From 11d06d909e83252e1d85b1936a2540e533077a40 Mon Sep 17 00:00:00 2001
From: croneter <croneter@users.noreply.github.com>
Date: Mon, 13 Sep 2021 08:52:45 +0200
Subject: [PATCH] Transcoding: Fix Plex burning-in subtitles when it should not

---
 resources/lib/playback_decision.py | 15 +++++----------
 resources/lib/plex_functions.py    | 16 ++++++++++++++++
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/resources/lib/playback_decision.py b/resources/lib/playback_decision.py
index aa8f3ba5..8b2d3640 100644
--- a/resources/lib/playback_decision.py
+++ b/resources/lib/playback_decision.py
@@ -426,7 +426,8 @@ def setup_transcoding_audio_subtitle_prefs(mediastreams, part_id):
                          action_type='PUT',
                          parameters=args)
 
-    select_subs_index = ''
+    # Zero telling the PMS to deactivate subs altogether
+    select_subs_index = 0
     if sub_num == 1:
         # Note: we DO need to tell the PMS that we DONT want any sub
         # Otherwise, the PMS might pick-up the last one
@@ -445,15 +446,9 @@ def setup_transcoding_audio_subtitle_prefs(mediastreams, part_id):
                 LOG.info('User chose to not burn-in any subtitles')
             else:
                 LOG.info('User chose to burn-in subtitle %s: %s',
-                          select_subs_index,
-                          subtitle_streams[resp].decode('utf-8'))
+                         select_subs_index,
+                         subtitle_streams[resp].decode('utf-8'))
                 select_subs_index = subtitle_streams_list[resp - 1]
     # Now prep the PMS for our choice
-    args = {
-        'subtitleStreamID': select_subs_index,
-        'allParts': 1
-    }
-    DU().downloadUrl('{server}/library/parts/%s' % part_id,
-                     action_type='PUT',
-                     parameters=args)
+    PF.change_subtitle(select_subs_index, part_id)
     return True
diff --git a/resources/lib/plex_functions.py b/resources/lib/plex_functions.py
index 3d421122..dc26a164 100644
--- a/resources/lib/plex_functions.py
+++ b/resources/lib/plex_functions.py
@@ -1117,3 +1117,19 @@ def playback_decision(path, media, part, playmethod, video=True, args=None):
     return DU().downloadUrl(utils.extend_url(url, arguments),
                             headerOptions=v.STREAMING_HEADERS,
                             reraise=True)
+
+
+def change_subtitle(plex_stream_id, part_id):
+    """
+    Tell the PMS to display/burn-in the subtitle stream with id plex_stream_id
+    for the Part (PMS XML etree tag "Part") with unique id part_id.
+    - plex_stream_id = 0 will deactivate the subtitle
+    - We always do this for ALL parts of a video
+    """
+    arguments = {
+        'subtitleStreamID': plex_stream_id,
+        'allParts': 1
+    }
+    url = '{server}/library/parts/%s' % part_id
+    return DU().downloadUrl(utils.extend_url(url, arguments),
+                            action_type='PUT')