woolstar@nntp-server.caltech.edu (John D. Woolverton) (11/15/90)
I just returned from Comdex, where one of the principle things I went looking for was C-Cube. C-cube had a nice booth with companies showing off both a Macintosh and IBM version of video boards that could do real-time playback off of hard drives. In the center of the booth was a Mac playing back the ending of Star Wars and other video snippits at 25:1 compression from some nameless hard drive, and other displays were loading large images with little compression at nice speeds off of slow disks (like 100-200k/sec). Now at 25:1 compression, you can tell the difference between original and JPEG on a RGB monitor, but it is very difficult on a TV. A demonstration tape from C-Cube itself was showing off a very colorful moving image at 16:1, with even better results. I was curious if one could find a disk drive that could spit out enough bytes to keep out, and found several. Both Segate and HP, have 5,1/2" drives in 600, 1200, and 1600 MB capacities that will support > 3MB/s sync SCSI transfers. The high end HP claims were around 5MB/s. And if you are insane, you can get the 8" SABER IPI2 drives, with 3 GB capacity and unreal transfer rates. (Silicon Graphics has a demo where they display 16bit 500x300 real time raw off of two IPI2 drives.) As far as how this lossy compression compares against the $100k professional machines, I have a lot of experience working with the Abekas, a digital frame recorder. It too did bandwidth sampling and threw away about 33% of the incoming data, storing YUV with U and V averaged across pairs of pixels. You could tell the difference between the Abekas and a RGB original as well. Again, once you went to NTSC, nobody could tell the difference. So, I'm looking to jump on the JPEG bandwagon, dump the single frame recorder, and video controllers (about a $12k investment), and work with a much simpler system. John D. Woolverton, video engineer woolstar@cobalt.caltech.edu "Read my MIPS: No new VAXes"
mcdonald@aries.scs.uiuc.edu (Doug McDonald) (11/16/90)
In article <1990Nov15.023216.12172@nntp-server.caltech.edu> woolstar@nntp-server.caltech.edu (John D. Woolverton) writes: > > Now at 25:1 compression, you can tell the difference between >original and JPEG on a RGB monitor, but it is very difficult on >a TV. On some pictures. >A demonstration tape from C-Cube itself Meaningless. Lets see demonstrations tapes from neutral parties. Or people out to find problems. > > So, I'm looking to jump on the JPEG bandwagon, dump the single >frame recorder, and video controllers (about a $12k investment), >and work with a much simpler system. > For broadcast TV, quality is not very important, NTSC is so crappy anyway. Lets think about real high definition TV, not poorer than NTSC. Doug MCDonald