YouTube on desktop has recently received an update which introduces the ability for videos to be automatically adjusted to better fit the aspect ratio of the viewer's device, irrespective of the aspect ratio of the original video. As this update is primarily aimed at the desktop experience, this mainly applies to vertical videos that have been uploaded to YouTube.
Previously, YouTube on desktop accommodated vertical videos by placing the video in a pre-set box and filling up the additional space with "black bars." This is the most notable change here as those same videos (as well as other irregular sized/shaped videos including some 16:9 aspect ratio videos) will no longer be surrounded by black bars. Instead, they will now fill up as much of the space as possible, with the remainder of the space filled in white (as shown above), much like the rest of the YouTube experience. In some cases, this may also result in the video being larger, although YouTube says this enlarging wont come at a cost to the video quality.
This is not the first time YouTube has announced a change like this as an almost identical change came through back in March of this year, with the difference being the previous change was aimed at the mobile version of YouTube. Therefore, this latest change not only looks to improve the viewing experience regardless of the aspect ratio in use, but also to ensure the experience received by users is consistent from mobile to desktop. This desktop-focused announcement was made via Google's Product Forums and since then it has garnered a number of complaints, with users suggesting the feature is not quite as ready as it could be. For example, some users are noting that during the enlargement process parts of the video are effectively being cropped from view. While others are complaining of other deformations and/or adjustments that reduce and not improve the viewing experience in general. In either case, the update is understood to now be live for everyone accessing the video-sharing platform on desktop. YouTube has provided a few 'before and after' examples, one of which can be seen below.