fix unchanged tracks for external files

src/ffx/media_descriptor.py

@@ -317,6 +317,7 @@ class MediaDescriptor:
 
 
     def getImportFileTokens(self, use_sub_index: bool = True):
+        """Generate ffmpeg import options for external stream files"""
 
         importFileTokens = []
 
@@ -347,14 +348,11 @@ class MediaDescriptor:
         filePointer = 1
         for trackIndex in range(len(self.__trackDescriptors)):
 
-            td = self.__trackDescriptors[trackIndex]
+            td: TrackDescriptor = self.__trackDescriptors[trackIndex]
 
             stdi = self.__trackDescriptors[td.getSourceIndex()].getIndex()
             stdsi = self.__trackDescriptors[td.getSourceIndex()].getSubIndex()
 
-            # sti = self.__trackDescriptors[trackIndex].getSourceIndex()
-            # sotd = sourceOrderTrackDescriptors[sti]
-
             trackType = td.getType()
             
             if (trackType == TrackType.VIDEO or not only_video):

src/ffx/media_descriptor_change_set.py

@@ -269,6 +269,7 @@ class MediaDescriptorChangeSet():
 
                         addedTrackTags = tagsDiffObj[DIFF_ADDED_KEY] if DIFF_ADDED_KEY in tagsDiffObj.keys() else {}
                         changedTrackTags = tagsDiffObj[DIFF_CHANGED_KEY] if DIFF_CHANGED_KEY in tagsDiffObj.keys() else {}
+                        unchangedTrackTags = tagsDiffObj[DIFF_UNCHANGED_KEY] if DIFF_UNCHANGED_KEY in tagsDiffObj.keys() else {}
                         removedTrackTags = tagsDiffObj[DIFF_REMOVED_KEY] if DIFF_REMOVED_KEY in tagsDiffObj.keys() else {}
 
                         outputTrackTags = addedTrackTags | changedTrackTags
@@ -285,6 +286,15 @@ class MediaDescriptorChangeSet():
                                                 + f":{trackDescriptor.getSubIndex()}",
                                                 f"{removeKey}="]
                             
+                        #HINT: In case of loading a track from an external file
+                        # no tags from source are present for the track so
+                        # the unchanged tracks are passed to the output file as well
+                        if trackDescriptor.getExternalSourceFilePath():
+                            for tagKey, tagValue in unchangedTrackTags.items():
+                                metadataTokens += [f"-metadata:s:{trackDescriptor.getType().indicator()}"
+                                                + f":{trackDescriptor.getSubIndex()}",
+                                                f"{tagKey}={tagValue}"]
+
         return metadataTokens