The YouTube desktop site was developed for 16: 9 videos with videos in any other aspect ratio – most often 4: 3 for old TV footage or 9:16 for vertical smart video with black bars until they match 16 : 9 boxes. With a change that Google is currently implementing, these black bars are now being scrapped, and the video box is taking over the aspect ratio of the displayed content instead.
For 4: 3 content this means a bigger picture. It will be both wider and larger and will move the title, description and comments further down the page. With vertical video, the benefits are less obvious – an empty space will open on each side of the video. But even there, removing the black bars will make the video less likely to resize in narrow browser windows. Even 16: 9 videos get a little bigger due to the reduced margins and voids.
You might expect a change that makes videos a bit bigger to be accepted by YouTube users, but the YouTube Help forum that describes the new design The rationale behind it is dissatisfied YouTube users looking to return to the more consistent layout and positioning of the old design.
In a change that should become better known, Google also brings out a dark theme for Android YouTube App The update is still being released. The option is not yet available on my phone. You can, however, see some pictures of the feature at 9to5Google. With this update, the Android app brings in the iOS app and the YouTube website, both of which have had a dark option for some time. For the late-night viewing, the darker look is certainly an improvement.