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Screen cap vs crt camera thread
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GREG1292




Joined: 10 Oct 2006
Posts: 417
Location: indiana


PostLink    Posted: Fri May 26, 2017 9:11 pm    Post subject: Screen cap vs crt camera thread Reply with quote


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This will be used to compare screen cap vs crt only for evaluation. Also to see
how close we can come to the source material. This will allow us to see how close
Crt can get to the original source material. Work in progress.
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gregstv




Joined: 27 Aug 2007
Posts: 628
Location: Australia


PostLink    Posted: Fri May 26, 2017 10:58 pm    Post subject: Reply with quote

What is a screen capture? I google it and it's no different to a screen shot. There is a picture on the screen you capture it with a camera and it then is a screen shot. Or are you capturing it on a computer straight from the source and then comparing it to the projected picture?
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racerxnet




Joined: 20 Jun 2007
Posts: 362
Location: Illinois


PostLink    Posted: Fri May 26, 2017 11:10 pm    Post subject: Reply with quote

The latter would be correct

MAK
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gregstv




Joined: 27 Aug 2007
Posts: 628
Location: Australia


PostLink    Posted: Fri May 26, 2017 11:33 pm    Post subject: Reply with quote

How does that work when you are comparing pixel with lines? At least with a screen shot you are taking a picture of the lines using a pixel camera.
Not sure how this could be used to compare the the technologies. But I am probably missing something here.
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mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Fri May 26, 2017 11:47 pm    Post subject: Reply with quote

gregstv wrote:
How does that work when you are comparing pixel with lines? At least with a screen shot you are taking a picture of the lines using a pixel camera.
Not sure how this could be used to compare the the technologies. But I am probably missing something here.


Dude, don't pull your hair out on this one. Have Greg post a screencap to match those shots that he have already posted going back before today, or even the one from Oblivion on the previous page. With that, you'll get to see his calibrated projector mated next to the exact same scene from Oblivion for comparison, and that will give you the best idea of what he's been saying here.
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cmjohnson




Joined: 03 Apr 2006
Posts: 5180
Location: Buried under G90s


PostLink    Posted: Sat May 27, 2017 3:57 am    Post subject: Reply with quote

The difficulty in matching screen caps to images captured of the projected image is that you are adding two more complete imaging systems into the workflow. Each with its own distinctive transfer characteristic.
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mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sat May 27, 2017 1:46 pm    Post subject: Reply with quote

cmjohnson wrote:
The difficulty in matching screen caps to images captured of the projected image is that you are adding two more complete imaging systems into the workflow. Each with its own distinctive transfer characteristic.




And to add, you are also adding an ANALOG video stage and optics (as we know have their weakness at this rate), which means there is source integrity loss...and you would be comparing this to a Digital SCREENCAP, which is totally LOSSLESS.

And of course, the resulting two images will be looking near perfectly alike..Rolling Eyes
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El Duderino




Joined: 23 Jan 2011
Posts: 4627
Location: Portland, OR


PostLink    Posted: Sat May 27, 2017 9:58 pm    Post subject: Reply with quote

I'd suggest calling it a frame buffer grab or capture as that's much more descriptive IMO. There is no screen involved in grabbing an image from the frame buffer memory, so including the name 'screen' to describe it is misleading and confusing as is already evidenced here.

Personally, I don't find much value or reason in isolated camera shots of projected images. I think it's much more telling of the camera rather than the projector. If camera shots were contrasted and compared to the image from the frame buffer in an A/B manner, it could at least be an arbitrator and help settle what/who is closer to that reference. Without a frame of reference, it's like debating taste or art rather than accuracy and fidelity.
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mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sat May 27, 2017 10:41 pm    Post subject: Reply with quote

El Duderino wrote:
I'd suggest calling it a frame buffer grab or capture as that's much more descriptive IMO. There is no screen involved in grabbing an image from the frame buffer memory, so including the name 'screen' to describe it is misleading and confusing as is already evidenced here


Good point. I've also wondered why they "screen" associated with them, when there is no relationship.



Quote:
Personally, I don't find much value or reason in isolated camera shots of projected images. I think it's much more telling of the camera rather than the projector. If camera shots were contrasted and compared to the image from the frame buffer in an A/B manner, it could at least be an arbitrator and help settle what/who is closer to that reference. Without a frame of reference, it's like debating taste or art rather than accuracy and fidelity.


I think we all agree that a reference would be great for verification. This came up several times over years going back. The problem that came from that, was the manipulation (Software enhancing, Darby, etc) of the image to match the reference as much as possible. Not simply showing what it looked like on the screen only. That resulted in shots that looked almost as sharp but looked very unnatural because they were enhanced so much.

