Discussion
Ive noticed on my tv, when ive been watching the euros on bbc hd or itv hd, when theres bright colours moving fast, i.e. football tops or socks, the coloured bit appears to flicker/vibrate.
I also noticed a similar thing on a cookery program where the camera panned over coloured vases.
Is this a normal trait of the hd channels or is my tv faulty, or is my tv just crap?
Tv has a 400mhz refresh rate, unable to change it
I also noticed a similar thing on a cookery program where the camera panned over coloured vases.
Is this a normal trait of the hd channels or is my tv faulty, or is my tv just crap?
Tv has a 400mhz refresh rate, unable to change it
Depends on the underlying tech of the TV (plasma generally does better than LCD, but LCD can vary from awful to OK!) and the amount of effort expended by the manufacturer. You can't rule out the broadcast provider either, so need to assess against similarly paced material via Bluray etc as a comparison.
Also depends how you've got the image setup - if it's on the default settings it can look far worse
Also depends how you've got the image setup - if it's on the default settings it can look far worse
Adrian E said:
Depends on the underlying tech of the TV (plasma generally does better than LCD, but LCD can vary from awful to OK!) and the amount of effort expended by the manufacturer. You can't rule out the broadcast provider either, so need to assess against similarly paced material via Bluray etc as a comparison.
Also depends how you've got the image setup - if it's on the default settings it can look far worse
Its an LED ive got, and ive tried with enhancement settings on or off it makes no difference, hmm.Also depends how you've got the image setup - if it's on the default settings it can look far worse
Worth searching on the avforums site for recommended settings - there's usually a lot you can tweak to improve the colour balance and tone which will improve the look of the picture.
If it's set on vivid or any other factory mode they tend to be too bright for a normal home - they're designed to have loads of 'pop' to the image when viewed in a shop under really bright artificial light, so finding some recommended settings is worth the effort. If the screen is working really hard to appear bright then lag will be more evident on fast moving images
If it's set on vivid or any other factory mode they tend to be too bright for a normal home - they're designed to have loads of 'pop' to the image when viewed in a shop under really bright artificial light, so finding some recommended settings is worth the effort. If the screen is working really hard to appear bright then lag will be more evident on fast moving images
You're either seeing the effects of deinterlacing (turning the i in 1080i into p), and/or the result of chroma subsampling. With a static image, interlaced video works fine. When you introduce motion, each field in effect records a different scene. The deinterlacer in your TV has to try and reconstruct a single image for the display from the two interlaced fields. This is where comb artefacts or blurring come from. This never used to be a problem with CRTs because they used to scan the screen in the pattern of the interlaced fields, and the gradual dimming of each line because of the phosphorescence means that consecutive lines (from the different fields) never appear next to each other at full brightness.
Then throw how colour is encoded into the mix. Freeview HD uses the AVCHD codec and encodes colour (technical chroma) at a lower resolution than luminance. With progressive video, this basically works out that only one colour is applied to a 2x2 pixel region. This reduces the data rate and is done because the eye is more sensitive to luminance.
With interlaced video, however, it gets more complicated because the subsampling is applied to each field, which has half the full vertical resolution. So what you get is actually colour information to be applied to a 2x4 pixel region. This again can lead to artifacts during motion because the colour information is being applied to luminance information that does not match.
It is the heavy lifting that goes on to try and reconstruct the full colour video image for display that is probably falling slightly short and causing the problem you're seeing. It used to be a massive issue on early DVD players.
Then throw how colour is encoded into the mix. Freeview HD uses the AVCHD codec and encodes colour (technical chroma) at a lower resolution than luminance. With progressive video, this basically works out that only one colour is applied to a 2x2 pixel region. This reduces the data rate and is done because the eye is more sensitive to luminance.
With interlaced video, however, it gets more complicated because the subsampling is applied to each field, which has half the full vertical resolution. So what you get is actually colour information to be applied to a 2x4 pixel region. This again can lead to artifacts during motion because the colour information is being applied to luminance information that does not match.
It is the heavy lifting that goes on to try and reconstruct the full colour video image for display that is probably falling slightly short and causing the problem you're seeing. It used to be a massive issue on early DVD players.
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