Short answer: no. (Unless you want to always cut off top and bottom, even when top and bottom aren't useless black bars, then yeah. I can do that. You probably don't want that, though, in which case it's 'no'.)


Long, technical answer: if you want to auto-fit video, as in "16:9 videos stay the way they are, but 21:9 videos should fit the screen" ... this actually looks potentially possible in theory and I might do it (but absolutely no guarantees that I'll actually do it), but there's a few problems I can see right off the bat:

0. I'd obviously need to have a way to read a column of pixels from the video. Our lord and saviour HTML5/Canvas apparently can do it, but is it even possible to get youtube video to a HTML5 canvas? So far, quick snooping suggest this is possible, but I haven't had any time to actually look at how this is done.

1. Detecting aspect ratio seems simple enough on the surface. Take couple of columns, compare if all columns have an equal amount of black pixels on the top or on the bottom. If yes - congrats, you detected black bars, proceed to correct the aspect ratio.

But there's a problem - a couple of them, in fact. If video starts completely black, you have no way of telling whether the video has the black bars or not. If you watch a movie trailer, should you trust the "This video is rated that" screen for aspect ratio? What about if the bars aren't pitch black, but greyish instead? What if video features two completely solid, horizontal objects at the beginning - imagine a camera looking through a horizontal square hole in the wall? How long and how often you try to detect the aspect ratio when the video is playing? What if video changes aspect ratios midway through, like in the first Hunger Games movie? Or in this video:
https://www.youtube.com/watch?v=4InaygqShwA (starts in 16:9, then goes to 21:9)
Or like in the Dark Souls III trailer, where trailer was 21:9 but got to 16:9 for about 10 seconds at the end of the video (obviously NSFW):
https://www.youtube.com/watch?v=_zDZYrIUgKE

2. Effect on performance. Autodetection could potentially require quite a bit of processing power. This in turn could make the video (or even the browser) to lag.

Now, I've actually been thinking about implementing this feature before, but the problems outlined above are the reason I haven't actually pinky-promised that feature in the "plans for the future" section. I can't guarantee it'll do it, I can't guarantee it'll work at all and I can't guarantee it'll work well.

Besides, my current priorities are:
* making a 'settings' page + configurable shortcuts (hopefully by the end of the month, but currently things aren't going exactly the way I've planned)
* Netflix support (probably by the end of the year, because December looks like a nice month to take advantage of their "you can try it for free for one month" offer)




E: sorry for this wall of text, but Moz seemingly doesn't allow any formatting in the text.