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| Unofficial VirtualDub Support Forums > Advanced Video Processing > Tips/tweaks/codec/etc. For Out To Projector |
| Posted by: David.Bucci Jan 6 2003, 04:59 PM |
| Hi, all -- i'm helping a non-profit do some video that they need to project out via two different RGB projectors (sorry if i'm using the incorrect terminology). One projector takes direct video feed from the PC, a different (older, cheaper) one requires a scan converter/TV out. I've done a few clips for them, and haven't been satisfied with the quality. Looking for any advice on best form of processing to get clearest results. E.g., what to do with the interlacing (and do the same thing for both projectors, or separately optimized clips), resolution to work at, filters to apply, etc. Our input source is usually my DVcam, Panasonic PV-DV600, which when I capture to DV-2 in EditStudio gives 720x480. We also sometimes use clips from movies/shows, and these come in at various resolutions etc. Thx! |
| Posted by: Morsa Jan 6 2003, 08:53 PM |
| Well your question isnīt very clear. What are the quality issues you are talking about? Always use standard resolution (720x480 NTSC, 720x576 PAL). If you use Standard video projectors use interlaced material unless the projectors support progressive material. The filters depend upon your source, so if we canīt see the problem we canīt tell what filter to use. The only advice I can give you by now is to take care of yellow.Video Projectors always have ugly yellows, so you could use a color correction software to retouch them and get a nicer projection. |
| Posted by: David.Bucci Jan 6 2003, 10:30 PM |
| > Well your question isnīt very clear. >What are the quality issues you are talking about? Thank you for replying, Morsa. We're seeing the following quality issues: - the typical kind of blockiness that you see with too low compression rate (it's not visible on the computer screen, though, i kept upping the bitrate till it was eliminated from the computer screen) - graininess at some points, again, which i've filtered away on the monitor - lnot bright enough (old projector has a weak bulb); i haven't yet tried the obvious fix for this, but while we're on the topic ... These are cheap projectors, i'm sure they're not progressive scan ... so you're recommending to not deinterlace at all? Would that be affected by how many lines the projector is actually sending out (scan lines ... don't know correct terminology in projector-speak). Thanks for any further feedback! |
| Posted by: Morsa Jan 6 2003, 10:42 PM |
| Try to be more specific please. The projectors can show you anything you send them.It doesnīt matter if the video was deinterlaced or not, if you are sending it through a video output it always will be interlaced. Donīt know what resolutions your projectors support, but if you are using a DV camera it doesnīt matter cause you only can get 720x480 or 720x576. If you use DIVX you need to deinterlace the video first. If the projector works directly with a VGA input, it should be progresive, so it would be good to send progressive material to it. What codec are you using and why? What kind of processing are you applying to them? What resolution are you using? What format are your sources? |
| Posted by: David.Bucci Jan 7 2003, 09:44 AM |
| Sorry for not providing enough info, I'm learning as I go ... >The projectors can show you anything you send them. >It doesnīt matter if the video was deinterlaced or not, >if you are sending it through a video output it always will >be interlaced. Am I to understand that the projector will interlace the material, even if I've deinterlaced? >Donīt know what resolutions your projectors support, I'm going to have to check, unsure. Is it required to send a supported resolution, or will a projector resize? otoh, is it better to send a size that eliminates the need for the projector to resize? >but if you are using a DV camera it doesnīt matter cause >you only can get 720x480 or 720x576. I'm getting NTSC 720x480. >If you use DIVX you need to deinterlace the video first. Oh ... could you explain why? and would I not need to with a different codec (e.g. on not MPEG based?)? I have been deinterlacing, but thought you were suggesting that I not deinterlace (at least for the projector that requires a scan converter) ... >If the projector works directly with a VGA input, it should >be progresive, so it would be good to send progressive to it. Ok ... I'll have to research how to accomplish that ... avisynth "separatefields" followed by Thalin's smart deinterlace? >What codec are you using and why? I've tried mpeg1, mpeg2, divx and the educational one. >What kind of processing are you applying to them? I've been deinterlacing (blend) with the internal filter, and then trying different resizing (or not) and smoothing. None have done much to reduce blockiness and graininess. >What resolution are you using? I've tried leaving it alone (720x480) and crop/resize to 320x240. >What format are your sources? DV. I've been studying tonight, and I suspect that a part of my problem is that the DV codec is mpeg-like (in terms of artifacts it tends to produce) and i'm then compressing with another MPEG codec (1, 2 or 4). Is that a reasonable supposition? Thank you again for your time, and sorry my questions are so basic, i'm coming up to speed here ... d. |