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scott wrote:
>> Must take some serious MPEG compression to fit that onto a disk - even
>> a bluray disk has only finite storage capacity.
>
> 50 GB max IIRC.
Well, let me see...
1,920 pixels x 1,080 pixels = 2,073,600 pixels / frame
3 bytes / pixel x 2,073,600 pixels / frame = 6,220,800 bytes / frame
25 frames / second x 6,220,800 bytes / frame = 155,520,000 bytes / second
Approx 148.31 MB / second. (Woah, that's some transfer rate!)
8.69 GB / minute.
512.40 GB / hour. So only 10x bigger than the disk. ;-)
>> My laptop doesn't go that high. ;-)
>
> You mean the VGA output or the LCD?
Both. They don't bother putting a video card in a laptop that can do
1600x1200 if the LCD itself is only 1024x768. (In fact, it seems my
laptop has only 3 resolutions, 3 colours depths and 1 scan rate.)
>> (Also, it has only VGA and S-Video output. I managed to find an
>> S-Video to SCART converter, which allows me to connect to the TV.)
>
> Yuk :-) you need VGA, component or DVI/HDMI for HD resolutions...
That's the other thing - HD seems to involve a whole zoo of different
connectors. For normal analogue video signals it's much simpler.
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> 512.40 GB / hour. So only 10x bigger than the disk. ;-)
So even if each frame was compressed using normal JPEG compression (with no
knowledge of previous frames) the result would probably look pretty good...
Given that the video codecs make use of huge amounts of info from the
previous frames, it seems that the video quality will be pretty good.
Actually I didn't notice any form of compression artifact while watching,
and I was looking pretty closely. Mind you, as these were "shorts", they
might have compressed them less than they would a feature-film, I don't know
if that is technically possible or not...
> Both. They don't bother putting a video card in a laptop that can do
> 1600x1200 if the LCD itself is only 1024x768. (In fact, it seems my laptop
> has only 3 resolutions, 3 colours depths and 1 scan rate.)
Oh ok, most laptops I've seen allow you to choose a higher resolution than
the screen itself, and then you can scroll about the laptop screen, or plug
in an external monitor. I know a lot of people here have those tiny Dells
with 1024x768 screens, but use a 1280x1024 or 1600x1200 monitor on their
desk.
> That's the other thing - HD seems to involve a whole zoo of different
> connectors. For normal analogue video signals it's much simpler.
Hmmm, digital HD you have the HDMI plug (looks a bit like a USB plug) or if
you want to include computers you have DVI too (both are electrically
compatible, so converters are cheap).
For analogue you have: component, composite, s-video and SCART, and if you
want to include computers, VGA too. VGA is not compatible with any of the
previous ones, so if you want to connect a computer to a TV you need
something more expensive.
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scott wrote:
>> 512.40 GB / hour. So only 10x bigger than the disk. ;-)
>
> So even if each frame was compressed using normal JPEG compression (with
> no knowledge of previous frames) the result would probably look pretty
> good... Given that the video codecs make use of huge amounts of info
> from the previous frames, it seems that the video quality will be pretty
> good. Actually I didn't notice any form of compression artifact while
> watching, and I was looking pretty closely. Mind you, as these were
> "shorts", they might have compressed them less than they would a
> feature-film, I don't know if that is technically possible or not...
The disk will have a maximum transfer rate. As long as the codec doesn't
exceed that it should be fine. (I have no idea what codec they actually
use and whether it places additional restrictions on the parameters.)
My point is just that you'll need some fairly serious compression to
make the data fit, that's all. I didn't say it's impossible. ;-)
> Oh ok, most laptops I've seen allow you to choose a higher resolution
> than the screen itself, and then you can scroll about the laptop screen,
> or plug in an external monitor. I know a lot of people here have those
> tiny Dells with 1024x768 screens, but use a 1280x1024 or 1600x1200
> monitor on their desk.
It's a cheap laptop.
>> That's the other thing - HD seems to involve a whole zoo of different
>> connectors. For normal analogue video signals it's much simpler.
>
> Hmmm, digital HD you have the HDMI plug (looks a bit like a USB plug) or
> if you want to include computers you have DVI too (both are electrically
> compatible, so converters are cheap).
And then there's the other thing. How can you fit 148 GB/sec down a 3
meter cable? Heck, they haven't worked out how to fit 148 GB/sec between
the CPU and the RAM yet, never mind between a player and a TV...!
> For analogue you have: component, composite, s-video and SCART, and if
> you want to include computers, VGA too. VGA is not compatible with any
> of the previous ones, so if you want to connect a computer to a TV you
> need something more expensive.
On the other hand, all analogue equipment known to man only provides
RF-modulated and possibly SCART. ;-)
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Invisible <voi### [at] dev null> wrote:
> As far as I know, a normal TV operates at something like 300x200 or so.
Not true. PAL has 625 vertical scanlines (which, assuming square pixels
on a 4:3 TV means 833x625 pixels). HDTV doubles that, which means something
like 1670x1250.
