View Full Version : High Definition-A brief Discussion
raj1402
15th February 2011, 18:22
Can some one Define what do you mean by High Definition
any video which got resolution of 1280x720 -for 720p
1920x1080- for 1080p is called as High Definition irrespective of the bitrates it got
Scenario-1:
Resolution - 1280 x720p
Bitrate - 1500kbps - 2500kbps
File Size 1/2DVDr- 2.25GB
Scenario -2
Resolution 720x304
Bitrate -3500kbps - 4500kbps
File Size 1DVDr -4.5GB
in scenario1 just because it got HD resolution of 1280x720p its called as HD video?
and in scenario 2 its not HD even though it got higher bitrate for given area!!!
for me second Scenario is considered as better Quality than first
expecting your opinion on this!!!
Regards
Raj1402
nurbs
15th February 2011, 18:43
in scenario1 just because it got HD resolution of 1280x720p its called as HD video?
Yes.
for me second Scenario is considered as netter Quality than first even
That's debatable, it depends on the content. 2.5 Mbps isn't too low for many HD sources, it's about in the middle of the bitrate range my own 720p CRF 21 encodes come out, and the first video has 4 times the number of pixels than the second. The downsizing also destroys some details and higher resolutions generally don't need proportionally higher bitrate to look good (e.g video 1 has 4 times more pixels than video 2, but you need less than 4 times the bitrate of video 2 to get the same subjective quality). Downscaling makes sense when you don't have much bitrate available, but unless the encode is really starved it can be better to keep the higher resolution.
Ghitulescu
15th February 2011, 21:04
Can some one Define what do you mean by High Definition
A sinple google could have answered you -> http://en.wikipedia.org/wiki/High-definition_video
Scenario-1:
Resolution - 1280 x720p
Bitrate - 1500kbps - 2500kbps
File Size 1/2DVDr- 2.25GB
Scenario -2
Resolution 720x304
Bitrate -1500kbps - 2500kbps
File Size 1/2DVDr -2.25GB
for me second Scenario is considered as better Quality than first
Quality is personal. And is to be judged on real samples, not on figures.
Besides bitrate is not a definition for quality. A static image (like the HDTV demos, with flowers and stuff) may be way better at 2Mbps that a sport event or an action movie at 6Mbps.
mariush
15th February 2011, 22:30
It also highly depends on the content of the video.
If you're recording a video tutorial recording your desktop screen, 2.5 mbps for 720p can be almost (if not) lossless.
But generally, I would consider 720p 2.5 mbps barely High Definition, 4-6 mbps would be HD in my opinion.
720x304 is not HD.
yetanotherid
15th February 2011, 22:50
HD and SD really just define resolutions. I'm not sure how you can say a lower bitrate 720p video isn't HD any more than you could claim a higher bitrate 480p video is high definition. Low quality maybe....
Obviously there's a point where the latter can actually look better than the former, but I've got plenty of 720p TV encodes at around 3000kbps that certainly look way better than the SD versions, so I'm not sure I'd be trying to draw some imaginary bitrate line.
Ghitulescu
16th February 2011, 10:50
HD and SD really just define resolutions. I'm not sure how you can say a lower bitrate 720p video isn't HD ...
720p is a HD format, a HD video is generally characterised by an enhanced optical resolution in comparison to SD.
Any 320x240 pixels youtube video can magically become HD just because it was scaled to 1280x720? Or even matted up to 1920x1080 with black borders?
Any HD format allows (or provides the prerequisites) for a HD video to be stored. It does not transform any video into a HD one. In mathematical language it is necessary but not sufficient. That's the trick they use in selling crappy camcorders - they pack SD optical resolution or even less into a nice FullHD package.
Low bitrate "decorates" the HD video with blocks, so the optical resolution will decrease.
yetanotherid
16th February 2011, 11:12
Any 320x240 pixels youtube video can magically become HD just because it was scaled to 1280x720? Or even matted up to 1920x1080 with black borders?
