[comp.sys.amiga] DCTV from digital creations

n350bq@tamuts.tamu.edu (Duane Fields) (09/05/90)

In the new Amiga World, there is an add for DCTV, a 24 bit frame buffer.
Has anyone used this?? Creative Computers sells it for under $400, and sounds
nice. It has digitize software and paint prg, but how good are they???

Duane

seanc@pro-party.cts.com (Sean Cunningham) (09/08/90)

In-Reply-To: message from n350bq@tamuts.tamu.edu

I'm also curious about this product...or more to the point, curious whether or
not it'll work on my A3000.
 
Since it not only is used for display, but digitizes as well, that means it
must plug into the parallel port.  Am I right?  Well, the RGB (15.75KHz) port
and Centronics port on the A3000 are in no way configured like the A2000.  I
wonder if you could use cables on it???  It's kludgy, but whatever works...
 
24bit image manipulation for $495 (retail) is hard to pass up...and their
screenshots were stunning (although they WERE abit small).
 
Anyone from DC out there?
 
Sean
////////////////////////////////////////////////////////////////////////////
  UUCP: ...!crash!pnet01!pro-party!seanc       | 
  ARPA: !crash!pnet01!pro-party!seanc@nosc.mil | " Fanatics have their 
  INET: seanc@pro-party.cts.com                |   dreams, wherewith they
                                               |   weave a paradise for
  RealWorld: Sean Cunningham                   |   a sect. "
      Voice: (512) 994-1602  PLINK: ce3k*      |                -Keats
                                               |
  Call C.B.A.U.G. BBS (512) 883-8351 w/SkyPix  | B^) VISION  GRAPHICS B^)
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

donb@bushido.uucp (Donald Burnett) (09/10/90)

As far as I can tell it's an external box.
Should work fine..


-- 
****************************************************************
*********    donb@bushido.uucp                            ******
********* "My Opinions are my own, not anyone else's      ******
********* Organizational Affiliations                     ******
********* CreativEdge Systems, the Multimedia Solution    ******
********* The Computer Shoppe, Ypsilanti-Ann Arbor, MI's  ******
********* Commodore-Amiga Education Dealer                ******

ceej@pawl.rpi.edu (Chris J Hillery) (09/12/90)

(I'm sure I'll be flamed if I'm getting this wrong, but I don't care. =)

Isn't DCTV the box which gets 256 screen colors by intercepting a 640x400
16 color screen and combining each pair a pixels (4 bits each) into one
8-bit pixel?  I know there is a box like this. In this case, all well and
good, you get 256 out of 16million (I think) colors, but only in 320x400
(or variations... not 640 mode at any rate).  This could be a consideration.

I saw the box that did this at the World of Amiga and it did quite a good
job. The actual screen in 640x400 16 color looked pretty funny though... (=


Ceej
aka Chris Hillery
ceej@pawl.rpi.edu

peterk@cbmger.UUCP (Peter Kittel GERMANY) (09/12/90)

In article <RQB%S}@rpi.edu> ceej@pawl.rpi.edu (Chris J Hillery) writes:
>
>Isn't DCTV the box which gets 256 screen colors by intercepting a 640x400
>16 color screen and combining each pair a pixels (4 bits each) into one
>8-bit pixel?  I know there is a box like this. In this case, all well and
>good, you get 256 out of 16million (I think) colors, but only in 320x400
>(or variations... not 640 mode at any rate).  This could be a consideration.

Ah, is that really true? Just recently I wondered that such a device
would be even simpler when built into the Amiga replacing the Video
Hybrid chip. But I found for myself that this wouldn't be such a big
advantage, because you don't get 256 colors! It's more limited in choice
of possible color combinations than the ExtraHalfBright mode. I tried
to imagine an algorithm to make up a palette for a certain set of
needed colors for a certain image. But I found no solution.
Well, perhaps they found one for the DCTV.

But question to all: Is this really the trick they use?

