Le Samedi 18 Mars 2006 23:10, Florian Lohoff a écrit : > On Sat, Mar 18, 2006 at 09:41:31PM +0100, michel Xhaard wrote: > > Flo, > > Are you sure a webcam with isochronous pipe can just get a single image ? > > The camera used to work a little while ago with vgrabbj like a charm - > It did on a Dual Xeon 2.4Ghz With your Dual Xeon 2.4Ghz you can play with 4 Vimicro webcams in real times :) > > I only support stable vanilla kernel, so wait for 2.6.16 > > official. Your PII is > > As i said - i also tried 2.6.15 with no success - same oops ... > > > to low to decode jpeg in real times with a Vimicro/zstar chipset. A video > > stream in VGA at 30 fp/s need a strong CPU, a PIII 500Mhz is a minimum :) > > regards > > Nevertheless it should rather send empty images or nothing than die. An > Oops or "BUG" is _always_ the kernels fault ... Hmm, spca5xx is design for running on a strong enought machine, your PII is to slow and cannot decode the jpeg stream in times. A usb isochronous webcam is a streaming video device and never provide a single picture but a stream of pictures send with small packet on the usb bus. The iso handler collect the packet and when a frame is empty schedule a tasklet to decode the jpeg. What happen here is the handler collect the frame faster than the decoder. I have set another driver for the vimicro chips design for small hardware (spca5xx-LE ) this one never decode the stream but instead forward the frame on userspace. I use it with a small TCP/IP server that way the video is forward to TCP and can be used by others TCP client. I use it with a Etrax Soc 100Mhz and can carry VGA stream in real times. Maybe have a look regards -- Michel Xhaard http://mxhaard.free.fr
