fix(dl): Log output from mkvmerge on failure

devine/commands/dl.py

@@ -701,15 +701,17 @@ def result(
                     ):
                         for task_id, task_tracks in multiplex_tasks:
                             progress.start_task(task_id)  # TODO: Needed?
-                            muxed_path, return_code = task_tracks.mux(
+                            muxed_path, return_code, output = task_tracks.mux(
                                 str(title),
                                 progress=partial(progress.update, task_id=task_id),
                                 delete=False
                             )
                             muxed_paths.append(muxed_path)
                             if return_code == 1:
+                                self.log.warning(output)
                                 self.log.warning("mkvmerge had at least one warning, will continue anyway...")
                             elif return_code >= 2:
+                                self.log.warning(output)
                                 self.log.error(f"Failed to Mux video to Matroska file ({return_code})")
                                 sys.exit(1)
                             for video_track in task_tracks.videos:

devine/core/tracks/tracks.py

@@ -316,7 +316,7 @@ def by_language(tracks: list[TrackT], languages: list[str], per_language: int =
             ][:per_language or None])
         return selected
 
-    def mux(self, title: str, delete: bool = True, progress: Optional[partial] = None) -> tuple[Path, int]:
+    def mux(self, title: str, delete: bool = True, progress: Optional[partial] = None) -> tuple[Path, int, str]:
         """
         Multiplex all the Tracks into a Matroska Container file.
 
@@ -410,15 +410,17 @@ def mux(self, title: str, delete: bool = True, progress: Optional[partial] = Non
 
         # let potential failures go to caller, caller should handle
         try:
+            output = ""
             p = subprocess.Popen([
                 *cl,
                 "--output", str(output_path),
                 "--gui-mode"
             ], text=True, stdout=subprocess.PIPE)
             for line in iter(p.stdout.readline, ""):
+                output += line
                 if "progress" in line:
                     progress(total=100, completed=int(line.strip()[14:-1]))
-            return output_path, p.wait()
+            return output_path, p.wait(), output
         finally:
             if chapters_path:
                 # regardless of delete param, we delete as it's a file we made during muxing