HDTV
Oh lord,
what a mess.
Living where I do I am capable of receiving a single TV channel quite poorly. I am expected to pay the government ca. $150 a year for this dubious pleasure.
So I download TV shows, go ahead; cut my head off.
Many TV shows I download comes with the mythological heading "HDTV". What I've come to learn is to run in the other direction as fast as possible. Why?
Well, HDTV has come to mean standard resolution(d1) TV with the interlacing removed using the wrong protocol played back at the wrong framerate.
Like imagine NTSC; 59,97 fps interlaced, turned into 23,97 fps progressive -not using the proper 3:2 inverse pull down.
Is this to technical to follow? well, at least it is to technical to follow for the people doing this, 'cause they're not doing it right. I have yet to download a single TV show in "HDTV" that has not been completely mangled. It's unwatchable, I get seasick from it.
The thing is, the world has been taught that progressive display is better than interlaced display, and in a perfect world it is. However, the world is far from perfect, and in reality well done interlacing beats poorly done progressive on any day of the week.
But people believe in gods and magic and deus ex machina, people believe that converting an mp3 to wav format will restore the original sound of the recording(no it won't), and people believe that converting interlaced images to progressive ones will magically improve them.
As a good professional I will tell you one of the basic rules of signal processing -think of it like newtons laws about gravity, they can't be explained but every test proves them right(Let's not get into relativity here -people who build houses and bridges use newton -not einstein).
The law of signal processing can ofcourse be explained, I just won't bother, go read a book if you want it.
It's this:
Any signal conversion will degrade the signal.
There.
And sure, there are exceptions, as there are to all laws. But that's irrelevant.
I now avoid all discussion of HDTV with everyone. Why? Because the subject is knee deep in myth and presenting facts brings alot of puzzled faces.
Even wikipedia has fallen prey to the myth and presents some of it as fact. Let's review their article on 1080p.
Line 2: 1080p is considered an HDTV video mode
No it isn't. It is a cinema format, used exclusively for cinema production. There exits no means of distribution outside of cinemas.
line 1 under production standards:
A new high-definition progressive scan format for picture creation is currently being developed to operate at 1080p at 50 or 60 frames per second.
Really? Never heard of it, who is developing it? wikipedia doesn't say.
Why? wikipedia doesn't say.
Yes, why? It is perfectly possible and also common to deliver a progressive format inside of an interlaced one. You've watched it all your life, every movie you saw on the telly, every VHS tape, every DVD disc. Films are progressive, but they are being delievered for distribution in an interlaced format. This does not mean that the quality is substandard, in fact -done right, the quality is identical. The process is not lossy.
And furthermore, a new standard is being developed, in fact it's being finalized. High rez cinema, 4k.
4k for the 4000 lines of resolution. Each frame is 8 megapixels, as opposed to current digital cinema which is 2 megapixels, and standard definition TV which is less than half a megapixel.
line 4 under production standards:
This format will improve final pictures because of the benefits of "oversampling" and removal of interlace artifacts.
Well, oversampling I can do on any signal. And many CD and DVD players(and TVs) do this as standard, and has been doing it for more than a decade.
The "removal of interlace artifacts" will only improve some images, if any at all. Seen any "interlace artifacts" lately? Maybe on the news, or the soccer match?
No? Really?
More likely you've seen mpeg2 artifacts. Going to digital might have improved that terrible thing they pass off for a "color" TV system in USA, but the quality of PAL went down. Analogue PAL is quite superior to digital PAL, just try watching MTV; the fast cutting and colorful images are really struggling in the mpeg2 compression, and the reduced colorspace makes graphical things look... well, terrible. Many a TV station graphics person threw his arms out towards the sky and cried from the bottom of his heart "Why, oh why?!?!?!?!!!" when management decided to go digital.
Then wikipedia cites TVs capable of displaying the 1080p signal(under "consumer televisions") -problem is, none of them can *receive* such a signal...
And besides, all flat screen TVs are progressive, they cannot interlace(I suppose there is a technical reason for this though I do not know what it is, I would theorize that pixels or lines cannot be individually addressed -does anyone know?) so any flat screen TV capable of 1080i *can* be called capable of 1080p, strictly speaking -it is *only* capable of 1080p.
wikipedia continues:
Also, 3-2 pulldown reversal for film-based 1080i60 signals is beginning to appear in some newer 1080p displays, which can produce a true 1080p quality image from film-based 1080i60 programs.
But how is that going to improve the picture? Either the picture will degrade or it will remain exactly how it was, it *cannot* be improved by such a crude process. You would need extremely sophisticated interpolation software to improve it, and I have extremely sophisticated interpolation software, and on my very fast computer I have to wait several minutes for each frame I process, besides -it can't work on time, only space.
To conclude, the wikipedia article on 1080p is crap, and it creates more myth than it breaks, and that's not the role of a dictionary.
