... >> y4mscaler -S option=sinc:8 ... >> >> will perform very high quality scaling and I think the artifacts >> will disappear. > >The sinc* kernels are very bad at removing noise. IMHO, the >cubic* kernels are better for this job...
A factor to consider (for why the sharp-cutoff sinc* filters are actually better than the gradually rolling cubic* filters) is the aliasing issue. The gradual filters leave more undesired HF content, which gets folded into the rest of the spectrum when scaling. This shows up as more power in the HF end of the result --- which, I think (someone correct me if I'm wrong), means that an MPEG encoder will try to allocate more bits to that part of the spectrum than it would otherwise. Aliasing will produce artifacts before encoding, and the strained bit allocation can make those artifacts worse after encoding. (Keep in mind that the aliasing with the cubic filters isn't so bad. Box filters, on the other hand, really suck ass.) -matt m. ------------------------------------------------------- The SF.Net email is sponsored by EclipseCon 2004 Premiere Conference on Open Tools Development and Integration See the breadth of Eclipse activity. February 3-5 in Anaheim, CA. http://www.eclipsecon.org/osdn _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
