On Mon, 17 Jun 2002 13:00:38 +0200 Ronald Bultje <rbultje@xxxxxxxxxxxxxxxxxxx> wrote: > There are several quickcam models. Some of them have compression, with > which you can get more than 5 fps. The problem is mainly that if you capture > (example) RGB24 frames at a resolution of 384x288, you're doing a total of > 3x384x288=331.776 byte/frame. given that the total busrate of USB (ideally) > is 2 MB/s, > you can get at moest 2*1024*1024 MB/s divided by 331776 byte/frame = 6 > frames/sec. AFAIK, USB bus is 12Mb/s. If images is 3*384*288 (331776 bytes), I should get 12000/332 = 36 frames per seconds, which is quite enought. I think that in fact, the driver is not always able to decode an image, since I get some error messages in the logs. My model is (from /proc/bus/usb/devices): D: Ver= 1.10 Cls=ff(vend.) Sub=ff Prot=ff MxPS= 8 #Cfgs= 1 P: Vendor=046d ProdID=0870 Rev= 1.00 S: Product=Camera C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr= 90mA I: If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none) E: Ad=81(I) Atr=01(Isoc) MxPS= 0 Ivl= 1ms E: Ad=82(I) Atr=03(Int.) MxPS= 1 Ivl= 16ms I: If#= 0 Alt= 1 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none) E: Ad=81(I) Atr=01(Isoc) MxPS=1023 Ivl= 1ms E: Ad=82(I) Atr=03(Int.) MxPS= 1 Ivl= 16ms T: Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2 B: Alloc=700/900 us (78%), #Int= 0, #Iso= 20 Whenever I had some time, I'll lock closer to the raw data send by the cam'. Benoit
