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0d5e8c4313
Commit 0ba2aeb6da
increased the internal control ranges
to 64 bit, but that caused problems in drivers that use the minimum/maximum/step/default_value
control values in a division or modulus operations since not all architectures support
those natively.
Luckily, in almost all cases it is possible to just cast to 32 bits (the control value
is known to be 32 bits, so it is safe to cast). Only in v4l2-ctrls.c was it necessary to
use do_div in one function.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
179 lines
5.5 KiB
C
179 lines
5.5 KiB
C
/*
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* Functions for auto gain.
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*
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* Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "gspca.h"
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/* auto gain and exposure algorithm based on the knee algorithm described here:
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http://ytse.tricolour.net/docs/LowLightOptimization.html
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Returns 0 if no changes were made, 1 if the gain and or exposure settings
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where changed. */
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int gspca_expo_autogain(
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struct gspca_dev *gspca_dev,
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int avg_lum,
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int desired_avg_lum,
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int deadzone,
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int gain_knee,
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int exposure_knee)
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{
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s32 gain, orig_gain, exposure, orig_exposure;
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int i, steps, retval = 0;
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if (v4l2_ctrl_g_ctrl(gspca_dev->autogain) == 0)
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return 0;
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orig_gain = gain = v4l2_ctrl_g_ctrl(gspca_dev->gain);
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orig_exposure = exposure = v4l2_ctrl_g_ctrl(gspca_dev->exposure);
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/* If we are of a multiple of deadzone, do multiple steps to reach the
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desired lumination fast (with the risc of a slight overshoot) */
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steps = abs(desired_avg_lum - avg_lum) / deadzone;
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PDEBUG(D_FRAM, "autogain: lum: %d, desired: %d, steps: %d",
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avg_lum, desired_avg_lum, steps);
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for (i = 0; i < steps; i++) {
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if (avg_lum > desired_avg_lum) {
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if (gain > gain_knee)
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gain--;
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else if (exposure > exposure_knee)
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exposure--;
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else if (gain > gspca_dev->gain->default_value)
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gain--;
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else if (exposure > gspca_dev->exposure->minimum)
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exposure--;
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else if (gain > gspca_dev->gain->minimum)
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gain--;
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else
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break;
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} else {
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if (gain < gspca_dev->gain->default_value)
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gain++;
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else if (exposure < exposure_knee)
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exposure++;
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else if (gain < gain_knee)
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gain++;
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else if (exposure < gspca_dev->exposure->maximum)
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exposure++;
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else if (gain < gspca_dev->gain->maximum)
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gain++;
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else
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break;
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}
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}
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if (gain != orig_gain) {
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v4l2_ctrl_s_ctrl(gspca_dev->gain, gain);
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retval = 1;
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}
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if (exposure != orig_exposure) {
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v4l2_ctrl_s_ctrl(gspca_dev->exposure, exposure);
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retval = 1;
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}
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if (retval)
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PDEBUG(D_FRAM, "autogain: changed gain: %d, expo: %d",
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gain, exposure);
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return retval;
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}
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EXPORT_SYMBOL(gspca_expo_autogain);
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/* Autogain + exposure algorithm for cameras with a coarse exposure control
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(usually this means we can only control the clockdiv to change exposure)
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As changing the clockdiv so that the fps drops from 30 to 15 fps for
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example, will lead to a huge exposure change (it effectively doubles),
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this algorithm normally tries to only adjust the gain (between 40 and
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80 %) and if that does not help, only then changes exposure. This leads
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to a much more stable image then using the knee algorithm which at
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certain points of the knee graph will only try to adjust exposure,
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which leads to oscilating as one exposure step is huge.
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Returns 0 if no changes were made, 1 if the gain and or exposure settings
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where changed. */
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int gspca_coarse_grained_expo_autogain(
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struct gspca_dev *gspca_dev,
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int avg_lum,
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int desired_avg_lum,
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int deadzone)
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{
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s32 gain_low, gain_high, gain, orig_gain, exposure, orig_exposure;
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int steps, retval = 0;
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if (v4l2_ctrl_g_ctrl(gspca_dev->autogain) == 0)
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return 0;
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orig_gain = gain = v4l2_ctrl_g_ctrl(gspca_dev->gain);
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orig_exposure = exposure = v4l2_ctrl_g_ctrl(gspca_dev->exposure);
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gain_low = (s32)(gspca_dev->gain->maximum - gspca_dev->gain->minimum) /
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5 * 2 + gspca_dev->gain->minimum;
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gain_high = (s32)(gspca_dev->gain->maximum - gspca_dev->gain->minimum) /
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5 * 4 + gspca_dev->gain->minimum;
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/* If we are of a multiple of deadzone, do multiple steps to reach the
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desired lumination fast (with the risc of a slight overshoot) */
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steps = (desired_avg_lum - avg_lum) / deadzone;
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PDEBUG(D_FRAM, "autogain: lum: %d, desired: %d, steps: %d",
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avg_lum, desired_avg_lum, steps);
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if ((gain + steps) > gain_high &&
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exposure < gspca_dev->exposure->maximum) {
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gain = gain_high;
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gspca_dev->exp_too_low_cnt++;
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gspca_dev->exp_too_high_cnt = 0;
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} else if ((gain + steps) < gain_low &&
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exposure > gspca_dev->exposure->minimum) {
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gain = gain_low;
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gspca_dev->exp_too_high_cnt++;
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gspca_dev->exp_too_low_cnt = 0;
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} else {
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gain += steps;
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if (gain > gspca_dev->gain->maximum)
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gain = gspca_dev->gain->maximum;
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else if (gain < gspca_dev->gain->minimum)
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gain = gspca_dev->gain->minimum;
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gspca_dev->exp_too_high_cnt = 0;
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gspca_dev->exp_too_low_cnt = 0;
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}
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if (gspca_dev->exp_too_high_cnt > 3) {
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exposure--;
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gspca_dev->exp_too_high_cnt = 0;
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} else if (gspca_dev->exp_too_low_cnt > 3) {
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exposure++;
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gspca_dev->exp_too_low_cnt = 0;
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}
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if (gain != orig_gain) {
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v4l2_ctrl_s_ctrl(gspca_dev->gain, gain);
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retval = 1;
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}
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if (exposure != orig_exposure) {
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v4l2_ctrl_s_ctrl(gspca_dev->exposure, exposure);
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retval = 1;
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}
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if (retval)
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PDEBUG(D_FRAM, "autogain: changed gain: %d, expo: %d",
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gain, exposure);
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return retval;
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}
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EXPORT_SYMBOL(gspca_coarse_grained_expo_autogain);
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