DVL-Digest 919 - Postings: Index CLEANER DVD VCD??. - (2) DVCams & Firewire & DV Capture I'm confused - progressive scan... would be better if the term INTERLACE ARTIFACTS had never be CLEANER DVD VCD??. - "Perry" This whole Pseudo DVD area is full of mines and short of affordable commercial applications, particularly for the Mac. Does anybody have any suggested web forums where these matters are discussed at length? cheers Perry Mitchell CLEANER DVD VCD??. - "Perry" From: Dany Coryet Why do you call it PSEUDO?...because there's MPEG-4 as well as 2? DVCams & Firewire & DV Capture - Adam Wilt Is there a way to capture video from a DVCAM via Firewire port a few > times faster than its normal speed? Sadly, no. > I mean is it possible to capture 40-mins video in a 5 minutes time, > since firewire supports up to 400 Mbps. Omneon Video Networks currently sends 4x realtime DV around on FireWire, but AFAIK they are the only ones. And to get 4x DV in and out of the system, the only way is to use an SDTI MediaPort which connects to third-party DV decks with 4x transfer mode. Cheers, Adam Wilt I'm confused - progressive scan... - "Perry" I think a lot of the confusion about progressive scan is caused by there being two main reasons for wanting it, that are quite different: 1) For maximum resolution stills 2) For 'movie effect' frame mode motion capture. There are many cameras that will do one or the other, but very few that do both at the same time! The other factor that maybe isn't obvious to the non-engineers, is that a CCD is an analog device that is locked into certain modes of operation when it is designed. When people ask 'why can't I have this?' The answer is often that the chip set simply cannot do it! Perry Mitchell would be better if the term INTERLACE ARTIFACTS had never be - Adam Wilt It probably would be better if the term INTERLACE ARTIFACTS had never > been used because when folks eliminate them by using Frame Mode -- they > think they have stopped using INTERLACE video and so must be using > PROGRESSIVE. They have not.... > > 1) the CCD -- always "progressive" > > 2) the manner in which lines are used -- almost always line-pair > averaged > > 3) the manner of creating a "frame" -- from one capture or two. > > 4) the video system -- interlaced or progressive. For any camcorder we > are talking about -- this is always interlace. > > Now let's hope things haven't gotten more confused. I fear this oversimplification *will* only confuse things further. Yes, the CCD is at its heart always proscan -- but the resulting frame can be either proscanned or interlaced depending on which lines are used, which are thrown away, and when in time the using/throwing is done. Most cameras in normal shooting create interlaced frames: two fields captured at separate points in time. A freeze frame of a scene with motion in it will show "combing" artifacts from the time difference between the fields. A PD150 in proscan, an XL1s in Frame Move Mode, or an HDW-F900 in 24p mode all capture progressive-scan images, where both fields are captured simultaneously and there is no interlaced artifact visible in an extracted frame. All of these cameras do indeed use segmented-field, interlaced recording formats, and we most often watch them on interlaced displays (unless we're using DLPs or LCDs, which are almost always progressive -- fun, huh?). But that doesn't make their image capture interlaced any more than film transferred to NTSC video is captured as interlaced! Cheers, Adam Wilt (diese posts stammen von der DV-L Mailingliste - THX to Adam Wilt and Perry Mitchell :-) [up] |
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