-- 
Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk

ceej@pawl.rpi.edu (Chris J Hillery) (09/13/90)

peterk@cbmger.UUCP (Peter Kittel GERMANY) writes:

>In article <RQB%S}@rpi.edu> ceej@pawl.rpi.edu (Chris J Hillery) writes:
>>
>>Isn't DCTV the box which gets 256 screen colors by intercepting a 640x400
>>16 color screen and combining each pair a pixels (4 bits each) into one
>>8-bit pixel?  I know there is a box like this. In this case, all well and
>>good, you get 256 out of 16million (I think) colors, but only in 320x400
>>(or variations... not 640 mode at any rate).  This could be a consideration.

>Ah, is that really true? Just recently I wondered that such a device
>would be even simpler when built into the Amiga replacing the Video
>Hybrid chip. But I found for myself that this wouldn't be such a big
>advantage, because you don't get 256 colors! It's more limited in choice
>of possible color combinations than the ExtraHalfBright mode. I tried
>to imagine an algorithm to make up a palette for a certain set of
>needed colors for a certain image. But I found no solution.

Nono, I don't think you understand what I was saying. Lemme try a li'l
numerical example...

On the Amiga's Screen:
pixel 0: F      pixel 1: 5

    1111 0101    <- binary representation of pixels 0 and 1 in memory

DCTV (or whatever the box was) gets this, and combines them to:

On the DCTV output screen:
pixel 0:F5    11110101

so this pixel is color F5, or 245. Then it sends this to the monitor, using
whatever color happens to be in palette slot 245.

Again, of course, this means you get 2-for-1, or 320 width, resolution.
But, you do have 256 colors on the screen wherever you want them (ie, color
246 somewhere else would have a pixel of color F followed by a pixel of
color 6; duplicate Amiga colors != duplicate output colors). This is why
the actual picture the Amiga thinks its showing in 640x400 looks so weird.

StdDisclaimer: Again, I don't know if DCTV is this device. I just know this
device exists. I THINK that's what the DCTV is.

Ceej
aka Chris Hillery
ceej@pawl.rpi.edu


>Well, perhaps they found one for the DCTV.

>But question to all: Is this really the trick they use?

>-- 
>Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
>Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk

huebner@aerospace.aero.org (Robert E. Huebner) (09/13/90)

In article <R-C%N%_@rpi.edu> ceej@pawl.rpi.edu (Chris J Hillery) writes:
>Again, of course, this means you get 2-for-1, or 320 width, resolution.
>But, you do have 256 colors on the screen wherever you want them (ie, color
>246 somewhere else would have a pixel of color F followed by a pixel of
>color 6; duplicate Amiga colors != duplicate output colors). This is why
>the actual picture the Amiga thinks its showing in 640x400 looks so weird.
>
>StdDisclaimer: Again, I don't know if DCTV is this device. I just know this
>device exists. I THINK that's what the DCTV is.
>

Actually, the device you described sounds more like HAM-E from Black 
Belt Systems.  This device (HAM-E) fits between the RGB port and the
monitor on an A500 up to A2500 (A3000 de-interlaced would probably confuse
the hell out of it).  From what I've read, its waits for a certain
signaling line at the top of a screen (first scanline) and then begins
processing the picture to give you a HAM display with a 256 color register
from a palette of ? (a lot).  If this special scanline isn't present,
HAM-E just passes the normal video through, resuling in a system that can
co-exist with your workbench and so on.

My impressions of DCTV from magazine articles (what little there has been)
is that it is a compression system for outputting video to composite NTSC
only.  Supposedly a digitzed picture from DCTV can take as little as
33K of disk space (!?), and there are special paint programs that let you
manipulate these special images.  Hopefully we will get a peak at it when
AmiExpo rolls through or something.

If anyone has definite information on these new video enhancement products,
please set the net.record straight.

