[patch] autogain support for bayer10 format (was Re: [patch] propagating controls in libv4l2)

Pavel Machek
2017-04-26T13:23:51Z

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Hi!

> > > I don't see why it would be hard to open files or have threads inside
> > > a library. There are several libraries that do that already, specially
> > > the ones designed to be used on multimidia apps.
> >
> > Well, This is what the libv4l2 says:
> >
> > This file implements libv4l2, which offers v4l2_ prefixed versions
> > of
> > open/close/etc. The API is 100% the same as directly opening
> > /dev/videoX
> > using regular open/close/etc, the big difference is that format
> > conversion
> >
> > but if I open additional files in v4l2_open(), API is no longer the
> > same, as unix open() is defined to open just one file descriptor.
> >
> > Now. There is autogain support in libv4lconvert, but it expects to use
> > same fd for camera and for the gain... which does not work with
> > subdevs.
> >
> > Of course, opening subdevs by name like this is not really
> > acceptable. But can you suggest a method that is?
>
> There are two separate things here:
>
> 1) Autofoucs for a device that doesn't use subdev API
> 2) libv4l2 support for devices that require MC and subdev API

Actually there are three: 0) autogain. Unfortunately, I need autogain
first before autofocus has a chance...

And that means... bayer10 support for autogain.

Plus, I changed avg_lum to long long. Quick calculation tells me int
could overflow with few megapixel sensor.

Oh, btw http://ytse.tricolour.net/docs/LowLightOptimization.html no
longer works.

Regards,
Pavel

diff --git a/lib/libv4lconvert/processing/autogain.c b/lib/libv4lconvert/processing/autogain.c
index c6866d6..0b52d0f 100644
--- a/lib/libv4lconvert/processing/autogain.c
+++ b/lib/libv4lconvert/processing/autogain.c
@@ -68,6 +71,41 @@ static void autogain_adjust(struct v4l2_queryctrl *ctrl, int *value,
}
}

+static int get_luminosity_bayer10(uint16_t *buf, const struct v4l2_format *fmt)
+{
+ long long avg_lum = 0;
+ int x, y;
+
+ buf += fmt->fmt.pix.height * fmt->fmt.pix.bytesperline / 4 +
+ fmt->fmt.pix.width / 4;
+
+ for (y = 0; y < fmt->fmt.pix.height / 2; y++) {
+ for (x = 0; x < fmt->fmt.pix.width / 2; x++)
+ avg_lum += *buf++;
+ buf += fmt->fmt.pix.bytesperline - fmt->fmt.pix.width / 2;
+ }
+ avg_lum /= fmt->fmt.pix.height * fmt->fmt.pix.width / 4;
+ avg_lum /= 4;
+ return avg_lum;
+}
+
+static int get_luminosity_bayer8(unsigned char *buf, const struct v4l2_format *fmt)
+{
+ long long avg_lum = 0;
+ int x, y;
+
+ buf += fmt->fmt.pix.height * fmt->fmt.pix.bytesperline / 4 +
+ fmt->fmt.pix.width / 4;
+
+ for (y = 0; y < fmt->fmt.pix.height / 2; y++) {
+ for (x = 0; x < fmt->fmt.pix.width / 2; x++)
+ avg_lum += *buf++;
+ buf += fmt->fmt.pix.bytesperline - fmt->fmt.pix.width / 2;
+ }
+ avg_lum /= fmt->fmt.pix.height * fmt->fmt.pix.width / 4;
+ return avg_lum;
+}
+
/* auto gain and exposure algorithm based on the knee algorithm described here:
http://ytse.tricolour.net/docs/LowLightOptimization.html */
static int autogain_calculate_lookup_tables(
@@ -100,17 +142,16 @@ static int autogain_calculate_lookup_tables(
switch (fmt->fmt.pix.pixelformat) {
+ case V4L2_PIX_FMT_SGBRG10:
+ case V4L2_PIX_FMT_SGRBG10:
+ case V4L2_PIX_FMT_SBGGR10:
+ case V4L2_PIX_FMT_SRGGB10:
+ avg_lum = get_luminosity_bayer10((void *) buf, fmt);
+ break;
+
case V4L2_PIX_FMT_SGBRG8:
case V4L2_PIX_FMT_SGRBG8:
case V4L2_PIX_FMT_SBGGR8:
case V4L2_PIX_FMT_SRGGB8:
- buf += fmt->fmt.pix.height * fmt->fmt.pix.bytesperline / 4 +
- fmt->fmt.pix.width / 4;
-
- for (y = 0; y < fmt->fmt.pix.height / 2; y++) {
- for (x = 0; x < fmt->fmt.pix.width / 2; x++)
- avg_lum += *buf++;
- buf += fmt->fmt.pix.bytesperline - fmt->fmt.pix.width / 2;
- }
- avg_lum /= fmt->fmt.pix.height * fmt->fmt.pix.width / 4;
+ avg_lum = get_luminosity_bayer8(buf, fmt);
break;

case V4L2_PIX_FMT_RGB24:
diff --git a/lib/libv4lconvert/processing/libv4lprocessing.c b/lib/libv4lconvert/processing/libv4lprocessing.c
index b061f50..b98d024 100644
--- a/lib/libv4lconvert/processing/libv4lprocessing.c
+++ b/lib/libv4lconvert/processing/libv4lprocessing.c
@@ -164,6 +165,10 @@ void v4lprocessing_processing(struct v4lprocessing_data *data,
case V4L2_PIX_FMT_SGRBG8:
case V4L2_PIX_FMT_SBGGR8:
case V4L2_PIX_FMT_SRGGB8:
+ case V4L2_PIX_FMT_SGBRG10:
+ case V4L2_PIX_FMT_SGRBG10:
+ case V4L2_PIX_FMT_SBGGR10:
+ case V4L2_PIX_FMT_SRGGB10:
case V4L2_PIX_FMT_RGB24:
case V4L2_PIX_FMT_BGR24:
break;