YouTube gives a full list of recommended bitrates for YouTube uploads right here, and a full record of supported file codecs here.

Youtube video advertisements:

Skippable video advertisements: most size of 12 hours, skippable after 5 seconds

Unskippable video advertisements: max size of 15 or 20 seconds (relying on area)

Bumper video advertisements: most size of 6 seconds

Linkedin shared movies:

Most dimension: 1920 x 1920 (sq.), 1920 x 1080 (panorama), 1080 x 1920 (vertical) 

Minimal dimension: 360 x 360 (sq.), 640 x 360 (panorama), 360 x 640 (vertical) 

Supported side ratios: 16:9, 1:1, and 9:16