Support refresh rates over 60 FPS in NewDisplayCapture

[eiyooooo]

When maxFps exceeds 60, use the setRequestedRefreshRate method to configure the refresh rate for the virtual display.
Otherwise, the refresh rate will default to a maximum of 60 FPS.

Related Android commit
Code limiting the frame rate to 60 FPS

[eiyooooo]

I think we could make the refresh rate of the virtual display an adjustable option for users.

[rom1v]

Thank you 👍

However, in practice, I never get more than 60fps:

scrcpy --new-display --max-fps=120 -m720

Whereas I get 120fps if I mirror the main display.

---

I think we could make the refresh rate of the virtual display an adjustable option for users.

--max-fps is intended to be a "limiter", passing --max-fps should never increase the frame rate compared to not passing the option.

Instead, we could add a new --vd-fps option, but better, maybe we could specify it directly to --new-display:

scrcpy --new-display=1920x1080@120

[eiyooooo]

However, in practice, I never get more than 60fps:

scrcpy --new-display --max-fps=120 -m720

diff --git a/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java b/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java
index cadba8f1..f8d9fa05 100644
--- a/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java
+++ b/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java
@@ -183,7 +183,7 @@ public class NewDisplayCapture extends SurfaceCapture {
             // If not do so, the refresh rate of the virtual display will be limited to 60.
             // https://android.googlesource.com/platform/frameworks/base/+/6c57176e9a2882eff03c5b3f3cccfd988d38488d
             // https://android.googlesource.com/platform/frameworks/base/+/6c57176e9a2882eff03c5b3f3cccfd988d38488d/services/core/java/com/android/server/display/VirtualDisplayAdapter.java#562
-            if (maxFps > 60 && Build.VERSION.SDK_INT >= AndroidVersions.API_34_ANDROID_14) {
+            if (Build.VERSION.SDK_INT >= AndroidVersions.API_34_ANDROID_14) {

Since my monitor doesn’t support 120Hz, I removed the condition and tested with scrcpy --new-display --max-fps=30 -m720 and scrcpy --new-display --max-fps=60 -m720. The difference in refresh rates is clearly noticeable, confirming that the setRequestedRefreshRate method is indeed necessary.

---

Maybe we could specify it directly to --new-display:

scrcpy --new-display=1920x1080@120

I agree with this approach. 👍

[rom1v]

The difference in refresh rates is clearly noticeable, confirming that the setRequestedRefreshRate method is indeed necessary.

I'm not sure to understand, even without setting setRequestedRefreshRate(), you will see a difference between --max-fps=30 and --max-fps=60 (it's a limit applied to the encoder). So setRequestedRefreshRate() would be useful to go beyond 60fps.

[eiyooooo]

I'm not sure to understand, even without setting setRequestedRefreshRate(), you will see a difference between --max-fps=30 and --max-fps=60 (it's a limit applied to the encoder). So setRequestedRefreshRate() would be useful to go beyond 60fps.

diff --git a/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java b/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java
index cadba8f1..f7dc49c0 100644
--- a/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java
+++ b/server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java
@@ -183,11 +183,11 @@ public class NewDisplayCapture extends SurfaceCapture {
             // If not do so, the refresh rate of the virtual display will be limited to 60.
             // https://android.googlesource.com/platform/frameworks/base/+/6c57176e9a2882eff03c5b3f3cccfd988d38488d
             // https://android.googlesource.com/platform/frameworks/base/+/6c57176e9a2882eff03c5b3f3cccfd988d38488d/services/core/java/com/android/server/display/VirtualDisplayAdapter.java#562
-            if (maxFps > 60 && Build.VERSION.SDK_INT >= AndroidVersions.API_34_ANDROID_14) {
+            if (Build.VERSION.SDK_INT >= AndroidVersions.API_34_ANDROID_14) {
                 VirtualDisplayConfig.Builder builder = new VirtualDisplayConfig.Builder("scrcpy", displaySize.getWidth(), displaySize.getHeight(), dpi);
                 builder.setFlags(flags);
                 builder.setSurface(surface);
-                builder.setRequestedRefreshRate(maxFps);
+                builder.setRequestedRefreshRate(24);
                 virtualDisplay = ServiceManager.getDisplayManager().createNewVirtualDisplay(builder.build());

I did make a mistake. Now, I directly set the refresh rate to 24 and tested using scrcpy --new-display -m720. The difference in refresh rates is still noticeable.

[rom1v]

scrcpy --new-display=1920x1080@120

I agree with this approach. 👍

I implemented that on branch display_capture_fps.

However, I will not merge it, because the virtual display rate feature in Android is very unstable/experimental (tested on Pixel 8):

• setting a value over 60 fps just does not work (I never get more than 60 fps, contrary to the main display)
• on low fps (not always the same value, but until 12 fps), there are either no frame at all, or a black screen
• on any other fps value, the target is very unstable: if I request 35 fps, I get 15~22, whereas with scrcpy --new-display=1920x1080 --max-fps=35 gives a "perfect" 35 fps.

So a scrcpy feature to configure the virtual display rate would be basically broken, it would just "not work" as expected.

I keep the branch for later if the situation improves.