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The new enemy of the HD Formats is Noise Reduction!

#121
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1/9/08 at 8:14pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Mark Zimmer
Zodiac is a new offender. Heavy DNR, heavy, heavy, heavy EE. Very disappointing.

I just watched Zodiac on HD-DVD and noticed no EE or DNR, just a crisp, clean, sharp and detailed digital image. Pan's Labyrinth OTOH...

Zodiac was shot digitally with the Viper camera, i.e. no grain. It never looked like film, nor was it intended to. Even in theaters, it was one of the most "digital" looking of the digitally photographed films I've seen.
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#122
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1/9/08 at 10:28pm
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Re: The new enemy of the HD Formats is Noise Reduction!

I totally missed this, I wish Mr. Monce would have asked me direcly:

Quote:
Interesting that in Sam Posten's review of Tremors he states that he can see NO edge enhancement, and a fair amount of normal film grain.

I didnt see any EE on Tremors, but I dont freak out about it as much as some people would when I do see it. I also dont freeze frame movies looking for EE and if you are crazy enough to miss a film because someone posted a screen shot (as some people both here and at AVS reportedly did) then you deserve to miss those films. I enjoy movies and I believe that pixel peeping is the devil. Sure I will point out flaws as I see them but some of you people are NUTS.

I noted some EE in Cat People and nobody else mentioned it, so I dunno. My theater has been run through DVD essentials more than once and I'm blown away by it every day, but it's not ISF calibrated and if I ever spend the money to do so, you all have permission to kick me in the shins with golf cleats. =)

I also believe that lossless audio is pretty cool but I have heard lossy 5.1 that blows away crappy lossless transfers and vice versa. Technology in and of itself is not going to make a better format. It's how the artists and engineers use what they have available that matters. Again, blind devotion to tech specs is not what I want out of Home Theater and those of you who let it get in the way of enjoying this hobby are NUTS and not helping grow any of the formats.

Just MNSHO.

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#123
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1/9/08 at 11:42pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Kyle_D
I just watched Zodiac on HD-DVD and noticed no EE or DNR, just a crisp, clean, sharp and detailed digital image. Pan's Labyrinth OTOH...

Zodiac was shot digitally with the Viper camera, i.e. no grain. It never looked like film, nor was it intended to. Even in theaters, it was one of the most "digital" looking of the digitally photographed films I've seen.
This is just another example that the same arguments we had with SD DVD regarding EE and DNR will continue with HDM. Personally, I'm too much into the film watching to notice any of those issues, unless, it was so pronounced that I couldn't help noticing it.





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#124
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1/10/08 at 12:38am
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Re: The new enemy of the HD Formats is Noise Reduction!

Same for me.

May I also add that some "EE" is regularly present on original film stock, especially as a result of background projection and classic (analog) unsharp-mask techniques? And that there's a fine (but important) line between "noise" (scratches, dust) and film-grain?

EE and DNR are excellent and highly necessary tools, but should be used (as any other processing technique) with due caution.
It's not the devil, therefore.


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#125
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1/10/08 at 3:16am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Cees Alons
EE and DNR are excellent and highly necessary tools, but should be used (as any other processing technique) with due caution.
It's not the devil, therefore.
Cees
I disagree. EE and DNR are at best crutches for issues better solved elsewhere, if they are considered issues at all. EE and DNR as used today on HD are most of the time just distortions of the original image to either
- cater to real or imaginary tastes of the public (I hate grain; I want of out of the window look; I want 3D pop all the time...)
- squeeze more content on one disc and camouflage the consequences of the resulting lower bit rates (can't handle much HF content/motion -> filter; looks too soft now -> enhance; too much blocking -> lower deblocking filter threshold...)
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#126
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1/10/08 at 5:14am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Michel_Hafner
I disagree. EE and DNR are at best crutches for issues better solved elsewhere, if they are considered issues at all. EE and DNR as used today on HD are most of the time just distortions of the original image to either
- cater to real or imaginary tastes of the public (I hate grain; I want of out of the window look; I want 3D pop all the time...)
- squeeze more content on one disc and camouflage the consequences of the resulting lower bit rates (can't handle much HF content/motion -> filter; looks too soft now -> enhance; too much blocking -> lower deblocking filter threshold...)

