Trying a different TV now (32" Sony Bravia. The other was 47" Bravia). I'm going to leave it for awhile and see if the flickering shows up. If not, then the outputs aren't clean on the TV.
The cable says 1.3 on it. I got it off Meritline when they had one of their 3 cable deals.
UPDATE 1: 7 minutes later, no white flickering has shown up on the screen. So it's something with my 47" when I have Deep Color Output on Autmoatic.
UPDATE 2: So, here's what I did today from the beginning (I let the PS3 on for 7-10 minutes since the white flickering started when I left it on for awhile).
On 47" Sony Bravia TV
PS3 displaying in 1080p, HDMI 2 port, Deep Color Output (DCO) on automatic, cheap HDMI cable=white flickering
PS3 displaying in 1080p, Component 2 port, DCO ??? (forget if this was on or off since I think it only applies to HDMI), 3-in-1 component cable=no flickering
PS3 displaying in 720p, HDMI 2 port, DCO Automatic, cheap HDMI=no flickering
PS3 displaying in 1080i, HDMI 2 port, DCO Automatic, cheap HDMI=no flickering
PS3 displaying in 1080p, HDMI 2 port, DCO off, cheap HDMI=no flickering
On 32" Sony Bravia TV
PS3 displaying in 1080p, HDMI 2 port, (DCO) Automatic, cheap HDMI cable=no flickering
PS3 displaying in 720p, HDMI 2 port, DCO Automatic, cheap HDMI=no flickering
PS3 displaying in 1080i, HDMI 2 port, DCO Automatic, cheap HDMI=no flickering
On 47" TV (same one)
PS3 displaying in 1080p, HDMI 1 port, (DCO) on automatic, IXOS HDMI cable =no flickering (This cable connects my sound system to TV. The DVR and DVD player connect into my sound system)
PS3 displaying in 1080p, HDMI 3 port, (DCO) on automatic, cheap HDMI cable=no flickering
And finally, I tried the combination that was giving me a problem before:
PS3 displaying in 1080p, HDMI 2 port, Deep Color Output (DCO) on automatic, cheap HDMI cable
and there was NO white flickering.
So it seems that there was a problem with the 47 incher's HDMI 2 output. And whatever was wrong with it, turning the DCO off fixed it. But for now, there's no more white flickering.
UPDATE 3: I turned my PS3 on with the problem settings (PS3 displaying in 1080p, HDMI 2 port, Deep Color Output (DCO) on automatic, cheap HDMI cable) looking at my trophy list and the white flickering came back. I put it in HDMI 3 and there was none. Put it back in HDMI 2 and it showed up. I sprayed some canned air into the HDMI 2 port. It was flickering but then went away. Though it's since come back.
Whatever the problem, it's something with the HDMI 2 port on my TV. We've had it awhile so I don't know if it's under warranty anymore.