The best way to do this would be in a single setting where comparisons came be done and verified as no steroids involved and on agreed upon terms. And this is why the thread basically turned into a post only thread. Any other attempt to use for comparing failed.

and with there being no real way to do the comparisons fairly using the same screen and source, camera, etc. is the reason I just post them for what they are worth. The cameras we use can never capture what is really on the screens anyway. The closer you get to resolving the higher bandwidth, the more difficult it becomes for these cheap cameras to capture it, and without matching cameras or the same camera being used. It really should not be considered fair.

Thanks for sharing this, it was much needed.
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El Duderino




Joined: 23 Jan 2011
Posts: 4627
Location: Portland, OR


PostLink    Posted: Sat May 27, 2017 11:20 pm    Post subject: Reply with quote

mp20748 wrote:
I think we all agree that a reference would be great for verification. This came up several times over years going back. The problem that came from that, was the manipulation (Software enhancing, Darby, etc) of the image to match the reference as much as possible.

If the frame buffer capture was accurate, pure, and unadulterated, this shouldn't be an issue or would be evident when any manipulation was done.

If I have the same BD disk as you do, both our disks would contain the exact same YCbCr traids and proper transform math for the YCbCr triads encoded on our disks into the frame buffer R'G'B' or sRGB should be applied the exact same way yielding the exact same results. If we both capture the same frame with the same proper method and post them in a lossless format, we should have 100% agreement if we diff those two files. If we don't have 100% agreement, then one of use didn't use the proper transform or used some image manipulation etc. If our frame buffer files don't agree, we can show the diff in objective terms of RGB triads rather than subjective terms like the green in my leaves aren't correct or the blacks in your background shadow details have more depth.
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mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 2:10 am    Post subject: Reply with quote

El Duderino wrote:
mp20748 wrote:
I think we all agree that a reference would be great for verification. This came up several times over years going back. The problem that came from that, was the manipulation (Software enhancing, Darby, etc) of the image to match the reference as much as possible.

If the frame buffer capture was accurate, pure, and unadulterated, this shouldn't be an issue or would be evident when any manipulation was done.

If I have the same BD disk as you do, both our disks would contain the exact same YCbCr traids and proper transform math for the YCbCr triads encoded on our disks into the frame buffer R'G'B' or sRGB should be applied the exact same way yielding the exact same results. If we both capture the same frame with the same proper method and post them in a lossless format, we should have 100% agreement if we diff those two files. If we don't have 100% agreement, then one of use didn't use the proper transform or used some image manipulation etc. If our frame buffer files don't agree, we can show the diff in objective terms of RGB triads rather than subjective terms like the green in my leaves aren't correct or the blacks in your background shadow details have more depth.


This makes sense, but would the transcoding and conversion on the Blu Ray tilt things towards the Frame Buffer Capture being a much better source and not quite the equal to Blu Ray?
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racerxnet




Joined: 20 Jun 2007
Posts: 362
Location: Illinois


PostLink    Posted: Sun May 28, 2017 4:20 am    Post subject: Reply with quote

mp20748 wrote:
El Duderino wrote:
mp20748 wrote:
I think we all agree that a reference would be great for verification. This came up several times over years going back. The problem that came from that, was the manipulation (Software enhancing, Darby, etc) of the image to match the reference as much as possible.

If the frame buffer capture was accurate, pure, and unadulterated, this shouldn't be an issue or would be evident when any manipulation was done.

If I have the same BD disk as you do, both our disks would contain the exact same YCbCr traids and proper transform math for the YCbCr triads encoded on our disks into the frame buffer R'G'B' or sRGB should be applied the exact same way yielding the exact same results. If we both capture the same frame with the same proper method and post them in a lossless format, we should have 100% agreement if we diff those two files. If we don't have 100% agreement, then one of use didn't use the proper transform or used some image manipulation etc. If our frame buffer files don't agree, we can show the diff in objective terms of RGB triads rather than subjective terms like the green in my leaves aren't correct or the blacks in your background shadow details have more depth.


This makes sense, but would the transcoding and conversion on the Blu Ray tilt things towards the Frame Buffer Capture being a much better source and not quite the equal to Blu Ray?


You are taking the information from the Blu Ray directly when doing a screen capture. The source is the disk and the frame buffer is only a temporary storage of said image for capture purposes/display.