I remember how disappointed I was when DVD came out. Just standard resolution? I thought, SVHS and Hi8 had been doing that for ages...
I've learned to live with it, and now finally HD video on disc is here. In a blaze of confusion and misunderstandings.
You must consider, I've been following HDTV since the only cameras capable of recording it used tubes. Now that's a while ago, but I own such a device now. The cheap Sony with the CMOS sensor. Sure it would have been nice to record progressive, but I don't really miss it, except....
One of the HDTV formats are 1280x720x60.
That is one megapixel of resolution, 60 times a second. The US army wanted this to be the default HDTV standard when congress held hearings.
So what's so great about it?
The framerate. The human eye perceives about 80 images per second, the human eye thinks films and TV are stuttering, and my brain isn't fooled into thinking I'm really looking through a window not at a screen.
You see, for most screen sizes that is feasable in a typical living room one megapixel is enough, at a typical viewing distance you'll be unable to see the individual pixels.
But you'll not be able to see fluid motion in films(which project 24 frames per second, no matter what format you keep it in) or TV which maxes out a 60 frames interlaced.
What it all comes down to is how much information is being conveyed in a given timespace. Lets try a second:
How many bits passes the eye by in a second?
1280x720x60x24=1327104000
1920x1080x30x24=1492992000
720x478x30x24=247795200
(24 is the number of bits allocated to color)
As is clear from the numbers, the superior temporal resolution of 1280x720x60 not only compensates for its lack of 2d resolution, it can basically match a format with twice the 2d rez.
But people focus alot on 2d rez, they tend to forget that motion pictures is a 3d format -and time is ofcourse the third dimension.
Film has been stuck on 24p for almost a century, too bad, film had real potential.
It saddens me when I watch people degrade their productions into 24p to get the "film look", they don't seem to realize that the entire language of film is designed to hide the fact that there is only 24 frames available per second. 24p is not even enough to show a person dropping a glass, you'll have to do it in slow motion if you want to see it fall on film.
It strikes me sometimes , how utterly ungraceful and mechanical film really is, like a simulacra made by satan. And still I'm a prisoner of this ridiculous train of thought. My HD camera is only HD in 2d, its temporal resolution is as lame as the first camera I ever bought. But soon bandwidth will be a non-issue and then many young people all over the world will throw the yoke away and make films in exactly the format of their choosing; and it will be goodbye to these ridiculous standards.
I can't wait.
b
what a mess.
Living where I do I am capable of receiving a single TV channel quite poorly. I am expected to pay the government ca. $150 a year for this dubious pleasure.
So I download TV shows, go ahead; cut my head off.
Many TV shows I download comes with the mythological heading "HDTV". What I've come to learn is to run in the other direction as fast as possible. Why?
Well, HDTV has come to mean standard resolution(d1) TV with the interlacing removed using the wrong protocol played back at the wrong framerate.
Like imagine NTSC; 59,97 fps interlaced, turned into 23,97 fps progressive -not using the proper 3:2 inverse pull down.
Is this to technical to follow? well, at least it is to technical to follow for the people doing this, 'cause they're not doing it right. I have yet to download a single TV show in "HDTV" that has not been completely mangled. It's unwatchable, I get seasick from it.
The thing is, the world has been taught that progressive display is better than interlaced display, and in a perfect world it is. However, the world is far from perfect, and in reality well done interlacing beats poorly done progressive on any day of the week.
But people believe in gods and magic and deus ex machina, people believe that converting an mp3 to wav format will restore the original sound of the recording(no it won't), and people believe that converting interlaced images to progressive ones will magically improve them.
As a good professional I will tell you one of the basic rules of signal processing -think of it like newtons laws about gravity, they can't be explained but every test proves them right(Let's not get into relativity here -people who build houses and bridges use newton -not einstein).
The law of signal processing can ofcourse be explained, I just won't bother, go read a book if you want it.
It's this:
Any signal conversion will degrade the signal.
There.
And sure, there are exceptions, as there are to all laws. But that's irrelevant.
I now avoid all discussion of HDTV with everyone. Why? Because the subject is knee deep in myth and presenting facts brings alot of puzzled faces.
Even wikipedia has fallen prey to the myth and presents some of it as fact. Let's review their article on 1080p.
Line 2: 1080p is considered an HDTV video mode
No it isn't. It is a cinema format, used exclusively for cinema production. There exits no means of distribution outside of cinemas.
line 1 under production standards:
A new high-definition progressive scan format for picture creation is currently being developed to operate at 1080p at 50 or 60 frames per second.
Really? Never heard of it, who is developing it? wikipedia doesn't say.
Why? wikipedia doesn't say.
Yes, why? It is perfectly possible and also common to deliver a progressive format inside of an interlaced one. You've watched it all your life, every movie you saw on the telly, every VHS tape, every DVD disc. Films are progressive, but they are being delievered for distribution in an interlaced format. This does not mean that the quality is substandard, in fact -done right, the quality is identical. The process is not lossy.
