Remove unused import.

app/jittermonitor.py

@@ -0,0 +1,56 @@
+from PyQt6.QtCore import QObject, QTimer, QElapsedTimer
+import logging
+import time
+
+from config import Config
+
+class EventLoopJitterMonitor(QObject):
+    def __init__(
+        self,
+        parent=None,
+        interval_ms: int = 20,
+        jitter_threshold_ms: int = 100,
+        log_cooldown_s: float = 1.0,
+    ):
+        super().__init__(parent)
+        self._interval = interval_ms
+        self._jitter_threshold = jitter_threshold_ms
+        self._log_cooldown_s = log_cooldown_s
+
+        self._timer = QTimer(self)
+        self._timer.setInterval(self._interval)
+        self._timer.timeout.connect(self._on_timeout)
+
+        self._elapsed = QElapsedTimer()
+        self._elapsed.start()
+        self._last = self._elapsed.elapsed()
+
+        # child logger: e.g. "musicmuster.jitter"
+        self._log = logging.getLogger(f"{Config.LOG_NAME}.jitter")
+        self._last_log_time = 0.0
+
+    def start(self) -> None:
+        self._timer.start()
+
+    def _on_timeout(self) -> None:
+        now_ms = self._elapsed.elapsed()
+        delta = now_ms - self._last
+        self._last = now_ms
+
+        if delta > (self._interval + self._jitter_threshold):
+            self._log_jitter(now_ms, delta)
+
+    def _log_jitter(self, now_ms: int, gap_ms: int) -> None:
+        now = time.monotonic()
+
+        # simple rate limit: only one log every log_cooldown_s
+        if now - self._last_log_time < self._log_cooldown_s:
+            return
+        self._last_log_time = now
+
+        self._log.warning(
+            "Event loop gap detected: t=%d ms, gap=%d ms (interval=%d ms)",
+            now_ms,
+            gap_ms,
+            self._interval,
+        )

app/logging.yaml

@@ -23,8 +23,8 @@ filters:
       #    - function-name-1
       #    - function-name-2
       musicmuster:
-        - update_clocks
         - play_next
+      jittermonitor: []
 
 handlers:
   stderr:

app/music_manager.py

@@ -30,6 +30,7 @@ from log import log
 from models import PlaylistRows
 from vlcmanager import VLCManager
 
+
 # Define the VLC callback function type
 # import ctypes
 # import platform
@@ -353,21 +354,6 @@ class _Music:
             self.player.set_position(position)
         self.start_dt = start_time
 
-        # For as-yet unknown reasons. sometimes the volume gets
-        # reset to zero within 200mS or so of starting play. This
-        # only happened since moving to Debian 12, which uses
-        # Pipewire for sound (which may be irrelevant).
-        # It has been known for the volume to need correcting more
-        # than once in the first 200mS.
-        # Update August 2024: This no longer seems to be an issue
-        # for _ in range(3):
-        #     if self.player:
-        #         volume = self.player.audio_get_volume()
-        #         if volume < Config.VLC_VOLUME_DEFAULT:
-        #             self.set_volume(Config.VLC_VOLUME_DEFAULT)
-        #             log.error(f"Reset from {volume=}")
-        #     sleep(0.1)
-
     def set_position(self, position: float) -> None:
         """
         Set player position
@@ -391,17 +377,6 @@ class _Music:
             volume = Config.VLC_VOLUME_DEFAULT
 
         self.player.audio_set_volume(volume)
-        # Ensure volume correct
-        # For as-yet unknown reasons. sometimes the volume gets
-        # reset to zero within 200mS or so of starting play. This
-        # only happened since moving to Debian 12, which uses
-        # Pipewire for sound (which may be irrelevant).
-        for _ in range(3):
-            current_volume = self.player.audio_get_volume()
-            if current_volume < volume:
-                self.player.audio_set_volume(volume)
-                log.debug(f"Reset from {volume=}")
-            sleep(0.1)
 
     def stop(self) -> None:
         """Immediately stop playing"""

app/musicmuster.py

@@ -90,6 +90,7 @@ from ui.main_window_footer_ui import Ui_FooterSection  # type: ignore
 from utilities import check_db, update_bitrates
 import helpers
 
+from jittermonitor import EventLoopJitterMonitor
 
 class Current:
     base_model: PlaylistModel
@@ -1206,6 +1207,16 @@ class Window(QMainWindow):
         self.action_quicklog = QShortcut(QKeySequence("Ctrl+L"), self)
         self.action_quicklog.activated.connect(self.quicklog)
 
