[libcamera-devel] [PATCH v4 1/5] src: ipa: raspberrypi: Avoid AGC filtering when both gain and shutter specified

[David Plowman]

When both gain and shutter have been directly specified, do not filter
slowly towards those target values, but adopt them immediately. This
should match user expectations better.

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 src/ipa/raspberrypi/controller/rpi/agc.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
index 4c56bdc9..30a1c1c1 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
@@ -588,7 +588,12 @@ bool Agc::applyDigitalGain(double gain, double target_Y)
 
 void Agc::filterExposure(bool desaturate)
 {
-	double speed = frame_count_ <= config_.startup_frames ? 1.0 : config_.speed;
+	double speed = config_.speed;
+	// AGC adapts instantly if both shutter and gain are directly specified
+	// or we're in the startup phase.
+	if ((status_.fixed_shutter && status_.fixed_analogue_gain) ||
+	    frame_count_ <= config_.startup_frames)
+		speed = 1.0;
 	if (filtered_.total_exposure == 0.0) {
 		filtered_.total_exposure = target_.total_exposure;
 		filtered_.total_exposure_no_dg = target_.total_exposure_no_dg;
-- 
2.20.1