From 618b5e446c4379c9d95fe7b30fd6a0fc6af19a70 Mon Sep 17 00:00:00 2001
From: chrisellsworth <chrisellsworth@users.noreply.github.com>
Date: Mon, 8 Jun 2026 23:42:48 -0700
Subject: [PATCH] [ie] Extract supplemental codecs from DASH manifests (#16827)

Authored by: chrisellsworth
---
 test/test_InfoExtractor.py                | 45 +++++++++++++++++++++++
 test/testdata/mpd/supplemental_codecs.mpd | 28 ++++++++++++++
 yt_dlp/extractor/common.py                |  4 +-
 3 files changed, 76 insertions(+), 1 deletion(-)
 create mode 100644 test/testdata/mpd/supplemental_codecs.mpd

diff --git a/test/test_InfoExtractor.py b/test/test_InfoExtractor.py
index f66fdbf8da..63aef689a1 100644
--- a/test/test_InfoExtractor.py
+++ b/test/test_InfoExtractor.py
@@ -1415,6 +1415,51 @@ jwplayer("mediaplayer").setup({"abouttext":"Visit Indie DB","aboutlink":"http:\/
                         },
                     ],
                 },
+            ), (
+                # SCTE 214 supplemental codecs (e.g. Dolby AV1)
+                # Based on unfragmented.mpd with scte214:supplementalCodecs on VIDEO-1 only
+                'supplemental_codecs',
+                'https://v.redd.it/hw1x7rcg7zl21/DASHPlaylist.mpd',  # mpd_url
+                'https://v.redd.it/hw1x7rcg7zl21',  # mpd_base_url
+                [{
+                    'url': 'https://v.redd.it/hw1x7rcg7zl21/audio',
+                    'manifest_url': 'https://v.redd.it/hw1x7rcg7zl21/DASHPlaylist.mpd',
+                    'ext': 'm4a',
+                    'format_id': 'AUDIO-1',
+                    'format_note': 'DASH audio',
+                    'container': 'm4a_dash',
+                    'acodec': 'mp4a.40.2',
+                    'vcodec': 'none',
+                    'tbr': 129.87,
+                    'asr': 48000,
+                }, {
+                    'url': 'https://v.redd.it/hw1x7rcg7zl21/DASH_240',
+                    'manifest_url': 'https://v.redd.it/hw1x7rcg7zl21/DASHPlaylist.mpd',
+                    'ext': 'mp4',
+                    'format_id': 'VIDEO-2',
+                    'format_note': 'DASH video',
+                    'container': 'mp4_dash',
+                    'acodec': 'none',
+                    'vcodec': 'avc1.4d401e',
+                    'tbr': 608.0,
+                    'width': 240,
+                    'height': 240,
+                    'fps': 30,
+                }, {
+                    'url': 'https://v.redd.it/hw1x7rcg7zl21/DASH_360',
+                    'manifest_url': 'https://v.redd.it/hw1x7rcg7zl21/DASHPlaylist.mpd',
+                    'ext': 'mp4',
+                    'format_id': 'VIDEO-1',
+                    'format_note': 'DASH video, dav1.10.02',
+                    'container': 'mp4_dash',
+                    'acodec': 'none',
+                    'vcodec': 'avc1.4d401e',
+                    'tbr': 804.261,
+                    'width': 360,
+                    'height': 360,
+                    'fps': 30,
+                }],
+                {},
             ),
         ]
 
diff --git a/test/testdata/mpd/supplemental_codecs.mpd b/test/testdata/mpd/supplemental_codecs.mpd
new file mode 100644
index 0000000000..f005cf4154
--- /dev/null
+++ b/test/testdata/mpd/supplemental_codecs.mpd
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<MPD mediaPresentationDuration="PT54.915S" minBufferTime="PT1.500S" profiles="urn:mpeg:dash:profile:isoff-on-demand:2011" type="static" xmlns="urn:mpeg:dash:schema:mpd:2011" xmlns:scte214="urn:scte:dash:scte214-extensions">
+    <Period duration="PT54.915S">
+        <AdaptationSet segmentAlignment="true" subsegmentAlignment="true" subsegmentStartsWithSAP="1">
+            <Representation bandwidth="804261" codecs="avc1.4d401e" frameRate="30" height="360" id="VIDEO-1" mimeType="video/mp4" scte214:supplementalCodecs="dav1.10.02" startWithSAP="1" width="360">
+                <BaseURL>DASH_360</BaseURL>
+                <SegmentBase indexRange="915-1114" indexRangeExact="true">
+                    <Initialization range="0-914"/>
+                </SegmentBase>
+            </Representation>
+            <Representation bandwidth="608000" codecs="avc1.4d401e" frameRate="30" height="240" id="VIDEO-2" mimeType="video/mp4" startWithSAP="1" width="240">
+                <BaseURL>DASH_240</BaseURL>
+                <SegmentBase indexRange="913-1112" indexRangeExact="true">
+                    <Initialization range="0-912"/>
+                </SegmentBase>
+            </Representation>
+        </AdaptationSet>
+        <AdaptationSet>
+            <Representation audioSamplingRate="48000" bandwidth="129870" codecs="mp4a.40.2" id="AUDIO-1" mimeType="audio/mp4" startWithSAP="1">
+                <AudioChannelConfiguration schemeIdUri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"/>
+                <BaseURL>audio</BaseURL>
+                <SegmentBase indexRange="832-1007" indexRangeExact="true">
+                    <Initialization range="0-831"/>
+                </SegmentBase>
+            </Representation>
+        </AdaptationSet>
+    </Period>
+</MPD>
diff --git a/yt_dlp/extractor/common.py b/yt_dlp/extractor/common.py
index 31c0266d4a..048c542858 100644
--- a/yt_dlp/extractor/common.py
+++ b/yt_dlp/extractor/common.py
@@ -2970,6 +2970,8 @@ class InfoExtractor:
                     content_type = representation_attrib.get('contentType', mime_type.split('/')[0])
 
                     codec_str = representation_attrib.get('codecs', '')
+                    supplemental_codecs = representation_attrib.get(
+                        '{urn:scte:dash:scte214-extensions}supplementalCodecs')
                     # Some kind of binary subtitle found in some youtube livestreams
                     if mime_type == 'application/x-rawcc':
                         codecs = {'scodec': codec_str}
@@ -3025,7 +3027,7 @@ class InfoExtractor:
                             'asr': int_or_none(representation_attrib.get('audioSamplingRate')),
                             'fps': int_or_none(representation_attrib.get('frameRate')),
                             'language': lang if lang not in ('mul', 'und', 'zxx', 'mis') else None,
-                            'format_note': f'DASH {content_type}',
+                            'format_note': join_nonempty(f'DASH {content_type}', supplemental_codecs, delim=', '),
                             'filesize': filesize,
                             'container': mimetype2ext(mime_type) + '_dash',
                             **codecs,