diff --git a/yt_dlp/extractor/common.py b/yt_dlp/extractor/common.py
index 30bdcdd02d..6b7ef0b014 100644
--- a/yt_dlp/extractor/common.py
+++ b/yt_dlp/extractor/common.py
@@ -2334,7 +2334,7 @@ def _parse_smil_formats_and_subtitles(
         for meta in smil.findall(self._xpath_ns('./head/meta', namespace)):
             b = meta.get('base') or meta.get('httpBase')
             if b:
-                base = f'{b.rstrip("/")}/'
+                base = b
                 break
 
         formats, subtitles = [], {}
@@ -2383,7 +2383,7 @@ def _parse_smil_formats_and_subtitles(
                     })
                 continue
 
-            src_url = src if src.startswith('http') else urllib.parse.urljoin(base, src)
+            src_url = src if src.startswith('http') else urllib.parse.urljoin(f'{b}/', src)
             src_url = src_url.strip()
 
             if proto == 'm3u8' or src_ext == 'm3u8':