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Old 04-02-2007, 02:18 PM
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Originally Posted by rdjam View Post

Whoa - being format neutral means giving both a chance, since they can use any of the three codecs.

Rabid preconception is still rabid preconception, regardless of what ever new name you want to call it. Saying you're "format neutral" doesn't really distinguish you from the "other" group who root for a pet codec. At the very heart of the matter was the codec, in the first place. So it really doesn't matter if you are format neutral or not, if you are still cheerleading one codec and bashing another.

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Old 04-02-2007, 02:18 PM
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Originally Posted by Mr. Hanky View Post

It sounds more like your gripe is against inherent film media characteristics, than codecs. Both codecs are going to pass the grain through, when used appropriately.

I think what they are pointing out is that VC1 "handles" the grain better, subjectively. I agree with their position on that also. Yes, you can still discern the grain with VC1, but there is no additional "noise" created (in a good VC1 encode) when the codec attempts to represent this noise.

With Mpeg2 (and to some extent AVC), the scenes can become very "noisy" when the codec doesn't handle the grain well. This extra noisiness can be very distracting in the moving images. VC1 can preserve the picture detail well without creating distracting noise from the film grain.

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Essentially, this brief moment in the film will have passed (under normal viewing conditions), and no one will have noticed a difference.

This frame is only one of many. Frames before it and after it also had this additional noise, which becomes distracting. Saying that the rest of the frames would not have this noise also does not make sense.
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Old 04-02-2007, 02:22 PM
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Originally Posted by swanlee View Post

"note that grain is not noise as some people on here incorrectly state."

Using that link look at the right above the car, the clouds clearly show more noise, mosquito noise is the term I hear used more, this is not film grain but actual compression artifacts. Right above the top of the car next to Tom, you can also clearly see this noise which is not film grain. Also the part of the explosion right above tom's knee shows a lot more noise. again not grain but artifact noise which is not apart of the film or the directors intent.

Using that link I don't see more actual detail I see a higher sharpness and I see more crap which should not be there but I do not see more detail, there isn't anything I'm missing on the HD-DVD side. Higher sharpness doesn't mean higher detail in this case it just means more crap that should not be there in the first place.

I totally agree with this - you've hit the nail on the head. When a codec screws up in representing the grain, it creates additional noise that did not exist before - it's VERY easy to spot this accidentally created noise, because it often groups the artifacting into little "blotches" that have vertical or horizontal characteristics in the patterns.
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Old 04-02-2007, 02:26 PM
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Quote:
Originally Posted by Mr. Hanky View Post

Rabid preconception is still rabid preconception, regardless of what ever new name you want to call it. Saying you're "format neutral" doesn't really distinguish you from the "other" group who root for a pet codec. At the very heart of the matter was the codec, in the first place. So it really doesn't matter if you are format neutral or not, if you are still cheerleading one codec and bashing another.

"rabid"? Isn't that another Wii game?

Since when does someone describing what they see, and without a "personalized" approach, "rabid".

Read the above posts back slowly.

1) Poster "x" is describing in an objective manner what they see in each image and dealing with the reasons they prefer one over the other.

2) Poster "y" calls these observations "rabid" and make personal attacks on poster "x"

3) Observer "z" observes conversation and draws their own conclusion...
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Old 04-02-2007, 02:37 PM
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The truth probably lies somewhere in the middle. Neither codec is doing the grain exactly right. One softens it, and the other hardens it.

It also seems to be an increasingly common assertion that you can somehow soften grain w/o losing detail. That seems to be a touch "convenient" for those who are resigned to admit their codec softens grain. The prevailing logic should not be ignored/dismissed that if you are doing any kind or some kind of filtering, whether it pre, post, in-loop, whatever, there will be a corresponding impact to detail. You don't get something for nothing, and if somebody says you can, I would like to see this substantiated somehow before people just recite this as if it is "common knowledge".

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Old 04-02-2007, 02:47 PM
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"The truth probably lies somewhere in the middle. Neither codec is doing the grain exactly right. One softens it, and the other hardens it."

