libv4l: add software autogain / exposure

From: Hans de Goede <hdegoede@redhat.com>

Add software autogain / exposure, for camera's which have gain and
exposure controls but do not contain the ability to calculate the average
lumination in hardware (which is needed to do this in the kernel). This
patch enables this for the spca561 rev12a, but it should be usefull for
other cameras too.

Priority: normal

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

8 files changed, 196 insertions, 8 deletions

diff --git a/v4l2-apps/libv4l/libv4lconvert/Makefile b/v4l2-apps/libv4l/libv4lconvert/Makefile
index 49d508694..f4f529c0d 100644
--- a/v4l2-apps/libv4l/libv4lconvert/Makefile
+++ b/v4l2-apps/libv4l/libv4lconvert/Makefile
@@ -16,7 +16,7 @@ CONVERT_OBJS  = libv4lconvert.o tinyjpeg.o sn9c10x.o sn9c20x.o pac207.o \
 		mr97310a.o flip.o crop.o jidctflt.o spca561-decompress.o \
 		rgbyuv.o spca501.o sq905c.o bayer.o hm12.o \
 		control/libv4lcontrol.o processing/libv4lprocessing.o \
-		processing/whitebalance.o
+		processing/whitebalance.o processing/autogain.o
 TARGETS       = $(CONVERT_LIB) libv4lconvert.pc
 INCLUDES      = ../include/libv4lconvert.h
 
diff --git a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c
index 4d227c366..edf86483d 100644
--- a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c
+++ b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.c
@@ -67,7 +67,7 @@ static const struct v4lcontrol_flags_info v4lcontrol_flags[] = {
   /* Asus N50Vn laptop */
   { 0x04f2, 0xb106, 0, "ASUSTeK Computer Inc.        ", "N50Vn      ",
     V4LCONTROL_HFLIPPED|V4LCONTROL_VFLIPPED },
-/* Second: devices which should use sw whitebalance by default */
+/* Second: devices which should use some software processing by default */
   /* Pac207 based devices */
   { 0x041e, 0x4028, 0,    NULL, NULL, V4LCONTROL_WANTS_WB },
   { 0x093a, 0x2460, 0x1f, NULL, NULL, V4LCONTROL_WANTS_WB },
@@ -78,6 +78,9 @@ static const struct v4lcontrol_flags_info v4lcontrol_flags[] = {
     V4LCONTROL_ROTATED_90_JPEG|V4LCONTROL_WANTS_WB },
   /* sq905 devices */
   { 0x2770, 0x9120, 0,    NULL, NULL, V4LCONTROL_WANTS_WB },
+  /* spca561 revison 12a devices */
+  { 0x041e, 0x403b, 0,    NULL, NULL, V4LCONTROL_WANTS_WB_AUTOGAIN },
+  { 0x046d, 0x0928, 7,    NULL, NULL, V4LCONTROL_WANTS_WB_AUTOGAIN },
 };
 
 static const struct v4l2_queryctrl fake_controls[];
@@ -223,13 +226,17 @@ struct v4lcontrol_data *v4lcontrol_create(int fd, int always_needs_conversion)
   /* If the device always needs conversion, we can add fake controls at no cost
      (no cost when not activated by the user that is) */
   if (always_needs_conversion || v4lcontrol_needs_conversion(data)) {
-    for (i = 0; i < V4LCONTROL_COUNT; i++) {
+    for (i = 0; i < V4LCONTROL_AUTO_ENABLE_COUNT; i++) {
       ctrl.id = fake_controls[i].id;
       if (syscall(SYS_ioctl, data->fd, VIDIOC_QUERYCTRL, &ctrl) == -1)
 	data->controls |= 1 << i;
     }
   }
 
+  if (data->flags & V4LCONTROL_WANTS_AUTOGAIN)
+    data->controls |= 1 << V4LCONTROL_AUTOGAIN |
+		      1 << V4LCONTROL_AUTOGAIN_TARGET;
+
   /* Allow overriding through environment */
   if ((s = getenv("LIBV4LCONTROL_CONTROLS")))
     data->controls = strtol(s, NULL, 0);
@@ -266,6 +273,10 @@ struct v4lcontrol_data *v4lcontrol_create(int fd, int always_needs_conversion)
   if (init) {
     /* Initialize the new shm object we created */
     memset(data->shm_values, 0, sizeof(V4LCONTROL_SHM_SIZE));
+
+    for (i = 0; i < V4LCONTROL_COUNT; i++)
+      data->shm_values[i] = fake_controls[i].default_value;
+
     if (data->flags & V4LCONTROL_WANTS_WB)
       data->shm_values[V4LCONTROL_WHITEBALANCE] = 1;
   }
@@ -316,6 +327,27 @@ static const struct v4l2_queryctrl fake_controls[V4LCONTROL_COUNT] = {
   .default_value = 0,
   .flags = 0
 },
+{}, /* Dummy place holder for V4LCONTROL_AUTO_ENABLE_COUNT */
+{
+  .id = V4L2_CID_AUTOGAIN,
+  .type = V4L2_CTRL_TYPE_BOOLEAN,
+  .name =  "Auto Gain (software)",
+  .minimum = 0,
+  .maximum = 1,
+  .step = 1,
+  .default_value = 1,
+  .flags = 0
+},
+{
+  .id = V4L2_CTRL_CLASS_USER + 0x2000, /* FIXME */
+  .type = V4L2_CTRL_TYPE_INTEGER,
+  .name =  "Auto Gain target",
+  .minimum = 0,
+  .maximum = 255,
+  .step = 1,
+  .default_value = 100,
+  .flags = 0
+},
 };
 
