diff --git a/youtube_dl/extractor/srf.py b/youtube_dl/extractor/srf.py
index a080eb7ca7..2ac55dcd18 100644
--- a/youtube_dl/extractor/srf.py
+++ b/youtube_dl/extractor/srf.py
@@ -75,7 +75,7 @@ def _real_extract(self, url):
                 else:
                     formats.append({
                         'url': full_url,
-                        'ext': 'mp4' if original_ext == 'm3u8' else original_ext,
+                        'ext': original_ext,
                         'format_id': format_id,
                         'quality': 0 if 'HD' in quality else -1,
                         'preference': 1,