And I prefer the one that softens it, at 1080P your already getting a lot of resolution detail so a little softening to get rid of un needed grain and also not introduce mosquito noise is prefered by me.

"It also seems to be an increasingly common assertion that you can somehow soften grain w/o losing detail. That seems to be a touch "convenient" for those who are resigned to admit their codec softens grain."

From my eyes whatever details may be lost by softening grain and not introducing mosquito noise is a much better result than the alternative. I find it to be a very worthwhile compromise.
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Old 04-02-2007, 02:52 PM
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Originally Posted by Mr. Hanky View Post

The truth probably lies somewhere in the middle. Neither codec is doing the grain exactly right. One softens it, and the other hardens it.

It also seems to be an increasingly common assertion that you can somehow soften grain w/o losing detail. That seems to be a touch "convenient" for those who are resigned to admit their codec softens grain. The prevailing logic should not be ignored/dismissed that if you are doing any kind or some kind of filtering, whether it pre, post, in-loop, whatever, there will be a corresponding impact to detail. You don't get something for nothing, and if somebody says you can, I would like to see this substantiated somehow before people just recite this as if it is "common knowledge".

The average "Grain" in a typical 35 mm film frame is roughly equivalent to 20 megapixels in detail. This would require roughly 10 times the resolution of Hi Definition in order to actually truly resolve each grain.

So 2 megapixel Hidef movies should never actually be showing each bit of grain to the detriment of the viewing experience (since, in reality, the HD pixel can only represent a small sample of the many "bits" of grain that was present in the "area" covered by a single HD pixel. The SUM of the grain represents what we are SUPPOSED to perceive. In reality, with the exception of a few movies where the director used grain for "artistic intent", what is being filmed is more important to the viewer than the film grain. Grain is simply just another artifact of the film medium itself and is usually no more desired than Mpeg artifacting would be on video.

So if a codec tries and fails to replicate grain that is far smaller than a 1920x1080 pixel, and creates additional "noise" as a result of failing, then this is bad, in my view.

This is why films that "overscanned" when they are being telecined look so much better than basic 1920x1080 telecine scans. Film that is scanned at 4K (which is 4 times the resolution of HD) looks great because undesired effects of the film grain is averaged out to it's proper proportion - ie. 4 pixels of the scan are averaged into 1 pixel of the final HD output.

This results in the detail from the grain being preserved without the picture quality being overly affected by the fairly random activity of the actual film grain.

...and is far more pleasing on the eye.

To recap in summary, grain is far smaller than the Hidef format's 1920x1080 resolution. As such, the grain should not be overbearing, since it's effect SHOULD be averaged out in order to leave the true information that the SUM of the grain was supposed to be representing in the first place. Unless the artist actually intended to use the grain to some overt effect, the grain should NOT dominate the picture.

Of course, some may disagree with that...

Now - as far as "filtering" is concerned, this addresses the "other end" of the spectrum. Movie encodes that are overly filtered to "eliminate" grain entirely end up looking much to soft and artificial.

Examples of this are pretty easy to find, since this softening is an "age old" trick to reduce the data rate required by Mpeg2. A good example of this is UltraViolet on Bluray. This was oversoftened and shows it.
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Old 04-02-2007, 02:58 PM
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This is fine, as long as you simply maintain it is your preference, not "evidence" that yours is doing it "right" and anything done differently must be "wrong" with respect to that.

From the purist standpoint, neither is doing it exactly right. One may degrade more "politely", but that is still one step away from what is really there. The other thing may degrade more distinctly, but it attempts to leave the material untouched (as opposed to purposely changing the material with a filter). It's possible the latter is simply mitigated with more bitrate. Why didn't they give it that bitrate in authoring?...probably because they thought the program integrity was, by far, intact, and never anticipated people would actually be studying frames down to the level/quality of the film grain.