 int v4lcontrol_vidioc_queryctrl(struct v4lcontrol_data *data, void *arg)
diff --git a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h
index 85129ee4c..a3640038b 100644
--- a/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h
+++ b/v4l2-apps/libv4l/libv4lconvert/control/libv4lcontrol.h
@@ -12,7 +12,7 @@
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
+# GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with this program; if not, write to the Free Software
@@ -27,13 +27,22 @@
 #define V4LCONTROL_VFLIPPED              0x02
 #define V4LCONTROL_ROTATED_90_JPEG       0x04
 #define V4LCONTROL_WANTS_WB              0x08
+#define V4LCONTROL_WANTS_AUTOGAIN        0x10
+
+/* Masks */
+#define V4LCONTROL_WANTS_WB_AUTOGAIN     (V4LCONTROL_WANTS_WB | V4LCONTROL_WANTS_AUTOGAIN)
 
 /* Controls */
 enum {
   V4LCONTROL_WHITEBALANCE,
   V4LCONTROL_HFLIP,
   V4LCONTROL_VFLIP,
-  V4LCONTROL_COUNT };
+  /* All fake controls above here are auto enabled when not present in hw */
+  V4LCONTROL_AUTO_ENABLE_COUNT,
+  V4LCONTROL_AUTOGAIN,
+  V4LCONTROL_AUTOGAIN_TARGET,
+  V4LCONTROL_COUNT
+  };
 
 struct v4lcontrol_data;
 
diff --git a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c
index afb0c854c..58d77e5ef 100644
--- a/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c
+++ b/v4l2-apps/libv4l/libv4lconvert/libv4lconvert.c
@@ -127,6 +127,9 @@ struct v4lconvert_data *v4lconvert_create(int fd)
       data->flags |= V4LCONVERT_IS_UVC;
     else if (!strcmp((char *)cap.driver, "sn9c20x"))
       data->flags |= V4LCONVERT_IS_SN9C20X;
+
+    if ((cap.capabilities & 0xff) & ~V4L2_CAP_VIDEO_CAPTURE)
+      always_needs_conversion = 0;
   }
 
   data->control = v4lcontrol_create(fd, always_needs_conversion);
@@ -136,7 +139,7 @@ struct v4lconvert_data *v4lconvert_create(int fd)
   }
   data->control_flags = v4lcontrol_get_flags(data->control);
 