And painting a pig grey doesn't make it an elephant, but thanks for stating the obvious.
Obviously there's a point where the latter can actually look better than the former, but I've got plenty of 720p TV encodes at around 3000kbps that certainly look way better than the SD versions, so I'm not sure I'd be trying to draw some imaginary bitrate line.
Forgetting the possibility of painting the pig grey, my point was that there's a subjective perception of quality which can't be determined by the bitrate.
2Bdecided
16th February 2011, 11:20
Anything shot native 720p or above and preserved at 720p or above through to the viewer is HD.
BTW, in Australia, 576p is classed as HD by the government when regulating broadcasters and minimum amounts of HD required.
Some people think anything less than 1080-lines isn't HD. But there's no official basis for this.
Cheers,
David.
yetanotherid
16th February 2011, 11:21
720p is a HD format, a HD video is generally characterised by an enhanced optical resolution in comparison to SD.
Any 320x240 pixels youtube video can magically become HD just because it was scaled to 1280x720? Or even matted up to 1920x1080 with black borders?
By scaling a 320x240 pixel YouTube video to 720p are you increasing it's resolution?? No.
What was it I said?
HD and SD really just define resolutions.
GodofaGap
16th February 2011, 11:35
By scaling a 320x240 pixel YouTube video to 720p are you increasing it's resolution?? No.
By some (and common) definitions of resolution, yes you would.
The problem here is if you want to define HD as a practical standard or as some sort of philosophical concept about quality. For the first 2Bdecided answer is clear enough. For the second I predict another 10 page episode of you and Ghitulescu having a go at eachother.
yetanotherid
16th February 2011, 11:54
By some (and common) definitions of resolution, yes you would.
I'll confess I'd completely disagree, but to be honest for the purpose of this discussion I'd have assumed it's generally understood, through the application of common sense, that upscaling a SD video doesn't make it HD and therefore it's not part of this discussion, but maybe that's just me.
The problem here is if you want to define HD as a practical standard or as some sort of philosophical concept about quality.
Well for me quality does come into it, but that's the area where it becomes subjective, I guess.
For the second I predict another 10 page episode of you and Ghitulescu having a go at eachother.
Nah.... not unless we're told we shouldn't be discussing the subject because we shouldn't be converting our discs, or learn how the definition of HD relates to the history of the analogue pixel. ;-)
Sharktooth
16th February 2011, 12:00
High Definition or HD is a sort of trade mark that defines a precise standard for video resolution. Bitrate is not included... so quality is subjective.
However, those words indicates not only the RESOLUTION (otherwise it would have been High Resolution) but the image "definition" too, that is by itself some sort of quality representation.
So, by HD you can assume a video has a higher resolution and quality than standard definition video.
GodofaGap
16th February 2011, 12:08
I'll confess I'd completely disagree
I don't see how you can disagree on the fact that people have been using the term resolution to describe horizontal and vertical pixel count of a video for years? You can just check the Avisynth documentation on their resize filters if you want.
but to be honest for the purpose of this discussion I'd have assumed it's generally understood, through the application of common sense, that upscaling a SD video doesn't make it HD and therefore it's not part of this discussion, but maybe that's just me.
Yeah sure, and that's why I don't understand why you fall for Ghitulescu's "trap". If he wants to state the over-obvious, let him.
yetanotherid
16th February 2011, 12:23
I don't see how you can disagree on the fact that people have been using the term resolution to describe horizontal and vertical pixel count of a video for years? You can just check the Avisynth documentation on their resize filters if you want.
I don't, in principle, but it's an argument of semantics. You can take a SD image and double it's size using some sort of pixel interpolation, but at best you're going to end up with an image of the same quality as the original, you're not going to increase the resolution of the image. But you know all that....
Yeah sure, and that's why I don't understand why you fall for Ghitulescu's "trap". If he wants to state the over-obvious, let him.
