Hi! > From: [EMAIL PROTECTED] > I decided to compare using the --reduce-hf switch of mpeg2enc to other > methods for reducing noise and the bitrate, after having ignored it > previously. I was pleasantly surprised. To take an example, I > converted noisy DV footage to DVD format with -q 5 and -b 8500:
Out of curiosity what threshold (-t) and depth (-d) values did you use with yuvdenoise? Or did you go with the defaults (5 and 3 respectively)? > no denoising : 8300 kb/s (mostly hitting the upper bound) > yuvdenoise : 7700 kb/s > --reduce-hf : 7400 kb/s > yuvdenoise + yuvmedianfilter: 6000 kb/s > yuvdenoise + --reduce-hf : 4900 kb/s > all of the above : 3600 kb/s > > Note that while --reduce-hf or yuvdenoise alone is only a modest > improvement, together they reduce the bitrate substantially. But Can I say "I told you so?" now? <grin> I have found the combination of light to moderate (-l 1 or -l 2 with yuvdenoise) and -N to mpeg2enc to produce excellent results without noticeable softening of the image and the bitrate's perfect for DVDs in the ~80-90 minute range. To get a 2hr6m movie to fit I did fall back to '-q 6' the other day. > here's the thing - I can't see the difference between yuvdenoise alone > and yuvdenoise with --reduce-hf. There's no free lunch, so can --reduce-hf|-N Reduce high frequency resolution - useful as a mild noise reduction It does say "mild" but, as you mention, it is extremely effective and without apparent side effects. > somebody please tell me what sorts of artifacts I need to look for? I I thought the effect was supposed to be a very slight reduction in sharpness. > filtering) look like, but unless my eyesight is worse than I think, > --reduce-hf is a lot more subtle. I was assuming that fine detail > would suffer, but I don't really see that. But then again my camera > doesn't really capture too much fine detail. I think all that is telling us is that there is information present which is not visible to the human eye (at least via a TV or monitor) but which of course the encoder "sees" and has to deal with. Thanks for the chart - it's quite similar to the one I'd done for myself a while back when I was experimenting with the options. Steven Schultz ------------------------------------------------------- This SF.net email is sponsored by:Crypto Challenge is now open! Get cracking and register here for some mind boggling fun and the chance of winning an Apple iPod: http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0031en _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users