* Steven M. Schultz on Thursday, April 06, 2006 at 11:03:49 -0700: > On Thu, 6 Apr 2006, Christian Ebert wrote: >> What about -H|--keep-hf ? Supposing I just want highest quality? > > I think it would be a good idea to define "highest quality" ;)
Oops, sorry for being so vague. > The > same type of request/desire comes up a lot on a couple forums I lurk > in. It's often in the form of a statment that implies the existence > of a magic option or tool that will give a perfect (restored/enhanced > to be what the user *wants*) Yeah, the mimimum I expect from mpeg2enc is to guess what I actually want ;-) Ok, let me try to be more specific. The case I had in mind was to how to put DV footage (shot and edited by yours truly) on DVD. Meaning that a) I have (at least for the projects I have in mind) not space constraints because the DVs are not long enough to cause worries in that direction. b) AFAICS the only constraint I have is the bitrate as I have to compress to MJPEG-2. So I don't mind waisting bits even for "unseen quality" (to quote your other mail), I just want to lose as little quality as possible when I compress. > -H can actually lower the quality. Remember - there is a hard limit > on the bitrate you can use and -H increases (often dramatically) the > number of bits used to encode an image. IF the number of bits/sec > available is not sufficient then the encoder has NO choice but to > lower the quality (by increasing the amount of lossy compression > performed). Using -H has, the times I've used it, raised the > average bitrate about 30%. IF you're already at the maximum for > a project (2hr movie on a DVD is limited to ~4.7Mb/s) then increasing > the number of bits required will cause the quality to be dropped (by > higher lossy compression) to make those bits available. > > If you're using double layer media and have sufficient space then -H > might be usable but many projects are bitrate/size constrained and > are already at those limits - no leeway or headroom left. As my source has much higher quality, if I understand you correctly, it would not make sense to apply the -H option because of the bitrate constraint for DVD. Please correct me if I am wrong. Hope I have been a few bits clearer. And thanks for taking your time for a "lossless" explanation. c -- _B A U S T E L L E N_ lesen! --->> <http://www.blacktrash.org/baustellen.html> ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ Mjpeg-users mailing list Mjpeg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mjpeg-users
