revert audio normalization feature

Neither loudnorm (EBU R128) nor dynaudnorm work well for this
use case — both are designed for continuous playback, not rapidly
switching between random short clips with wildly different levels.

booru_viewer/gui/main_window.py

@@ -335,7 +335,6 @@ class BooruApp(QMainWindow):
         self._right_splitter = right = QSplitter(Qt.Orientation.Vertical)
 
         self._preview = ImagePreview()
-        self._preview._video_player._loudnorm = self._db.get_setting_bool("loudnorm")
         self._preview.close_requested.connect(self._close_preview)
         self._preview.open_in_default.connect(self._open_preview_in_default)
         self._preview.open_in_browser.connect(self._open_preview_in_browser)
@@ -1078,13 +1077,6 @@ class BooruApp(QMainWindow):
         right_is_first = current_first is self._right_splitter
         if want_right_first != right_is_first:
             self._splitter.insertWidget(0, self._right_splitter if flip else self._stack)
-        # Apply audio normalization live
-        loudnorm = self._db.get_setting_bool("loudnorm")
-        af_val = "loudnorm" if loudnorm else ""
-        for vp in self._get_all_video_players():
-            vp._loudnorm = loudnorm
-            if vp._mpv is not None:
-                vp._mpv.af = af_val
         self._status.showMessage("Settings applied")
 
     # -- Fullscreen & Privacy --
@@ -1112,14 +1104,6 @@ class BooruApp(QMainWindow):
         if hasattr(self, '_main_window_save_timer'):
             self._main_window_save_timer.start()
 
-    def _get_all_video_players(self):
-        """Return every VideoPlayer instance that currently exists."""
-        players = [self._preview._video_player]
-        pw = self._popout_ctrl.window
-        if pw is not None:
-            players.append(pw._video)
-        return players
-
     # -- Keyboard shortcuts --
 
     def keyPressEvent(self, event) -> None:

booru_viewer/gui/media/video_player.py

@@ -337,7 +337,6 @@ class VideoPlayer(QWidget):
         self._stream_record_tmp: Path | None = None
         self._stream_record_target: Path | None = None
         self._seeked_during_record: bool = False
-        self._loudnorm: bool = False
 
     def _ensure_mpv(self) -> mpvlib.MPV:
         """Set up mpv callbacks on first use. MPV instance is pre-created."""
@@ -365,9 +364,6 @@ class VideoPlayer(QWidget):
         # exists. The qproperty-letterboxColor setter is a no-op if mpv
         # hasn't been initialized yet, so we have to (re)apply on init.
         self._apply_letterbox_color()
-        # Apply audio normalization if enabled in settings.
-        if self._loudnorm:
-            self._mpv.af = "loudnorm"
         return self._mpv
 
     # -- Public API (used by app.py for state sync) --

booru_viewer/gui/settings.py

@@ -205,11 +205,6 @@ class SettingsDialog(QDialog):
         self._flip_layout.setChecked(self._db.get_setting_bool("flip_layout"))
         form.addRow("", self._flip_layout)
 
-        # Audio normalization
-        self._loudnorm = QCheckBox("Normalize audio volume (EBU R128)")
-        self._loudnorm.setChecked(self._db.get_setting_bool("loudnorm"))
-        form.addRow("", self._loudnorm)
-
         # Slideshow monitor
         from PySide6.QtWidgets import QApplication
         self._monitor_combo = QComboBox()
@@ -816,7 +811,6 @@ class SettingsDialog(QDialog):
         self._db.set_setting("unbookmark_on_save", "1" if self._unbookmark_on_save.isChecked() else "0")
         self._db.set_setting("search_history_enabled", "1" if self._search_history.isChecked() else "0")
         self._db.set_setting("flip_layout", "1" if self._flip_layout.isChecked() else "0")
-        self._db.set_setting("loudnorm", "1" if self._loudnorm.isChecked() else "0")
         self._db.set_setting("slideshow_monitor", self._monitor_combo.currentText())
         _anchor_rmap = {"Center": "center", "Top-left": "tl", "Top-right": "tr", "Bottom-left": "bl", "Bottom-right": "br"}
         self._db.set_setting("popout_anchor", _anchor_rmap.get(self._popout_anchor.currentText(), "center"))