And furthermore, a new standard is being developed, in fact it's being finalized. High rez cinema, 4k.
4k for the 4000 lines of resolution. Each frame is 8 megapixels, as opposed to current digital cinema which is 2 megapixels, and standard definition TV which is less than half a megapixel.
line 4 under production standards:
This format will improve final pictures because of the benefits of "oversampling" and removal of interlace artifacts.
Well, oversampling I can do on any signal. And many CD and DVD players(and TVs) do this as standard, and has been doing it for more than a decade.
The "removal of interlace artifacts" will only improve some images, if any at all. Seen any "interlace artifacts" lately? Maybe on the news, or the soccer match?
No? Really?
More likely you've seen mpeg2 artifacts. Going to digital might have improved that terrible thing they pass off for a "color" TV system in USA, but the quality of PAL went down. Analogue PAL is quite superior to digital PAL, just try watching MTV; the fast cutting and colorful images are really struggling in the mpeg2 compression, and the reduced colorspace makes graphical things look... well, terrible. Many a TV station graphics person threw his arms out towards the sky and cried from the bottom of his heart "Why, oh why?!?!?!?!!!" when management decided to go digital.
Then wikipedia cites TVs capable of displaying the 1080p signal(under "consumer televisions") -problem is, none of them can *receive* such a signal...
And besides, all flat screen TVs are progressive, they cannot interlace(I suppose there is a technical reason for this though I do not know what it is, I would theorize that pixels or lines cannot be individually addressed -does anyone know?) so any flat screen TV capable of 1080i *can* be called capable of 1080p, strictly speaking -it is *only* capable of 1080p.
wikipedia continues:
Also, 3-2 pulldown reversal for film-based 1080i60 signals is beginning to appear in some newer 1080p displays, which can produce a true 1080p quality image from film-based 1080i60 programs.
But how is that going to improve the picture? Either the picture will degrade or it will remain exactly how it was, it *cannot* be improved by such a crude process. You would need extremely sophisticated interpolation software to improve it, and I have extremely sophisticated interpolation software, and on my very fast computer I have to wait several minutes for each frame I process, besides -it can't work on time, only space.
To conclude, the wikipedia article on 1080p is crap, and it creates more myth than it breaks, and that's not the role of a dictionary.
I remember how disappointed I was when DVD came out. Just standard resolution? I thought, SVHS and Hi8 had been doing that for ages...
I've learned to live with it, and now finally HD video on disc is here. In a blaze of confusion and misunderstandings.
You must consider, I've been following HDTV since the only cameras capable of recording it used tubes. Now that's a while ago, but I own such a device now. The cheap Sony with the CMOS sensor. Sure it would have been nice to record progressive, but I don't really miss it, except....
One of the HDTV formats are 1280x720x60.
That is one megapixel of resolution, 60 times a second. The US army wanted this to be the default HDTV standard when congress held hearings.
So what's so great about it?
The framerate. The human eye perceives about 80 images per second, the human eye thinks films and TV are stuttering, and my brain isn't fooled into thinking I'm really looking through a window not at a screen.
You see, for most screen sizes that is feasable in a typical living room one megapixel is enough, at a typical viewing distance you'll be unable to see the individual pixels.
But you'll not be able to see fluid motion in films(which project 24 frames per second, no matter what format you keep it in) or TV which maxes out a 60 frames interlaced.
What it all comes down to is how much information is being conveyed in a given timespace. Lets try a second:
How many bits passes the eye by in a second?
1280x720x60x24=1327104000
1920x1080x30x24=1492992000
720x478x30x24=247795200
(24 is the number of bits allocated to color)
As is clear from the numbers, the superior temporal resolution of 1280x720x60 not only compensates for its lack of 2d resolution, it can basically match a format with twice the 2d rez.
But people focus alot on 2d rez, they tend to forget that motion pictures is a 3d format -and time is ofcourse the third dimension.
Film has been stuck on 24p for almost a century, too bad, film had real potential.
It saddens me when I watch people degrade their productions into 24p to get the "film look", they don't seem to realize that the entire language of film is designed to hide the fact that there is only 24 frames available per second. 24p is not even enough to show a person dropping a glass, you'll have to do it in slow motion if you want to see it fall on film.
It strikes me sometimes , how utterly ungraceful and mechanical film really is, like a simulacra made by satan. And still I'm a prisoner of this ridiculous train of thought. My HD camera is only HD in 2d, its temporal resolution is as lame as the first camera I ever bought. But soon bandwidth will be a non-issue and then many young people all over the world will throw the yoke away and make films in exactly the format of their choosing; and it will be goodbye to these ridiculous standards.
I can't wait.
b
posted by bangskij at 01:00
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