Like you're doing now??? :confused:
It's not fair.... now I'm really confused..... :):D
GodofaGap
16th February 2011, 12:26
I don't, in principle, but it's an argument of semantics. You can take a SD image and double it's size using some sort of pixel interpolation, but at best you're going to end up with an image of the same quality as the original, you're not going to increase the resolution of the image. But you know all that....
So what you mean is "definition", not resolution.
Like you're doing now??? :confused:
I'm not responding to him, I'm responding to you saying that resolution is not resolution.
yetanotherid
16th February 2011, 12:33
So what you mean is "definition", not resolution.
No, I mean "real" resolution.
I'm not responding to him, I'm responding to you saying that resolution is not resolution.
I meant me falling for your trap. Obviously my humour meter is a little off... ;)
But no, I'm not saying resolution isn't resolution, I'm saying interpolated resolution isn't resolution. :)
GodofaGap
16th February 2011, 12:49
I meant me falling for your trap. Obviously my humour meter is a little off... ;)
Or mine. ;)
Groucho2004
16th February 2011, 12:50
I'm saying interpolated resolution isn't resolution. :)
Huh? Resolution represents the number of pixels. The content is irrelevant.
Midzuki
16th February 2011, 12:57
High Definition or HD is a sort of trade mark that defines a precise standard for video resolution. Bitrate is not included... so quality is subjective.
However, those words indicates not only the RESOLUTION (otherwise it would have been High Resolution) but the image "definition" too, that is by itself some sort of quality representation.
So, by HD you can assume a video has a higher resolution AND quality than standard definition video.
:goodpost: && :thanks:
yetanotherid
16th February 2011, 13:05
Huh? Resolution represents the number of pixels. The content is irrelevant.
It can't be, otherwise a 320x240 pixel YouTube video to upscaled to 720p would be high definition. :)
Did we just come full circle?
Maybe the content isn't irrelevant?
Groucho2004
16th February 2011, 13:10
It can't be, otherwise a 320x240 pixel YouTube video to upscaled to 720p would be high definition. :)
Did we just come full circle?
Maybe the content isn't irrelevant?
You're obviously not reading the posts you're replying to. "High Definition" has nothing to do with what I stated.
AnonCrow
16th February 2011, 16:11
There is really only one way to take an existing 320x240 video and upscale it to 720p and have it actually increase the quality:
if the QVGA video is shot at a high framerate (120+ fps), and it's upscaled to 720p30 using some fancy spatiotemporal upscaling trickery.
Otoh, by some definitions, even a 16:9 video with a resolution of 64*720 can be called HD (that's sixtyfour, not 640)
Personally (since that is what the OP was asking), I tend to consider almost anything better than DVD resolution HD, but usually draw the line at 960 horizontal OR 600 vertical (actual content, no black borders)
Ghitulescu
16th February 2011, 18:24
For the second I predict another 10 page episode of you and Ghitulescu having a go at eachother.No, no, it's your turn I see :p to discuss this matter with yetanotherid.
yetanotherid
16th February 2011, 18:30
You're obviously not reading the posts you're replying to. "High Definition" has nothing to do with what I stated.
No, I'm reading them, it's just that arguing semantics is really fairly pointless.
yetanotherid
16th February 2011, 18:36
No, no, it's your turn I see :p to discuss this matter with yetanotherid.
Well, eventually the task had to be undertaken by someone who's up to the job. :p
In fact I've kind of given up, so I guess it means he won.
Did you notice I'm arguing the point you made, or did that get by you as well? :stupid:
Groucho2004
16th February 2011, 18:44
No, I'm reading them, it's just that arguing semantics is really fairly pointless.
Sigh. How is it semantics? You wouldn't argue about a square of 10 inches x 10 inches having 100 square inches, would you?
You wrote "I'm saying interpolated resolution isn't resolution". This does not make sense.
"High Definition" is a marketing statement whereas Resolution is something one can quantify.
Edit: As for the OP's question - I think Sharktooth answered this quite eloquently and I don't think there's much to be added.
yetanotherid
16th February 2011, 18:59
Sigh. How is it semantics? You wouldn't argue about a square of 10 inches x 10 inches having 100 square inches, would you?