I think thats an over simplification of the situation. There are times when film transfered to video doesn't look like it does when projected. DNR and EE are excellent tools and are sometimes necessary to get the video representation of the film to look like it does when projected on a screen. Of course like any tool it can be over used and abused, but taking away some of the colorists most valuable tools is not the answer.

Doug
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#127
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1/10/08 at 5:18am
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Re: The new enemy of the HD Formats is Noise Reduction!

I don't like seeing heavy doses of EE and DNR either, but I agree w/ Cees (and Doug). When such techniques/tools are used properly, they should work like good SFX in the original filmmaking process and be transparent to the audience, not draw attention to itself -- well, unless the moviemaker intentionally want an obvious SFX look.

I don't really know from experience, but I suspect the nature of motion picture film and the telecine process itself (and whatever shortfall from the technological ideal) necessitate some judicious use of EE and DNR in many (if not quite all) instances for the best possible presentation. This happens w/ still photography -- even for digital still photography -- so I don't see why it'd be all that different for motion pictures. Of course, "best possible presentation" is a subjective matter though most of us do believe it's best determined by the filmmakers themselves -- and we're not always/often privy to what they really think of specific cases...

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#128
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1/10/08 at 5:25am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Douglas Monce
I think thats an over simplification of the situation. There are times when film transfered to video doesn't look like it does when projected. DNR and EE are excellent tools and are sometimes necessary to get the video representation of the film to look like it does when projected on a screen. Of course like any tool it can be over used and abused, but taking away some of the colorists most valuable tools is not the answer.

Doug

DNR and EE are not valuable tools, care in product from restoration (when needed) thru mastering to encoding what we see on the disc is what needs to be done right, EE and DNR is for lazy folks who are asleep at the wheel and in no way will they ever help a image look like what it should projected, I could possibly see a small and I mean very small amount of slight DNR in very rare cases but EE no way, they both should be long gone because there is no way they can either one be used without altering the image in a bad way, you simply can't use DNR without sacrificing high frequency detail information, when that detail is gone then you are taking away one of the biggest advantages of a HD image, the much higher frequency details over DVD, this is where the natural very faint film grain lay and is why you never see it on SD DVD

Sony is who everyone should be looking at, their BD releases from the past 6 to 9 months are so amazing it is unreal, zero EE, not a hint of DNR, very high bitrate mpeg4 and PCM/TrueHD to boot, they stumbled a little at first but listened to folks like us and now have some amazing product that I am proud to own, on top of that their pricing is splendid, I just paid 18.96$ for Resident Evil at Wally a few days back

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#129
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1/10/08 at 5:32am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Gary Murrell
DNR and EE are not valuable tools, care in product from restoration (when needed) thru mastering to encoding what we see on the disc is what needs to be done right, EE and DNR is for lazy folks who are asleep at the wheel and in no way will they ever help a image look like what it should projected, I could possibly see a small and I mean very small amount of slight DNR in very rare cases but EE no way, they both should be long gone because there is no way they can either one be used without altering the image in a bad way, you simply can't use DNR without sacrificing high frequency detail information, when that detail is gone then you are taking away one of the biggest advantages of a HD image, the much higher frequency details over DVD, this is where the natural very faint film grain lay and is why you never see it on SD DVD

Sony is who everyone should be looking at, their BD releases from the past 6 to 9 months are so amazing it is unreal, zero EE, not a hint of DNR, very high bitrate mpeg4 and PCM/TrueHD to boot, they stumbled a little at first but listened to folks like us and now have some amazing product

-Gary

Sorry Garry to say that Sony is using zero EE or DNR on their releases is to completely miss understand the process of transferring film to video. Some DNR and EE are used on virtually every film that is put on to video. It's just not over used.

