wrote:
I just did some tests in Firefox, Opera and Windows Media Player, with Battlefield 5 movie:

https://www.youtube.com/watch?v=Gk_t2Ijn6I8&t=527s

I would pull a copy using youtube-dl.

youtube-dl --list-formats https://www.youtube.com/watch?v=Gk_t2Ijn6I8
[youtube] Gk_t2Ijn6I8: Downloading webpage
[youtube] Gk_t2Ijn6I8: Downloading video info webpage
[youtube] Gk_t2Ijn6I8: Extracting video information
[info] Available formats for Gk_t2Ijn6I8:
format code extension resolution note
140 m4a audio only DASH audio 133k , m4a_dash container, mp4a.40.2@128k, 46.60MiB
160 mp4 256x144 144p 138k , avc1.4d400c, 30fps, video only, 37.14MiB
133 mp4 426x240 240p 311k , avc1.4d4015, 30fps, video only, 83.28MiB
134 mp4 640x360 360p 807k , avc1.4d401e, 30fps, video only, 188.27MiB
135 mp4 854x480 480p 1518k , avc1.4d401f, 30fps, video only, 354.98MiB
136 mp4 1280x720 720p 3057k , avc1.4d401f, 30fps, video only, 720.34MiB
298 mp4 1280x720 720p60 4412k , avc1.4d4020, 60fps, video only, 998.88MiB
137 mp4 1920x1080 1080p 5451k , avc1.640028, 30fps, video only, 1.36GiB
299 mp4 1920x1080 1080p60 7106k , avc1.64002a, 60fps, video only, 1.77GiB
17 3gp 176x144 small , mp4v.20.3, mp4a.40.2@ 24k
36 3gp 320x180 small , mp4v.20.3, mp4a.40.2
18 mp4 640x360 medium , avc1.42001E, mp4a.40.2@ 96k
22 mp4 1280x720 hd720 , avc1.64001F, mp4a.40.2@192k (best)

Format 22 is 766.59MiB in size.

youtube-dl --format 22 https://www.youtube.com/watch?v=Gk_t2Ijn6I8

803827575 Dec 7 20:37 The Last Tiger Battlefield 5-Gk_t2Ijn6I8.mp4

I'm using the copy of youtube-dl I've installed in Mint18.1

Format 298 looks good, but then you'd have to add a sound track to it.
Probably around 1GB of downloads.

Length is 50 minutes.

codec AVC1 H.264/MPEG-4 AVC
codec mp4a: MPEG-4 AAC LC

There's no VP9 listed for that.

Download time on my crappy broadband was 8 minutes 30 seconds.

It's possible you were receiving one of the higher rate videos.
Try using the "properties" in the video window to double-check
what is being sent.

Paul