diff --git a/yt_dlp/extractor/youtube.py b/yt_dlp/extractor/youtube.py
index 56cd2ed8d3..64475edec0 100644
--- a/yt_dlp/extractor/youtube.py
+++ b/yt_dlp/extractor/youtube.py
@@ -2434,7 +2434,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
         return prs, player_url
 
     def _extract_formats(self, streaming_data, video_id, player_url, is_live):
-        itags, stream_ids = [], []
+        itags, stream_ids = {}, []
         itag_qualities, res_qualities = {}, {}
         q = qualities([
             # Normally tiny is the smallest video-only formats. But
@@ -2498,7 +2498,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                     throttled = True
 
             if itag:
-                itags.append(itag)
+                itags[itag] = 'https'
                 stream_ids.append(stream_id)
 
             tbr = float_or_none(
@@ -2548,46 +2548,36 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
             and 'dash' not in skip_manifests and self.get_param('youtube_include_dash_manifest', True))
         get_hls = 'hls' not in skip_manifests and self.get_param('youtube_include_hls_manifest', True)
 
-        def guess_quality(f):
-            for val, qdict in ((f.get('format_id'), itag_qualities), (f.get('height'), res_qualities)):
-                if val in qdict:
-                    return q(qdict[val])
-            return -1
+        def process_manifest_format(f, proto, itag):
+            if itag in itags:
+                if itags[itag] == proto or f'{itag}-{proto}' in itags:
+                    return False
+                itag = f'{itag}-{proto}'
+            if itag:
+                f['format_id'] = itag
+                itags[itag] = proto
+
+            f['quality'] = next((
+                q(qdict[val])
+                for val, qdict in ((f.get('format_id'), itag_qualities), (f.get('height'), res_qualities))
+                if val in qdict), -1)
+            return True
 
         for sd in streaming_data:
             hls_manifest_url = get_hls and sd.get('hlsManifestUrl')
             if hls_manifest_url:
                 for f in self._extract_m3u8_formats(hls_manifest_url, video_id, 'mp4', fatal=False):
-                    itag = self._search_regex(
-                        r'/itag/(\d+)', f['url'], 'itag', default=None)
-                    if itag in itags:
-                        itag += '-hls'
-                        if itag in itags:
-                            continue
-                    if itag:
-                        f['format_id'] = itag
-                        itags.append(itag)
-                    f['quality'] = guess_quality(f)
-                    yield f
+                    if process_manifest_format(f, 'hls', self._search_regex(
+                            r'/itag/(\d+)', f['url'], 'itag', default=None)):
+                        yield f
 
             dash_manifest_url = get_dash and sd.get('dashManifestUrl')
             if dash_manifest_url:
                 for f in self._extract_mpd_formats(dash_manifest_url, video_id, fatal=False):
-                    itag = f['format_id']
-                    if itag in itags:
-                        itag += '-dash'
-                        if itag in itags:
-                            continue
-                    if itag:
-                        f['format_id'] = itag
-                        itags.append(itag)
-                    f['quality'] = guess_quality(f)
-                    filesize = int_or_none(self._search_regex(
-                        r'/clen/(\d+)', f.get('fragment_base_url')
-                        or f['url'], 'file size', default=None))
-                    if filesize:
-                        f['filesize'] = filesize
-                    yield f
+                    if process_manifest_format(f, 'dash', f['format_id']):
+                        f['filesize'] = int_or_none(self._search_regex(
+                            r'/clen/(\d+)', f.get('fragment_base_url') or f['url'], 'file size', default=None))
+                        yield f
 
     def _real_extract(self, url):
         url, smuggled_data = unsmuggle_url(url, {})