From 913b61980d5e59f50e5c73ecea9b3ac277a54e73 Mon Sep 17 00:00:00 2001
From: Arkadiusz Fal <arek@arekf.net>
Date: Sat, 31 Oct 2026 11:44:27 +0100
Subject: [PATCH] Reload the avfoundation audio output when it restarts while
 paused

The heat in the iOS 27.2 TestFlight report (~36% CPU for 85 minutes with
playback paused) started right after an audio route change while paused:
mpv's ao_avfoundation logged "restarting due to system notification"
and an unnamed thread went to ~36% immediately, still in the foreground.
Its restart handler calls stop() then start() regardless of pause state;
start() sets the synchronizer rate to 1 and requests media data, but
paused mpv supplies no samples, so the empty renderer re-requests in a
tight loop and the running renderer keeps iOS from suspending the app.

When that log line arrives and mpv is paused, issue ao-reload so the AO
is rebuilt paused. (The display link guard in the previous commit did not
reproduce the spin when tested on a device.)
---
 Yattee/Services/Player/MPV/MPVClient.swift | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Yattee/Services/Player/MPV/MPVClient.swift b/Yattee/Services/Player/MPV/MPVClient.swift
index 1d5f452a..0d9c7ccf 100644
--- a/Yattee/Services/Player/MPV/MPVClient.swift
+++ b/Yattee/Services/Player/MPV/MPVClient.swift
@@ -252,6 +252,10 @@ final class MPVClient: @unchecked Sendable {
 
         let line = MPVLogLine(prefix: prefix, level: level, text: text)
 
+        if prefix == "ao/avfoundation", text.hasPrefix("restarting due to system notification") {
+            reloadAudioOutputIfPaused()
+        }
+
         logBufferLock.lock()
         recentLogBuffer.append(line)
         if recentLogBuffer.count > recentLogBufferCapacity {
@@ -277,6 +281,22 @@ final class MPVClient: @unchecked Sendable {
         }
     }
 
+    /// mpv's avfoundation AO restarts its renderer on route changes and automatic
+    /// flushes, and the restart always starts it (synchronizer rate 1, requesting
+    /// data) even while paused. Paused mpv supplies no samples, so the empty
+    /// renderer re-requests in a tight loop on its dispatch queue (~35% CPU), and
+    /// the running renderer keeps iOS from suspending the app in the background.
+    /// Reloading the AO rebuilds it in the paused state.
+    private func reloadAudioOutputIfPaused() {
+        mpvQueue.async { [weak self] in
+            guard let self, let mpv = self.mpv, !self.isDestroyed else { return }
+            var paused: Int32 = 0
+            guard mpv_get_property(mpv, "pause", MPV_FORMAT_FLAG, &paused) >= 0, paused != 0 else { return }
+            self.logWarning("avfoundation AO restarted while paused - reloading audio output")
+            _ = self.commandUnsafe(["ao-reload"])
+        }
+    }
+
     /// Snapshot the recent log buffer (most-recent-last). Thread-safe.
     func recentLogLines(minimumSeverity: Int = 0) -> [MPVLogLine] {
         logBufferLock.lock()