diff --git a/devine/core/tracks/subtitle.py b/devine/core/tracks/subtitle.py
index 97111da5..300b8946 100644
--- a/devine/core/tracks/subtitle.py
+++ b/devine/core/tracks/subtitle.py
@@ -16,6 +16,7 @@
 from pycaption.geometry import Layout
 from pymp4.parser import MP4
 from subtitle_filter import Subtitles
+from subby import ISMTConverter
 
 from devine.core import binaries
 from devine.core.tracks.track import Track
@@ -274,6 +275,12 @@ def convert(self, codec: Subtitle.Codec) -> Path:
                 stdout=subprocess.DEVNULL,
                 stderr=subprocess.DEVNULL
             )
+        elif self.codec in Subtitle.Codec.fTTML:
+            output_path = self.path.with_suffix(".srt")
+            converter = ISMTConverter()
+            srt = converter.from_file(self.path)
+            srt.save(output_path)
+            codec = Subtitle.Codec.SubRip
         else:
             writer = {
                 # pycaption generally only supports these subtitle formats
diff --git a/pyproject.toml b/pyproject.toml
index 5b6012ea..502ee32a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -62,6 +62,7 @@ Unidecode = "^1.3.8"
 urllib3 = "^2.2.1"
 chardet = "^5.2.0"
 curl-cffi = "^0.7.0b4"
+subby = {git = "https://github.com/Parasitic5283/subby.git", rev = "Update-lxml"} # Until https://github.com/vevv/subby/pull/31 is merged
 
 [tool.poetry.dev-dependencies]
 pre-commit = "^3.7.0"