Comparison on video resolutions after uploading to Youtube

This is a reference on the size and resolution differences between original video file and processed by youtube.

From left to right:

Original file:
Source: DJI Osmo Pocket, 1080p 50fps
Type: mov
Size: (span to 3 files, here is the total size) 9.51GB

After merging (the source used for uploading to Youtube):
Source: merged by Quicktime player, 1080p 50fps
Type: mov
Size: 1.68GB (17.7% of original)

After processing by Youtube (the default download option):
Source: Youtube, 720p 25fps
Type: mp4
Size: 295MB (17.6% of uploaded, 3.1% of original)

After processing by Youtube (downloaded via youtube-dl with the best resolution)
Source: Youtube, 1080p 50fps
Type: mp4
Size: 725MB (43.2% of uploaded, 7.6% of original)

Attached a comparison on the information generated by mediainfo cli tool.