[youtube] fixup m4a_dash formats(closes #28165)

diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index ff32758dffd2445ede5e0fdf063a5bc0cf707223..72d9fbbc6f9ecd768c34552d96b5dead0c4b80a3 100644 (file)
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -1603,6 +1603,8 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                     # Youtube throttles chunks >~10M
                     'http_chunk_size': 10485760,
                 }
+                if dct.get('ext'):
+                    dct['container'] = dct['ext'] + '_dash'
             formats.append(dct)
 
         hls_manifest_url = streaming_data.get('hlsManifestUrl')