[ie/mediastream] Pass default={} to _yield_json_ld during embed extraction

Authored by: bashonly

yt_dlp/extractor/common.py

@@ -1578,7 +1578,9 @@ class InfoExtractor:
         if default is not NO_DEFAULT:
             fatal = False
         for mobj in re.finditer(JSON_LD_RE, html):
-            json_ld_item = self._parse_json(mobj.group('json_ld'), video_id, fatal=fatal)
+            json_ld_item = self._parse_json(
+                mobj.group('json_ld'), video_id, fatal=fatal,
+                errnote=False if default is not NO_DEFAULT else None)
             for json_ld in variadic(json_ld_item):
                 if isinstance(json_ld, dict):
                     yield json_ld

yt_dlp/extractor/mediastream.py

@@ -17,7 +17,7 @@ class MediaStreamBaseIE(InfoExtractor):
     _BASE_URL_RE = r'https?://mdstrm\.com/(?:embed|live-stream)'
 
     def _extract_mediastream_urls(self, webpage):
-        yield from traverse_obj(list(self._yield_json_ld(webpage, None, fatal=False)), (
+        yield from traverse_obj(list(self._yield_json_ld(webpage, None, default={})), (
             lambda _, v: v['@type'] == 'VideoObject', ('embedUrl', 'contentUrl'),
             {lambda x: x if re.match(rf'{self._BASE_URL_RE}/\w+', x) else None}))