You can check for Rod Knock by bringing RPMs to 3000, then letting off the gas. If it's a rod, you'll hear it when RPM comes down. Your video sounds like start up rattle from the chain. The positioning of the oil pan is what varies the time it takes for the oil to get up and make pressure. I take it this usually only happens at a cold start? I am also going to assume you have the TSB PI1803W/X (or SC147/SC200) complied with for rod knock?