-  data->processing = v4lprocessing_create(data->control);
+  data->processing = v4lprocessing_create(fd, data->control);
   if (!data->processing) {
     v4lcontrol_destroy(data->control);
     free(data);
diff --git a/v4l2-apps/libv4l/libv4lconvert/processing/autogain.c b/v4l2-apps/libv4l/libv4lconvert/processing/autogain.c
new file mode 100644
index 000000000..ed4b8224f
--- /dev/null
+++ b/v4l2-apps/libv4l/libv4lconvert/processing/autogain.c
@@ -0,0 +1,140 @@
+/*
+#             (C) 2008-2009 Hans de Goede <hdegoede@redhat.com>
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation; either version 2.1 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <syscall.h>
+#include <unistd.h>
+
+#include "libv4lprocessing.h"
+#include "libv4lprocessing-priv.h"
+#include "../libv4lconvert-priv.h" /* for PIX_FMT defines */
+
+static int autogain_active(struct v4lprocessing_data *data) {
+  return v4lcontrol_get_ctrl(data->control, V4LCONTROL_AUTOGAIN);
+}
+
+/* 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(
+  struct v4lprocessing_data *data,
+  unsigned char *buf, const struct v4l2_format *fmt)
+{
+  int x, y, target, steps, avg_lum = 0;
+  int gain, exposure, orig_gain, orig_exposure;
+  struct v4l2_control ctrl;
+  struct v4l2_queryctrl gainctrl, expoctrl;
+  const int deadzone = 8;
+
+  ctrl.id = V4L2_CID_EXPOSURE;
+  expoctrl.id = V4L2_CID_EXPOSURE;
+  if (syscall(SYS_ioctl, data->fd, VIDIOC_QUERYCTRL, &expoctrl) ||
+      syscall(SYS_ioctl, data->fd, VIDIOC_G_CTRL, &ctrl))
+    return 0;
+  exposure = orig_exposure = ctrl.value;
+
+  ctrl.id = V4L2_CID_GAIN;
+  gainctrl.id = V4L2_CID_GAIN;
+  if (syscall(SYS_ioctl, data->fd, VIDIOC_QUERYCTRL, &gainctrl) ||
+      syscall(SYS_ioctl, data->fd, VIDIOC_G_CTRL, &ctrl))
+    return 0;
+  gain = orig_gain = ctrl.value;
+
+  switch (fmt->fmt.pix.pixelformat) {
+    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;
+      break;
+
+    case V4L2_PIX_FMT_RGB24:
+    case V4L2_PIX_FMT_BGR24:
+      buf += fmt->fmt.pix.height * fmt->fmt.pix.bytesperline / 4 +
+	     fmt->fmt.pix.width * 3 / 4;
+
+      for (y = 0; y < fmt->fmt.pix.height / 2; y++) {
+	for (x = 0; x < fmt->fmt.pix.width / 2; x++) {
+	  avg_lum += *buf++;
+	  avg_lum += *buf++;
+	  avg_lum += *buf++;
+	}
+	buf += fmt->fmt.pix.bytesperline - fmt->fmt.pix.width * 3 / 2;
+      }
+      avg_lum /= fmt->fmt.pix.height * fmt->fmt.pix.width * 3 / 4;
+      break;
+  }
+
+  /* If we are off a multiple of deadzone, do multiple steps to reach the
+     desired lumination fast (with the risc of a slight overshoot) */
+  target = v4lcontrol_get_ctrl(data->control, V4LCONTROL_AUTOGAIN_TARGET);
+  steps = abs(target - avg_lum) / deadzone;
+
+  for (x = 0; x < steps; x++) {
+    if (avg_lum > target) {
+      if (exposure > expoctrl.default_value)
+	exposure--;
+      else if (gain > gainctrl.default_value)
+	gain--;
+      else if (exposure > expoctrl.minimum)
+	exposure--;
+      else if (gain > gainctrl.minimum)
+	gain--;
+      else
+	break;
+    } else {
+      if (gain < gainctrl.default_value)
+	gain++;
+      else if (exposure < expoctrl.default_value)
+	exposure++;
+      else if (gain < gainctrl.maximum)
+	gain++;
+      else if (exposure < expoctrl.maximum)
+	exposure++;
+      else
+	break;
+    }
+  }
+
+  if (gain != orig_gain) {
+    ctrl.id = V4L2_CID_GAIN;
+    ctrl.value = gain;
+    syscall(SYS_ioctl, data->fd, VIDIOC_S_CTRL, &ctrl);
+  }
+  if (exposure != orig_exposure) {
+    ctrl.id = V4L2_CID_EXPOSURE;
+    ctrl.value = exposure;
+    syscall(SYS_ioctl, data->fd, VIDIOC_S_CTRL, &ctrl);
+  }
+
+  return 0;
+}
+
+struct v4lprocessing_filter autogain_filter = {
+  autogain_active, autogain_calculate_lookup_tables };
diff --git a/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing-priv.h b/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing-priv.h
index fb514d7f5..b848317f7 100644
--- a/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing-priv.h
+++ b/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing-priv.h
@@ -27,6 +27,7 @@
 
 struct v4lprocessing_data {
   struct v4lcontrol_data *control;
+  int fd;
   int do_process;
   /* True if any of the lookup tables does not contain
      linear 0-255 */
@@ -49,5 +50,6 @@ struct v4lprocessing_filter {
 };
 
 extern struct v4lprocessing_filter whitebalance_filter;
+extern struct v4lprocessing_filter autogain_filter;
 
 #endif
diff --git a/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.c b/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.c
index 3a3802aab..01de6c111 100644
--- a/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.c
+++ b/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.c
@@ -30,9 +30,10 @@
 
 static struct v4lprocessing_filter *filters[] = {
   &whitebalance_filter,
+  &autogain_filter,
 };
 
-struct v4lprocessing_data *v4lprocessing_create(struct v4lcontrol_data* control)
+struct v4lprocessing_data *v4lprocessing_create(int fd, struct v4lcontrol_data* control)
 {
   struct v4lprocessing_data *data =
     calloc(1, sizeof(struct v4lprocessing_data));
@@ -40,6 +41,7 @@ struct v4lprocessing_data *v4lprocessing_create(struct v4lcontrol_data* control)
   if (!data)
     return NULL;
 
+  data->fd = fd;
   data->control = control;
 
   return data;
diff --git a/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.h b/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.h
index 3c50d9fb9..f1892a279 100644
--- a/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.h
+++ b/v4l2-apps/libv4l/libv4lconvert/processing/libv4lprocessing.h
@@ -32,7 +32,7 @@
 struct v4lprocessing_data;
 struct v4lcontrol_data;
 
-struct v4lprocessing_data *v4lprocessing_create(struct v4lcontrol_data *data);
+struct v4lprocessing_data *v4lprocessing_create(int fd, struct v4lcontrol_data *data);
 void v4lprocessing_destroy(struct v4lprocessing_data *data);
 
 /* Prepare to process 1 frame, returns 1 if processing is necesary,