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Old 04-02-2007, 03:11 PM
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Quote:
Originally Posted by rdjam View Post

The average "Grain" in a typical 35 mm film frame is roughly equivalent to 20 megapixels in detail. This would require roughly 10 times the resolution of Hi Definition in order to actually truly resolve each grain.

Since the end-use format will be 1080p, then the required Mpix will inherently be constrained. By definition of making a 1080p rendition, you explicitly agree to give up any detail or grain that exists beyond that bandwidth.

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So if a codec tries and fails to replicate grain that is far smaller than a 1920x1080 pixel, and creates additional "noise" as a result of failing, then this is bad, in my view.

You made a faulty assertion here. If the grain is smaller than the pixel, the pixel will be the sampled average of the grains in that locality. There is no contingency that dictates extra noise will be generated due to this.

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This is why films that "overscanned" when they are being telecined look so much better than basic 1920x1080 telecine scans. Film that is scanned at 4K (which is 4 times the resolution of HD) looks great because undesired effects of the film grain is averaged out to it's proper proportion - ie. 4 pixels of the scan are averaged into 1 pixel of the final HD output.

Exactly, so all is well, as long as adequate bitrate is in hand. Also note that grain isn't strictly one size nor completely random, either. So there may very well be grain contributions all along the bandwidth of the media, not just neatly 1 for every 4 pixels. So averaging isn't necessarily going to make all individual grains disappear or blend nicely.

The end result could turn out any number of ways. So it is a bit arrogant for someone to dictate how it should look in the end or that one way is categorically right which makes anything different wrong.

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Old 04-02-2007, 03:12 PM
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Originally Posted by Mr. Hanky View Post

This is fine, as long as you simply maintain it is your preference, not "evidence" that yours is doing it "right" and anything done differently must be "wrong" with respect to that.

From the purist standpoint, neither is doing it exactly right. One may degrade more "politely", but that is still one step away from what is really there. The other thing may degrade more distinctly, but it attempts to leave the material untouched (as opposed to purposely changing the material with a filter). It's possible the latter is simply mitigated with more bitrate. Why didn't they give it that bitrate in authoring?...probably because they thought the program integrity was, by far, intact, and never anticipated people would actually be studying frames down to the level/quality of the film grain.

No probs - just remember that you are paying to watch the movie, not the grain that is (by necessity) required in order to represent the movie.

Given that there may be 10 or 20 "bits" of grain in the original "source" film stock for each "pixel" of a 1920x1080 image, how does one "choose" which "bits" of grain to represent or not. In truth it is the "SUM" of the bits of grain which creates the image for that pixel.

Since much of the telecined video material available is "scanned" from the film at 1920x1080, the scanner itself often only gets a few of these "bits" for that pixel (think of it like scanning a printed magazine page, and seeing artifacts from the print patterns, only more random). As a result, the individual pixels may not truly represent what the actual film may have. The "art and science" of these encoders is trying to determine how much of the "grain variation" is reasonable and how much of it is an artifact of the scanning which should be controlled.

But again, when a film is "overscanned" to a 4K master, these issues are much less of an issue. I'd be willing to bet that AVC would look very similar to VC1 if a 4K master is used to encode the HD release.

But much of the source material used for these BD/HD releases is in 1920x1080, and so there will be "grain artifacting" that must be accounted for.

Remember - grain is an unfortunate artifact of film itself. It is a means to an end, NOT the end result of the means. Unless the director intended the grain to make some sort of visual impact (ie to portray older scenes in a flashback, etc), grain is NOT what we want to see - we want to see the picture. Because of the scanning/telecine process (and they vary in quality) the grain ITSELF can create artifacts in the original source material that are not desirable...
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Old 04-02-2007, 03:20 PM
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My response to you appears in a different post. The post you quoted was a response to swanlee.

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Old 04-02-2007, 03:38 PM
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Originally Posted by Mr. Hanky View Post

Since the end-use format will be 1080p, then the required Mpix will inherently be constrained. By definition of making a 1080p rendition, you explicitly agree to give up any detail or grain that exists beyond that bandwidth.

