Path: utzoo!attcan!uunet!samsung!sdd.hp.com!elroy.jpl.nasa.gov!jarthur!nntp-server.caltech.edu!ziggurat!tim From: tim@ziggurat.gg.caltech.edu (Tim Kay) Newsgroups: comp.sys.next Subject: Re: NeXT Dimension as descrambler Keywords: descrambler, digital video, real-time Message-ID: Date: 2 Oct 90 22:22:36 GMT References: <443@kaos.MATH.UCLA.EDU> Sender: news@nntp-server.caltech.edu Organization: California Institute of Technology, Pasadena Lines: 30 Nntp-Posting-Host: ziggurat.gg.caltech.edu In <443@kaos.MATH.UCLA.EDU> dgc@euphemia.math.ucla.edu (David G. Cantor) writes: >Most cable TV scrambling systems simply suppress or otherwise confuse >the synch and may invert the color in the composite video signal. >Presumebably, since the NeXT Dimension can do real-time video digital >computations, it could perform real-time descrambling quite easily. >Would this make it the most expensive descrambling "black box" that one >can purchase? No, no, no. The C-Cubed CL550 chip implements the JPEG (Joint Photographic Experts Group) image compression and decompression algorithm. That algorithm is hard-wired into the chip. The chip can't do any real-time video processing except for that one task (plus simple RGB to YUV, and similar conversions). I would guess that, before any data could be gotten to that chip (after all, the chip takes digital data), the incoming video must be genlocked. Before you can genlock, you need a sync. Therefore, you would need a descrambler before you can even feed the data to the NeXT machine. So, while the NeXT box can do some fast, general purpose signal processing on audio data, it can't do any fast (e.g. real-time) processing on video data. Besides, read-time descramblers are incredibly easy to build. Why tie up a $14,000 work station when $20 worth of parts will do the trick. And even then, you aren't doing the trick. While the video is scrambled with simple sync suppression or inversion, the audio is usually encrypted with DES. That is much harder to decode (without the key). Tim