This is a list of formats available for this video: https://www.youtube.com/watch?v=2w5B1Ne-fy4
It's new, from a channel that gets viewers by the millions so it's uploads get transcoded to all available formats
[info] Available formats for 2w5B1Ne-fy4:
format code extension resolution note
139 m4a audio only DASH audio 49k , m4a_dash container, mp4a.40.5@ 48k (22050Hz), 3.46MiB
249 webm audio only DASH audio 57k , opus @ 50k, 3.75MiB
250 webm audio only DASH audio 77k , opus @ 70k, 5.34MiB
171 webm audio only DASH audio 121k , vorbis@128k, 8.22MiB
140 m4a audio only DASH audio 128k , m4a_dash container, mp4a.40.2@128k (44100Hz), 9.23MiB
251 webm audio only DASH audio 143k , opus @160k, 9.52MiB
17 3gp 176x144 small , mp4v.20.3, mp4a.40.2@ 24k
36 3gp 320x180 small , mp4v.20.3, mp4a.40.2
43 webm 640x360 medium , vp8.0, vorbis@128k
18 mp4 640x360 medium , avc1.42001E, mp4a.40.2@ 96k
22 mp4 1280x720 hd720 , avc1.64001F, mp4a.40.2@192k (best)
So this is the best all videos can get transcoded to: opus @160kbps, or aac@192kbps.... all of them vbr, so the actual bitrate changes from one video to another.
Although you can upload flac (and pcm) in hi-res, you don't get hi-res when playing the video, and the original upload is not available to anybody else but google.
And this is what you get on a 480p video with less than 10 views on a really small channel:
format code extension resolution note
139 m4a audio only DASH audio 51k , m4a_dash container, mp4a.40.5@ 48k (22050Hz)
140 m4a audio only DASH audio 130k , m4a_dash container, mp4a.40.2@128k (44100Hz)
160 mp4 192x144 DASH video 108k , avc1.4d400b, 30fps, video only
133 mp4 320x240 DASH video 242k , avc1.4d400c, 30fps, video only
134 mp4 480x360 DASH video 554k , avc1.4d401e, 30fps, video only
135 mp4 640x480 DASH video 1025k , avc1.4d401e, 30fps, video only
17 3gp 176x144 small , mp4v.20.3, mp4a.40.2@ 24k
36 3gp 320x240 small , mp4v.20.3, mp4a.40.2
18 mp4 480x360 medium , avc1.42001E, mp4a.40.2@ 96k
43 webm 640x360 medium , vp8.0, vorbis@128k (best)
128kbps AAC and Vorbis.