CompuServe Messages

Richard: Perhaps I can start to answer some of your questions… >>Of course this makes you wonder why they sell boards with hardware compression on the fly on input, but it does look nice on promo copy on the outside of the box. <g>.<< The answer is data rate. Video is a lot of information every frame and there are, at a full NTSC frame rate, 30 fps. If you try to save 30 uncompressed frames or pictures a second to a hard disk, you'll need very good through-put. With a standard system, they're likely to be small pictures or you're likely not to get all 30 frames. Compression technology reduces the amount of data the system needs to store. Sure, that may mean quality is likely to go down depending on the amount and quality of compression, but at least you're more likely to get all the frames. MPEG and M-JPEG are not the same. Both are based on the JPEG standard (used for compressing still photograph) but they're different after that. For NTSC video, M-JPEG, or Motion-JPEG, is simplistically like storing 30 JPEG frames each second. MPEG on the other hand stores a JPEG frame every, say, twice a second (these are called I-frames) and stores only differences in the rest of the frames (these are a combination of B- & P-frames). In other words, if a person is walking past a solid white wall, MPEG will store the white wall only in the I-frames. The rest of the frames will ignore the white wall, where it is the same, and store just the man walking. That means much lower data rate because there much less information needed. BUT, you don't have every frame for editing. Also, MPEG is much more difficult to do in real time (see New Media Mag, current issue). >>I spoke to Adobe and they "suggested" boards from Alpha (MegaMotion), Diamond (VideoStar) and Fast (MovieMaker Pro) and kept mumbling about Miro.<< All will work. If you're going back out to tape, I'd say the miro card has the best picture quality. If you're going not going out to tape (ie. multimedia type app.) you'll do better with another. For multimedia, though NOT for printing to tape, I'd add the Intel Smart Video Recorder Pro to the list. That's just a start. For what it's worth… Jeff Sauer