MAK
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El Duderino




Joined: 23 Jan 2011
Posts: 4627
Location: Portland, OR


PostLink    Posted: Sun May 28, 2017 5:35 am    Post subject: Reply with quote

mp20748 wrote:
This makes sense, but would the transcoding and conversion on the Blu Ray tilt things towards the Frame Buffer Capture being a much better source and not quite the equal to Blu Ray?

I don't understand the question. The image information on a BD is encoded in YCbCr format. Most displays use an RGB format so there is a necessary mathematical transcode from YCbCr space to RGB space. If we are going to examine, contrast or compare images on an internet based forum like curtpalme.com using a base HTML browser, then the images will be 8-bit RGB based (sRGB) no matter if the source was BD, DVD, or from a camera pointed at a screen as 8-bit sRGB is the default color space for the internet presently.

No display can be more 'accurate' than what is fed to it. One may argue that something looks 'better' or 'more pleasing' in an A/B comparison, but this would then be in realm of the subjective like taste and art and out of the realm of the objective like fidelity and accuracy.
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mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 9:28 am    Post subject: Reply with quote

El Duderino wrote:
The image information on a BD is encoded in YCbCr format


Is this information "pure, and unadulterated" as what you indicated about the Screencap (Frame buffered capture). Are both lossless (no compression). We know there could be mpeg2, mpeg4, VC-1, etc. for the length of the movies we're familiar with.


Quote:
Most displays use an RGB format so there is a necessary mathematical transcode from YCbCr space to RGB space. If we are going to examine, contrast or compare images on an internet based forum like curtpalme.com using a base HTML browser, then the images will be 8-bit RGB based (sRGB) no matter if the source was BD, DVD, or from a camera pointed at a screen as 8-bit sRGB is the default color space for the internet presentl


I follow this point, but still need to distinguish where we are with Blu Ray and Frame Capture. Are they the same source?


Quote:
No display can be more 'accurate' than what is fed to it. One may argue that something looks 'better' or 'more pleasing' in an A/B comparison, but this would then be in realm of the subjective like taste and art and out of the realm of the objective like fidelity and accuracy.


Yes, but let's deal with the source first. Because if one source is a screencap Not even being on the screen (but shown on a monitor) and the other is from Blu Ray projected onto the screen (disk, player, projector, etc), then captured by any camera would the two be equal in quality?

We know there will be something going on when it get to the forum, but that should be the case with both. Are they equal before the forum is my question.

The image (below) is a "screencap" taking directly from a sight and loaded directly to Curtpalm.com. There is no image hosting or software manipulation involved.


Did some searching and did find some that looked more like what I see on my screen.



apocalypto-movie-screencaps.com-5929.jpg
 Description:
 Filesize:  320.89 KB
 Viewed:  10932 Time(s)

apocalypto-movie-screencaps.com-5929.jpg


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Pzyked




Joined: 02 Apr 2017
Posts: 30
Location: Sweden


PostLink    Posted: Sun May 28, 2017 10:39 am    Post subject: Reply with quote

That's why picture compartment are just silly, a picture will not show how good or bad your projector is.
Its more to how good you are with your camera and adjustments. You can use many tricks like, small screen 50-80 inch, maximum over scan to get sharper pictures on CRT. Adjust in photo program after taken picture then sharpness, color, contrast, details, shadows so the picture are closer to the screen cap and much better than in real. So why bother?
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redfox001




Joined: 16 Mar 2009
Posts: 2251
Location: The Netherlands


PostLink    Posted: Sun May 28, 2017 10:45 am    Post subject: Reply with quote

I do not want to make a clame what crt projector is better but screenshots are big lies let me tell you that. I can make every projector look good by using the right exposure time. I can make it have a very high contrast while there actual pictures is dimm. Also noise is suppressed in most cameras. So choose your camera (not a phone camera), user right exposure and a tripod and voila you got your marvelous pictures coming out.
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701s->runco933->8500ultra->hd1->hd350->vw100->cinemax+919sp+3x919+9500mp->cinemax+919sp(modded)+kuro600a
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mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 11:06 am    Post subject: Reply with quote

Pzyked wrote:
That's why picture compartment are just silly, a picture will not show how good or bad your projector is.
Its more to how good you are with your camera and adjustments. You can use many tricks like, small screen 50-80 inch, maximum over scan to get sharper pictures on CRT. Adjust in photo program after taken picture then sharpness, color, contrast, details, shadows so the picture are closer to the screen cap and much better than in real. So why bother?


redfox001 wrote:
I do not want to make a clame what crt projector is better but screenshots are big lies let me tell you that. I can make every projector look good by using the right exposure time. I can make it have a very high contrast while there actual pictures is dimm. Also noise is suppressed in most cameras. So choose your camera (not a phone camera), user right exposure and a tripod and voila you got your marvelous pictures coming out.



