HD? I thought HD meant High Definition

RokWatch · November 18th, 2015, 12:25 PM

This collage is made from a medium definition source which is larger than your file. I'm confused. Please explain my misunderstanding. Thank you.

black Wolfe · November 18th, 2015, 05:17 PM

Quote:

Originally Posted by RokWatch

This collage is made from a medium definition source which is larger than your file. I'm confused. Please explain my misunderstanding. Thank you.

Yours is a collage. The previous post is referring to the quality of the video [which I have not downloaded so can't comment on] not the caps collage. Because the caps are low res doesn't mean anything except whomever made them compressed the hell out of them.

As to the difference in size between medium and high definition, I wish people would finally get it through their skulls that BIG has nothing to do with QUALITY. Definition is not a matter of size but of RESOLUTION of the ORIGINAL MATERIAL. I can take a low res image and blow it up so it's the size of my plasma and weighs in at 12mb. That doesn't make it "HD". It just makes it bloated and badly processed.

**seany65** · November 18th, 2015, 09:37 PM

Quote:

Originally Posted by black Wolfe

As to the difference in size between medium and high definition, I wish people would finally get it through their skulls that BIG has nothing to do with QUALITY. Definition is not a matter of size but of RESOLUTION of the ORIGINAL MATERIAL. I can take a low res image and blow it up so it's the size of my plasma and weighs in at 12mb. That doesn't make it "HD". It just makes it bloated and badly processed.

I agree entirely, black wolfe.

**DTravel** · November 19th, 2015, 02:13 AM

From the link in my sig:

Quote:

A note regarding image and screencap sizes. http://xkcd.com/732/ TV and movie resolutions are small compared to computers. Standard definition TV is 640 by 480, "widescreen" is 852 by 480. High definition is 1920 by 1080 but some TV stations broadcast a smaller 1280 by 720 and still call that "High Def". (By comparison most digital cameras take photos that are in the neighborhood of 5000 by 3000 pixels.) Older material (such as movies from the 1960s) was filmed in 640 by 480 or 852 by 480 and "blowing it up" to HD isn't practical in many cases (or even possible in some). Same with screencaps, I could enlarge the caps but they would simply come out blocky and grainy and would be poor quality in my opinion. High resolution, sure, but not high quality. (Pet peeve of mine, the common usage of HQ for high resolution. Resolution and quality are two separate things.)

Lurk_D · November 19th, 2015, 06:40 AM

When first introduced, HD meant High Density, referring exclusively to the fact that the HD discs could hold approximately 40 times the information as the standard DVD discs. Once movies started getting released in the format, someone decided to adapt the HD reference to what they were advertising as the nature of the content of the disc, to wit; Higher resolution audio/video.

It actually hasn't been until recently that that's been true, though. File sizes on the DVDs and equivalent Blu-rays, for instance, have been identical for most of the last decade or so, and now that the file sizes are starting to reflect the promised higher resolution content, Blu-ray is going to start having the same problems DVD has as far as being able to put everything on one disc: if the files are too big, you can't.

black Wolfe · November 21st, 2015, 04:46 AM

The last two messages are largely right [though the dimensions given are a little missleading]. Standard DVD size in 16:9 is 720 x 480 pixels (NTSC) or 720 x 576 pixels (PAL) HD video has a dizzying array of dimensions but it always comes in at 16:9 aspect ratio whereas SD [standard] video comes in at either 16:9 OR 4:3. This has NOTHING to do with the number of pixels but refers to the SHAPE of the pixels, which is how DVD of older TV shows can be 720 x 576 and still 4:3 [old TVs were square not rectangular]
What we now call "Widescreen" in old cinema terms was called Cinemascope® and didn't come into use until 1953 when a man called Spyros P. Skouras, the president of 20th Century-Fox at the time, presided over the creation of the new lens system. This was later advanced by PanaVision® but this system changed everything in terms of how we make and process images and the term "Scope" is still used by film makers today.

A surprising number of classic films were shot in 4:3. The Wizard of Oz is one such, and the first time you see it on the big screen and the curtains come in to frame a square projection is quite jarring. This fact was used in the making of the 2011 Oscar winner The Artist which was shot in 4:3.
These old movies are put on DVD and Blu-Ray discs as HD because the original 35mm film is rescanned at massively improved resolutions then processsed to clean up and improve the quality of each frame image. Some films originally shown in 4:3 [because TVs were all 4:3 until recently] were actually shot in anamorphic aspect [16:9] so the remaster comes out in widescreen and the cropping reveals surprising directorial framing.
People have written books on this subject and there are piles of info on aspect ratios and resolution on the web, especially on sites that tutor digital video editing, so rather than read some half digested info on this thread you'd be better served looking out some of these. Start with Wikipedia and use Google.

