If you have the upload bandwidth, then upload stuff like cineform or prores (video) + uncompressed audio (wav), afaik youtube will always re-compress everything to many lossy codecs. You can analyze what it may return with a tool like youtube-dl:
youtube-dl -F "https://www.youtube.com/watch?v=QGzxkRileIM"
[youtube] QGzxkRileIM: Downloading webpage
[youtube] QGzxkRileIM: Downloading video info webpage
[info] Available formats for QGzxkRileIM:
format code extension resolution note
249 webm audio only DASH audio 60k , opus @ 50k, 7.45MiB
250 webm audio only DASH audio 77k , opus @ 70k, 9.58MiB
140 m4a audio only DASH audio 129k , m4a_dash container, mp4a.40.2@128k, 20.01MiB
171 webm audio only DASH audio 138k , vorbis@128k, 16.24MiB
251 webm audio only DASH audio 149k , opus @160k, 18.92MiB
278 webm 256x144 144p 97k , webm container, vp9, 30fps, video only, 12.53MiB
160 mp4 256x144 144p 111k , avc1.4d400c, 30fps, video only, 7.09MiB
242 webm 426x240 240p 224k , vp9, 30fps, video only, 21.75MiB
133 mp4 426x240 240p 246k , avc1.4d4015, 30fps, video only, 13.12MiB
243 webm 640x360 360p 420k , vp9, 30fps, video only, 41.92MiB
134 mp4 640x360 360p 633k , avc1.4d401e, 30fps, video only, 33.02MiB
17 3gp 176x144 small , mp4v.20.3, mp4a.40.2@ 24k, 12.34MiB
36 3gp 320x180 small , mp4v.20.3, mp4a.40.2, 33.43MiB
18 mp4 640x360 medium , avc1.42001E, mp4a.40.2@ 96k, 70.03MiB
43 webm 640x360 medium , vp8.0, vorbis@128k, 104.56MiB (best)