Hi Guennadi, On Friday 27 August 2010 21:16:26 Guennadi Liakhovetski wrote: > On Sat, 7 Aug 2010, Laurent Pinchart wrote: > > On Saturday 07 August 2010 15:20:58 Guennadi Liakhovetski wrote: > > > On Sat, 7 Aug 2010, lawrence rust wrote: > > [snip] > > > > > > A mean squared error metric such as hypot() could be better but > > > > requires FP. An integer only version wouldn't be too difficult. > > > > > > No FP in the kernel. And I don't think this simple task justifies any > > > numerical acrobatic. But we can just compare x^2 + y^2 - without an > > > sqrt. Is it worth it? > > > > What about comparing areas ? The uvcvideo driver does (rw and rh are the > > request width and request height, format is a structure containing an > > array of supported sizes) > > > > /* Find the closest image size. The distance between image sizes > > is > > > > * the size in pixels of the non-overlapping regions between the > > * requested size and the frame-specified size. > > */ > > Well, nice, but, tbh, I have no idea what's better. With your metric > 640x489 is further from 640x480 than 650x480, with my it's the other way > round. Which one is better? Mine of course ;-) It's a good question... Your method minimizes the width/height cumulative difference while mine minimizes the area difference. What's better ? Or maybe the right question is does it matter ? > What we can do, if this really is important, we could make a callback for > user-provided metric function... Shall we? That sounds too complex for such a simple problem. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