You made a faulty assertion here. If the grain is smaller than the pixel, the pixel will be the sampled average of the grains in that locality. There is no contingency that dictates extra noise will be generated due to this.

Exactly, so all is well, as long as adequate bitrate is in hand. Also note that grain isn't strictly one size nor completely random, either. So there may very well be grain contributions all along the bandwidth of the media, not just 1 for every 4 pixels. So averaging isn't necessarily going to make all individual grains disappear or blend nicely.

The end result could turn out any number of ways. So it is a bit arrogant for someone to dictate how it should look in the end or that one way is categorically right which makes anything different wrong.

"arrogant", now? Why can't you have discussions without making personalisations?

I think it's clear that you may have missed the meaning of what I posted.

What I am saying applies to the telecine process whereby the film stock is scanned to a digital master - it has nothing to do with any particular codec, but more to do with preventing random bits of grain from being overemphasized to the extend where it compromises the frame.

There is a lot of material on the web to describe this, but here is a "rough" portrayal:

Remember, for the sake of this example, that the distribution of the grains (of each color) are randomly distributed within the area to be sampled...

lets say that a particular area covered by a 1920x1080 "pixel" has 15 specks of grain on it, and the "color" of the pixel should be a particular "shade". I'm going to show the Red, green and Blue specks with the letters RGB. Spaces without pigment and transparent and show white light.

This is an oversimplification, so don't everyone get twitchy - in reality there will be "bits" or "specks" that have multiple colors filtered out to create blacks, etc, and they are not lined up pretty like this...

. . R . . . . R . . . . .B
. . B. . . . . . G. . . . . . G
. . B. . . . G. . . . . . R
. . . R. . . . . . . G. . . . . . B
. . . . G. . . . R. . . . B

I'd love to draw a fancy scope that shows a little "scanner" that doesn't view the whole "clump", but if you visualise a circle that covers a portion of the image, you can see that it will show a slightly different overall value depending on where it lands.

Not only that, but picture that a lot of those values above could be "clumps" of grain from different colors that stuck together during the film processing.

Not only that, but figure that most masters are not made from the original film, but copies. Anyone who has made photographic copies of negatives (I used to have a developing lab) knows that the "grain" from the original mostly doesn't line up with the particles on the new film, so the copy becomes much more "grainy" than the original.

Being able to average the grains or specks which describe the image would be crucial to getting a smooth representation of the image to the end viewer. Grain is NOT good, most of the time - it is simply just an artifact of the medium.

Spatial averaging is pretty standard - but I suspect that there are differences in how particular encoders handle averaging the grain TEMPORAlY - meaning, perhaps, that some encoders track a particular spot in a scene through multiple frames of motion. Some of the superior Video Processors on the market do this already to improve the picture on playback - so it would not be far fetched to assume that the competing encoders may have a few tricks up their sleeves as well.

Is the more "desirable" nature of the VC1 encodes (as expressed by some users here) a direct result of the "codec" or the "encoder"? We don't know.

Right now, one can be forgiven for assuming it is the codec, since most of us agree that the VC1 encodes (on the whole) look better.

But it is also possible that the MS encoder itself is doing a few tricks in the prepocessing to improve the structure of the picture before it is encoded.

All a guess - we can only speculate - but the end result is a very subjective matter. I prefer what I am seeing in the VC1 encodes at this time...

Peace
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Old 04-02-2007, 03:50 PM
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I said it is a bit arrogant for someone to dictate how it should look in the end or that one way is categorically right which makes anything different wrong.

This is in reference to someone who assumes "their" codec must be doing it right, simply because it looks pleasing, and that any other codec that deviates from this look must then be doing it wrong. The reality is that neither is doing it exactly right, just different.

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Old 04-02-2007, 04:10 PM
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"simply because it looks pleasing,"

Isn't that the whole point of HD and codecs in general to look pleasing? If one codec tends to look more pleasing than another does it really matter which one is doing it right or not? I don't care if VC-1 is doing it right, i know from all the movies I own that I tend to like VC-1 transfers alot more. And I'm not like this cause VC-1 is "MY" codec, I don't own any part of VC-1 and have no vested interest in the codec.

