For millions of people, that is still 520p.
If you are watching on a phone, traveling, managing a tight data cap, or curating a massive retro library, do not scoff at 520p. It is not about being "good enough." It is about being to match resolution to reality. 520p movies
There is no standard video resolution known as "520p." It's possible that you came across a mislabelled or obscure video file with this resolution. If you meant to ask about a different resolution, feel free to let me know. For millions of people, that is still 520p
Old netbooks, Raspberry Pi 1/2 units, early iPads, and cheap Android TV boxes often choke on 720p but play 520p flawlessly. It is the resolution of functional preservation. There is no standard video resolution known as "520p
The "p" stands for progressive scan, meaning the entire frame is drawn at once (unlike interlaced "i" formats). The number (520) refers to the vertical resolution: 520 horizontal lines of vertical detail. With a standard widescreen aspect ratio (approx. 2.35:1 or 16:9), the actual dimensions usually hover around or 848x520 pixels.
However, assuming you meant to ask about 520p or perhaps movies with a lower resolution or a specific encoding, here's some general information:
Why would someone seek out 520p instead of just going for 720p? The answer usually comes down to three factors: file size, bandwidth, and device compatibility.