>> (With the two bug fixes, I can now wholeheartedly recommend the sinc4lan >> and sinc8lan kernels if you have cycles to burn.) > > Hmmm, what makes one kernel preferable to another? If, for example, > I'm mainly cropping/scaling from 720x480 to 352x480 (for either CVD > or 1/2 DVD) I've normally used 'cubicB' - is there a better choice > for that operation?
Well, it depends on what you want. The "sinc8lan" kernel gives the closest (implemented) to the ideal low-pass filter response needed for downsampling, but it is also the widest of all the kernels and thus takes more CPU. (For scaling in one direction only, the processing time is O(n) in the width of the kernel.) Of the cubic kernels, "cubic" is considered "ideal" from the perceptual standpoint (trade-off of softening/ringing/aliasing) according to a paper or two. Compared to that "cubicB" softens/blurs the image more (by rolling off more lower-frequency material than necessary) --- but that helps you squeeze more bits out of your MPEG encoding. This is all revealed in the table of frequency response graphs on the web page. (I need to add a table of timing benchmarks, too.) (That's pretty much what I know so far; if anyone has any more factors to take into account, pleae enlighten me!) -matt m. ------------------------------------------------------- This SF.net email is sponsored by: eBay Get office equipment for less on eBay! http://adfarm.mediaplex.com/ad/ck/711-11697-6916-5 _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
