CompuServe Thread

#Field rendering question

4 messages in this thread
#95962From: Gregory MacNicolApr 7, 1994 3:49 PM
Jonas, I am experimenting with rendering on fields (to disk, then to tape). But there are some things I don't understand. Perhaps you can clarify them. When I render a field to the display (and disk), I first see a field being displayed during the "transforming" process. Then it renders another field over the original image. Thus the image, like the file, has 2 fields instead of one. I thought that I would be rendering a field instead of 2. Could you explain what is going on? Incidently, I am doing this to circumvent the problems indiginous to MPEG where only the fields are compressed; I want to Y-blur the fields before I put them to tape. Thanks. – Gregory
#96114From: Yost GroupApr 8, 1994 10:27 AM
When 3DS renders to fields, it first writes field 0 to the frame, leaving field 1 scanlines blank. It then goes back and writes field 1 to the frame on those blank scanlines. – G
#96150From: Gregory MacNicolApr 8, 1994 1:05 PM
Gary, Sure, but that's not what I want. I want the fields, not sequential TGA files consisting of two fields in a file. What I want to do is save the individual fields, filter them in the Y direction, and then combine them in one TGA file (and then convert them to exebyte format, then MPEG the images at PVR). The problem that I am trying to solve is MPEG's using only the fields when it converts and compresses the images. I'd like to get the highest image quality in MPEG, which, if done normally, looks awful. I've tried a lot of tricks but encountered Moire patterns or worse. Other alternatives will be gleefully appreciated. – Gregory
#96172From: Yost GroupApr 8, 1994 3:08 PM
There are a couple of very straightforward ways to get just individual fields out of the system. The way I'd do it is to Rescale time 2x to double the number of frames, and then halve the vertical resolution (to 243 for a 486-pixel frame). Another way would be to render in fields at full res with normal time-scale, and then use a matte in video post to strip out one field or the other. A third way would be to use an IPAS routine. I think that Greg Pyros and Gus might've come up with something that'll do that. You could check with them about it. – G