[pitivi] viewer: Fixes peak meter not updated on audio channels change Fixes #2607

[Alexandru Băluț <alexbalut src gnome org>]

commit 01854f2cf74871647a906cd97293d1473deeda95
Author: Aryan Kaushik <73686-Aryan20 users noreply gitlab gnome org>
Date:   Sun May 8 23:48:19 2022 +0530

    viewer: Fixes peak meter not updated on audio channels change
    Fixes #2607

 pitivi/project.py        |  2 ++
 pitivi/viewer/viewer.py  |  7 ++++++-
 tests/test_peak_meter.py | 12 ++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)
---
diff --git a/pitivi/project.py b/pitivi/project.py
index 3da5d298b..9c10938ec 100644
--- a/pitivi/project.py
+++ b/pitivi/project.py
@@ -636,6 +636,7 @@ class Project(Loggable, GES.Project):
         "settings-set-from-imported-asset": (GObject.SignalFlags.RUN_LAST, None,
                                              (GES.Asset,)),
         "video-size-changed": (GObject.SignalFlags.RUN_LAST, None, ()),
+        "audio-channels-changed": (GObject.SignalFlags.RUN_LAST, None, ()),
         "safe-area-size-changed": (GObject.SignalFlags.RUN_LAST, None, ())
     }
 
@@ -1002,6 +1003,7 @@ class Project(Loggable, GES.Project):
         """Updates the audio profile and the corresponding project settings."""
         res = Project._set_restriction(self.audio_profile, name, value)
         if res:
+            self.emit("audio-channels-changed")
             self._has_default_audio_settings = False
             self.update_restriction_caps()
         return res
diff --git a/pitivi/viewer/viewer.py b/pitivi/viewer/viewer.py
index 042bddb66..00266d52e 100644
--- a/pitivi/viewer/viewer.py
+++ b/pitivi/viewer/viewer.py
@@ -111,18 +111,22 @@ class ViewerContainer(Gtk.Box, Loggable):
     def _project_manager_project_closed_cb(self, unused_project_manager, project):
         if self.project == project:
             project.disconnect_by_func(self._project_video_size_changed_cb)
+            project.disconnect_by_func(self._project_audio_channels_changed_cb)
         self.project = None
 
     def _project_video_size_changed_cb(self, project):
         """Handles Project metadata changes."""
         self._reset_viewer_aspect_ratio(project)
-        self.__update_peak_meters(project)
 
     def _reset_viewer_aspect_ratio(self, project):
         """Resets the viewer aspect ratio."""
         self.target.update_aspect_ratio(project)
         self.timecode_entry.set_framerate(project.videorate)
 
+    def _project_audio_channels_changed_cb(self, project):
+        """Handles Project audio channels changes."""
+        self.__update_peak_meters(project)
+
     def __update_peak_meters(self, project):
         for peak_meter in self.peak_meters:
             self.peak_meter_box.remove(peak_meter)
@@ -168,6 +172,7 @@ class ViewerContainer(Gtk.Box, Loggable):
         project.pipeline.pause()
 
         project.connect("video-size-changed", self._project_video_size_changed_cb)
+        project.connect("audio-channels-changed", self._project_audio_channels_changed_cb)
 
     def __create_new_viewer(self):
         _, sink_widget = self.project.pipeline.create_sink()
diff --git a/tests/test_peak_meter.py b/tests/test_peak_meter.py
index e2086b96e..76b508b13 100644
--- a/tests/test_peak_meter.py
+++ b/tests/test_peak_meter.py
@@ -117,3 +117,15 @@ class TestPeakMeter(common.TestCase):
         for peak in peaks:
             self.assertGreaterEqual(0, peak, peaks)
             self.assertGreaterEqual(peak, MIN_PEAK, peaks)
+
+    @common.setup_project(["tears_of_steel.webm"])
+    def test_peak_meter_channels_update(self):
+        """Checks that the peak meter channels updates correctly when audio channels changes."""
+        viewer = ViewerContainer(self.app)
+        viewer.set_project(self.project)
+
+        self.assertEqual(self.project.audiochannels, 1)
+        self.assertEqual(len(viewer.peak_meters), 1)
+
+        self.project.audiochannels = 6
+        self.assertEqual(len(viewer.peak_meters), 6)