i think you are having a weak reception on the signal. each image frame in the digital transmission is compressed inside the frame as well as across frames. depending on what bitrate your transmission arrives at you may loose a sub block which creates local pixelation. i'd check the signal strength by monitoring incoming bitrates if you have the tools to do so. many TV viewing software on PC's are able to display bitrates.
perhaps a different antenna or different placement will help.
if they reduce the bitrates and remove bits as part of fitting more content into the frequency they transmit in then you can have issues both with image resolution as well as color/luma. while you wont know for sure until you monitor it indirectly via some kind of tool, this is my suspicion.
the main painpoint with low bit rates of high compression h.264 content is that removal of bits removes the ability to use predictions to anticipate the next block and if content is missing then the decoder cant use speculative algorithms to guess what the next frame should look like and it kind of defaults to just displaying a frozen block.
the standard allows for providers to limit the bit rates as well as the resolution the broadcast in and the decoders will provide backwards compatibility. but the image will typically look like crap. these decisions generally happen if they need to fit content in older equipment or frequencies so they pack them tighter. in a different area the same content may look much better.
its flexible but the end-user experience definately differs...
perhaps a different antenna or different placement will help.
if they reduce the bitrates and remove bits as part of fitting more content into the frequency they transmit in then you can have issues both with image resolution as well as color/luma. while you wont know for sure until you monitor it indirectly via some kind of tool, this is my suspicion.
the main painpoint with low bit rates of high compression h.264 content is that removal of bits removes the ability to use predictions to anticipate the next block and if content is missing then the decoder cant use speculative algorithms to guess what the next frame should look like and it kind of defaults to just displaying a frozen block.
the standard allows for providers to limit the bit rates as well as the resolution the broadcast in and the decoders will provide backwards compatibility. but the image will typically look like crap. these decisions generally happen if they need to fit content in older equipment or frequencies so they pack them tighter. in a different area the same content may look much better.
its flexible but the end-user experience definately differs...
It's fast becoming a success, but not at the consumer level - at the professional level such as digital cinema, museums, control rooms, etc. Agree with you about consumer level, don't see it coming anytime soon. There is still room for improvement on the HD we already have.
That is. Even 1080p is usually more than you can perveice (note that I didn't say good enough, but what your eyes are capable of) if you follow the distance/screen size charts. The problem is the high compression, what we want are less artifacts and more frames per second.
I am very inclined to agree.
But is it the compression that is the basic problem?
Or is it the expansion where we have variability in how the receiver manufacturers implement the decompression?
I've watched this year's Tour de France on Eurosport (I'm a cyclist fan) for the first time since I switched to a LCD TV with a built-in digital decoder and I can say I'm very, very disappointed with the image quality. since there is a lot of aerial shooting from the helicopter, during the mountain stages where large forest areas are seen the artifacts are unbearable. especially considering that all this benefits from what are obvious technological advances.
You're looking at about the hardest thing for video compression to do. Lots of fine detail moving all the time. In the old days it didn't matter because the analog "compression" of PAL, Secam and NTSC was continuous and just threw away all fine detail anyway.
What you are seeing may have looked good at the broadcast truck (maybe), but once it gets squeezed and re-squeezed on its way to you..... well, it ain't pretty. It should be better, but it isn't.
What you are seeing may have looked good at the broadcast truck (maybe), but once it gets squeezed and re-squeezed on its way to you..... well, it ain't pretty. It should be better, but it isn't.
That's exactly where the (good) CRT display/decoder scores points. I didn't watch any of what you mention but know 100% what you mean. Also, and without wishing to cast aspersions on your TV, many "generic" LCD sets(supermarket brand type offerings) are really little more than PC monitors that are not really optimised for the TV role.
CRT displays hung on for a long time in color critical uses, too. Most LCDs are not color accurate (usually the reds are orange). They are getting much better, tho.
Mr. P_P, were you watching HD on your CRT, or standard def? We have a similar problem at work, old analog cameras that looked great on CRT seem noisy and aliased as hell on new digital displays.
Mr. P_P, were you watching HD on your CRT, or standard def? We have a similar problem at work, old analog cameras that looked great on CRT seem noisy and aliased as hell on new digital displays.
Some of the loss of quality of the Tour broadcast was due to loss of signal at source.
I could only watch via standard Digital since ITV4 is only available to me at that resolution.
Most was of acceptable standard, since it was a Live sporting event. I would not mind loss of clarity of moving trees, since I would not be watching the trees.
I could only watch via standard Digital since ITV4 is only available to me at that resolution.
Most was of acceptable standard, since it was a Live sporting event. I would not mind loss of clarity of moving trees, since I would not be watching the trees.
well, as long as the faces are distinguishable, why not 320x240 resolution, maybe 15 fps?
speaking of which, on some scenes, the faces of the riders were pretty much solid color.
my point was that the artifacts are very annoying there and those (images of trees/forests) are typical lossy image compression artifacts, visible with JPEG too. definitely not the ones visible on very dynamic scenes only that you're likely referring to.
but since I don't watch much TV lately...
speaking of which, on some scenes, the faces of the riders were pretty much solid color.
my point was that the artifacts are very annoying there and those (images of trees/forests) are typical lossy image compression artifacts, visible with JPEG too. definitely not the ones visible on very dynamic scenes only that you're likely referring to.
but since I don't watch much TV lately...
I noticed the same problem with grass on a football field. As soon as the camera pans, the grass turns into a perfect billard table. Fine in analogue, horrible in digital.
Perhaps they could improve things by spotting that part of the raw signal is almost random, and telling the decoder to substitute a local random signal with similar statistics. Then grass, trees etc. will look a bit like grass, trees etc. even if not the actual grass, trees etc. in the scene. When the pan stops the decoder can fade back to the actual scene.
Perhaps they could improve things by spotting that part of the raw signal is almost random, and telling the decoder to substitute a local random signal with similar statistics. Then grass, trees etc. will look a bit like grass, trees etc. even if not the actual grass, trees etc. in the scene. When the pan stops the decoder can fade back to the actual scene.
Don't forget that what you're viewing may be squeezed to barest acceptable. We were just talking about that at work. One guy was complaining that as soon as football season starts, the NFL hogs all the bandwidth. When he tries to watch a race on Sunday, even on ESPN, the signal is poor to non-existent.
As for grass on the football pitch, could you really see it in standard def? Or did you just imagine that you saw it?
As for grass on the football pitch, could you really see it in standard def? Or did you just imagine that you saw it?
I didn't follow the tour this year - but asked a video engineer at work who did. He watched it on NBC Sorts here in the U.S. He said no problems overall, and that the aerial shots where "stunning". Only problems he saw we loss of signal from the motorcycle cams in the mountains.
So maybe Eurosport, or someone downstream from there, is re-compressing the signal to make it fit in a tight bandwidth. Seems it looked great here.
So maybe Eurosport, or someone downstream from there, is re-compressing the signal to make it fit in a tight bandwidth. Seems it looked great here.
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