Doug
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#130
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1/10/08 at 5:43am
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Re: The new enemy of the HD Formats is Noise Reduction!

please explain, as this is news to me

if DNR/EE is used it is there, or should I say the ill effects of it is

-Gary

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#131
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1/10/08 at 5:56am
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Re: The new enemy of the HD Formats is Noise Reduction!

Gary,

I know you asked Doug, but I'll offer a simple answer based on what I know from still photography.

Basically, the problem is film and the telecine process have not achieved the technological (nor methodological) ideal that you are thinking of. You may think it's a crutch to use EE and DNR, but in practice, it's about producing the bottom line, which is the best presentation possible -- and that does not always (or even often) coincide w/ the ideals you are thinking.

Consider this. In digital still photography, you have the problem of most digital cameras using the Bayer interpolation algorithm/process for imaging. IOW, your 10MP camera isn't actually capturing true 10MP resolution as most people might think. To yield what seems like a 10MP image from said camera, some EE needs to be applied in the image processing. The same things happen when one transfers still film photos to digital images. If still photography works that way, I can definitely see the telecine process needing EE and DNR to some extent as well.

FWIW, I'm definitely *not* one of the serious pixel peepers who demand every digital image to be noise/grain free. Afterall, I use Nikon (and not the new D3) afterall.

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#132
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1/10/08 at 5:57am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Gary Murrell
please explain, as this is news to me

if DNR/EE is used it is there, or should I say the ill effects of it is

-Gary

The raw video of a transfered film doesn't look much like it does in the theater. Of course color and contrast have to be tweaked quite a bit to get it too look right because film has a much wider range from light to dark than video does, and can represent FAR more colors than even HD can. But also depending on the film stock used in the original photography, film grain can cause strange noise on video, even HD video. DNR used carefully can help that situation look more like natural film grain.

In situations where there is extreme contrast in the frame, a very bright object and a shadowy area, the shadow detail can vanish. EE is a useful tool to help bring out that detail. Of course you are right sometimes the tech will get lazy and just leave the EE set at the same level for every shot. Thats when you get images that can end up with ringing around light or dark objects. EE and DNR have to be used carefully but they are VERY valuable tools for getting the image to look right on our home screens. But if used correctly you shouldn't see these tools.

Another thing to take into account is that not everything that you see that looks like EE was done at the telecine step. Sometimes filters will be used on the lens of the camera that can create effects that can look a bit like EE or ringing. in the mid to late 80s when T-grain film stocks were introduced, many DPs thought they looked too sharp because the grain of the film had been so drastically reduced. So many DPs started using filters to take a bit of the sharpness out of it and get the look they were used to seeing. So a film like say The Last Starfighter, that was so criticized for looking soft and having EE, actually looks pretty much the way it was supposed too.

Doug
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#133
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1/10/08 at 6:10am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Douglas Monce
The raw video of a transfered film doesn't look much like it does in the theater. Of course color and contrast have to be tweaked quite a bit to get it too look right because film has a much wider range from light to dark than video does, and can represent FAR more colors than even HD can. But also depending on the film stock used in the original photography, film grain can cause strange noise on video, even HD video. DNR used carefully can help that situation look more like natural film grain.

In situations where there is extreme contrast in the frame, a very bright object and a shadowy area, the shadow detail can vanish. EE is a useful tool to help bring out that detail. Of course you are right sometimes the tech will get lazy and just leave the EE set at the same level for every shot. Thats when you get images that can end up with ringing around light or dark objects. EE and DNR have to be used carefully but they are VERY valuable tools for getting the image to look right on our home screens. But if used correctly you shouldn't see these tools.

Another thing to take into account is that not everything that you see that looks like EE was done at the telecine step. Sometimes filters will be used on the lens of the camera that can create effects that can look a bit like EE or ringing. in the mid to late 80s when T-grain film stocks were introduced, many DPs thought they looked too sharp because the grain of the film had been so drastically reduced. So many DPs started using filters to take a bit of the sharpness out of it and get the look they were used to seeing. So a film like say The Last Starfighter, that was so criticized for looking soft and having EE, actually looks pretty much the way it was supposed too.