I'm in agreement with you both 100% and we know this from experience and what has been demonstrated so many time over the years on the various forums. Beyond just pain trickery, there could be an art of knowing what to do to make any display look good to better. Would either of these measures make for a professional evaluation or anything that True requirements can be attached to. The answer to that of course is No. It's basically a performance of either trickery or deception for the most part. And other than for entertainment sake, they could never be used to determine what a setup or projector really looks like.

El Duderino mention of using the caps to compare your own shots to (instead of grabbing others for comparison) does have some merit, though trickery and camera skills would still be important here.
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racerxnet




Joined: 20 Jun 2007
Posts: 362
Location: Illinois


PostLink    Posted: Sun May 28, 2017 3:11 pm    Post subject: Reply with quote

mp20748 wrote:
Pzyked wrote:
That's why picture compartment are just silly, a picture will not show how good or bad your projector is.
Its more to how good you are with your camera and adjustments. You can use many tricks like, small screen 50-80 inch, maximum over scan to get sharper pictures on CRT. Adjust in photo program after taken picture then sharpness, color, contrast, details, shadows so the picture are closer to the screen cap and much better than in real. So why bother?


redfox001 wrote:
I do not want to make a clame what crt projector is better but screenshots are big lies let me tell you that. I can make every projector look good by using the right exposure time. I can make it have a very high contrast while there actual pictures is dimm. Also noise is suppressed in most cameras. So choose your camera (not a phone camera), user right exposure and a tripod and voila you got your marvelous pictures coming out.



I'm in agreement with you both 100% and we know this from experience and what has been demonstrated so many time over the years on the various forums. Beyond just pain trickery, there could be an art of knowing what to do to make any display look good to better. Would either of these measures make for a professional evaluation or anything that True requirements can be attached to. The answer to that of course is No. It's basically a performance of either trickery or deception for the most part. And other than for entertainment sake, they could never be used to determine what a setup or projector really looks like.

El Duderino mention of using the caps to compare your own shots to (instead of grabbing others for comparison) does have some merit, though trickery and camera skills would still be important here.


Mike, I am not knocking El Dude, but we have mentioned using screen caps prior to his explanation and appreciate his contribution. Taking a screen cap and comparing it to your image on screen can help see if details are present or not. Making A DISPLAY LOOK ITS BEST REQUIRES A CALIBRATION. PERIOD. This has been explained by Kal as well. If your calibration is not done then the colors are also an impediment to judging your mods. Your whole proceeds of showing what to look for is compromised. Lumping people into a category of dishonesty because you may think the image is manipulated only limits you in trusting others. I think at the end of the day, if you cannot provide a professional calibration with scientific results to show your improvement, then you are going to lose faith from your followers. Excuses are plenty.

I have taken many very poor shots with my camera and posted what was taken. Some were deleted because of the bad image quality. You cannot take a SDVD and make a sows ass look like a silk purse, there is not enough information in the image to do so. I post what the camera takes, and hope others do as well.

Once again, the screen cap is taken from the Blu Ray disk itself. The results on the display (using the same display), if set up correctly, between the screen cap and player software should look identical.

MAK
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mp20748




Joined: 12 Sep 2006
Posts: 5681
Location: Maryland

TV/Projector: 9500LC Ultra / Super 02 and 03 VIM


PostLink    Posted: Sun May 28, 2017 4:08 pm    Post subject: Reply with quote

racerxnet wrote:

Mike, I am not knocking El Dude, but we have mentioned using screen caps prior to his explanation and appreciate his contribution. Taking a screen cap and comparing it to your image on screen can help see if details are present or not. Making A DISPLAY LOOK ITS BEST REQUIRES A CALIBRATION. PERIOD. This has been explained by Kal as well. If your calibration is not done then the colors are also an impediment to judging your mods. Your whole proceeds of showing what to look for is compromised. Lumping people into a category of dishonesty because you may think the image is manipulated only limits you in trusting others. I think at the end of the day, if you cannot provide a professional calibration with scientific results to show your improvement, then you are going to lose faith from your followers. Excuses are plenty.

I have taken many very poor shots with my camera and posted what was taken. Some were deleted because of the bad image quality. You cannot take a SDVD and make a sows ass look like a silk purse, there is not enough information in the image to do so. I post what the camera takes, and hope others do as well.

Once again, the screen cap is taken from the Blu Ray disk itself. The results on the display (using the same display), if set up correctly, between the screen cap and player software should look identical.

