diff --git a/unshackle/core/tracks/subtitle.py b/unshackle/core/tracks/subtitle.py
index de8fb22f..8208b220 100644
--- a/unshackle/core/tracks/subtitle.py
+++ b/unshackle/core/tracks/subtitle.py
@@ -61,7 +61,7 @@ class Subtitle(Track):
                 return Subtitle.Codec.SubStationAlpha
             elif mime == "ass":
                 return Subtitle.Codec.SubStationAlphav4
-            elif mime == "ttml":
+            elif mime in ("ttml", "ttml+xml"):
                 return Subtitle.Codec.TimedTextMarkupLang
             elif mime == "vtt":
                 return Subtitle.Codec.WebVTT