Blu Vs. DVD screenshots... POTC 2 (i got bored)

[maxmcleod]

Figured I would share with everyone the sheer difference I noticed when my wife wanted to watch POTC 2 on DVD... made my eyes hurt...
There is some bad compression on the shots, and they will take a while to load
big difference if you ask me...

[jw]

Its a DVD did you expect anything more

[Tru-way]

http://www.avsforum.com/avs-vb/showthread.php?t=811102

[maxmcleod]

Originally Posted by Tru-way

http://www.avsforum.com/avs-vb/showthread.php?t=811102

I've seen that before, but to be honest, I don't trust those results, those were taken at their natural resolutions and blown up to size with another program like photoshop...
these that im posting were photographed (due to lack of capture software) and the DVD at SD was only altered by the software that was playing it.
I think its a little more accurate, as you can see its not HORRIBLE but its in need of some blu... haha

The link you posted doesn't look at all like a dvd really looks... its not all blurry, its just lacking details... there is a difference, and my examples show that DVDs don't look that bad, but Bluray definately shows it up in color/detail/contrast/everything

[prerich]

Originally Posted by maxmcleod

I've seen that before, but to be honest, I don't trust those results, those were taken at their natural resolutions and blown up to size with another program like photoshop...
these that im posting were photographed (due to lack of capture software) and the DVD at SD was only altered by the software that was playing it.
I think its a little more accurate, as you can see its not HORRIBLE but its in need of some blu... haha

The link you posted doesn't look at all like a dvd really looks... its not all blurry, its just lacking details... there is a difference, and my examples show that DVDs don't look that bad, but Bluray definately shows it up in color/detail/contrast/everything

Did you do this with WinDVD9 Plus BD with All2HD on? I have some photos of Meet the Robinson's - Blu is the clear winner but WinDVD 9 All2HD wasn't a slouch. I'm going to see if I can get them off of this camera (old SM type memory).

[maxmcleod]

no actually i didn't use all2hd, i should have but was running short of time

I was wanting to try it on a really dark movie, and potc2 was readily on hand, and about as dark as it gets

there is only so much detail there to bring out, i wish i captured the shots of the shark head guy, he was covered in scars on blu, but was hard to see anything on dvd

[syncguy]

It is hard to take an accurate picture of a blu-ray image unless you have a high end digital camera. Perhaps at least 8 mega pixels are needed (based on the Nyquist theorem). It may be argued that even 8 mega pixels are not sufficient. If the resolution of the digital camera is low, it would disadvantage blu-ray in comparison to DVD and therefore the comparison is not fair.

The direct capture technique would give a more faithful reproduction in comparison to a digital photograph of the image (in most cases).

[maxmcleod]

you have a point in theory, but you can CLEARLY see the difference in my shots, and those are only at 6 megapixel, before my crops

Technically you can see the difference in the shots even if they are scaled down, becuase they are a direct comparison with each other...
and actually if you could get a shot of the screen framed perfectly you would need roughly 5-6 megapixel camera to get the full effect.

But for a comparison they need to be played on the same machine same program, same setup to capture... which is what i did...

The link that was posted to the king kong comparison is lacking the same setup for the two shots...

anyway we could argue it all day, just wanted to share what my shots look like from the same program, same screen, same camera, same sized image... Blu wins hands down (duh) and DVD barely makes it worth the time watching the movie.

[syncguy]

Originally Posted by maxmcleod

you have a point in theory, but you can CLEARLY see the difference in my shots, and those are only at 6 megapixel, before my crops

Technically you can see the difference in the shots even if they are scaled down, becuase they are a direct comparison with each other...
and actually if you could get a shot of the screen framed perfectly you would need roughly 5-6 megapixel camera to get the full effect.

But for a comparison they need to be played on the same machine same program, same setup to capture... which is what i did...

The link that was posted to the king kong comparison is lacking the same setup for the two shots...

anyway we could argue it all day, just wanted to share what my shots look like from the same program, same screen, same camera, same sized image... Blu wins hands down (duh) and DVD barely makes it worth the time watching the movie.

Thanks for your post, it gives a reasonable perspective of dvd and blu-ray releases of the same movie. I just wanted to make a general comment, as I see that many people using digital cameras to take blu-ray screenshots. So, my comments are not directly aimed at your work.

Of course a difference can be seen and blu-ray is better. However, if the pixel resolution of the digital camera is low, that would disadvantage blu-ray. If a 16 mega pixel camera is used, the difference could have been profound (provided the display is perfect).

The famous Nyquist-Shannon sampling theorem says that the sampling frequency should be at least twice the frequency of the original. Based on this, the digital camera should have at least twice the resolution (of the original) in both horizontal and vertical directions. This gives the requirement of about 8 mega pixel camera. Some might say that in real world resolution should be even higher for satisfactory capture.

This is similar to the requirement of at least 44 KHz sampling rate to truly represent a sound signal up to 22 KHz. (Some say that they can hear the difference between 44KHz and 96KHz.)

[maxmcleod]

That only applies to signal conversion... as in if I were to use a camcorder to record a bluray being played on my TV or use a mic to record the sound from my tv and rebroadcast it.

This scenario is different. Its a still shot, of a video source that is on pause. Hence there is no signal to capture only a light source. Digital cameras are more than equipped to capture a light source as the eye sees it, IF you know how to set your camera...