+----
Robert Huebner		huebner@aerospace.aero.org
			The Aerospace Corporation
+----

Radagast@cup.portal.com (sullivan - segall) (09/14/90)

>>>
>>>Isn't DCTV the box which gets 256 screen colors by intercepting a 640x400
>>>16 color screen and combining each pair a pixels (4 bits each) into one
>>>8-bit pixel?  I know there is a box like this. In this case, all well and
>>>good, you get 256 out of 16million (I think) colors, but only in 320x400
>>>(or variations... not 640 mode at any rate).  This could be a consideration.
>
>>Ah, is that really true? Just recently I wondered that such a device
>>would be even simpler when built into the Amiga replacing the Video
>>Hybrid chip. But I found for myself that this wouldn't be such a big
>>advantage, because you don't get 256 colors! It's more limited in choice
>>of possible color combinations than the ExtraHalfBright mode. I tried
>>to imagine an algorithm to make up a palette for a certain set of
>>needed colors for a certain image. But I found no solution.
>
>Nono, I don't think you understand what I was saying. Lemme try a li'l
>numerical example...
>
>On the Amiga's Screen:
>pixel 0: F      pixel 1: 5
>
>    1111 0101    <- binary representation of pixels 0 and 1 in memory

The name of the box that does this is the HAM-E device by Black Belt
systems.  Although 256 colors are theoretically possible, Black Belt
limited the number to 240 colors, and gives you 16 palettes (reselectable
on the fly) instead.  In its other mode, the HAM-E device uses a base
palette of 64 24bit colors, and then updates the 7 bits of either red,
green, or blue, in a HAM like fashion for each pixel.  
 
DCTV is similar in some ways, but isn't limited to working with 4 hi-res
bitplanes.  Instead it takes advantage of certain redundancies in the 
NTSC signal definition and makes those combinations impossible to describe
thereby making their data somewhat more compact.  Thus the DCTV box is
capable of somewhat greater output control, as long as the monitor is
an NTSC monitor. 

Instead of changing RGB values like the HAM-E, the DCTV works with Hue,
Saturation and Intensity.  Since saturation and Hue are co-dependent,
(changing one will also change the other over the next pixel or so which
is why you get color fringes in NTSC signals when changing between certain
colors) they are only modified half as often as the Intensity signal.
In general you have control over Intensity on every pixel produced, but
only have control over Hue and Saturation on alternate pixels.  As a 
result, DCTV produces quite useful output with 3 bitplanes of high-res
input.

All of the above was gleaned from open discussions on BIX and from 
Digital Creations' presentation at the First Amiga Users Group in
Palo Alto, California.  Any misunderstandings or misrepresentations
are purely my own...
...I do not speak for Digital Creations, nor are they accountable for
anything I might imagine them to have said.

                           -Sullivan_-_Segall (a.k.a. Radagast)
_______________________________________________________________
 
/V\ "I regret to say that we of the FBI are powerless to act in
 '   cases of oral-genital intimacy,  unless it has in some way
obstructed interstate commerce." -- J. Edgar Hoover
_______________________________________________________________
 
Mail to: ...sun!portal!cup.portal.com!radagast or
         radagast@cup.portal.com
 
Bix: radagast

peterk@cbmger.UUCP (Peter Kittel GERMANY) (09/14/90)

In article <R-C%N%_@rpi.edu> ceej@pawl.rpi.edu (Chris J Hillery) writes:
>>>Isn't DCTV the box which gets 256 screen colors by intercepting a 640x400
>>>16 color screen and combining each pair a pixels (4 bits each) into one
>>>8-bit pixel?  I know there is a box like this. In this case, all well and
>
>On the Amiga's Screen:
>pixel 0: F      pixel 1: 5
>
>    1111 0101    <- binary representation of pixels 0 and 1 in memory
>
>DCTV (or whatever the box was) gets this, and combines them to:
>
>On the DCTV output screen:
>pixel 0:F5    11110101
>
>so this pixel is color F5, or 245. Then it sends this to the monitor, using
>whatever color happens to be in palette slot 245.