Of course not. But if for every square inch there's 10 dots, just because I stretch it out to 100 inches it doesn't mean I've got more than 10 real dots per inch.
Edit:.... Well that's not quite right, I maybe should have said it doesn't mean I've still got any more than a line of 100 real dots.
You wrote "I'm saying interpolated resolution isn't resolution". This does not make sense.
See above.
"High Definition" is a marketing statement whereas Resolution is something one can quantify.
The number of pixels is something you can quantify. Maybe instead of thinking I should be using the term definition in preference to resolution, you should consider using the term pixels instead?
10 inches of resolution isn't the same as 100 inches of resolution no matter how much you stretch the 10 inches of resolution and try to fill in the gaps.
Groucho2004
16th February 2011, 19:10
Of course not. But if for every square inch there's 10 dots, just because I stretch it out to 100 inches it doesn't mean I've got more than 10 real dots per inch.
Edit:.... Well that's not quite right, I maybe should have said it doesn't mean you've got any more than a line of 100 real dots.
See above.
The number of pixels is something you can quantify. Maybe instead of thinking I should be using the term definition in preference to resolution, you should consider using the term pixels instead?
10 inches of resolution isn't the same as 100 inches of resolution no matter how much you stretch the 10 inches of resolution and try to fill in the gaps.
I was trying to make a point, the example wasn't necessarily apt.
Now I hope Ghitulescu will take over and I can have dinner.
yetanotherid
16th February 2011, 19:12
I was trying to make a point, the example wasn't necessarily apt.
It worked for me.
Now I hope Ghitulescu will take over and I can have dinner.
Nah.... I'm off too. Maybe tomorrow once he's worked out which side he's on.
ramicio
16th February 2011, 19:39
I would rather watch something that's 720p72 versus 1080p24. The way the eyes see it the 720p72 would be higher resolution than 1080p24.
Mug Funky
17th February 2011, 02:38
resolution is a much older term than would be implied by the world of pixels. it's a term that comes from analog land, where sample rates were irrelevant and not considered, and actual, measurable detail determined the resolution of a system. this is usually done with test charts of converging lines, densitometry measurements (for film), etc.
really, people should be saying "sample rate" when they define an array of pixels like "1920x1080". it says nothing of the resolution of the pictures depicted - it just defines an upper limit to the resolution that can be achieved when all other parts of the chain are perfect.
Ghitulescu
17th February 2011, 08:49
Any HD format allows (or provides the prerequisites) for a HD video to be stored. It does not transform any video into a HD one.
resolution is ... a term that comes from analog land, where sample rates were irrelevant and not considered, and actual, measurable detail determined the resolution of a system. this is usually done with test charts of converging lines, densitometry measurements (for film), etc.
really, people should be saying "sample rate" when they define an array of pixels like "1920x1080". it says nothing of the resolution of the pictures depicted - it just defines an upper limit to the resolution that can be achieved when all other parts of the chain are perfect.
HD per se became, like someone said, a marketing issue. A HD format is however something quantised, something that can be assessed and compared, and more important, assures compatibility. What's inside the HD format, that's another story and this provides the manufacturers with a huge playground for marketing halffacts and halflies. Why would a professional spend 15000€ for a pro model of a HDV camcorder when an entry level consumer HDV has the same format and thus the same resolution :p, at only 2-5% of the price? Because the optical details of the first simply kills the last one...
Planet Earth was taped on 720p which is less than 1Mpixels, yet it's far superior to any home-made FullHD video (more than 2Mpixels) in terms of details (or optical resolution).
smok3
17th February 2011, 09:45
the wikipedia starts so well:
High-definition video or HD video refers to any video system of higher resolution than standard-definition (SD) video
so based on the continent, High Definition is either:
721*577 or 721 x 481
:devil:
(ignoring the analog era)
2Bdecided
17th February 2011, 17:09
High Definition is either:
721*577 or 721 x 481
:devil:
(ignoring the analog era)Oh you youngsters, don't you know that anything with more than a few tens of lines lines is HD...
http://en.wikipedia.org/wiki/High-definition_television#History_of_high-definition_television
Cheers,
David.
raj1402
27th May 2011, 15:14
High Definition or HD is a sort of trade mark that defines a precise standard for video resolution. Bitrate is not included... so quality is subjective.
