Yeah, filtering... but which one??greenspun.com : LUSENET : Video CD : One Thread
Hi all. After reading a lot of Q&A in this forum, it seems that everybody agrees that to obtain the best possible MPEG-1 file, it is desirable to "filter" the .AVI before the encoding process. Little information however had I found about which exact filter(s) to use and its settings (I mean: numeric values).
I would particulary appreciate any suggestion, and in general, invite all of you to share your experiences with Premiere's filters and which one(s) had given you the best final MPEG file, so we can find out if there is a general agreement at this point and, of course, learn more and more about this stuff called VideoCD which is undoubtly the main reason for all of us to be here. Thank you!
-- Matias (firstname.lastname@example.org), October 04, 1999
All I can tell you about is those which I use: after capturing the video half-res with PC-VCR or VirtualDub with Matrox Marvel G200, I encode either with Panasonic or DVMPEG. The filters we're talking about here are those that can be found in the encoders I mentioned: in DVMPEG's AVI2MPEG app, in the global properties you are given a choice of low-pass or smoothing. These filters have to do only with cleaning up a noisy video to begin with. Panasonic is more flexible because apart from filtering out the noise (and allaows how much amount you want to take out) there is also an adaptive filter which corelates movements between frames and greatly reduces blockiness in the final MPEG file. Both encoders give you a choice of half- or full- pel motion estimation; this basically has to do with how much change in adjacent pixels are to be taken as an indication of so much difference from one area of a frame to the same area in the next. Half-pel gives better motion estimation (smoother movement) but creates a smoothing effect which might cut out details too much; full- pel more or less retains sharpness at the expense of more blockiness & pixelation in areas of greater motion. The presence or absence of these filters in any encoder, h/w or s/w, can spell the difference between great MPEG-1 and something fit for the dumps. It's not easy to filter a h/w encoder situation, and to get around that Darimvision, for example, has a dedicated M-filter card that connects between your VCD output and the MPEGator (for one) input; this is an ISA card whose attributes you control with an aplet on your PC.
-- EMartinez (email@example.com), October 10, 1999.