Failed to start audio capture / Demuxer 'audio': stream explicitly disabled by the device on Android 11

[PureIncompetence]

• I have read the FAQ.

• I have searched in existing issues.

• OS: Ubuntu

• scrcpy version: 2.1

• installation method: manual build

• device model: ASUS

• Android version: 11 (LOS-based Custom ROM)

Sound does not work by default. As I've read in several other issues regarding sound, you bring up the Shell Heap Dump report activity for a short period of time to make android (11) think that scrcpy - which has the same uid - would be running upfront. That does not work on my device (ofc. with the screen on).
If I, however, run adb shell "am start com.android.shell/.HeapDumpActivity" before I run scrcpy, it does work. (The Heap Dump report activity pops up, scrcpy starts, closes it and audio works as expected.) Below I will post the output of what scrcpy logs without the manually started activity:

scrcpy 2.1 <https://github.com/Genymobile/scrcpy>
scrcpy-server-v2.1: 1 file pushed. 1.4 MB/s (56955 bytes in 0.040s)
[server] INFO: Device: [asus] asus ASUS_[redacted] (Android 11)
INFO: Renderer: opengl
INFO: OpenGL version: 4.6 (Compatibility Profile) Mesa 23.1.3
INFO: Trilinear filtering enabled
INFO: Texture: 1080x2336
[server] ERROR: Failed to start audio capture
[server] ERROR: On Android 11, audio capture must be started in the foreground, make sure that the device is unlocked when starting scrcpy.
WARN: Demuxer 'audio': stream explicitly disabled by the device

When searching for similar Issues, I found #3796 which looked a lot like my issue. I therefore tried to apply the same fix which was successfull there: Setting SystemClock.sleep() to a higher value (I tried 500 ms). After that I recompiled the scrcpy-server according to https://github.com/Genymobile/scrcpy/blob/master/doc/build.md#option-1-build-everything-from-sources (which is a real PITA btw, thank you for delivering that one pre-build by default.) and didnt notice any difference. On the other hand I have no experience with java whatsoever so I might have done some mistakes when recompiling.

[rom1v]

On dev branch, try with:

diff --git a/server/src/main/java/com/genymobile/scrcpy/AudioCapture.java b/server/src/main/java/com/genymobile/scrcpy/AudioCapture.java
index 7b20cce4f..8b30d6f26 100644
--- a/server/src/main/java/com/genymobile/scrcpy/AudioCapture.java
+++ b/server/src/main/java/com/genymobile/scrcpy/AudioCapture.java
@@ -118,7 +118,7 @@ public final class AudioCapture {
         if (Build.VERSION.SDK_INT == Build.VERSION_CODES.R) {
             startWorkaroundAndroid11();
             try {
-                tryStartRecording(3, 100);
+                tryStartRecording(6, 100);
             } finally {
                 stopWorkaroundAndroid11();
             }

and run with scrcpy -Vdebug. What is the result?

[PureIncompetence]

Thank you for your very fast response.
Turns out I was kind of stupid. I didnt notice any difference after my patch because I replaced the /usr/share/scrcpy/scrcpy-server binary with my self-compiled one. Thanks to the verbose output of scrcpy -Vdebug I noticed and replaced the correct one (/usr/local/share/scrcpy/scrcpy-server) which is actually used by scrcpy.
Now it does work - with my patch (replacing the Variable delayMs with plain 500) as well as with yours (increasing the attempts from 3 to 6). I tried it 5 times, it worked each time. The following output is logged by scrcpy -Vdebug with your patch applied:

scrcpy 2.1 <https://github.com/Genymobile/scrcpy>
DEBUG: ADB device found:
DEBUG:     --> (tcpip)  [redacted]             device  ASUS_[redacted]
DEBUG: Device serial: [redacted]
DEBUG: Using server: /usr/local/share/scrcpy/scrcpy-server
/usr/local/share/scrcpy/scrcpy-server: 1 file pushed, 0 skipped. 160.7 MB/s (56971 bytes in 0.000s)
[server] INFO: Device: [asus] asus ASUS_[redacted] (Android 11)
DEBUG: Server connected
DEBUG: Starting controller thread
DEBUG: Starting receiver thread
[server] DEBUG: Using video encoder: 'OMX.qcom.video.encoder.avc'
[server] DEBUG: Using audio encoder: 'c2.android.opus.encoder'
[server] DEBUG: Failed to start audio capture, retrying...
INFO: Renderer: opengl
INFO: OpenGL version: 4.6 (Compatibility Profile) Mesa 23.1.3
INFO: Trilinear filtering enabled
DEBUG: Using icon: /usr/local/share/icons/hicolor/256x256/apps/scrcpy.png
DEBUG: Demuxer 'video': starting thread
DEBUG: Demuxer 'audio': starting thread
INFO: Texture: 1080x2336
[server] DEBUG: Failed to start audio capture, retrying...
[server] DEBUG: Failed to start audio capture, retrying...
DEBUG: [Audio] Buffer underflow, inserting silence: 21 samples
DEBUG: [Audio] Buffer underflow, inserting silence: 240 samples
DEBUG: [Audio] Buffer underflow, inserting silence: 240 samples
DEBUG: [Audio] Buffer underflow, inserting silence: 7 samples

[rom1v]

OK, so I will change from 3 to 5 attempts (so the last one is after ~500ms). Thank you for your report.

[PureIncompetence]

Happy if I can contribute. Thank you for colaborating and finding the cause / fix in no time.

[rom1v]

Merged into dev: 01d785d