You see taking a picture of the screen isn't converting a signal, its merely photographing a light source. The Nyquist-Shannon doesn't apply here...

If I had taken the time to adjust my camera and fill the viewfinder with the TV more, you would have noticed even more details come through.. that's because the camera doesn't have to convert anything, its merely capturing exactly what is being shown.

[Lucy Diamond]

I'm big into text.

I LOVE opening credits. When I look at all the fuzz and crap around the text on DvD's, I want to yakk in my own boots!!! (and...they are good boots)

The difference is huge for some of us, but I am envious of those who can't tell. Ignorance is always bliss. (although knowlege is divine)

[syncguy]

Nyquist theorem indeed applies to the digital still photography and it determines the spatial sampling limits of digital cameras. Also, it applies to the still film cameras, however, in this case the size of the film grain is needed to determine the limits of the film.

I will try to explain using a crude example. Say the still camera sensor is 100x100 array (i.e. 10K pixels), and use this camera to take a still photo of a 1080p projected image. The outcome can be easily visualized. The photo will be pixilated and will not be a good representation of the original. If the sensor resolution of the still camera is increased to 200x200, the picture will get better. So, it can be easily visualized that by increasing the pixel resolution of the still camera, a better picture of the projected image can be obtained. Now what would happen if the pixel resolution of the still camera is identical to the projected image (i.e. 1920x1080). In this case, if you could exactly map the pixel grid of the still camera on to the pixel grid of the display device, the you could capture the state of each pixel of the image. However, what would happen if the two grids are not exactly aligned (this is the case in reality). Then a single pixel of the still camera may photograph up to 4 partial pixels of the projected image. In this case, the still camera cannot capture the projected image correctly and aliasing of the edges of the projected image will occur. This is a well known phenomenon in digital cameras and many cameras use anti-aliasing (blur) filters to blur the edges to hide aliasing art-effects when the camera’s sampling ability (or the resolution) approaches the Nyquist limit in relation to the photographed image.

This is where the Nyquist theorem helps to work out the minimum amount of still camera pixels needed to truthfully capture the projected image. As I said in my previous post, this would be about 8 mega pixels for HD. This is the Nyquist limit. Some people may see an improvement to the picture if the resolution of the still camera is further increased (i.e. 16 or 32 mega pixels). At least this is the case for audio sampling – some say they hear the difference between 44 and 96kHz sampling.

Since the Nyquist limit is a function of the original image resolution, DVDs would benefit when compared with HD if the still camera resolution is below the Nyquist limit for HD. So, about 10 mega pixel still camera is suitable to carryout an unbiased comparison of HD and DVD images.

[maxmcleod]

Originally Posted by syncguy

Nyquist theorem indeed applies to the digital still photography and it determines the spatial sampling limits of digital cameras. Also, it applies to the still film cameras, however, in this case the size of the film grain is needed to determine the limits of the film.

I will try to explain using a crude example. Say the still camera sensor is 100x100 array (i.e. 10K pixels), and use this camera to take a still photo of a 1080p projected image. The outcome can be easily visualized. The photo will be pixilated and will not be a good representation of the original. If the sensor resolution of the still camera is increased to 200x200, the picture will get better. So, it can be easily visualized that by increasing the pixel resolution of the still camera, a better picture of the projected image can be obtained. Now what would happen if the pixel resolution of the still camera is identical to the projected image (i.e. 1920x1080). In this case, if you could exactly map the pixel grid of the still camera on to the pixel grid of the display device, the you could capture the state of each pixel of the image. However, what would happen if the two grids are not exactly aligned (this is the case in reality). Then a single pixel of the still camera may photograph up to 4 partial pixels of the projected image. In this case, the still camera cannot capture the projected image correctly and aliasing of the edges of the projected image will occur. This is a well known phenomenon in digital cameras and many cameras use anti-aliasing (blur) filters to blur the edges to hide aliasing art-effects when the camera’s sampling ability (or the resolution) approaches the Nyquist limit in relation to the photographed image.

This is where the Nyquist theorem helps to work out the minimum amount of still camera pixels needed to truthfully capture the projected image. As I said in my previous post, this would be about 8 mega pixels for HD. This is the Nyquist limit. Some people may see an improvement to the picture if the resolution of the still camera is further increased (i.e. 16 or 32 mega pixels). At least this is the case for audio sampling – some say they hear the difference between 44 and 96kHz sampling.

Since the Nyquist limit is a function of the original image resolution, DVDs would benefit when compared with HD if the still camera resolution is below the Nyquist limit for HD. So, about 10 mega pixel still camera is suitable to carryout an unbiased comparison of HD and DVD images.

i see your point, makes more sense now

but this is just a comparison, so im not too worried about all that for this.
Still a better comparison than the king kong example, which doesn't truly reflect a dvd on a large screen... I've never watched a movie that was blurry like that, because it doesn't exist, its still clear, just less details

[syncguy]

Originally Posted by maxmcleod

i see your point, makes more sense now

but this is just a comparison, so im not too worried about all that for this.
Still a better comparison than the king kong example, which doesn't truly reflect a dvd on a large screen... I've never watched a movie that was blurry like that, because it doesn't exist, its still clear, just less details

No worries. Thanks for your comparison.

I made those comments as I have seen many people using digital cameras to capture HD images and may assist when choosing a camera for this purpose.