diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index 6b40a8323..359bdd299 100644
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -1224,6 +1224,7 @@ def _parse_smil_formats(self, smil, smil_url, video_id, namespace=None, f4m_para
                 continue
 
             src_url = src if src.startswith('http') else compat_urlparse.urljoin(base, src)
+            src_url = src_url.strip()
 
             if proto == 'm3u8' or src_ext == 'm3u8':
                 m3u8_formats = self._extract_m3u8_formats(