Uncompressed PCM Video

[Radium]

Why aren't there any PCM video devices?

I have seen countless PCM audio devices. Why not use the same for
video?

Just give it a strong bit-resolution, a low frequency sample rate, and
multiple video channels and you will get quality much better than MPEG
video.

MPEG is data reduction and looks bad on the screen. It may work for 2D
video but not for 3D video.

I would like to use strong bit-resolution, slow sample rate, multiple
channels PCM video for virtual reality.

 

[Chris Schumann]

Why aren't there any PCM video devices?

I have seen countless PCM audio devices. Why not use the same for
video?

Because PCM video has the same issues as PCM audio, the main one
being that high data rates are required.

Just give it a strong bit-resolution, a low frequency sample rate, and
multiple video channels and you will get quality much better than MPEG
video.

Oh I see, by low frequency, you mean a few frames per second. Each
frame still has to be captured quickly, but that's simple.

MPEG is data reduction and looks bad on the screen. It may work for 2D
video but not for 3D video.

I would like to use strong bit-resolution, slow sample rate, multiple
channels PCM video for virtual reality.

I'd imagine there are such things for applications such as
security and surveillance. But for VR? In my mind, and I think to
many others, high frame rate is MORE important than image quality,
especially for moving images. The human eye has a lot of motion blur,
so there's no point in showing a lot of detail over the whole frame
if your head is spinning.

I'd rather have 30fps cartoons in my VR world than 5fps photographs,
unless I'm doing something like very methodical environment exploration.

Let us know what you find.

 

[Radium]

Because PCM video has the same issues as PCM audio, the main one
being that high data rates are required.


Oh I see, by low frequency, you mean a few frames per second. Each
frame still has to be captured quickly, but that's simple.


I'd imagine there are such things for applications such as
security and surveillance. But for VR? In my mind, and I think to
many others, high frame rate is MORE important than image quality,
especially for moving images. The human eye has a lot of motion blur,
so there's no point in showing a lot of detail over the whole frame
if your head is spinning.

Well I was thinking about designing psychedelic VR equipment. My
theoretical design is not for movies or stories but for VR effects
with different patterns of colors and images to entertain the visual
cortex. There is no audio and none needed. Multi-channel video would
intrigue the mind more than one-channel video. The slow sample rate
would add to the mystical vertigo. Video with stronger bit-resolution
is more appealing to the eyes than video with weaker bit-resolution.

The artifacts affecting MPEG video are imperceptible on a
television/computer monitor. In VR, however, they would be a real
annoyance. That is why I prefer to use PCM video. My theoretical PCM
video is stored on a laser disc.

 

[Gary Tait]

Why aren't there any PCM video devices?

I have seen countless PCM audio devices. Why not use the same for
video?

Just give it a strong bit-resolution, a low frequency sample rate, and
multiple video channels and you will get quality much better than MPEG
video.

MPEG is data reduction and looks bad on the screen. It may work for 2D
video but not for 3D video.

I would like to use strong bit-resolution, slow sample rate, multiple
channels PCM video for virtual reality.

Becuase it would terribly hog bandwidth or storage.

 

[MR_ED_of_Course]

Well I was thinking about designing psychedelic VR equipment. My
theoretical design is not for movies or stories but for VR effects
with different patterns of colors and images to entertain the visual
cortex. There is no audio and none needed. Multi-channel video would
intrigue the mind more than one-channel video. The slow sample rate
would add to the mystical vertigo. Video with stronger bit-resolution
is more appealing to the eyes than video with weaker bit-resolution.

The artifacts affecting MPEG video are imperceptible on a
television/computer monitor. In VR, however, they would be a real
annoyance. That is why I prefer to use PCM video. My theoretical PCM
video is stored on a laser disc.

You do realize that Laserdisc *is* analog video, don't you?

Obviously, the limiting factor is data rates. You get a lot more storage on
DVD than you would on laserdisc.

Next stop...Blu-Ray. That will give us much more storage for higher quality
video...coming soon!

Speaking of which, it annoys me to no end to see tv reporters use video
phones where they crank up the frame rate and the image quality is crap. In
a 30 second report, they could deliver 10 really great images, but instead
choose to send 500 images that are all one big fuzzy mess. I don't
understand why they don't pre-load a slideshow of high quality images before
the broadcast and then during the broadcast just do high quality audio,
letting the studio mix the audio with the pre-sent images. If it is
something happening *live* then it makes sense to do both at the same time,
but lower the frigggin frame rates!