--
- Warp
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scott <sco### [at] laptopcom> wrote:
> But Oh My God, the picture quality was amazing.
Yeah, assuming the bluray player/drive doesn't decide that your 1-year-old
TV/monitor (or if you are using a computer, almost anything in it, more
prominently your 1-year-old top-of-the-line graphics card) is an illegal
ripping machine and thus decides to give you a low-resolution blurred
version of the image.
--
- Warp
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> And then there's the other thing. How can you fit 148 GB/sec down a 3
> meter cable?
You mean MB per second?
> Heck, they haven't worked out how to fit 148 GB/sec between the CPU and
> the RAM yet, never mind between a player and a TV...!
Even single-channel DVI (an old standard) can handle 1920x1080x60fps,
anything higher and you need dual-channel DVI. The specs for HDMI supports
10 Gbit/s, which is enough for something stupid like 3840x2160x50fps, or
slightly lower and a stupid number of digital audio channels.
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Invisible nous apporta ses lumieres en ce 2007/11/22 04:15:
> That's interesting. I was in some shop the other day, and they had a
> huge LCD with "HD Ready" splashed all over it, and huge cardboard signs
> saying "WOW! LOOK AT THE DIFFERENCE!" And I remember thinking "...I
> can't see any difference."
>
> I mean, let's face it, HD is only 4x the imagine resolution. If you
> compare the two side by side you'd probably notice. But if you just look
> at an HD TV, there really isn't much to notice. The picture is very
> slightly more crisp, but that's about it.
Do you mean 4x the total numbet of pixels, or 4x the number of LINES?
4x the pixels == double the pixels per lines and double the lines.
4x the lines is more like 16x the resolution!
>
> Certainly it hardly seems worth paying £7,000 just for a very slightly
> more crisp picture. I could buy a *car* for that amount of money! Hell,
> I could almost buy a copy of *Oracle* for that!
You are slightly outdated! HD prices have come down a LOT in just 2 years.
--
Alain
-------------------------------------------------
You know you've been raytracing too long when you look at waterfalls, dust,
rain, snow, etc, and think: "If only I had a fractalized, vector based
particle-system modeler with collision detection!"
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Invisible nous apporta ses lumieres en ce 2007/11/22 07:55:
> scott wrote:
>>> Must take some serious MPEG compression to fit that onto a disk -
>>> even a bluray disk has only finite storage capacity.
>>
>> 50 GB max IIRC.
>
> Well, let me see...
>
> 1,920 pixels x 1,080 pixels = 2,073,600 pixels / frame
>
> 3 bytes / pixel x 2,073,600 pixels / frame = 6,220,800 bytes / frame
>
> 25 frames / second x 6,220,800 bytes / frame = 155,520,000 bytes / second
>
> Approx 148.31 MB / second. (Woah, that's some transfer rate!)
>
> 8.69 GB / minute.
>
> 512.40 GB / hour. So only 10x bigger than the disk. ;-)
>
Now, each non-key frame only contains the difference from the preceding one.
Normaly, every frame is compressed. The end result is that you have compression
ratio well over 10, it can get in the 20 to 50 time.
They probably use MPEG2, it gives you about twice the compression of regular
MPEG (MPEG1), with a slightly beter quality.
--
Alain
-------------------------------------------------
You know you've been raytracing too long when you think it's a failing of the
universe that the large software companies like Corel or Fractal Design do NOT
export to POV primitives.
George Erhard
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Alain wrote:
> They probably use MPEG2, it gives you about twice the compression of
I believe they do. At least for standard def DVD.
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And lo on Thu, 22 Nov 2007 11:50:12 -0000, Invisible <voi### [at] devnull> did
spake, saying:
> scott wrote:
>>> That's interesting. I was in some shop the other day, and they had a
>>> huge LCD with "HD Ready" splashed all over it, and huge cardboard
>>> signs saying "WOW! LOOK AT THE DIFFERENCE!" And I remember thinking
>>> "...I can't see any difference."
>> They were probably feeding in some crappy HD or worse even SD
>> material... NExt time take along a copy of the pixar shorts on blu-ray
>> and ask them to play that on a 1080p TV. It will knock you out!
>
> They were running National Geographic HD. (Doesn't mean they had an HD
> decoder of course...) Lots of long short of mountains, jungles, big
> savanas and stuff that's clearly meant to make you go "wow". It honestly
> didn't look much different to what I get on my 7 year old TV at home.
Remembering that all the training they've had in electronics is to
remember to ask "So you want the extended warranty on that?". It's scary
at times watching HD televisions being fed an input via an unshielded
multifeed or from an HD Box via a SCART connector.
>>> I mean, let's face it, HD is only 4x the imagine resolution.
>> "only". What resolution do run your desktop in? Now imagine dividing
>> that by 4. It wouldn't be pretty...
>
> As far as I know, a normal TV operates at something like 300x200 or so.
> That means that 4x would only be 600x400 - still extremely low.
As has already been mentioned PAL has 625 lines with normally only 576
active lines.
>
> I think we've established that the shop was overpriced. ;-)
You seem to have a few of those :-)
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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