Hmm, so they have own Color Lookup Table (CLU) circuitry built into
their device?

Anyone knows facts?

-- 
Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk

skank@du248-09.cc.iastate.edu (Skank George L) (09/14/90)

In article <403@cbmger.UUCP> peterk@cbmger.UUCP (Peter Kittel GERMANY) writes:
>In article <RQB%S}@rpi.edu> ceej@pawl.rpi.edu (Chris J Hillery) writes:
>>
>>Isn't DCTV the box which gets 256 screen colors by intercepting a 640x400
>>16 color screen and combining each pair a pixels (4 bits each) into one
>>8-bit pixel?  I know there is a box like this. In this case, all well and
>>good, you get 256 out of 16million (I think) colors, but only in 320x400
>>(or variations... not 640 mode at any rate).  This could be a consideration.

     This falls into the current Amiga video discussion, try this idea on for
size.  A third party developer designs a video card that fits into one of the
Amiga slots based on their favorite graphics coprocessor, Intuition is modified
slightly so that all graphic operations can either execute using the standard
Amiga graphics hardware *OR* they can use a jump table to jump to routines in
autoconfig memory occupied by this hypothetical card.  It also seemed to me
that such a card would invariably be loaded with it's own dedicated graphics
memory, freeing up chip ram and reducing bus contention.  This seems as though
this shouldn't be THAT difficult, however I just got my first Amiga a few days
ago, so I have no REAL idea of the problems involved.  The Macintosh uses a
similar scheme unless I'm mistaken?
     On a similar note, I heard a rumor, I think it was printed in Amiga World,
that Pixar, who did a very impressive graphics card for the Mac, was working on
a similar card for the Amiga.  Has anyone else heard this rumor, can anyone
lend creedance to it one way or the other?

                                         -- George

peterk@cbmger.UUCP (Peter Kittel GERMANY) (09/14/90)

In article <1990Sep14.063455.5219@news.iastate.edu> skank@iastate.edu (Skank George L) writes:
>
>     This falls into the current Amiga video discussion, try this idea on for
>size.  A third party developer designs a video card that fits into one of the
>Amiga slots based on their favorite graphics coprocessor, Intuition is modified
>slightly so that all graphic operations can either execute using the standard
>Amiga graphics hardware *OR* they can use a jump table to jump to routines in
>autoconfig memory occupied by this hypothetical card.  It also seemed to me
>that such a card would invariably be loaded with it's own dedicated graphics
>memory, freeing up chip ram and reducing bus contention.  This seems as though
>                                         -- George

Well, this *IS* difficult, because the different parts of the operating
system all depend on this current hardware, so a big part of the OS would
have to be rewritten. Also you risk to lose some of the important Amiga
features, eg being able to drag a screen and split your display into
two or more screens with totally different display modes. I don't think
you can teach a framebuffer card these tricks.

-- 
Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk

seanc@pro-party.cts.com (Sean Cunningham) (09/15/90)

In-Reply-To: message from ceej@pawl.rpi.edu

You're getting the Black-Belt HAM-E board mixed up with DCTV.
 
DCTV does full 24bit color.  They haven't stated any pixel resolution, just
that it's NTSC, which is measured in MHz...something like 5-5.5MHz
 
The HAM-E box is an entirely different beast.
 
Sean
////////////////////////////////////////////////////////////////////////////
  UUCP: ...!crash!pnet01!pro-party!seanc       | 
  ARPA: !crash!pnet01!pro-party!seanc@nosc.mil | " Fanatics have their 
  INET: seanc@pro-party.cts.com                |   dreams, wherewith they
                                               |   weave a paradise for
  RealWorld: Sean Cunningham                   |   a sect. "
      Voice: (512) 994-1602  PLINK: ce3k*      |                -Keats
                                               |
  Call C.B.A.U.G. BBS (512) 883-8351 w/SkyPix  | B^) VISION  GRAPHICS B^)
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\