 

[Bob May]

Actually, a lower frame rate just makes for a jumpy video. You do want the
minimal speed of 30FPS to integrate the images into a smoothly moving stream
in the brain. There is a reason whey the major video transport systems were
built on interlaced scanning and it wasn't to make things simple. The high
speed of the construction of the image at 60 or 50 FPS helps in making the
images blur into a continous stream rather than a number of photos.
I'll also note that the input/output of the MPEG stream is indeed PCM video
and it is simple math to figure out the bit rate that is needed to
accomplish the result, something that I'll leave to your calculating.
MPEG can be adjusted to produce a higher basic data stream or a lower,
depending upon the desired quality but for a local application, it is a
layer that is really not needed. Anybody transporting video data over a
short link is really wasting money converting it to a MPEG stream.
BTW, can you tell me where you have seen MPEG artifacts in any video? Do
you see it in movies or other stuff on TV? Do you see it in Satellite TV?

 

[Samuel Paik]

Why aren't there any PCM video devices?

If you mean, video codecs that support raw video, then almost all
the cheap devices do (well, technically the hardware only supports
4:2:2 YCrCb video)

 

[Radium]

You do realize that Laserdisc *is* analog video, don't you?

Yes, however, my design of it isn't. What I meant by "laserdisc" is a
disc of the same size and shape of those commercial laserdiscs. The
signals stored on mine are digital PCM.

Obviously, the limiting factor is data rates. You get a lot more storage on
DVD than you would on laserdisc.

Next stop...Blu-Ray. That will give us much more storage for higher quality
video...coming soon!

My design of laserdiscs uses long-wave UV lasers (black light) to burn
pits into the disc. Commercial ones use infrared lasers. Since UV is
of a shorter wavelength than IR, I can store more pits of info on my
discs than the commercial discs.

Also since laserdiscs are bigger than DVDs, they store more data.

Speaking of which, it annoys me to no end to see tv reporters use video
phones where they crank up the frame rate and the image quality is crap. In
a 30 second report, they could deliver 10 really great images, but instead
choose to send 500 images that are all one big fuzzy mess. I don't
understand why they don't pre-load a slideshow of high quality images before
the broadcast and then during the broadcast just do high quality audio,
letting the studio mix the audio with the pre-sent images. If it is
something happening *live* then it makes sense to do both at the same time,
but lower the frigggin frame rates!

I agree.

The solution is strong bit-resolution and slow sample frequency.
Driving up the frame rate can make a painful eyesore out of any
original video.

For an aural equivalent try encoding digital audio at 2 KHz. After
recording increase the sample rate of the file to 44.1 KHz. Scrathy
high-pitched hiss will give you a migraine.

 

[Valentín Guillén]

Why aren't there any PCM video devices?

Well I was thinking about designing psychedelic VR equipment.>

You can throw out all the "seemingly correct and aweinspiring"
terminology, and obviously many "will bite the bait", but methings
you've snorted WAY WAY too much of that multicolored, psychedelic "pixie
dust."

Either that or you're having one hell of a laugh at the expense of what
appears to be an endless supply of hapless fools.

OK, you made me chuckle, so maybe it's worth it.....

 

[luminos]

Total and complete idiocy. See Roederer: Introduction to the Physics and
Psychophysics of Music, 3rd edition, Springer Verlag.

 

[Skywise]

BTW, can you tell me where you have seen
MPEG artifacts in any video? Do you see it in movies or other stuff on
TV? Do you see it in Satellite TV?

I see it all the time on my Direct TV system, and I'm not talking about
the occasional glitching caused by loss of data. I see it mostly in
areas of the image that are mostly the same color, like say a background
wall. Also, video-text has what I call 'jaggies' all around it, just
like in a computer jpeg image of low quality. And no, I dont' have a
high res TV...just your garden variety cheap 28 incher.

I've thought of sending them an email saying that considering I'm
paying $xx for their service and they advertise 'digital quality' that
I should expect a better picture. They're obviously over compressing
their signal.

Most of the time it's not obvious, but there are times when it just
jumps out at me.

Brian

 

[Glenn Gundlach]

Why aren't there any PCM video devices?

I have seen countless PCM audio devices. Why not use the same for
video?

Just give it a strong bit-resolution, a low frequency sample rate, and
multiple video channels and you will get quality much better than MPEG
video.

MPEG is data reduction and looks bad on the screen. It may work for 2D
video but not for 3D video.

I would like to use strong bit-resolution, slow sample rate, multiple
channels PCM video for virtual reality.