One note on digital stills. Pixel count is bullshit. Pixel numbers are relatively easy and very cheap to bloat and many companies marketing consumer and prosumer cameras have concentrated on that. However this doesn't matter a toss if the lens is inferior and the sensor chips are undersized. Standard chips in consumer and prosumer cameras today are 1/6". This is very small so even though the pixel count is 15MP the image pales by comparison to older pro cameras which use the much larger 1/3" sensor chip. The bigger the surface of the light sensor, the more information is captured and the better the quality of the image.
The best example of this is the Konica Minolta Dynax 7D, a 6MP camera that takes a full array of Alpha Mount lenses and is widely accepted by photographers to take superior images to many modern cameras. It's in huge demand and has held its price amazingly for old tech.
This is beginning to change again as CCD is replaced by CMOS though [IMO] we're another year or two away from CMOS being truly superior to CCD/3CCD.However that supercession is inevitable as tech improves.
The bottom line however, esp if you are shopping for a new camera, ignore the pixel count and find out EVERYTHING about the image sensor and the lens. You can have a 20MP camera but if the sensor is inferior and the lens poor then you may as well shoot on an iPhone.

November 18th, 2015, 12:25 PM	#1
RokWatch Senior Member Join Date: Oct 2010 Posts: 102 Thanks: 27 Thanked 3,032 Times in 100 Posts	HD? I thought HD meant High Definition This collage is made from a medium definition source which is larger than your file. I'm confused. Please explain my misunderstanding. Thank you.

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November 19th, 2015, 06:40 AM	#5
Lurk_D Senior Member Join Date: Mar 2011 Posts: 489 Thanks: 22 Thanked 3,914 Times in 467 Posts	When first introduced, HD meant High Density, referring exclusively to the fact that the HD discs could hold approximately 40 times the information as the standard DVD discs. Once movies started getting released in the format, someone decided to adapt the HD reference to what they were advertising as the nature of the content of the disc, to wit; Higher resolution audio/video. It actually hasn't been until recently that that's been true, though. File sizes on the DVDs and equivalent Blu-rays, for instance, have been identical for most of the last decade or so, and now that the file sizes are starting to reflect the promised higher resolution content, Blu-ray is going to start having the same problems DVD has as far as being able to put everything on one disc: if the files are too big, you can't.

November 21st, 2015, 04:46 AM	#6
black Wolfe Member Join Date: May 2011 Posts: 23 Thanks: 7 Thanked 104 Times in 23 Posts	The last two messages are largely right [though the dimensions given are a little missleading]. Standard DVD size in 16:9 is 720 x 480 pixels (NTSC) or 720 x 576 pixels (PAL) HD video has a dizzying array of dimensions but it always comes in at 16:9 aspect ratio whereas SD [standard] video comes in at either 16:9 OR 4:3. This has NOTHING to do with the number of pixels but refers to the SHAPE of the pixels, which is how DVD of older TV shows can be 720 x 576 and still 4:3 [old TVs were square not rectangular] What we now call "Widescreen" in old cinema terms was called Cinemascope® and didn't come into use until 1953 when a man called Spyros P. Skouras, the president of 20th Century-Fox at the time, presided over the creation of the new lens system. This was later advanced by PanaVision® but this system changed everything in terms of how we make and process images and the term "Scope" is still used by film makers today. A surprising number of classic films were shot in 4:3. The Wizard of Oz is one such, and the first time you see it on the big screen and the curtains come in to frame a square projection is quite jarring. This fact was used in the making of the 2011 Oscar winner The Artist which was shot in 4:3. These old movies are put on DVD and Blu-Ray discs as HD because the original 35mm film is rescanned at massively improved resolutions then processsed to clean up and improve the quality of each frame image. Some films originally shown in 4:3 [because TVs were all 4:3 until recently] were actually shot in anamorphic aspect [16:9] so the remaster comes out in widescreen and the cropping reveals surprising directorial framing. People have written books on this subject and there are piles of info on aspect ratios and resolution on the web, especially on sites that tutor digital video editing, so rather than read some half digested info on this thread you'd be better served looking out some of these. Start with Wikipedia and use Google. One note on digital stills. Pixel count is bullshit. Pixel numbers are relatively easy and very cheap to bloat and many companies marketing consumer and prosumer cameras have concentrated on that. However this doesn't matter a toss if the lens is inferior and the sensor chips are undersized. Standard chips in consumer and prosumer cameras today are 1/6". This is very small so even though the pixel count is 15MP the image pales by comparison to older pro cameras which use the much larger 1/3" sensor chip. The bigger the surface of the light sensor, the more information is captured and the better the quality of the image. The best example of this is the Konica Minolta Dynax 7D, a 6MP camera that takes a full array of Alpha Mount lenses and is widely accepted by photographers to take superior images to many modern cameras. It's in huge demand and has held its price amazingly for old tech. This is beginning to change again as CCD is replaced by CMOS though [IMO] we're another year or two away from CMOS being truly superior to CCD/3CCD.However that supercession is inevitable as tech improves. The bottom line however, esp if you are shopping for a new camera, ignore the pixel count and find out EVERYTHING about the image sensor and the lens. You can have a 20MP camera but if the sensor is inferior and the lens poor then you may as well shoot on an iPhone.