+
+        # Jitter monitor - log delays in main event loop
+        self.jitter_monitor = EventLoopJitterMonitor(
+            parent=self,
+            interval_ms=20,
+            jitter_threshold_ms=100,   # only care about >~100 ms
+            log_cooldown_s=1.0,        # at most 1 warning per second
+        )
+        self.jitter_monitor.start()
+
         self.load_last_playlists()
         self.stop_autoplay = False
 
@@ -2206,14 +2217,6 @@ class Window(QMainWindow):
         if self.return_pressed_in_error():
             return
 
-        # Issue #223 concerns a very short pause (maybe 0.1s) sometimes
-        # when starting to play at track. Resolution appears to be to
-        # disable timer10 for a short time. Timer is re-enabled in
-        # update_clocks.
-
-        self.timer10.stop()
-        log.debug("issue223: play_next: 10ms timer disabled")
-
         # If there's currently a track playing, fade it.
         if track_sequence.current:
             track_sequence.current.fade()
@@ -2725,8 +2728,7 @@ class Window(QMainWindow):
 
             # WARNING_MS_BEFORE_FADE milliseconds before fade starts, set
             # warning colour on time to silence box and enable play
-            # controls. This is also a good time to re-enable the 10ms
+            # controls. 
-            # timer (see play_next() and issue #223).
 
             elif time_to_fade <= Config.WARNING_MS_BEFORE_FADE:
                 self.footer_section.frame_fade.setStyleSheet(
@@ -2734,11 +2736,6 @@ class Window(QMainWindow):
                 )
                 self.catch_return_key = False
                 self.show_status_message("Play controls: Enabled", 0)
-                # Re-enable 10ms timer (see above)
-                log.debug(f"issue287: {self.timer10.isActive()=}")
-                if not self.timer10.isActive():
-                    self.timer10.start(10)
-                    log.debug("issue223: update_clocks: 10ms timer enabled")
 
             else:
                 self.footer_section.frame_silent.setStyleSheet("")

app/playlistmodel.py

@@ -51,7 +51,7 @@ from models import db, NoteColours, Playdates, PlaylistRows, Tracks
 from music_manager import RowAndTrack, track_sequence
 
 
-HEADER_NOTES_COLUMN = 1
+HEADER_NOTES_COLUMN = 0
 scene_change_re = re.compile(r"SetScene=\[([^[\]]*)\]")
 
 
@@ -417,7 +417,7 @@ class PlaylistModel(QAbstractTableModel):
         if column == HEADER_NOTES_COLUMN:
             column_span = 1
             if header_row:
-                column_span = self.columnCount() - 1
+                column_span = self.columnCount() - HEADER_NOTES_COLUMN
             self.signals.span_cells_signal.emit(
                 self.playlist_id, row, HEADER_NOTES_COLUMN, 1, column_span
             )
@@ -534,7 +534,7 @@ class PlaylistModel(QAbstractTableModel):
             Col.ARTIST.value,
             Col.NOTE.value,
             Col.INTRO.value,
-        ]:
+        ] or self.is_header_row(index.row()) and index.column() == HEADER_NOTES_COLUMN:
             return default | Qt.ItemFlag.ItemIsEditable
 
         return default
@@ -765,8 +765,6 @@ class PlaylistModel(QAbstractTableModel):
         Signal to view to refresh invalidated row
         """
 
-        log.debug(f"issue285: {self}: invalidate_row({modified_row=})")
-
         self.dataChanged.emit(
             self.index(modified_row, 0),
             self.index(modified_row, self.columnCount() - 1),
@@ -778,8 +776,6 @@ class PlaylistModel(QAbstractTableModel):
         Signal to view to refresh invlidated rows
         """
 
-        log.debug(f"issue285: {self}: invalidate_rows({modified_rows=})")
-
         for modified_row in modified_rows:
             # only invalidate required roles
             self.invalidate_row(modified_row, roles)
@@ -1201,8 +1197,6 @@ class PlaylistModel(QAbstractTableModel):
         looking up the playlistrow_id and retrieving the row number from the database.
         """
 
-        log.debug(f"issue285: {self}: reset_track_sequence_row_numbers()")
-
         # Check the track_sequence.next, current and previous plrs and
         # update the row number
         with db.Session() as session:
@@ -1667,8 +1661,6 @@ class PlaylistModel(QAbstractTableModel):
         Update track start/end times in self.playlist_rows
         """
 
-        log.debug(f"issue285: {self}: update_track_times()")
-
         next_start_time: Optional[dt.datetime] = None
         update_rows: list[int] = []
         row_count = len(self.playlist_rows)