Fix error dialog not showing when playback fails

Timed updates were hanging when the player isn't ready.

Closes #153

TODO.md

@@ -3,5 +3,6 @@ Gaupol 1.9
 
 * [x] Add framerates 30, 50, 59.94 and 60 fps (#164)
 * [x] Allow shifting positions of all open projects (#66)
+* [x] Fix error dialog when video playback fails (#153)
 * [x] Fix the order of audio tracks in the menu (#129, qnga)
 * [x] Fix spell-check split words correction task to not hang (#171)

gaupol/agents/video.py

@@ -226,6 +226,7 @@ def _on_player_state_changed(self, player, state):
 
     def _on_player_update_seekbar(self, data=None):
         """Update seekbar from video position."""
+        if not self.player.ready: return
         duration = self.player.get_duration(mode=None)
         position = self.player.get_position(mode=None)
         if duration is not None and position is not None:
@@ -235,6 +236,7 @@ def _on_player_update_seekbar(self, data=None):
 
     def _on_player_update_subtitle(self, data=None):
         """Update subtitle overlay from video position."""
+        if not self.player.ready: return
         pos = self.player.get_position(aeidon.modes.SECONDS)
         if pos is None:
             return True # to be called again.
@@ -250,6 +252,7 @@ def _on_player_update_subtitle(self, data=None):
 
     def _on_player_update_volume(self, data=None):
         """Update volume from player."""
+        if not self.player.ready: return
         self.volume_button.set_value(self.player.volume)
         return True # to be called again.