However, those words indicates not only the RESOLUTION (otherwise it would have been High Resolution) but the image "definition" too, that is by itself some sort of quality representation.
So, by HD you can assume a video has a higher resolution and quality than standard definition video.
well in my opinion HD should include bps too with resolution
here is something i got it from another forum
HD can be considered video which got pixels/bps as 100 - 400
do you ppl accept this?
ramicio
27th May 2011, 15:22
No, I don't accept that. If you want to base the bitrate off the dimensions you are better of using the square root of the area. HD is defined by the vertical resolution, not bitrate. 8,300 kbps for 1080p is also a joke. Why is there an upper cap? Would something 401 pixels/kbps not be HD anymore? HD for video is very very muddled, as there have been mentions of and standards of it since the 1930s. "HD audio" is something very recent, and it's clearly anything over 16/44.1, plain and simple. 24/44.1 is HD, 16/48 is HD.
manono
28th May 2011, 04:07
do you ppl accept this?
Of course not. It's utter nonsense. HD isn't defined by quality (and pixels/bps is only distantly related to quality), but by resolution. Did you learn nothing from the 2-page discussion?
jmac698
29th May 2011, 17:44
Fun discussion.
I think High Definition is a marketing perception; the very word Definition implies some aspect of quality, not strictly resolution.
One can refer to HD standards and official declarations, but I don't think this is really answering the question. HD standards are only partially related to the perception of HD meaning higher definition.
I think what we have here is a layperson trying to come to terms with their perception of what HD is compared to the technical people referring to it in precise terms. I think the technical answer is, they are not the same, I mean that what is technically HD (say, one of the ATSC standards for resolution above 720P), is not necessarily the quality you are expecting.
Sharktooth was perceptive enough to note this ;)
Now try to answer this the other way around - find technical specs which nearly guarantee a perception of quality. I would propose a simple answer to this, any codec with it's -quality preset. For example x264 has been examined in great depth for quality, and it seems to be quite successful. As for bitrate, we'll have to arbitrarily pick a bitrate which can handle the most difficult content and call that a minimum for quality. This would be similar to the famous "transparent" audio quality tests (see Hydrogen audio forums).
Finally, perception and specs can meet in the middle.
As for upscaling, let me point out that some rescale methods create true detail, it's just not accurate detail. I would propose this technical definition:
-It's upscaled with a linear filter, and the new version cannot have frequency components near nyquist - in other words there is no extra detail, it's just blown up. This is definitely not HD in perception.
-It's upscaled with new details, which are artificial and not accurate. This is HD, and I think is probably perceived as HD and high quality even though the details are artificial, unless they are obviously artificial.
-It's upscaled with accurate details recreated somehow (such as super resolution), in a way that's measureably accurate (perceptionally measured like SSIM), then it's also HD, though people will feel it's theoretically better and demand it.
-It's created in high quality, high resolution which is kept through the production process until viewing, or reduced to a suitable high quality format (such as Blu Ray). This is intuitively, without a doubt HD perception-wise, both philosophically and in blind quality measurements.
Even in the last case, the technical picture quality may not be good enough. If you look at BluRay reviews, some get higher video marks, how can that be when the technical quality is excellent? Things like color palette, grain, focus, perhaps some other things add to the perception.
Some of my own perceptions:
-I had an old tube-style SD TV which made the most beautiful picture, I even preferred it (for SD pictures) over my newer LCD HDTV. I think the colors were a lot more accurate (more gamut, better saturation) and the picture was also brighter (more contrast).