There is uncompressed PCM for video. The data rate is 270 Mbit/sec for
standard definition, 525 line, 60 field interlaced. The computer folks
refer to this as 480i. For Hi def, the data rate bumps up to 1.5
Gbit/sec for 1920x1080 interlaced. Looks danged fine,too. This stuff
is only seen in studios and post production facilities. It makes going
to work fun.

GG

 

[Bob May]

Brian, digital TV is like digital audio. The frequency response is horrible
but the rendition is wonderful for the most part and you can copy it forever
without loss of that quality.
Depending upon the level of compression, the artifacts may show up and at
the higher compression levels the thing to look for is blocks )basic
luminance block is 8x8 and a color block is 8x16) of a solid color (best
seen with a slowly varying color or shade due to shadows) over a surface.
With MPEG, fast motion can produce some blocks Reduce the level of
compression and the artifacts become a lot scarcer.
Audio has the same problems in that the basic highest reproducable frequency
with the basic digiatal audio is in the range of about 15KHz and the earlier
tape and vinyl was able to reproduce that high stuff a lot better. It does
have the ability to be a quieter medium tho if the processing of the audio
is done properly before being converted to digital.

 

[Radium]

There is uncompressed PCM for video.

What medium is it stored in?

The data rate is 270 Mbit/sec for
standard definition, 525 line, 60 field interlaced.
The computer folks
refer to this as 480i. For Hi def, the data rate bumps up to 1.5
Gbit/sec for 1920x1080 interlaced.

Do they have any video PCM file formats?

Looks danged fine,too. This stuff
is only seen in studios and post production facilities. It makes going
to work fun.

Any of these studios make visual psychedelic virtual reality with PCM video?

 

[Ian Stirling]

What medium is it stored in?


Do they have any video PCM file formats?

You don't typically store these on hard disks, they are too big.
At 270Mbit/sec, you can only store an hours video on a 120G disk.
At 1920*1080, you need several disks just to cope with the bandwidth.
5 120G disks will just about cope with an hour.

--
http://inquisitor.i.am/ | mailto:[email protected] | Ian Stirling.
---------------------------+-------------------------+--------------------------
"Melchett : Unhappily Blackadder, the Lord High Executioner is dead
Blackadder : Oh woe! Murdered of course.
Melchett : No, oddly enough no. They usually are but this one just got
careless one night and signed his name on the wrong dotted line.
They came for him while he slept." - Blackadder II

 

[Ian Stirling]

Brian, digital TV is like digital audio. The frequency response is horrible
but the rendition is wonderful for the most part and you can copy it forever
without loss of that quality.

Digital with decent bitrates beats 99% of analog systems, and uses less
bandwidth.
Then the accountants get to it and decide that you don't want picture quality,
you want hundreds of channels in the space where ten should really be
put.

This is the reason that the latest DAB digital radio currently rolling out
over the last bits of the UK is lower quality than a FM signal.

 

[Radium]

You don't typically store these on hard disks, they are too big.
At 270Mbit/sec, you can only store an hours video on a 120G disk.
At 1920*1080, you need several disks just to cope with the bandwidth.
5 120G disks will just about cope with an hour.

But these are for movies. Movies usually have a long story and thus
need a lot of storage space.

Would psychedelic patterns of different images and colors in virtual
reality require a similar amount of storage space? Minus the audio
because my design doesn't contain any.

In addition, an optical disc can store more information in the same
distance than a magnetic disc of the same size.

 

[Ian Stirling]

But these are for movies. Movies usually have a long story and thus
need a lot of storage space.

Would psychedelic patterns of different images and colors in virtual
reality require a similar amount of storage space? Minus the audio
because my design doesn't contain any.

Why would you need to store them as PCM?

In addition, an optical disc can store more information in the same
distance than a magnetic disc of the same size.

Not with commonly available technology.
DVDs get around 5Gb/disk, which is around 1.6 times the area of a hard
drive platter.
I haven't looked inside my 120Gb drive, but there is no way there are 36
platters in there.

 

[luminos]

Why would you need to store them as PCM?

Because this guy knows nothing and needs to study more carefully.

 

[Bob May]

Methinks that you should really just sit down and look at the things that
you are talking about rather than arguing about it with people that know
exactly what you are talking about. These problems have all been worked
over in many different ways - every few decades, the technology gets a major
revamping due to better abilities in recording and storing data. Who knows
when the generation of video in the digital domain will change but some are
already calling for changes. Are you ready for 12 bit video? That will
increase the raw stream by 50% and make all of the present day encoding
schemes obselete.