fix: recover audio after Windows sleep via ao-null-reload

windows/runner/mpv/mpv_core.cpp

@@ -124,11 +124,6 @@ std::optional<HRESULT> MpvCore::WindowProc(HWND hwnd, UINT message,
           ::RedrawWindow(flutter_window_, nullptr, nullptr,
                          RDW_INVALIDATE | RDW_UPDATENOW | RDW_ALLCHILDREN);
         }
-      } else if (wparam == kPowerResumeTimerId) {
-        ::KillTimer(flutter_window_, kPowerResumeTimerId);
-        if (power_resume_cb_) {
-          power_resume_cb_();
-        }
       }
       break;
     }
@@ -149,14 +144,6 @@ std::optional<HRESULT> MpvCore::WindowProc(HWND hwnd, UINT message,
       }
       break;
     }
-    case WM_POWERBROADCAST: {
-      if (wparam == PBT_APMRESUMEAUTOMATIC && power_resume_cb_) {
-        // Delay audio reload to let WASAPI fully reinitialize after wake.
-        ::KillTimer(flutter_window_, kPowerResumeTimerId);
-        ::SetTimer(flutter_window_, kPowerResumeTimerId, kPowerResumeAudioDelay, nullptr);
-      }
-      break;
-    }
     case WM_CLOSE: {
       ::SendMessage(container_, WM_CLOSE, 0, 0);
       for (const auto& [mpv_view, rect] : mpv_views_) {
@@ -207,10 +194,6 @@ void MpvCore::DisableComposition() {
   ::DwmFlush();
 }
 
-void MpvCore::SetPowerResumeCallback(PowerResumeCallback callback) {
-  power_resume_cb_ = std::move(callback);
-}
-
 std::unique_ptr<MpvCore> MpvCore::instance_ = nullptr;
 
 }  // namespace mpv

windows/runner/mpv/mpv_core.h

@@ -4,7 +4,6 @@
 #include <Windows.h>
 
 #include <cmath>
-#include <functional>
 #include <map>
 #include <memory>
 #include <optional>
@@ -16,9 +15,7 @@ namespace mpv {
 class MpvCore {
  public:
   static constexpr auto kPositionAndShowDelay = 300;
-  static constexpr auto kPowerResumeAudioDelay = 500;
   static constexpr UINT_PTR kCompositionRestoreTimerId = 1001;
-  static constexpr UINT_PTR kPowerResumeTimerId = 1002;
 
   static MpvCore* GetInstance();
   static void SetInstance(std::unique_ptr<MpvCore> instance);
@@ -45,10 +42,6 @@ class MpvCore {
   std::optional<HRESULT> WindowProc(HWND hwnd, UINT message, WPARAM wparam,
                                     LPARAM lparam);
 
-  // Callback invoked when Windows resumes from sleep/hibernate.
-  using PowerResumeCallback = std::function<void()>;
-  void SetPowerResumeCallback(PowerResumeCallback callback);
-
  private:
   RECT GetGlobalRect(int32_t left, int32_t top, int32_t right, int32_t bottom);
   void EnableComposition();
@@ -62,7 +55,6 @@ class MpvCore {
   bool was_window_hidden_due_to_minimize_ = false;
   bool visible_ = true;
   bool composition_enabled_ = false;
-  PowerResumeCallback power_resume_cb_;
 
   static std::unique_ptr<MpvCore> instance_;
 };

windows/runner/mpv/mpv_player.cpp

@@ -53,6 +53,11 @@ bool MpvPlayer::Initialize(HWND container, HWND flutter_window) {
   mpv_set_option_string(mpv_, "tone-mapping", "auto");
   mpv_set_option_string(mpv_, "hdr-compute-peak", "auto");
 
+  // When WASAPI becomes unavailable (sleep, device unplug), fall back to null
+  // audio output instead of permanently dropping the audio track. Recovery is
+  // handled in the event loop when audio-device-list changes.
+  mpv_set_option_string(mpv_, "audio-fallback-to-null", "yes");
+
   // Default to warn-level logging; Dart side can raise to "v" if debug logging is enabled.
   mpv_request_log_messages(mpv_, "warn");
 
@@ -355,6 +360,18 @@ void MpvPlayer::HandleMpvEvent(mpv_event* event) {
         UpdateHDRMode(sigPeak);
       }
 
+      // Audio recovery: when the device list changes and audio has fallen back
+      // to null output (e.g. after sleep/wake or device unplug), re-set
+      // audio-device to switch back to the real output.
+      // Mirrors mpv's TOOLS/lua/ao-null-reload.lua for embedded libmpv.
+      if (strcmp(prop->name, "audio-device-list") == 0 &&
+          GetProperty("current-ao") == "null") {
+        auto device = GetProperty("audio-device");
+        if (!device.empty()) {
+          mpv_set_property_string(mpv_, "audio-device", device.c_str());
+        }
+      }
+
       SendPropertyChange(prop->name, &node);
       break;
     }

windows/runner/mpv/mpv_plugin.cpp

@@ -65,12 +65,6 @@ MpvPlayerPlugin::MpvPlayerPlugin(flutter::PluginRegistrarWindows* registrar)
 }
 
 MpvPlayerPlugin::~MpvPlayerPlugin() {
-  // Clear power-resume callback and kill pending timer so they cannot
-  // invoke a dangling `this`.
-  if (MpvCore::GetInstance()) {
-    MpvCore::GetInstance()->SetPowerResumeCallback(nullptr);
-    ::KillTimer(GetWindow(), MpvCore::kPowerResumeTimerId);
-  }
   // Unregister window proc delegate.
   if (proc_id_) {
     registrar_->UnregisterTopLevelWindowProcDelegate(proc_id_.value());
@@ -135,16 +129,6 @@ void MpvPlayerPlugin::HandleMethodCall(
       RECT rect = {0, 0, 100, 100};
       MpvCore::GetInstance()->CreateMpvView(player_->GetHwnd(), rect, 1.0);
 
-      // Reload audio output on wake from sleep to recover stale WASAPI sessions.
-      MpvCore::GetInstance()->SetPowerResumeCallback([this]() {
-        if (player_ && player_->IsInitialized()) {
-          auto device = player_->GetProperty("audio-device");
-          if (!device.empty()) {
-            player_->SetProperty("audio-device", device);
-          }
-        }
-      });
-
       // Start hidden.
       MpvCore::GetInstance()->SetVisible(false);
       result->Success(flutter::EncodableValue(true));
@@ -153,11 +137,6 @@ void MpvPlayerPlugin::HandleMethodCall(
       result->Error("INIT_FAILED", "Failed to initialize MPV player");
     }
   } else if (method == "dispose") {
-    // Clear power-resume callback and kill pending timer before disposing.
-    if (MpvCore::GetInstance()) {
-      MpvCore::GetInstance()->SetPowerResumeCallback(nullptr);
-      ::KillTimer(GetWindow(), MpvCore::kPowerResumeTimerId);
-    }
     if (player_) {
       auto hwnd = player_->GetHwnd();
       player_->Dispose();