Mauro Carvalho Chehab wrote: > Em Sat, 4 Jul 2009 21:58:31 +0200 > Erik Andrén <erik.andren@xxxxxxxxx> escreveu: > >> 08/24: gspca - m5602-ov7660: Create blue gain control >> http://linuxtv.org/hg/~eandren/v4l-dvb?cmd=changeset;node=5675978999c5 >> >> 09/24: gspca - m5602-ov7660: Add red gain control >> http://linuxtv.org/hg/~eandren/v4l-dvb?cmd=changeset;node=802e9a025e93 > > +#define RED_BALANCE_IDX 3 > + { > + { > + .id = V4L2_CID_RED_BALANCE, > + .type = V4L2_CTRL_TYPE_INTEGER, > + .name = "red balance", > + .minimum = 0x00, > + .maximum = 0x7f, > + .step = 0x1, > + .default_value = OV7660_DEFAULT_RED_GAIN, > + .flags = V4L2_CTRL_FLAG_SLIDER > + }, > + .set = ov7660_set_red_gain, > + .get = ov7660_get_red_gain > + }, > }; > x > Hmm... as far as I understand, "Red Balance" and "Red gain" are different ways > to see the same measure. Unfortunately, the V4L2 API is not clear about those > controls. > > According with the spec, we have: > > V4L2_CID_CONTRAST integer Picture contrast or luma gain. > V4L2_CID_SATURATION integer Picture color saturation or chroma gain. > V4L2_CID_HUE integer Hue or color balance. > V4L2_CID_RED_BALANCE integer Red chroma balance. > V4L2_CID_BLUE_BALANCE integer Blue chroma balance. > V4L2_CID_GAIN integer Gain control. > > From what I'm understanding from the term "balance", it should be a shift over > the gain control (so, 0 means normal colors, like on HUE balance). > > So, in order to convert from a RED GAIN into a RED BALANCE, we need to > calculate it as a function of the V4L2_CID_GAIN or V4L2_CID_SATURATION. > Positive values should mean more gain than the other colors, while negative > values would mean the opposite. Is such a function defined somewhere? Do you have an example implementing it? I've done the same thing in the m5602 ov9650 sensor code. Regards, Erik > > Since there are other patches that touch on it, I'll stop analyzing your series > on those two patches. > > > > Cheers, > Mauro > -- 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
