diff --git a/yt_dlp/extractor/dropbox.py b/yt_dlp/extractor/dropbox.py
index ec86d7ad24..bc2efce123 100644
--- a/yt_dlp/extractor/dropbox.py
+++ b/yt_dlp/extractor/dropbox.py
@@ -66,10 +66,10 @@ class DropboxIE(InfoExtractor):
         for encoded in reversed(re.findall(r'registerStreamedPrefetch\s*\(\s*"[\w/+=]+"\s*,\s*"([\w/+=]+)"', webpage)):
             decoded = base64.b64decode(encoded).decode('utf-8', 'ignore')
             transcode_url = self._search_regex(
-                r'\n\x03(https://[^\x12\x03\n]+\.m3u8)', decoded, 'transcode url', default=None)
+                r'\n.(https://[^\x03\x08\x12\n]+\.m3u8)', decoded, 'transcode url', default=None)
             if not transcode_url:
                 continue
-            formats, subtitles = self._extract_m3u8_formats_and_subtitles(transcode_url, video_id)
+            formats, subtitles = self._extract_m3u8_formats_and_subtitles(transcode_url, video_id, 'mp4')
             has_anonymous_download = self._search_regex(r'(anonymous:\tanonymous)', decoded, 'anonymous', default=False)
             break