I don't care what is used as long as it gives me the best results to my eyes in my home and so far that has been VC-1.

Your creating this strawman argument that simply does not exist. I don't care if one codec is more accurate or which is doing it right or wrong all I care about is which looks better on my TV.
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Old 04-02-2007, 04:19 PM
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Originally Posted by swanlee View Post

Isn't that the whole point of HD and codecs in general to look pleasing?

It may be to some people. Then again, there will be others who seek accuracy. Which one seems more "right" to you or which one is more legitimate a concern is really beyond the scope of this topic. The most you should express in this topic on that end is preference. Going beyond that (making a basis on what codecs should or shouldn't do) requires a healthy lump of presumption. That's all I was trying to say.

You should be aware, however, that oftentimes "accuracy" and "pleasing" are not in agreement. This is not to say that "accuracy" is always unpleasant. It's really saying that accuracy is whatever it is going to be, and whether it is pleasant or not really is an independent factor, altogether. Making things pleasant really opens the door to all sorts of manipulations of the material, because different people will inevitably find different things pleasant. Hopefully, pleasant was achieved much earlier in the chain when it was in the director's hands. When it comes to the various operations thereafter, hopefully, all is needed is accuracy.

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Old 04-02-2007, 04:25 PM
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I'm no fan of MPEG2, but this particular shot of MI3 is a great case study.

To my eyes, the MPEG2 transfer is crisper and more detailed, with more grain.

The VC-1 transfer is cleaner, but softer. Grain is still present, but muted, and it's evident that some detail has been lost in the encoding process.

Unlike other comparisons, I think this is one of those cases where we know the encodes were probably made from identical HD masters, so the question becomes which one is more true to the master, and which one is more aesthetically pleasing?

Things that jump out at me:

VC-1 softness:
Look at the sparks on the lower left corner of the image, directly below the exploding car. The MPEG2 version has much better color contrast on the sparks in the smoke. For that matter, the smoke itself is much more particulate on the MPEG2 version than the VC-1 version.

MPEG2 grain:
Look at the back of the white Dodge. The expanse of the white chassis should be pretty uniform, but it's much less smooth with the MPEG2 encode.

I think this is really the first definitive empirical proof I've personally seen that VC-1 plays some merry tricks with softening to improve aesthetics, but at the cost of detail. It'd be nice to know what the bitrate on the VC-1 encode is in this scene, and how it compares to the MPEG2.

EDIT: Before I get accused of liking MPEG2, let me state here that I'm personally unimpressed with how MPEG2 handles objects in motion, which is an area where I feel both AVC and VC-1 outperform it, and at a better bitrate efficiency.
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Old 04-02-2007, 04:38 PM
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Originally Posted by joshd2012 View Post

From post #12:



Which is Blu-ray and which is HD DVD?

Of course it's the mpeg-2 BRD that is grainy and sharp while the vc-1 HD-DVD that is smooth and not as crisp. I think as we see more comparisons this will come up again and again: VC-1 handles grain by softening it. Mpeg-2 handles grain by introducing artifacts but still leaving the sharpness.
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Old 04-02-2007, 04:43 PM
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Zoom in on the window pillar and just below it to enjoy some artifacts.
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Old 04-02-2007, 06:15 PM
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Hey, congratulations! You found a nasty spot, and I have no idea why it is just that little area in a whole picture that seems to be just fine. You definitely found it, though!

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Old 04-02-2007, 06:58 PM
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Quote:
Originally Posted by Issac Hunt View Post

removing detail from a frame is not a good thing in my opinion. some may prefer that flim grain is removed, and be willing to accept a subsequent loss of fine detail along with that. it's their choice. as i understand it this type of softening of the image is not a pre-requesite of vc-1 use, simply an option at the encoder's disposal. for myself i hope encoders quit monkeying around with the image like this on future vc-1 encodes.


