Flying from Vietnam to Canada via Guangzhou.

Do I need to apply for a transit G type or can I just get on the plane in Saigon without any type of Chinese visas. Fly to Guangzhou, get off the plane and wait for my connection (4 hours) and then leave. I would not leave the arrival/departure area.

I do not know if I would need to pass through Immigration/customs after deplaning in Guangzhou.