feat(playready): Enhance KID extraction from PSSH with base64 support and XML parsing

unshackle/core/drm/playready.py

@@ -39,17 +39,23 @@ class PlayReady:
         if not isinstance(pssh, PSSH):
             raise TypeError(f"Expected pssh to be a {PSSH}, not {pssh!r}")
 
-        kids: list[UUID] = []
-        for header in pssh.wrm_headers:
-            try:
-                signed_ids, _, _, _ = header.read_attributes()
-            except Exception:
-                continue
-            for signed_id in signed_ids:
+        if pssh_b64:
+            kids = self._extract_kids_from_pssh_b64(pssh_b64)
+        else:
+            kids = []
+
+        # Extract KIDs using pyplayready's method (may miss some KIDs)
+        if not kids:
+            for header in pssh.wrm_headers:
                 try:
-                    kids.append(UUID(bytes_le=base64.b64decode(signed_id.value)))
+                    signed_ids, _, _, _ = header.read_attributes()
                 except Exception:
                     continue
+                for signed_id in signed_ids:
+                    try:
+                        kids.append(UUID(bytes_le=base64.b64decode(signed_id.value)))
+                    except Exception:
+                        continue
 
         if kid:
             if isinstance(kid, str):
@@ -72,6 +78,66 @@ class PlayReady:
         if pssh_b64:
             self.data.setdefault("pssh_b64", pssh_b64)
 
+    def _extract_kids_from_pssh_b64(self, pssh_b64: str) -> list[UUID]:
+        """Extract all KIDs from base64-encoded PSSH data."""
+        try:
+            import xml.etree.ElementTree as ET
+
+            # Decode the PSSH
+            pssh_bytes = base64.b64decode(pssh_b64)
+
+            # Try to find XML in the PSSH data
+            # PlayReady PSSH usually has XML embedded in it
+            pssh_str = pssh_bytes.decode("utf-16le", errors="ignore")
+
+            # Find WRMHEADER
+            xml_start = pssh_str.find("<WRMHEADER")
+            if xml_start == -1:
+                # Try UTF-8
+                pssh_str = pssh_bytes.decode("utf-8", errors="ignore")
+                xml_start = pssh_str.find("<WRMHEADER")
+
+            if xml_start != -1:
+                clean_xml = pssh_str[xml_start:]
+                xml_end = clean_xml.find("</WRMHEADER>") + len("</WRMHEADER>")
+                clean_xml = clean_xml[:xml_end]
+
+                root = ET.fromstring(clean_xml)
+                ns = {"pr": "http://schemas.microsoft.com/DRM/2007/03/PlayReadyHeader"}
+
+                kids = []
+
+                # Extract from CUSTOMATTRIBUTES/KIDS
+                kid_elements = root.findall(".//pr:CUSTOMATTRIBUTES/pr:KIDS/pr:KID", ns)
+                for kid_elem in kid_elements:
+                    value = kid_elem.get("VALUE")
+                    if value:
+                        try:
+                            kid_bytes = base64.b64decode(value + "==")
+                            kid_uuid = UUID(bytes_le=kid_bytes)
+                            kids.append(kid_uuid)
+                        except Exception:
+                            pass
+
+                # Also get individual KID
+                individual_kids = root.findall(".//pr:DATA/pr:KID", ns)
+                for kid_elem in individual_kids:
+                    if kid_elem.text:
+                        try:
+                            kid_bytes = base64.b64decode(kid_elem.text.strip() + "==")
+                            kid_uuid = UUID(bytes_le=kid_bytes)
+                            if kid_uuid not in kids:
+                                kids.append(kid_uuid)
+                        except Exception:
+                            pass
+
+                return kids
+
+        except Exception:
+            pass
+
+        return []
+
     @classmethod
     def from_track(cls, track: AnyTrack, session: Optional[Session] = None) -> PlayReady:
         if not session: