That looks like quite a short barrel. I wonder why they've not gone for something with longer range.
I wonder what the cannon is. Vietnam has shown off multiple SP artillery systems before that consisted of an old gun stuck on a new chassis. I suspect, despite the modern-looking armored chassis, that this is more of the same.
EDIT: Another look at the video and the armoring on the truck cabin looks kind of like some of the up-armor kits Russia has been using on their Kamaz trucks in Ukraine. While I doubt it's an export, maybe there's some involvement in the development or sale of tech?
EDIT2: It's a D-20, also known as the 2S3 in self-propelled format. According to this the truck armor is original, which might be true, I don't know.
Vietnam is preparing a presentation of a new self-propelled artillery system based on the Soviet 152 mm D-20 howitzer.
militarnyi.com