Doug

Hehheh... Yeah, what he said. BTW, EE and DNR was -- and still can be -- a very hot topic in the digital still photography world. It (along w/ some of the other issues Doug mentioned, eg. contrast and color) gets brought up in discussion forums just about everytime someone buys an expensive dSLR for the first time and asks questions about "why my images look worse than my old $200 digicam".

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#134
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1/10/08 at 6:47am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
EE and DNR are excellent and highly necessary tools, but should be used (as any other processing technique) with due caution.
It's not the devil, therefore.

Hmmm. Maybe RAH should chime in...

I think we can all agree with you that digital tools can often be used to correct problems on film masters. Cees, correct me if I'm wrong but I think that's what you're saying in your statement above. And "due caution" should mean that when all is said and done, the most ardent cinephile can't detect that his film-image has been "processed" because it should look perfectly natural (like a perfectly restored film print).

I think that the point cinefiles are making in this thread is that when you watch the result, if you can *see the artifacts* of EE or DNR in the digital signature, then it's a problem.

I hope we can all agree on that.

Note: DNR done "right" is very, very expensive and it typically describes what happens when LDI/DTS-digital images spends top dollar. This is very rare, and often controversial even when done with the best of intentions. EE, however, NEVER has a place in HD media. It's a fake sharpening tool try try to make low-resolution SD formats have more "snap" by adding false edge-contours that aren't there. With HD, you can see the film as it was intended to look. If it's soft, it should be soft. If it's sharp, it should be sharp. It's not up to the tech behind the wheel of a console with lots of dials to change what the director wanted you to see.
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#135
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1/10/08 at 6:53am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by DaViD Boulet
Hmmm. Maybe RAH should chime in...

I think we can all agree with you that digital tools can often be used to correct problems on film masters. Cees, correct me if I'm wrong but I think that's what you're saying in your statement above. And "due caution" should mean that when all is said and done, the most ardent cinephile can't detect that his film-image has been "processed" because it should look perfectly natural (like a perfectly restored film print).

I think that the point cinefiles are making in this thread is that when you watch the result, if you can *see the artifacts* of EE or DNR in the digital signature, then it's a problem.

I hope we can all agree on that.

I absolutely agree with this David. These tools should be used to try and make the images look as close to the original as possible with out exaggerating anything. Properly used they should be invisible.

I will disagree with your added note. EE is also a very valuable tool and often images on video couldn't look like they do in the theater with out it. Even in HD. Again when done right you shouldn't see the EE.

Doug
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#136
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1/10/08 at 7:25am
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Re: The new enemy of the HD Formats is Noise Reduction!

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#137
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1/10/08 at 8:13am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by DaViD Boulet
EE, however, NEVER has a place in HD media. It's a fake sharpening tool try try to make low-resolution SD formats have more "snap" by adding false edge-contours that aren't there. With HD, you can see the film as it was intended to look. If it's soft, it should be soft. If it's sharp, it should be sharp. It's not up to the tech behind the wheel of a console with lots of dials to change what the director wanted you to see.


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#138
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1/10/08 at 10:31am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Mark Zimmer
QFT

I say the same for DNR as well, if a particular print wanting to be used is severly grainy, meaning not what was intended then it should be scrapped until a better source can be found, people really started to catch on to EE, but DNR is never noticed or mentioned and goes by unchecked

how anyone cannot see the dreadful DNR on Top Gun, Untouchables, Jack Ryan set, Face/Off is beyond me

contrast, greyscale and color tweaking of course, but DNR and EE needed? sorry I just don't buy it, now if one is saying that the process inherent to transferring films to a video source is using DNR and EE to unseen degrees or other methods then whatever so be it, but to lump in all EE and DNR to any degree and say "oh it's part of the process so it's not that bad and can be good" is just plain wrong

if DNR is part of the transfer process then explain to me how we ever see natural true film grain on anything? this grain is so high in detail and frequency that it would never make it past any form of DNR

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#139
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1/10/08 at 11:31am
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Gary Murrell
how anyone cannot see the dreadful DNR on Top Gun, Untouchables, Jack Ryan set, Face/Off is beyond me


-Gary
I guess some of us don't have your eye for such defects. Furthermore, I'm not sure I would want your level of awareness in such matters due to it affecting my viewing pleasure too much. What I said is no swipe at you, but sometimes, "ignorance is bliss" for some of us.
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#140
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1/10/08 at 12:44pm
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Re: The new enemy of the HD Formats is Noise Reduction!

