Hi! > > > + /* Auto/manual exposure */ > > > + ctrls->auto_exp = v4l2_ctrl_new_std_menu(hdl, ops, > > > + V4L2_CID_EXPOSURE_AUTO, > > > + V4L2_EXPOSURE_MANUAL, 0, > > > + V4L2_EXPOSURE_AUTO); > > > + ctrls->exposure = v4l2_ctrl_new_std(hdl, ops, > > > + V4L2_CID_EXPOSURE_ABSOLUTE, > > > + 0, 65535, 1, 0); > > > > Is exposure_absolute supposed to be in microseconds...? > > Yes. OTOH V4L2_CID_EXPOSURE has no defined unit, so it's a better fit IMO. > Way more drivers appear to be using EXPOSURE than EXPOSURE_ABSOLUTE, too. > > Ideally we should have only one control for exposure. No. N-o. No no no. NO! No. N-o. NONONO. No. NooooooooooOOO!!!!!!!!!!!!! Sorry, no. Userspace needs to know exposure times. It is not so important for a webcam, but it is mandatory for digital camera. As it gets darker, autogain wants to scale exposure to cca 1/100 sec, then it wants to scale gain up to maximum, and only then it wants to continue scaling exposure. (Threshold will be shorter in "sports" mode, perhaps 1/300sec?) Plus, we want user to be able to manually set exposure parameters. So... _this_ driver probably should use V4L2_CID_EXPOSURE. (If the units are not known). But in general we'd prefer drivers using V4L2_CID_EXPOSURE_ABSOLUTE. Your car has speedometer calibrated in km/h or mph, not in "% of max", right? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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