feat: add pysubs2 subtitle conversion with extended format support

- Add pysubs2 as default conversion method for 'auto' mode
- Add support for MicroDVD (.sub), MPL2 (.mpl2), and TMP (.tmp) formats
- Implement convert_with_pysubs2() method with fallback to standard conversion
- Update from_mime() to handle new subtitle format types
- Map all supported formats to pysubs2 format identifiers
- Update docstrings to reflect new capabilities

pyproject.toml

@@ -58,6 +58,7 @@ dependencies = [
     "httpx>=0.28.1,<0.29",
     "cryptography>=45.0.0",
     "subby",
+    "pysubs2>=1.7.0,<2",
 ]
 
 [project.urls]

unshackle/core/tracks/subtitle.py

@@ -10,6 +10,7 @@ from pathlib import Path
 from typing import Any, Callable, Iterable, Optional, Union
 
 import pycaption
+import pysubs2
 import requests
 from construct import Container
 from pycaption import Caption, CaptionList, CaptionNode, WebVTTReader
@@ -33,6 +34,9 @@ class Subtitle(Track):
         TimedTextMarkupLang = "TTML"  # https://wikipedia.org/wiki/Timed_Text_Markup_Language
         WebVTT = "VTT"  # https://wikipedia.org/wiki/WebVTT
         SAMI = "SMI"  # https://wikipedia.org/wiki/SAMI
+        MicroDVD = "SUB"  # https://wikipedia.org/wiki/MicroDVD
+        MPL2 = "MPL2"  # MPL2 subtitle format
+        TMP = "TMP"  # TMP subtitle format
         # MPEG-DASH box-encapsulated subtitle formats
         fTTML = "STPP"  # https://www.w3.org/TR/2018/REC-ttml-imsc1.0.1-20180424
         fVTT = "WVTT"  # https://www.w3.org/TR/webvtt1
@@ -56,6 +60,12 @@ class Subtitle(Track):
                 return Subtitle.Codec.WebVTT
             elif mime in ("smi", "sami"):
                 return Subtitle.Codec.SAMI
+            elif mime in ("sub", "microdvd"):
+                return Subtitle.Codec.MicroDVD
+            elif mime == "mpl2":
+                return Subtitle.Codec.MPL2
+            elif mime == "tmp":
+                return Subtitle.Codec.TMP
             elif mime == "stpp":
                 return Subtitle.Codec.fTTML
             elif mime == "wvtt":
@@ -391,15 +401,67 @@ class Subtitle(Track):
             # Fall back to existing conversion method on any error
             return self._convert_standard(codec)
 
+    def convert_with_pysubs2(self, codec: Subtitle.Codec) -> Path:
+        """
+        Convert subtitle using pysubs2 library for broad format support.
+
+        pysubs2 is a pure-Python library supporting SubRip (SRT), SubStation Alpha
+        (SSA/ASS), WebVTT, TTML, SAMI, MicroDVD, MPL2, and TMP formats.
+        """
+        if not self.path or not self.path.exists():
+            raise ValueError("You must download the subtitle track first.")
+
+        if self.codec == codec:
+            return self.path
+
+        output_path = self.path.with_suffix(f".{codec.value.lower()}")
+        original_path = self.path
+
+        codec_to_pysubs2_format = {
+            Subtitle.Codec.SubRip: "srt",
+            Subtitle.Codec.SubStationAlpha: "ssa",
+            Subtitle.Codec.SubStationAlphav4: "ass",
+            Subtitle.Codec.WebVTT: "vtt",
+            Subtitle.Codec.TimedTextMarkupLang: "ttml",
+            Subtitle.Codec.SAMI: "sami",
+            Subtitle.Codec.MicroDVD: "microdvd",
+            Subtitle.Codec.MPL2: "mpl2",
+            Subtitle.Codec.TMP: "tmp",
+        }
+
+        pysubs2_output_format = codec_to_pysubs2_format.get(codec)
+        if pysubs2_output_format is None:
+            return self._convert_standard(codec)
+
+        try:
+            subs = pysubs2.load(str(self.path), encoding="utf-8")
+
+            subs.save(str(output_path), format_=pysubs2_output_format, encoding="utf-8")
+
+            if original_path.exists() and original_path != output_path:
+                original_path.unlink()
+
+            self.path = output_path
+            self.codec = codec
+
+            if callable(self.OnConverted):
+                self.OnConverted(codec)
+
+            return output_path
+
+        except Exception:
+            return self._convert_standard(codec)
+
     def convert(self, codec: Subtitle.Codec) -> Path:
         """
         Convert this Subtitle to another Format.
 
