On 04/17/2012 01:28 PM, Sylwester Nawrocki wrote: > On 04/17/2012 12:51 PM, Rémi Denis-Courmont wrote: >> On Tue, 17 Apr 2012 12:09:42 +0200, Sylwester Nawrocki >> <s.nawrocki@xxxxxxxxxxx> wrote: >>> This patch adds definition of additional color effects: >>> - V4L2_COLORFX_AQUA, >>> - V4L2_COLORFX_ART_FREEZE, >>> - V4L2_COLORFX_SILHOUETTE, >>> - V4L2_COLORFX_SOLARIZATION, >>> - V4L2_COLORFX_ANTIQUE, >> >> There starts to be a lot of different color effects with no obvious way to >> determine which ones the current device actually suppots. Should this not >> be a menu control instead? > > Fortunately this has been a menu control, since it was introduced. Only > the DocBook erroneously defined it as an enum. This patch also fixes that, > please see the DocBook part. > >>> - V4L2_COLORFX_ARBITRARY. >>> >>> The control's type in the documentation is changed from 'enum' to 'menu' >>> - V4L2_CID_COLORFX has always been a menu, not an integer type control. >>> >>> The V4L2_COLORFX_ARBITRARY option enables custom color effects, which >> are >>> impossible or impractical to define as the menu items. For example, the >>> devices may provide coefficients for Cb and Cr manipulation, which yield >>> many permutations, e.g. many slightly different color tints. Such >> devices >>> are better exporting their own API for precise control of non-standard >>> color effects. >> >> I don't understand why you need a number for this, if it's going to use >> another control anyway... ? > > In my use case, the hardware has 3 registers: one of them selects the colour > effect and two others determine Cr, Cb coefficients (probably I could use > V4L2_CID_RED_BALANCE, V4L2_CID_BLUE_BALANCE for that, but so far these are > just private controls). > > If I would have removed the V4L2_COLORFX_ARBITRARY item, another control > would have to be added (let's say boolean V4L2_PRIV_IMG_EFFECT). Just to > enable the "arbitrary" effect. > > Then, to enable the arbitrary effect V4L2_CID_COLORFX would have to be set > to V4L2_COLORFX_NONE, and V4L2_PRIV_IMG_EFFECT to true. > > The CB, CR coefficients are meaningful only when the arbitrary effect is > selected. So having another option in the menu, which drivers can just mask > if they don't support it, appeared better to me. > > It's a bit similar to gain/autogain scenario, where gain is active only when > autogain is off. > Maybe I should just add another private control (V4L2_PRIV_IMG_EFFECT) and > remove V4L2_COLORFX_ARBITRARY item. Instead of an imprecise V4L2_COLORFX_ARBITRARY, I'm considering adding V4L2_COLORFX_CHROMA_BALANCE item and document that it should be used together with V4L2_CID_RED_BALANCE and V4L2_CID_BLUE_BALANCE controls. Would something like this be acceptable ? I'd like to avoid (many) private controls if possible. --- Regards, Sylwester -- 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
