;
 		}
 
 		Pattern modelNumberPattern = Pattern.compile("(.*)([0-9]{3})(.*)");
 
 		Matcher matcher = modelNumberPattern.matcher(glRenderer);
 		if (!matcher.matches()) {
-			return false;
+			return null;
 		}
 
 		String modelNumber = matcher.group(2);
 		LimeLog.info("Found Adreno GPU: "+modelNumber);
+		return modelNumber;
+	}
+
+	private static boolean isLowEndSnapdragonRenderer(String glRenderer) {
+		String modelNumber = getAdrenoVersionString(glRenderer);
+		if (modelNumber == null) {
+			// Not an Adreno GPU
+			return false;
+		}
 
 		// The current logic is to identify low-end SoCs based on a zero in the x0x place.
 		return modelNumber.charAt(1) == '0';
 	}
 
+	// This is a workaround for some broken devices that report
+	// only GLES 3.0 even though the GPU is an Adreno 4xx series part.
+	// An example of such a device is the Huawei Honor 5x with the
+	// Snapdragon 616 SoC (Adreno 405).
+	private static boolean isGLES31SnapdragonRenderer(String glRenderer) {
+		String modelNumber = getAdrenoVersionString(glRenderer);
+		if (modelNumber == null) {
+			// Not an Adreno GPU
+			return false;
+		}
+
+		// Snapdragon 4xx and higher support GLES 3.1
+		return modelNumber.charAt(0) >= '4';
+	}
+
 	public static void initialize(Context context, String glRenderer) {
 		if (initialized) {
 			return;
@@ -208,9 +232,10 @@ public class MediaCodecHelper {
 			// 3xx - bad
 			// 4xx - good
 			//
-			// Unfortunately, it's not that easy to get that information here, so I'll use an
-			// approximation by checking the GLES level (<= 3.0 is bad).
-			if (configInfo.reqGlEsVersion > 0x30000) {
+			// The "good" GPUs support GLES 3.1, but we can't just check that directly
+			// (see comment on isGLES31SnapdragonRenderer).
+			//
+			if (isGLES31SnapdragonRenderer(glRenderer)) {
 				// We prefer reference frame invalidation support (which is only doable on AVC on
 				// older Qualcomm chips) vs. enabling HEVC by default. The user can override using the settings
 				// to force HEVC on. If HDR or mobile data will be used, we'll override this and use