That's because what you're seeing is NOT "video lag," it's NETWORK LAG.
As I've said here before (somewhere!): what-you-see on your screen in multiplayer Halo is NOT necessarily what THE SERVER SAYS is reality. (Your system will keep on doing what it THINKS has happened until it hears back from THE SERVER - who's word is golden - that you MISSED (or whatever...)
Whenever YOUR Halo client is "more out-of-whack" than what's to be expected, you'll see this.
Also, if you think about it, this explains why you do NOT get in in LAN games! (All your pings/connectivity is virtually INSTANT, hence, little-to-no network lag!)
What To Do!:
0) Do as is described in this thread to correctly set your Halo Network Setting, and what's more: BE SURE TO CHANGE IT (per profile!) whenever you SWITCH from one NETWORK TYPE TO ANOTHER! (If you're playing with it set to "LAN" ( >10Mb) and you're on a 256kb upload connection, you're WAAAY out of whack!)
1) Go to broadbandreports.com and get Dr. Ping (
see reply #11 in this thread) to check out your latency versus others around you. Bandwidth isn't the only thing that comes into play here....
2) If you have folks over for LAN games and they bring/lug their own systems, have one of THEM hook up to your network and go into a game with you ON THE SAME CONNECTION (with IDENTICAL Halo Network Settings!) and see what you can learn from that!
In the end... There Can Be Only ONE!: The Server Rulz!