MAK


Other than Kal, very few on here that's really been around awhile disagree with my posting, because they know when I've posted WHY I'm posting them and that to believe that there is a camera out there that will actually convey the proper color coordinance of 6500 through a $100.00 point-and-shoot ain't gonna happen, then that's why so many know and agree with me that 'as been said so many time already' these shots are a WASTE OF TIME.

And to the point of scientific data, how is that possible if you really understand how sensitive a video system is from source the screen. Over the years, as has been these past almost 20 years, the debate seems to always involve those who have not been on the forums long and prefer to deal with Theory.

The most important thing on my mods was said a few days ago here:
jbmeyer13 wrote:


Screenshots are a waste of time. I suppose if you had identical cameras, settings (ISO, exposure, etc.), hosting site you might be able to draw some comparison but then there's the screen material, size and PJ lenses and calibration to account for. So unless all of those variables were constants with the lone variable being the video chain it would be difficult to ascertain any definitive conclusions.

I've seen MP's projector in person (not his most recent mods) but a few years ago and his screenshots never came close to doing justice to what was onscreen


So with the above comments that I agree with 100% how could you go after data or facts from the shots, when it's really NOT POSSIBLE..

To include, and was also said above. My setup looks way better than any shot I've ever posted. And since it is NOT POSSIBLE to capture what is on my screen, why would I get into other means of making that happen, when those of us in the know, know that it's really not possible to properly convey that, plus there is no scientific means to prove what has been posted. And to be honest, we've always known when certain shots have been manipulated. I just would rather remain truthful about what I'm doing opposed to trying to convince of make possible something that I'll never be able to prove really exist on my screen. You'd have to see for yourself. Otherwise I'm only claiming an IDEA of what's on my screen.

My only argument has been, when my shots have been compared or used to show and say my setup is bad - my work is bad. Now that is something you will not see me do to anyone, nor would I be on a mission to make someone or what they do appear bad. That is also why I've never been banned on any forum or giving a warning to be banned.

I have said a many time, just post your work without using someone else to make what you do look better.

And one thing better, I've said this a many time and it is fact. The same original neck boards that are claimed to be so special...well, and this is something Tim Martin knows for a fact. I've been working for one of the engineers of Electrohome all up to two years ago for the past 15 years. Both in my shop and at various locations in the country. We know each other well, and at one time when he visited my shop, he saw my work. And then his comment was "Mike you found the problem wit the neck boards. We have been working on that, and you fixed it - that's great" But no, not only that problem. I've fixed all five of the problems on those boards. Just like what I've done with the Barco 909 tasked they sent me and was also acknowledged by Barco when they sent me out there. So when they brought me on as a consultant, the problems they put before me I solved. That was the case with the neck boards and many other things I've worked on over the many years. So after nearly 20 years of doing this mods, with the past two being thee ONLY period why my work has been challenged as not doing what it should. Included in my saying I've made changes, is also the FACT that I've also improved and fixed both VIM and neck boards, this has also been verify from both Electrohome Engineer as well as Scott the head engineer at VDC, who by the way invited me down there when he was designing the new neck boards. A lot is not known on the forum today, but Mike's claims have not been without much verification ALREADY by the Top guys in video design already. And to add, the same people who challenge my work, are also using my modified VIM.. Rolling Eyes

At least I can redesign and design my own work. And with the above, maybe I'm feeling there should be no need for me to consistently defend what I have ALREADY done and done so for so many years.

My latest is with out doubt my best. What I have on the table right now that I'm slow to turn out is no question above expectations. being able to show that on the forum, not possible. The workmanship and testing is also on a whole another never. And being the guy who has (proven at both manufactures) greatly improved and fixed problems on their work. Why should I try and prove anything beyond that fact, that I have already done so many times.

The real and TRUE upgrade or improvement to these latest mods, a point and shoot camera can't capture...that's really what's meant by "a waste of time"
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Pzyked




Joined: 02 Apr 2017
Posts: 30
Location: Sweden


PostLink    Posted: Sun May 28, 2017 5:05 pm    Post subject: Reply with quote

You can see and take some conclusion from a picture taken from your screen compared to a screen cap, but for the fact cant be compared to see it live, I think we all agree on that. Seen 8" better than 9" on screenshot, for shore not reality. A screen cap might look boring to what some here like. MP20748 don't calibrate, I don't know if he uses c-elements with color or not, and you will see that by his pictures. Also like Kal said, camera skills important.
What is the point of bombing screenshots when goal is, not to get it as close to the source as possible? I will say ?
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