What's My Vertical‪?‬ 4+

It’s decent but could be better

It’s a decent app however when you have a portrait video you often can’t even see your feet to place when they leave the ground which makes it unusable. I wish the video player would extend because when you put it in landscape mode it doesn’t take into account the scale of the video and only gives you the middle portion of the video

Good app

Dope app. Does what it says and seems very accurate

Buggy, probably inaccurate too

The video frame feature is buggy, doesn’t let you fwd-rew through each frame very well. Sometimes skips A LOT of frames!

Also, nowhere in this app does it ask for weight. I’m no expert in physics but common sense would indicate that a heavier person would spend less time in the air than a lighter person jumping the same height. For example (using an extremity) if you threw a balloon 20 feet into the air and a Basketball 20 feet air, we would expect the Basketball to return to the ground a lot quicker due to the gravitational force being applied to the heavier object being much greater....however they both went the same height!

Developer Response ,

About the buggy frame selection: Yes, sometimes there are problems in very short videos with skipping between frames. Unfortunately, this is a problem of the video codex used by the iPhone, as it seems to use a variable frame rate and takes 2-3 seconds to run stable at a higher frame rate. If you shoot a video that is longer than 5 seconds, there should be no problems.

About the weight:
This is not very intuitive, but weight does really NOT influence hang time. The reason why the balloon in your example is a lot slower is air resistance. In a vacuum, a feather and a piece of lead will fall exactly at the same speed which is determined by gravity. As the difference in air resistance is negligible between two athletes (and impossible to compute anyway) it doesn't make any difference in this use case. You can try this yourself by letting a basketball and medicine ball fall from the same height, they have the same shape but different weights - but will fall to the ground at the same speed.