I understand that Robert, believe me if I could choose I wouldn't be this way, I have nearly ruined myself being this hard on video

-Gary

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#141
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1/10/08 at 12:53pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Gary Murrell
I say the same for DNR as well, if a particular print wanting to be used is severly grainy, meaning not what was intended then it should be scrapped until a better source can be found, people really started to catch on to EE, but DNR is never noticed or mentioned and goes by unchecked

how anyone cannot see the dreadful DNR on Top Gun, Untouchables, Jack Ryan set, Face/Off is beyond me

contrast, greyscale and color tweaking of course, but DNR and EE needed? sorry I just don't buy it, now if one is saying that the process inherent to transferring films to a video source is using DNR and EE to unseen degrees or other methods then whatever so be it, but to lump in all EE and DNR to any degree and say "oh it's part of the process so it's not that bad and can be good" is just plain wrong

if DNR is part of the transfer process then explain to me how we ever see natural true film grain on anything? this grain is so high in detail and frequency that it would never make it past any form of DNR

-Gary

Why is it so hard to believe that some type/amount of DNR could potentially be needed in the process?

I'm not saying I know that's what's going on -- and I'm sure cases where it yields particularly bad artifacts, etc. would not be desirable at all -- but you're making some pretty big blanket statements about what should and should not be done (or can be possible at all) though.

I think if you've spent some time in still photography (and the processing of such) for instance, you'll see that EE and DNR could very well be needed to some degree. For instance, not all types of DNR are equal or applied at the same stage for digital still photography -- even if we're talking transfering from film to digital, instead of using a digital camera for the source. And don't forget that the process of transfering film to video itself could possbily be adding some noise that needs to be reduced -- I don't really know, but we're just talking hypothetically anyway. It's very possible that we're just splitting hairs here, but we'll probably need an actual telecine guy to tell us what's really going on.

FWIW, I'm not sure if anyone brought this up here, but Kubrick's 2001 also looks like there might be an excessive amount of EE leading to halos (based on a couple sample captures I saw elsewhere), but it might not look like the uglier kind of artifact that we normally notice in this medium. If you showed it to still photography folks, they would probably all wonder what's up w/ the halos. I've never seen the original theatrical projection, so I have no idea if those halos were intended by Kubrick or not. But to me, it looks like a heavy dose of what's sometimes called "local contrast enhancement", which you can easily apply via the unsharp mask in Photoshop (in a way different than how one normally applies sharpening). Does anyone know?

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#142
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1/10/08 at 1:05pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
I'm not saying I know that's what's going on -- and I'm sure cases where it's yield particularly bad artifacts, etc. would not be desirable at all -- but you're making some pretty big blanket statements about what should and should not be done (or possible at all) though. I think if you've spent sometime in still photography (and the processing of such) for instance, you'll see that EE and DNR could very well be needed to some degree. For instance, not all types of DNR are equal or applied at the same stage for digital still photography -- even if we're talking transfering from film to digital, instead of using a digital camera for the source.

If it was applied to the DI before being printed back to film for the theater... anything is fine since that was the director's intent.

but if a film print (or DI) was director-approved to look correct on a 50' theater screen... why in the world does it need to be "noise reduced" for home-theater?

That makes no logical sense.... you're viewing an even *smaller* image at home, which reveals less detail than possible in a 35mm print, and yet you need to "fix" the image to clean it because the original wasn't ok the way it was... even though it was already director-approved for projection on a 50' screen???

Now, obviously things are not so simple if no first, or secong-generation prints or inter-mediates can be located. But what we're establishing here is a logical progression from camera to screen in a normal film-transfer process... and it if was director-approved for a 50" screen, then why does the image need to be additionally filtered for your screen which can't even show you as much detail as was in the original print to begin with?

