CompuServe Messages

>> What kind of compression settings have you tried? How much time do you get on what size hard-drive before you run into problems? << PMFJI, but here are some of my Perception experiences: I'm using the Perception (w/ capture card) and a Micropolis 3243AV Gold drive. The computer is a DEC XL90 — I originally installed the PVR in a P66, but the PVR didn't like the bus speed, so I had to swap computers (contact DPS on this issue before purchasing!). Other than the bus speed issue, installing the PVR was a no-brainer. The 3243 drive, a 4Gb Fast SCSI-2 interface device, has MAX/MIN advertised sustained data rates of 7.2/4.0 Mb/second and an average seek time of 8.9 msec. Actual performance will vary across the surface of the drive, decreasing as you move to the inside tracks; disk analysis through the PVR suggests I am getting about 6.2 Mb/second on the outside tracks and about 3.75 Mb/second in the innermost tracks. The PVR uses adaptive compression at the frame level (it may be at the field level, but the documentation says frame) to maximize compression efficiency. The main quality factor, as in the PAR, is block limit (the maximum amount of space provided for each frame). There appears to be approximately 68 DPS "blocks" per Mb per second. DPS includes four default "record quality" settings (you can create your own) which are as follows: Name Block limit MB/Sec —————————————————— Offline 100 1.5 Industrial 270 4 Broadcast 340 5 Digital 410 6 For perspective, the best block limit I could ever get away with on the PAR was 210. (There are various explanations for this: my IDE drive was slower, the PAR has less-sophisticated compression, etc.) There's no point in comparing the PAR and PVR from an equipment standpoint: they are completely different devices. It is worthy to note that the PVR is component throughout–an important issue for broadcast applications. From a subjective standpoint, there is definitely NO comparison: the PVR is produces (and digitizes) vastly superior video than the PAR. Speaking simply in terms of JPEG artifacting, the PAR at its best falls a little below the "Industrial" setting on the PVR. At "Broadcast" and better, you cannot really discern artifacting, even on a BVM-1910. The signal quality (rendering) leaving the PVR is top-notch (to be expected from DPS). My animation looks, well… like it came off an Abekas. Everything we've done with the PVR has been at the "Digital" level, out of sheer principle (and glee). I have digitized as many as ten minutes of video and I've output many minutes of 3D Studio frames, and I have yet to see the PVR glitch–all at "6 Mb/second". (Because of the adaptive compression, I'm finding also that the video rarely gets anywhere near the block limit threshold, so the PVR isn't really even pushing 6 Mb/sec.) Editing performance is, so far, very good with the 3243: we've done some simple cuts-only output from the PVR with flawless results. I havent had the opportunity yet to test the PVR with Speed Razor for editing and generation degradation: that will be the acid test. I expect to get about 15 minutes of video out of the 3243 at the 6Mb/sec setting. A special note about the capture card on the PVR: its ability to capture image detail from video is astonishingly good. We digitized several minutes of ultra-detailed Betacam imagery and the PVR retained almost everything. I hope to run some tests on this, now that my curiosity is piqued.