--- Mathieu Bouchard <[EMAIL PROTECTED]> schrieb: > On Thu, 28 Dec 2006, Ivica Ico Bukvic wrote: > > > Thanks for the advice but I am hoping to avoid > webcam due to inherent > > quality/fps decrease. > > USB2 is 40 times faster than USB1: at 400 mbps, in > 720x576, full color 24 > bits per pixel, cameras could do 40 fps... but > typically they don't, they > use half the data rate (decimation of chroma > columns, as in most broadcast > video) and have a cap at 30 fps because anyway the > motion is already > blurry enough at 30 fps.
anyway, though it theoretically should be possible to capture a webcam with [EMAIL PROTECTED], i couldn't find a cam yet, that supports these values. also, it is so confusing, that often they are advertized as usbII capable cams, but actually they don't make use of the bandwidth. further you find often a maximum framerate in the specs, but not which dimensions these maximum rate is related to. webcam sellers are really pissing me off. i bought a spc900nc, which works with the opensource pwc linux webcam driver. though this cam should be capable of capturing at 90fps according to the specs, i couldn't reach that rate neither with the proprietary windows driver nor with the pwc driver. the maximum with the pwc i could get is [EMAIL PROTECTED], which is less than 1/4 of what you say should be possible with usbII. more moanings about webcams: it's hard to tell in advance, if it will be possible to switch automatic gain control/automatic white balance/automatic shutter time on and off, which could be important when using a cam with gem/pdp/gridflow. with the cam i mentioned above, i have the following colospace problems: -pdp is capturing the cam as expected -gridflow captures it only in yuv420p colorspace and one needs to convert it to RGB using gridflow objects, which is heavily cpu expensive. -gem shows the captured image as bgr instead of rgb, so colors red and blue are swapped. it is possible to convert it to rgb with [pix_colormatrix], which is also very cpu expensive. fazit: webcams are kind of an annoying topic and i can really understand ivico's efforts to get a dv-cam working with gem. roman ___________________________________________________________ Telefonate ohne weitere Kosten vom PC zum PC: http://messenger.yahoo.de _______________________________________________ PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list