On Tue, Sep 06, 2011 at 01:41:11PM +0200, Laurent Pinchart wrote: > Hi Sakari, > > 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? 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? 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. Better names are always welcome. :-) -- Sakari Ailus e-mail: sakari.ailus@xxxxxx jabber/XMPP/Gmail: sailus@xxxxxxxxxxxxxx -- 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