(ie, we're not talking about air-brushing out ad-hoc film scratches when we talk about DNR, we're talking about an algorithm that's applied to reduce film-grain)
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#143
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1/10/08 at 1:31pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Again, don't forget that the process of transfering film to video could be adding some noise. I don't really know whether such noise is actually noticeable/appreciable, but it's not hard to see that could be the case if the technology for such is not advanced enought to produce completely noise-free transfers.

Also, if there are any need for addition image processing after the transfer, eg. gamma or color correction, etc., there's the possibility that noise or film grain might get accentuated to a degree that needs to be controlled w/ DNR.

Again, these are all just hypothetical things, but it should not be all that surprising if true (for someone who's familiar w/ the processing of still photography in the digital realm).

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#144
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1/10/08 at 3:21pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Man is on the right track here. The whole process of transferring film to video is not a "natural" process.

Film wasn't designed to be seen on a system that has scan lines where information can slip between those lines. Even when you have thousands of scan lines, very small details, like film grain, can slip between those lines and create very strange noise patterns, almost like Moiré patterns, only not that regular. DNR is useful in these situation because it can limit those unexpected noise patterns with out reducing the sharpness of the image. Really the only other option would be to use a de sharpening filter which will effect far more of the image than DNR that looks for specific patterns and levels of noise.

And again edge enhancement is useful for bringing out detail that can be lost because of the limited range of the HD display system. Even HD has a very limited range of light to dark when compared to film, and an extremely limited range of colors when compared to film. EE can help bring out details that get lost because of the limitations of the system.

These tools are used to some extent on virtually every film released on video. Anyone who tells you differently either doesn't really know themselves or is just telling you what you want to hear. And again I'm not talking about things that you see when the film is projected on a screen in the theater, these are things that are caused by the actual process of transferring a film to video and the limitations of that video system.

Of course some producers over use these tools to get the "freshly waxed" look, and that is in my opinion totally wrong. I must say however in the case of The Untouchables, my understanding is that some DNR has been used on the film, I still see fairly normal film grain.

Doug
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#145
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1/10/08 at 3:47pm
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Re: The new enemy of the HD Formats is Noise Reduction!

EE does not bring out lost detail, in fact it limits it or hides it if you will

to quote various websites on the subject of EE in regards to video, I find it interesting that the same idea I said above is in thought, that was my personal opinion that detail is lost:

"In reality, edge enhancement only increases the perceived sharpness. It actually makes the picture less detailed because fine details are covered by the resulting "halo" artifacts.

IMHO, what you are saying about EE is absurd

and speaking of noise reduction, no DNR will ever function without removing sharpness or high frequency detail, it simply isn't possible

speaking on EE, Bjoern Roy is one of my hereos, he has a great article on EE:

Ultimate Guide to 'Edge Enhancement'

-Gary

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#146
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1/10/08 at 3:49pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Film wasn't designed to be seen on a system that has scan lines where information can slip between those lines. Even when you have thousands of scan lines, very small details, like film grain, can slip between those lines and create very strange noise patterns, almost like Moiré patterns, only not that regular.

That's why they filter out high-frequencies *before* the image is scanned to digital (or during) to avoid what we would have called "aliasing" in a digital audio signal. that's part of the "analog to digital" conversion process.

What we're criticizing here isn't the necessary steps needed to produce a 1080p image that's free from aliasing/moire (ie produce a proper film transfer)... What's being criticized here are the DNR algorithms used to further remove natural film-grain details for home-theater eyes to an already-proper digital film transfer.

Also be mindful that most films these days have a D1 that's 2K or 4K. These films are *already* digital... the work has already been done. For the theater this gets printed back to film, and for home-video, just scaled to the proper 1080p resolution (if it's not already 1080p native to begin with). There should be no need to take an image that's already optimized in the digital domain and apply additional noise-reduction during this step.
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1/10/08 at 4:07pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by Gary Murrell
EE does not bring out lost detail, in fact it limits it or hides it if you will

to quote various websites on the subject of EE in regards to video, I find it interesting that the same idea I said above is in thought, that was my personal opinion that detail is lost:

"In reality, edge enhancement only increases the perceived sharpness. It actually makes the picture less detailed because fine details are covered by the resulting "halo" artifacts.

