Hi Sakari, On Tuesday 06 September 2011 14:22:27 Sakari Ailus wrote: > On Tue, Sep 06, 2011 at 01:41:11PM +0200, Laurent Pinchart wrote: > > On Tuesday 06 September 2011 13:36:53 Sakari Ailus wrote: > > > Hi all, > > > > > > We are beginning to have raw bayer image sensor drivers in the > > > mainline. Typically such sensors are not controlled by general purpose > > > applications but e.g. require a camera control algorithm framework in > > > user space. This needs to be implemented in libv4l for general purpose > > > applications to work properly on this kind of hardware. > > > > > > These sensors expose controls such as > > > > > > - Per-component gain controls. Red, blue, green (blue) and green (red) > > > > > > gains. > > > > > > - Link frequency. The frequency of the data link from the sensor to the > > > > > > bridge. > > > > > > - Horizontal and vertical blanking. > > > > Other controls often found in bayer sensors are black level compensation > > and test pattern. > > > > > None of these controls are suitable for use of general purpose > > > applications (let alone the end user!) but for the camera control > > > algorithms. > > > > > > We have a control class called V4L2_CTRL_CLASS_CAMERA for camera > > > controls. However, the controls in this class are relatively high > > > level controls which are suitable for end user. The algorithms in the > > > libv4l or a webcam could implement many of these controls whereas I > > > see that only V4L2_CID_EXPOSURE_ABSOLUTE might be implemented by raw > > > bayer sensors. > > > > > > My question is: would it make sense to create a new class of controls > > > for the low level sensor controls in a similar fashion we have a > > > control class for the flash controls? > > > > I think it would, but I'm not sure how we should name that class. > > V4L2_CTRL_CLASS_SENSOR is tempting, but many of the controls that will be > > found there (digital gains, black leverl compensation, test pattern, ...) > > can also be found in ISPs or other hardware blocks. > > I don't think ISPs typically implement test patterns. Do you know of any? Not from the top of my head, but I don't think it would be too uncommon. > Should we separate controls which clearly apply to sensors only from the > rest? > > For sensors only: > > - Analog gain(s) > - Horizontal and vertical blanking > - Link frequency > - Test pattern > > The following can be implemented also on ISPs: > > - Per-component gains > - Black level compensation > > Do we have more to add to the list? Not right now. > If we keep the two the same class, I could propose the following names: > > V4L2_CTRL_CLASS_LL_CAMERA (for low level camera) > V4L2_CTRL_CLASS_SOURCE > V4L2_CTRL_CLASS_IMAGE_SOURCE > > The last one would be a good name for the sensor control class, as far as I > understand some are using tuners with the OMAP 3 ISP these days. For the > another one, I propose V4L2_CTRL_CLASS_ISP. The issue with ISP is that pretty much any digital-based control can fall into that class. Maybe we should group controls by what they do, instead of the kind of component that implements them ? -- 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
