@@ -155,7 +155,7 @@ Agc::Agc(Controller *controller)
: AgcAlgorithm(controller), metering_mode_(nullptr),
exposure_mode_(nullptr), constraint_mode_(nullptr),
frame_count_(0), lock_count_(0),
- last_target_exposure_(0.0),
+ last_target_exposure_(0.0), last_sensitivity_(0.0),
ev_(1.0), flicker_period_(0.0),
max_shutter_(0), fixed_shutter_(0), fixed_analogue_gain_(0.0)
{
@@ -261,7 +261,7 @@ void Agc::SetConstraintMode(std::string const &constraint_mode_name)
constraint_mode_name_ = constraint_mode_name;
}
-void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
+void Agc::SwitchMode(CameraMode const &camera_mode,
Metadata *metadata)
{
housekeepConfig();
@@ -285,9 +285,20 @@ void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
filtered_.shutter = fixed_shutter;
filtered_.analogue_gain = fixed_analogue_gain_;
} else if (status_.total_exposure_value) {
- // On a mode switch, it's possible the exposure profile could change,
- // or a fixed exposure/gain might be set so we divide up the exposure/
- // gain again, but we don't change any target values.
+ // On a mode switch, various things could happen:
+ // - the exposure profile might change
+ // - a fixed exposure or gain might be set
+ // - the new mode's sensitivity might be different
+ // We cope with the last of these by scaling the target values. After
+ // that we just need to re-divide the exposure/gain according to the
+ // current exposure profile, which takes care of everything else.
+
+ double ratio = last_sensitivity_ / camera_mode.sensitivity;
+ target_.total_exposure_no_dg *= ratio;
+ target_.total_exposure *= ratio;
+ filtered_.total_exposure_no_dg *= ratio;
+ filtered_.total_exposure *= ratio;
+
divideUpExposure();
} else {
// We come through here on startup, when at least one of the shutter
@@ -301,6 +312,10 @@ void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
}
writeAndFinish(metadata, false);
+
+ // We must remember the sensitivity of this mode for the next SwitchMode.
+ ASSERT(camera_mode.sensitivity != 0.0);
+ last_sensitivity_ = camera_mode.sensitivity;
}
void Agc::Prepare(Metadata *image_metadata)
@@ -122,6 +122,7 @@ private:
int lock_count_;
DeviceStatus last_device_status_;
double last_target_exposure_;
+ double last_sensitivity_; // sensitivity of the previous camera mode
// Below here the "settings" that applications can change.
std::string metering_mode_name_;
std::string exposure_mode_name_;