As this blog point out
YouTube started to adopt a new video resolution. They moved from the old standard 4:3 to the new more common 19:9.
I like the new resolution but I’m curious to know what’s the impact in terms of bandwidth for google to switch from the old to the new format.
All the news video seems to be in the new format. I don’t think people is uploading only videos in the new format so I guess google is cropping the new videos like some TV does, while for the old one they’re showing 2 black stripes on the left and right of the video.
One more thing I discovered it that YouTube use his own CDN : ytimg.com to serve video thimbnails