I find it a bit amusing that the absolute MAXIMUM quality of an NTSC DVD movie is 720 × 480 pixels at 29.97 frames per second. It doesn't matter what cameras were used to film it or what device you use to display it, the format just does not support anything higher.
And that used to be considered high-quality video! It was a big deal for my family when my dad got a great deal on a 480p widescreen TV and we got to experience the full viewing potential of DVDs for the first time!
Compare that to today, where smartphones are being offered with 4K displays so you can stream 3840 × 2160 pixels, 60-frames-per-second videos from YouTube over Wi-Fi (or even cellular networks if you have a good connection).
For reference, here is a frame from the DVD version of Pirates of the Caribbean: The Curse of the Black Pearl displayed at 100% scale in a 4K UHD frame (original image is 3840 × 2160 pixels, which will be downscaled to 2048 × 1152 pixels by Tumblr since that's the widest image they support):
The black bars at the top and bottom of the movie frame are there because this movie, like many major films, was filmed at a 2.39:1 aspect ratio, not the 16:9 of consumer HD video formats, so the actual used resolution of the DVD frame is only 720 × 360 pixels. Those black bars are just wasted space.
You might notice that 720:360 simplifies to 2:1, not 2.39:1, and that DVD's maximum resolution for ostensibly-HD video of 720:480 simplifies to 3:2, not 16:9. This is because DVD video is often not displayed with square pixels, as a holdover from pre-digital television technology. Standard-definition broadcast color television has an aspect ratio of 4:3 with 480 horizontal lines at 29.97 frames per second (59.94 interlaced fields per second). With square pixels, that would have a width of 640 pixels. That fits fine within the frame of a DVD video, leaving 40-pixel-wide black bars on the left and right sides of the digital frame. But for widescreen 16:9 video with 480 horizontal lines, you would need 854 (precisely 853.333..., which usually gets rounded up) pixels, or 134 pixels wider than will fit on a DVD. The DVD video format deals with that by squashing the video horizontally to fit, then telling the TV or computer to display it with a pixel aspect ratio of 1.186:1 to stretch it out to the right size. So if you watched the DVD version of The Curse of the Black Pearl at "full size" on a 4K UHD screen, you'd probably see it like this, at 100% height but 118.6% width:
Slightly wider, but still pretty darn tiny.