Quote:
Originally Posted by
dhan 
Hi
,
I was finally able to see a 58" VT25 under (semi) controlled lighting conditions (not pitch black) and I have to say that the blacks on this TV really impressed me. The VT25 was installed just next to a Pioneer 151FD and, from what I saw, blacks were almost as deep as they were on the Kuro.
One thing bothered me though. All the sets were on the same feed (cable I think) and a show with pretty high contrasts was broadcasted. When the camera was moving/zooming fast in scenes with bright lights on a dark background I was clearly seeing blocks forming in lighter portions of the 58VT25 screen image. Also, stair stepped (aliasing?) diagonal edges were becoming really apparent in some parts of the screen but not on those other sets sitting next to it. It looked like some portions of the screen dropped into low res for a few seconds and just to come back to normal after the action had passed. I remember seeing the a similar issue with camera movements on a Samsung 530 LCD set in a store last year.
Any of you guys ever experienced such a thing with the VT25? I was wondering about what could be causing this issue?
I'm really thinking about buying the 65VT25 but if I see that low resolution macroblocking each time the camera moves fast in high contrast scenes I know it will drive crazy!!
It's not the TV, it's the source. Cable and Satellite services compress the holy heck out of all video signals. Cable does it because their 1 wire into your house and their wire or fiber trunk to their sub-stations can only carry so much data at the same time... they have to run all those channels, on-demand, PPV, telephone service, internet service, etc. on those wires and fibers... something has to give and one of the things that "gives" is the bandwidth allocated to the TV channels. When there's a lot of motion, each frame is different than the next so there's little opportunity for compression by conventional (usually non-destructive) means. So the compression scheme makes the offending frames (pans, explosions, etc.) into big mosaic's of large blocks to minimize the peak in data that those sorts of scenes would need to avoid the block artifacts.
Satellite services use a lot of compression because satellites are expensive to develop and launch and maintain - and because each satellite has a specific bandwidth limit. Their choices (like cable) is to provide a more limited number of channels with full 1080p quality all the time or more channels with something considerably less than 1080p quality all the time... both cable and satellite use more channels as a competitive talking point so we get highly compressed action sequences and pans with a ton of block artifacts.
Blu-ray video is also compressed, but not enough that you should ever see block artifacts from a Blu-ray movie.
In fact, cable and satellite services almost never deliver 1080px1920... so much so that the term "HD Lite" has popped up as a description for what cable and satellite deliver compared to "full" HDTV. Your local broadcast channels may also be delivering "HD Lite" if they have more than 1 digital channel. Each additional channel they deliver robs bandwidth from their primary channel. That means they have to compress the primary programming to get enough bandwidth for their second channel. And if they run a 3rd channel, they have to apply even more compression to the primary channel's programming. We have channels here with 2 and 3 "sub channels" and I'm sure we're not alone. In fact, broadcast channel here has sub-channels so we have no access to full HD network programming over the air and the cable and satellite services compress everything so you won't get full HD from them either. Everything we get is HD Lite except Blu-ray.
Easy fix !
. It was more like a momentary drop in resolution... as if I was watching a low res video on the net for a few sec. The VT25 didn't loose the image content like we can see with a dirty DVD for exemple.
