What is the time limit for the video when you are the seller?
Not sure this has ever been definitively established.
There are older (grand-fathered) videos that run to 2 minutes. The new Fiverr school of thought seems to favor under 1 minute. You are limited to 30Mb, so a shorter vid heavy with effects will larger than a longer vid light on effects.
From a sales and marketing perspective, the shorter you can make your presentation, the more likely it is to be effective, usually under a minute.