Adding noise to the picture isn't preferable either. That's why Joe Kane suggests adjusting sharpness by starting at 0 and keeping it very near that point.

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Old 04-02-2007, 07:28 PM
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Originally Posted by swanlee View Post

Using this link
http://xylon.haloapplications.com/fo...mpossible3/01/

Great comparison. Since both are sourced from the same master this is a better comparison. The loss of grain and detail between the two is dramatic. Now the mpeg2 version does show more noise however (assuming no noise reduction was done as a preprocess). I wish we had a master frame grab to compare all three. Then we would know just how much grain is "smoothed" over and how much noise is actually on the master.

The only way to give any encode a fair shake is to do a butterfly comparison between the source and master.

I guess the best option would be the sharpness and grain retention of mpeg2 but without objectionable noise. I like the crispness of high bitrate mpeg2 but high motion scenes are more difficult to encode without blocking.

By the way there is no way a smooth image necessarily implies a "transparent" image.
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Old 04-02-2007, 09:10 PM
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If you are looking to nit pik, blow the MI:III bridge pics up to 200%. One of them is loaded with compression artifacts. If you take the now infamous Vatican crop and apply a .9 radius, 125%, 0 threshold unsharp mask to the "soft" version, it now looks very similar to the other.
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Old 04-03-2007, 01:17 AM
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Originally Posted by swanlee View Post

Using that link I don't see more actual detail I see a higher sharpness and I see more crap which should not be there but I do not see more detail, there isn't anything I'm missing on the HD-DVD side. Higher sharpness doesn't mean higher detail in this case it just means more crap that should not be there in the first place.

it's difficult to know what you're talking about with your continued use of non-technical terms. there is clearly more detail in the mpeg2 frame as compared to the vc-1 frame, as has been noted by most posters to this thread. this is not some sort of sharpening of the mpeg2 but an actual loss of detail on the vc-1 enconde. look again at the star or the arches from the first two frames, and it's clear that consistent information (that could not be created via sharpening) is missing from the vc-1 encoded frame.
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Old 04-03-2007, 01:28 AM
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Originally Posted by Kram Sacul View Post

Of course it's the mpeg-2 BRD that is grainy and sharp while the vc-1 HD-DVD that is smooth and not as crisp. I think as we see more comparisons this will come up again and again: VC-1 handles grain by softening it. Mpeg-2 handles grain by introducing artifacts but still leaving the sharpness.

What you refer to as sharp and detailed is actually compression artefacts.
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Old 04-03-2007, 01:47 AM
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^lol
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Old 04-03-2007, 01:53 AM
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Originally Posted by Issac Hunt View Post

it's difficult to know what you're talking about with your continued use of non-technical terms. there is clearly more detail in the mpeg2 frame as compared to the vc-1 frame, as has been noted by most posters to this thread. this is not some sort of sharpening of the mpeg2 but an actual loss of detail on the vc-1 enconde. look again at the star or the arches from the first two frames, and it's clear that consistent information (that could not be created via sharpening) is missing from the vc-1 encoded frame.

Heh! I guess those Mpeg compression artifacts are now called "detail" - wonderful! What will they think of next?

When you have 24 to 60 of these extra-noisey frames per second, you'll see the difference between "detail" and mpeg noise.
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Old 04-03-2007, 02:04 AM
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please point out the mpeg compression artifacts in the comparison pic quoted by josh and kram. we're trying to have a discussion of mpeg2 vs vc-1 encoding performance. what are you trying to do?
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Old 04-03-2007, 02:09 AM
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Originally Posted by kschmit2 View Post

What you refer to as sharp and detailed is actually compression artefacts.

It is loaded with artifacts but why are the points on the "star" much punchier in mpeg-2? What's going on there?

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Old 04-03-2007, 03:30 AM
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That star comparison is very telling.
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Old 04-03-2007, 03:47 AM - Thread Starter
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