-Even though I know it's a "dirty trick", I still like sharpening my videos, they just look better even though I haven' increased resolution.
-Upscaling does work, this whole board is proof of that, and some people are quite happy with the result after a lot of work. The perceived quality has increased quite a bit, probably you could say it's nearly HD.
I should add another thought, I will probably to define HD as "transparent" rather than "high PQ (Production Qualtiy)" as it's often called. This would mean that a high PQ could be displayed without distortion, so that would be HD.
ramicio
29th May 2011, 18:18
Upscaling only adds noise, it doesn't add any useful information, just like your precious Hydrogen Audio Nyquist foolery and their mathematical wizardry thinking that what works on paper applies in the real world. Sharpening is another thing that is preferential, not actually adding quality (to everyone.) Audio and video are two completely different animals, so let's stop comparing them and using the word transparent. HD in the modern time is defined as anything over SD.
jmac698
29th May 2011, 20:11
HD in the modern time is defined as anything over SD
But I agree - you are missing the point, the original question was about the layperson's perception of what HD means, not a question about a technical standard.
Upscaling only adds noise
Upscaling is used in video forensics to read previously unreadable license plate numbers. There's no doubt that we can make a visible, and practical difference in quality. What I think you're saying, is that you would only accept my last definition of HD as your philosophy.
so let's stop comparing them and using the word transparent
I don't see why I can't apply transparent to video, but do you have another term? I think they say perceptionally lossless in video research. Probably transparent would be confusing because it has alternate meanings.
your precious Hydrogen Audio Nyquist foolery
It's not precious to me, I just referred to it offhand. There's no doubt, dozens of people did ABX testing and proved some audio codecs transparent. I participated in one myself, I certainly know that lossy audio can be transparent.
I have some friends that insist that any lossy audio is just not the same even if they can't tell the difference. My sense is that they have a gut feeling that something is less real and organic when processed. I take it as more of a philosophical opinion.
My post contained some technical points that not necessarily everyone will understand; you'd have to see different types of upscaling or you may not realize how good (and bad) it can be.
ramicio
29th May 2011, 20:16
No, they "proved" that their ears & brain couldn't tell a difference. In reality it is far from transparent. It's not hard to tell and ABX test that you can't hear a difference, so I don't even buy their "proof." Where did you get this license plate stuff? CSI on TV? We're talking about deciphering letters. If they can't be resolved then they can't be read. No amount of forensics can change that. Take an image of a letter, shrink it to 1 pixel, and then upscale that back up and try to tell me you can decipher that letter. We're not talking about quality with that forensic stuff, it's just to be able to read a plate, not comfortably watch a video.
smok3
29th May 2011, 20:29
In reality it is far from transparent.
which reality would that be? (maybe from a bat?)
ramicio
29th May 2011, 20:36
You really think bats can make conscious sense of ultrasonic sounds? They don't hear an echo and then think about where it comes from, it's an involuntary mechanism in their brain. Just because an animal can detect a tone doesn't mean they can extract any meaningful information in those tones. This is about lossy vs. lossless. You CANNOT prove that you CANNOT hear a difference. Lossy is for idiots. Idiots also cling to mathematical theorems and think they apply in the real world.
AnonCrow
29th May 2011, 22:42
HD can be considered video which got pixels/bps as 100 - 400
That itself would limit HD video to something that is digital as opposed to analog, encoded in a lossy format
(, and with a format that has any concept of a pixel to begin with).
Even if you increase the range to 32-1024 ,to have any hope of something that your Average Joe consumer
might call 'High Definition' for most sources, without needlessly high bitrate, the lossy codec used would
have to fall somewhere between MPEG1/2/4 and H.264/265 with regard to how well it compresses video.
Take an image of a letter, shrink it to 1 pixel, and then upscale that
If you take only a single image, then yes, there's almost[1] zero chance. When you have multiple images where the car ,the camera or both are moving , resolving a letter slowly starts becoming possible.
