AAF Clip Enabled/Muting Update (#1277)

* When reading AAF files with muted clips, use the OTIO `enabled = False` toggle to represent the muted state.
* Some ground work for supporting muted tracks is here, but that is left for a future PR.

contrib/opentimelineio_contrib/adapters/advanced_authoring_format.py

@@ -754,23 +754,51 @@ def _transcribe(item, parents, edit_rate, indent=0):
     elif isinstance(item, aaf2.components.Selector):
         msg = "Transcribe selector for  {}".format(_encoded_name(item))
         _transcribe_log(msg, indent)
-        # If you mute a clip in media composer, it becomes one of these in the
-        # AAF.
-        result = _transcribe(item.getvalue("Selected"),
-                             parents + [item], edit_rate, indent + 2)
-
-        alternates = [
-            _transcribe(alt, parents + [item], edit_rate, indent + 2)
-            for alt in item.getvalue("Alternates")
-        ]
 
-        # muted case -- if there is only one item its muted, otherwise its
-        # a multi cam thing
-        if alternates and len(alternates) == 1:
-            metadata['muted_clip'] = True
-            result.name = str(alternates[0].name) + "_MUTED"
+        selected = item.getvalue('Selected')
+        alternates = item.getvalue('Alternates', None)
+
+        # First we check to see if the Selected component is either a Filler
+        # or ScopeReference object, meaning we have to use the alternate instead
+        if isinstance(selected, aaf2.components.Filler) or \
+                isinstance(selected, aaf2.components.ScopeReference):
+
+            # Safety check of the alternates list, then transcribe first object -
+            # there should only ever be one alternate in this situation
+            if alternates is None or len(alternates) != 1:
+                err = "AAF Selector parsing error: object has unexpected number of " \
+                      "alternates - {}".format(len(alternates))
+                raise AAFAdapterError(err)
+            result = _transcribe(alternates[0], parents + [item], edit_rate, indent + 2)
+
+            # Filler/ScopeReference means the clip is muted/not enabled
+            result.enabled = False
+
+            # Muted tracks are handled in a slightly odd way so we need to do a
+            # check here and pass the param back up to the track object
+            # if isinstance(parents[-1], aaf2.mobslots.TimelineMobSlot):
+            #     pass # TODO: Figure out mechanism for passing this up to parent
+
+        else:
+
+            # This is most likely a multi-cam clip
+            result = _transcribe(selected, parents + [item], edit_rate, indent + 2)
+
+            # Perform a check here to make sure no potential Gap objects
+            # are slipping through the cracks
+            if isinstance(result, otio.schema.Gap):
+                err = "AAF Selector parsing error: {}".format(type(item))
+                raise AAFAdapterError(err)
 
-        metadata['alternates'] = alternates
+            # A Selector can have a set of alternates to handle multiple options for an
+            # editorial decision - we do a full parse on those obects too
+            if alternates is not None:
+                alternates = [
+                    _transcribe(alt, parents + [item], edit_rate, indent + 2)
+                    for alt in alternates
+                ]
+
+            metadata['alternates'] = alternates
 
     # @TODO: There are a bunch of other AAF object types that we will
     # likely need to add support for. I'm leaving this code here to help
@@ -1378,15 +1406,26 @@ def _simplify(thing):
                     # Note: we don't merge effects, because we already made
                     # sure the child had no effects in the if statement above.
 
+                    # Preserve the enabled/disabled state as we merge these two.
+                    thing.enabled = thing.enabled and child.enabled
+
                     c = c + num
                 c = c - 1
 
         # skip redundant containers
         if _is_redundant_container(thing):
             # TODO: We may be discarding metadata here, should we merge it?
             result = thing[0].deepcopy()
+
+            # As we are reducing the complexity of the object structure through
+            # this process, we need to make sure that any/all enabled statuses
+            # are being respected and applied in an appropriate way
+            if not thing.enabled:
+                result.enabled = False
+
             # TODO: Do we need to offset the markers in time?
             result.markers.extend(thing.markers)
+
             # TODO: The order of the effects is probably important...
             # should they be added to the end or the front?
             # Intuitively it seems like the child's effects should come before

contrib/opentimelineio_contrib/adapters/tests/test_aaf_adapter.py

@@ -873,13 +873,15 @@ def test_read_misc_speed_effects(self):
         # do then this effect is a "Speed Bump" from 166% to 44% to 166%
 
     def test_muted_clip(self):
-        sc = otio.adapters.read_from_file(MUTED_CLIP_PATH, simplify=False)
-        gp = sc[0].tracks[8][0][0]
-
-        self.assertIsNotNone(gp)
-        self.assertTrue(gp.metadata['AAF']['muted_clip'])
-        self.assertIsInstance(gp, otio.schema.Gap)
-        self.assertEqual(gp.name, 'Frame Debugger 0h.mov_MUTED')
+        timeline = otio.adapters.read_from_file(MUTED_CLIP_PATH)
+        self.assertIsInstance(timeline, otio.schema.Timeline)
+        self.assertEqual(len(timeline.tracks), 1)
+        track = timeline.tracks[0]
+        self.assertEqual(len(track), 1)
+        clip = track[0]
+        self.assertIsInstance(clip, otio.schema.Clip)
+        self.assertEqual(clip.name, 'Frame Debugger 0h.mov')
+        self.assertEqual(clip.enabled, False)
 
     def test_essence_group(self):
         timeline = otio.adapters.read_from_file(ESSENCE_GROUP_PATH)

tests/test_item.py

@@ -298,9 +298,9 @@ def test_enabled(self):
             duration=otio.opentime.RationalTime(10, 1)
         )
         it = otio.core.Item(source_range=tr)
-        self.assertEquals(it.enabled, True)
+        self.assertEqual(it.enabled, True)
         it.enabled = False
-        self.assertEquals(it.enabled, False)
+        self.assertEqual(it.enabled, False)
         encoded = otio.adapters.otio_json.write_to_string(it)
         decoded = otio.adapters.otio_json.read_from_string(encoded)
         self.assertIsOTIOEquivalentTo(it, decoded)