IMHO, what you are saying about EE is absurd

and speaking of noise reduction, no DNR will ever function without removing sharpness or high frequency detail, it simply isn't possible

speaking on EE, Bjoern Roy is one of my hereos, he has a great article on EE:

Ultimate Guide to 'Edge Enhancement'

-Gary


Yes DNR can reduce sharpness to some extent, but not necessarily across the entire frame like a de sharp filter would which would be the other and rather drastic option.

Yes EE could be described a creating fake sharpness, but that only talking about when EE applied with a trowel rather than a fine detail brush, to use a bit of a metaphor here. When EE is used carefully, you won't see it.

Gary I actually do this for a living. I've transfered several films that I was the DP on to video, one of them in high definition. Though I'm not a expert telecine tech, I do know a little bit about what I'm talking about.

Doug
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1/10/08 at 4:12pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by DaViD Boulet
That's why they filter out high-frequencies *before* the image is scanned to digital (or during) to avoid what we would have called "aliasing" in a digital audio signal. that's part of the "analog to digital" conversion process.

What we're criticizing here isn't the necessary steps needed to produce a 1080p image that's free from aliasing/moire (ie produce a proper film transfer)... What's being criticized here are the DNR algorithms used to further remove natural film-grain details for home-theater eyes to an already-proper digital film transfer.

Also be mindful that most films these days have a D1 that's 2K or 4K. These films are *already* digital... the work has already been done. For the theater this gets printed back to film, and for home-video, just scaled to the proper 1080p resolution (if it's not already 1080p native to begin with). There should be no need to take an image that's already optimized in the digital domain and apply additional noise-reduction during this step.


Yeah David I'm not talking about attempts to remove grain, only to tame it when it creates strange effects that were not intended. It doesn't really matter at what point in the process DNR is applied, it is applied to almost every film made in some way or another and not necessarily in every shot. There is just no getting around it.

Also scaling from 4K to 1080 can in itself cause problems. Just because its already digital doesn't mean going from one format to another is seamless.

Doug
"I'm in great shape, for the shape I'm in."
Bob Hope in The Ghostbreakers
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1/10/08 at 5:35pm
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Re: The new enemy of the HD Formats is Noise Reduction!

True.

Quote:
Also scaling from 4K to 1080 can in itself cause problems. Just because its already digital doesn't mean going from one format to another is seamless.

The digital downscaling algorithms can actually do a very good job of preserving greater apparent detail than a direct-1080 scan that relies on HF roll-off (similar to the way 96 kHz a/d conversion decimated to 48 sound better than raw analog-digital 48 kHz). Downscaling does involve making sure high-frequency detail doesn't produce moire/aliasing, but it's typically not the same algorithm as what we refer to as "DNR".
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1/10/08 at 6:11pm
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Re: The new enemy of the HD Formats is Noise Reduction!

Quote:
Originally Posted by DaViD Boulet
True.



The digital downscaling algorithms can actually do a very good job of preserving greater apparent detail than a direct-1080 scan that relies on HF roll-off (similar to the way 96 kHz a/d conversion decimated to 48 sound better than raw analog-digital 48 kHz). Downscaling does involve making sure high-frequency detail doesn't produce moire/aliasing, but it's typically not the same algorithm as what we refer to as "DNR".

You are correct that it's not what most people would call DNR, but it is a method of altering the original image so that the image doesn't create problems in the in the destination format, just as DNR is. Again its just another tool in the toolbox that allows for a high quality presentation.

Frankly if you saw a film that was unprocessed using the selection of tools available, you would probably hit the roof complaining about a sub standard transfer.

Doug
"I'm in great shape, for the shape I'm in."
Bob Hope in The Ghostbreakers
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