[1] surrounding pixels - color of the car , image meta-data, DMV meta-data, etc.
ramicio
29th May 2011, 22:44
You're talking about combining multiple images plus using other known data...what forensics doing stuff like that has to do with upscaling for video playback I have no idea.
jmac698
30th May 2011, 07:36
r,
I think that you are not familiar with image processing and how it works, therefore you don't believe these claims. I'll make a simple explanation for you.
How can a scanner build an image of a picture when it only "sees" one row of pixels at a time? Obviously it scans the many rows and puts them together. So if you want to read a license plate, you merge several frames of video together. The result is a provably, real high resolution image. Here's an example
The original letter A
o
e e
eoe
e e
e e
an unreadable, half-resolution version (the even pixels in this case)
ee
ee
ee
ee
an unreadable, half-resolution version, diferent frame, odd pixels:
o
o
And now we upscale them and put them together:
and o gives o
e e e e
e e o eoe
e e e e
e e e e
Some questions you may have, how do we know that frame 1 has even pixels and frame 2 has odd pixels? We know from measuring how the surrounding images have moved in general. I can show an example of this, but it starts getting more complicated to explain.
And no this isn't from CSI, you can do it yourself, for free, right now, I can give you a list of links to this software. I've used them myself, I wanted to see the same thing.
It's not hard to tell and ABX test that you can't hear a difference, so I don't even buy their "proof."
I'm sorry, I don't understand your sentence. Can you say it a different way? I realize that not all of us have English as a native language.
jmac698
30th May 2011, 07:51
Here's another example, fractal compression. Imagine a field of flowers. Each flower looks about the same, but in different places and positions. If you store just one image of a flower, and then record all their positions, you can recreate the picture artificially from one flower, with an amazing 1000:1 compression. The picture looks real, but it isn't. How do you know that the real flowers were in a slightly different position, or that one flower looked slightly different? You can't tell.
Upscaling based on that would look HD, it's just not the real one.
Here's another example: the nneedi3 plugin, has a type of smart "brain" that recognizes images, and fills in the missing information based on what it should look like. Let's say you have a picture of bricks. It learned in the past what bricks look like (from real HD pictures), and so it upscales and fills in the missing pixels.
It's not easy to explain, but at some level, things look the same - so all bricks look the same, even different ones - when you think about them as lines and textures. So the brain understands what it's looking at. It turns out that is is provably accurate, that is it's filling in the real pixels. It's adding information based on an example, from learning from a lot of videos to teach it.
manono
30th May 2011, 08:00
But I agree - you are missing the point, the original question was about the layperson's perception of what HD means, not a question about a technical standard.
I disagree, although I don't quite catch the distinction you're trying to make. The OP was asking for exactly that - the technical standard. And, once again, Hi-Def has nothing to do with quality, or 'perception', or anything else other than resolution. You can upscale 640x360 to 1920x1080. It may look like crap but it's still Hi-Def (from a Standard-Def source).
Can some one Define what do you mean by High Definition
.
.
.
in scenario1 just because it got HD resolution of 1280x720p its called as HD video?
GodofaGap
30th May 2011, 08:12
You really think bats can make conscious sense of ultrasonic sounds? They don't hear an echo and then think about where it comes from, it's an involuntary mechanism in their brain. Just because an animal can detect a tone doesn't mean they can extract any meaningful information in those tones. This is about lossy vs. lossless. You CANNOT prove that you CANNOT hear a difference.
So you mean to say that you don't understand the purpose of an ABX test?
Lossy is for idiots. Idiots also cling to mathematical theorems and think they apply in the real world.
Lets just say if they wouldn't apply in the real world, you wouldn't be typing any of this unless it were on an old-fashioned mechanical typewriter.
:readfaq::search:
Ghitulescu
30th May 2011, 08:30
So you mean to say that you don't understand the purpose of an ABX test?
Many ABX tests are flawed and many people simply lost the confidence. It's so easy to trick an ABX test, I said it too many times. The only real ABX tests are done internally in a company and they never get public.
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