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From: rjc@geech.gnu.ai.mit.edu (Ray Cromwell)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: What the heck IS "Interactive TV"? (long)
Message-ID: <1991Apr16.033813.4745@mintaka.lcs.mit.edu>
Date: 16 Apr 91 03:38:13 GMT
References: <1991Apr15.111414.10624@ncsu.edu> <1991Apr15.164226.15219@cunixf.cc.columbia.edu> <1991Apr16.003917.1628@ncsu.edu>
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In article <1991Apr16.003917.1628@ncsu.edu> kdarling@hobbes.catt.ncsu.edu (Kevin Darling) writes:
>es1@cunixb.cc.columbia.edu (Ethan Solomita) writes:
>>>> DCTV provides DYUV color the same as CD-I.
>>>
>>>That's the first I'd heard that about DCTV. Please tell us more details!
>>>In fact, I haven't yet seen a decent article up here about DCTV's guts.
>>>Got a file or two you can post over in .graphics or .hardware?  (There
>>>are some questions from others there too).  
>>>
>>	Ohh. I think I understand. At one point I was saying that
>>DCTV provided TV quality video and you thought I was crazy. You
>>probably assumed I was typing CDTV. No, no!
>>	DCTV, by Digital Creations, plugs into the Amiga RGB port
>
>No sir, I knew what you meant :-).  I'd just never read that DCTV used DYUV.
>Ahh, maybe you mean it can read/write DYUV files?  That makes perfect sense.
>But no, my question had nothing to do with CDTV/CD-I.  It was curiousity
>about DCTV, about which I don't think I've seen a good tech report up yet.
>  thx again - kev <kdarling@catt.ncsu.edu>

  DCTV encodes a 3 or 4 bitplane hires image into a composite NTSC
'television' quality image contain ~4million colors. DCTV usually
demos their unit by playing back a movie clip at 30fps from the
harddrive. DCTV uses a proprietary file format, but I've heard them
mention their box works on DYUV space. Usually DCTV IFF files
compress down to ~30k which is suitable for animation especially
if frame to frame delta's are applied.

 CDTV+DCTV would not only rival CD-I video, it would beat it. With
this combination you'd have the Amiga's sprites and blitter at your
disposal which is much better than the simple dual-playfield/overlay
CD-I has.

  DCTV will work with CDTV, however since Commodore hasn't licensed it
for CDTV as default, it won't really be used much.

 One thing I don't understand is why CD-I chose RLE compression
for their images. RLE isn't a very good compression technique. It works
best on line art, not raw digitized picturres. Quad Trees, Huffman encoding, or
LZ/Yabba/Whap all provide better compression.

--
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| rjc@gnu.ai.mit.edu   |   //  The opinions expressed here do not in any way  |
| uunet!tnc!m0023      | \X/   reflect the views of my self.                  |
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