         The conversion method is determined by the 'conversion_method' setting in config:
-        - 'auto' (default): Uses subby for WebVTT/SAMI, standard for others
+        - 'auto' (default): Uses pysubs2 (supports SRT/SSA/ASS/WebVTT/TTML/SAMI)
         - 'subby': Always uses subby with CommonIssuesFixer
         - 'subtitleedit': Uses SubtitleEdit when available, falls back to pycaption
         - 'pycaption': Uses only pycaption library
+        - 'pysubs2': Uses pysubs2 library (same as auto)
         """
         # Check configuration for conversion method
         conversion_method = config.subtitle.get("conversion_method", "auto")
@@ -407,15 +469,13 @@ class Subtitle(Track):
         if conversion_method == "subby":
             return self.convert_with_subby(codec)
         elif conversion_method == "subtitleedit":
-            return self._convert_standard(codec)  # SubtitleEdit is used in standard conversion
+            return self._convert_standard(codec)
         elif conversion_method == "pycaption":
             return self._convert_pycaption_only(codec)
+        elif conversion_method == "pysubs2":
+            return self.convert_with_pysubs2(codec)
         elif conversion_method == "auto":
-            # Use subby for formats it handles better
-            if self.codec in (Subtitle.Codec.WebVTT, Subtitle.Codec.SAMI):
-                return self.convert_with_subby(codec)
-            else:
-                return self._convert_standard(codec)
+            return self.convert_with_pysubs2(codec)
         else:
             return self._convert_standard(codec)
 

uv.lock

@@ -1174,6 +1174,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/8d/59/b4572118e098ac8e46e399a1dd0f2d85403ce8bbaad9ec79373ed6badaf9/PySocks-1.7.1-py3-none-any.whl", hash = "sha256:2725bd0a9925919b9b51739eea5f9e2bae91e83288108a9ad338b2e3a4435ee5", size = 16725, upload-time = "2019-09-20T02:06:22.938Z" },
 ]
 
+[[package]]
+name = "pysubs2"
+version = "1.8.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/31/4a/becf78d9d3df56e6c4a9c50b83794e5436b6c5ab6dd8a3f934e94c89338c/pysubs2-1.8.0.tar.gz", hash = "sha256:3397bb58a4a15b1325ba2ae3fd4d7c214e2c0ddb9f33190d6280d783bb433b20", size = 1130048, upload-time = "2024-12-24T12:39:47.769Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/99/09/0fc0719162e5ad723f71d41cf336f18b6b5054d70dc0fe42ace6b4d2bdc9/pysubs2-1.8.0-py3-none-any.whl", hash = "sha256:05716f5039a9ebe32cd4d7673f923cf36204f3a3e99987f823ab83610b7035a0", size = 43516, upload-time = "2024-12-24T12:39:44.469Z" },
+]
+
 [[package]]
 name = "pywidevine"
 version = "1.8.0"
@@ -1523,6 +1532,7 @@ dependencies = [
     { name = "pymp4" },
     { name = "pymysql" },
     { name = "pyplayready" },
+    { name = "pysubs2" },
     { name = "pywidevine", extra = ["serve"] },
     { name = "pyyaml" },
     { name = "requests", extra = ["socks"] },
@@ -1562,7 +1572,7 @@ requires-dist = [
     { name = "httpx", specifier = ">=0.28.1,<0.29" },
     { name = "jsonpickle", specifier = ">=3.0.4,<4" },
     { name = "langcodes", specifier = ">=3.4.0,<4" },
-    { name = "lxml", specifier = ">=5.2.1,<6" },
+    { name = "lxml", specifier = ">=5.2.1,<7" },
     { name = "pproxy", specifier = ">=2.7.9,<3" },
     { name = "protobuf", specifier = ">=4.25.3,<5" },
     { name = "pycaption", specifier = ">=2.2.6,<3" },
@@ -1572,6 +1582,7 @@ requires-dist = [
     { name = "pymp4", specifier = ">=1.4.0,<2" },
     { name = "pymysql", specifier = ">=1.1.0,<2" },
     { name = "pyplayready", specifier = ">=0.6.0,<0.7" },
+    { name = "pysubs2", specifier = ">=1.7.0,<2" },
     { name = "pywidevine", extras = ["serve"], specifier = ">=1.8.0,<2" },
     { name = "pyyaml", specifier = ">=6.0.1,<7" },
     { name = "requests", extras = ["socks"], specifier = ">=2.31.0,<3" },