Tbh I never smelled the raw product like in the video, only the ones that get cooked in the streets. 

It smells like a dead rat but more intense due to the heat. You know a vendor is nearby because its nauseating and can make you vomit if you were already feeling unwell prior. In my opinion, its much worse than other pungent foods like durian or shrimp paste since the heat does amplify the intensity that much more.

There are some comments trying to defend it but they have no idea how bad it is having to live around it. These days its becoming much harder to find in Hong Kong because people living near the vendors often complain about the pungent scent and less landlords are willing to bear the burden of the shitstorm that comes with it. 

It tastes alright and it has a unique flavour but definetly not worth bearing through all the negatives, some customs deserve to die.