"uses the MKV and WEBM containers" Maybe, but not exclusively VP9: https://www.webmproject.org/vp9/mp4/ https://www.webmproject.org/vp9/mp4/ (uses 'vp09' & 'v

"uses the MKV and WEBM containers" Maybe, but not exclusively VP9: https://www.webmproject.org/vp9/mp4/ https://www.webmproject.org/vp9/mp4/ (uses 'vp09' & 'vpcC' in the stsd) AV1: https://aomedia.org/wp-content/uploads/2018/09/AV1-ISO-Base-Media-File-Format-Binding-Specification.pdf https://aomedia.org/wp-content/uploads/2018/09/AV1-ISO-Base-... (uses 'av01' & 'av1C' in the stsd) YouTube's AV1 playlist https://www.youtube.com/watch?v=2nXYbGmF3_Q&list=PLyqf6gJt7KuHBmeVzZteZUlNUQAVLwrZS https://www.youtube.com/watch?v=2nXYbGmF3_Q&list=PLyqf6gJt7K... uses mp4 as the container for the av1 (av01.0.05M.08), webm for the VP9 (vp9) ./youtube-dl --list-formats https://www.youtube.com/watch?v=2nXYbGmF3_Q [youtube] 2nXYbGmF3_Q: Downloading webpage [youtube] 2nXYbGmF3_Q: Downloading video info webpage [info] Available formats for 2nXYbGmF3_Q: format code extension resolution note 249 webm audio only DASH audio 55k , opus @ 50k, 1.43MiB 250 webm audio only DASH audio 70k , opus @ 70k, 1.81MiB 171 webm audio only DASH audio 118k , vorbis@128k, 2.99MiB 140 m4a audio only DASH audio 128k , m4a_dash container, mp4a.40.2@128k, 3.65MiB 251 webm audio only DASH audio 133k , opus @160k, 3.38MiB 278 webm 256x144 144p 101k , webm container, vp9, 30fps, video only, 2.57MiB 160 mp4 256x144 144p 109k , avc1.4d400c, 30fps, video only, 1.02MiB 242 webm 426x240 240p 205k , vp9, 30fps, video only, 2.81MiB 133 mp4 426x240 240p 241k , avc1.4d4015, 30fps, video only, 2.27MiB 243 webm 640x360 360p 377k , vp9, 30fps, video only, 5.08MiB 395 mp4 426x240 240p 426k , av01.0.05M.08, 30fps, video only, 3.33MiB 134 mp4 640x360 360p 514k , avc1.4d401e, 30fps, video only, 4.66MiB 244 webm 854x480 480p 696k , vp9, 30fps, video only, 8.29MiB 396 mp4 640x360 360p 751k , av01.0.05M.08, 30fps, video only, 6.04MiB 135 mp4 854x480 480p 989k , avc1.4d401f, 30fps, video only, 8.54MiB 397 mp4 854x480 480p 1175k , av01.0.05M.08, 30fps, video only, 9.86MiB 247 webm 1280x720 720p 1282k , vp9, 30fps, video only, 12.27MiB 136 mp4 1280x720 720p 1675k , avc1.4d401f, 30fps, video only, 14.43MiB 398 mp4 1280x720 720p 2075k , av01.0.05M.08, 30fps, video only, 18.99MiB 248 webm 1920x1080 1080p 2349k , vp9, 30fps, video only, 20.93MiB 137 mp4 1920x1080 1080p 2768k , avc1.640028, 30fps, video only, 23.33MiB 399 mp4 1920x1080 1080p 3759k , av01.0.05M.08, 30fps, video only, 39.32MiB 18 mp4 640x360 medium , avc1.42001E, mp4a.40.2@ 96k, 11.11MiB 43 webm 640x360 medium , vp8.0, vorbis@128k, 16.66MiB 22 mp4 1280x720 hd720 , avc1.64001F, mp4a.40.2@192k (best)