18 files changed, 868 insertions, 321 deletions

diff --git a/src/ipa/simple/algorithms/agc.cpp b/src/ipa/simple/algorithms/agc.cpp
new file mode 100644
index 00000000..df92edd7
--- /dev/null
+++ b/src/ipa/simple/algorithms/agc.cpp
@@ -0,0 +1,139 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Exposure and gain
+ */
+
+#include "agc.h"
+
+#include <stdint.h>
+
+#include <libcamera/base/log.h>
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(IPASoftExposure)
+
+namespace ipa::soft::algorithms {
+
+/*
+ * The number of bins to use for the optimal exposure calculations.
+ */
+static constexpr unsigned int kExposureBinsCount = 5;
+
+/*
+ * The exposure is optimal when the mean sample value of the histogram is
+ * in the middle of the range.
+ */
+static constexpr float kExposureOptimal = kExposureBinsCount / 2.0;
+
+/*
+ * This implements the hysteresis for the exposure adjustment.
+ * It is small enough to have the exposure close to the optimal, and is big
+ * enough to prevent the exposure from wobbling around the optimal value.
+ */
+static constexpr float kExposureSatisfactory = 0.2;
+
+Agc::Agc()
+{
+}
+
+void Agc::updateExposure(IPAContext &context, double exposureMSV)
+{
+	/*
+	 * kExpDenominator of 10 gives ~10% increment/decrement;
+	 * kExpDenominator of 5 - about ~20%
+	 */
+	static constexpr uint8_t kExpDenominator = 10;
+	static constexpr uint8_t kExpNumeratorUp = kExpDenominator + 1;
+	static constexpr uint8_t kExpNumeratorDown = kExpDenominator - 1;
+
+	double next;
+	int32_t &exposure = context.activeState.agc.exposure;
+	double &again = context.activeState.agc.again;
+
+	if (exposureMSV < kExposureOptimal - kExposureSatisfactory) {
+		next = exposure * kExpNumeratorUp / kExpDenominator;
+		if (next - exposure < 1)
+			exposure += 1;
+		else
+			exposure = next;
+		if (exposure >= context.configuration.agc.exposureMax) {
+			next = again * kExpNumeratorUp / kExpDenominator;
+			if (next - again < context.configuration.agc.againMinStep)
+				again += context.configuration.agc.againMinStep;
+			else
+				again = next;
+		}
+	}
+
+	if (exposureMSV > kExposureOptimal + kExposureSatisfactory) {
+		if (exposure == context.configuration.agc.exposureMax &&
+		    again > context.configuration.agc.againMin) {
+			next = again * kExpNumeratorDown / kExpDenominator;
+			if (again - next < context.configuration.agc.againMinStep)
+				again -= context.configuration.agc.againMinStep;
+			else
+				again = next;
+		} else {
+			next = exposure * kExpNumeratorDown / kExpDenominator;
+			if (exposure - next < 1)
+				exposure -= 1;
+			else
+				exposure = next;
+		}
+	}
+
+	exposure = std::clamp(exposure, context.configuration.agc.exposureMin,
+			      context.configuration.agc.exposureMax);
+	again = std::clamp(again, context.configuration.agc.againMin,
+			   context.configuration.agc.againMax);
+
+	LOG(IPASoftExposure, Debug)
+		<< "exposureMSV " << exposureMSV
+		<< " exp " << exposure << " again " << again;
+}
+
+void Agc::process(IPAContext &context,
+		  [[maybe_unused]] const uint32_t frame,
+		  [[maybe_unused]] IPAFrameContext &frameContext,
+		  const SwIspStats *stats,
+		  [[maybe_unused]] ControlList &metadata)
+{
+	/*
+	 * Calculate Mean Sample Value (MSV) according to formula from:
+	 * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf
+	 */
+	const auto &histogram = stats->yHistogram;
+	const unsigned int blackLevelHistIdx =
+		context.activeState.blc.level / (256 / SwIspStats::kYHistogramSize);
+	const unsigned int histogramSize =
+		SwIspStats::kYHistogramSize - blackLevelHistIdx;
+	const unsigned int yHistValsPerBin = histogramSize / kExposureBinsCount;
+	const unsigned int yHistValsPerBinMod =
+		histogramSize / (histogramSize % kExposureBinsCount + 1);
+	int exposureBins[kExposureBinsCount] = {};
+	unsigned int denom = 0;
+	unsigned int num = 0;
+
+	for (unsigned int i = 0; i < histogramSize; i++) {
+		unsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin;
+		exposureBins[idx] += histogram[blackLevelHistIdx + i];
+	}
+
+	for (unsigned int i = 0; i < kExposureBinsCount; i++) {
+		LOG(IPASoftExposure, Debug) << i << ": " << exposureBins[i];
+		denom += exposureBins[i];
+		num += exposureBins[i] * (i + 1);
+	}
+
+	float exposureMSV = (denom == 0 ? 0 : static_cast<float>(num) / denom);
+	updateExposure(context, exposureMSV);
+}
+
+REGISTER_IPA_ALGORITHM(Agc, "Agc")
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/agc.h b/src/ipa/simple/algorithms/agc.h
new file mode 100644
index 00000000..ad5fca9f
--- /dev/null
+++ b/src/ipa/simple/algorithms/agc.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Exposure and gain
+ */
+
+#pragma once
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+class Agc : public Algorithm
+{
+public:
+	Agc();
+	~Agc() = default;
+
+	void process(IPAContext &context, const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     const SwIspStats *stats,
+		     ControlList &metadata) override;
+
+private:
+	void updateExposure(IPAContext &context, double exposureMSV);
+};
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/algorithm.h b/src/ipa/simple/algorithms/algorithm.h
new file mode 100644
index 00000000..41f63170
--- /dev/null
+++ b/src/ipa/simple/algorithms/algorithm.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024 Red Hat, Inc.
+ *
+ * Software ISP control algorithm interface
+ */
+
+#pragma once
+
+#include <libipa/algorithm.h>
+
+#include "module.h"
+
+namespace libcamera {
+
+namespace ipa::soft {
+
+using Algorithm = libcamera::ipa::Algorithm<Module>;
+
+} /* namespace ipa::soft */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/awb.cpp b/src/ipa/simple/algorithms/awb.cpp
new file mode 100644
index 00000000..195de41d
--- /dev/null
+++ b/src/ipa/simple/algorithms/awb.cpp
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Auto white balance
+ */
+
+#include "awb.h"
+
+#include <numeric>
+#include <stdint.h>
+
+#include <libcamera/base/log.h>
+
+#include "simple/ipa_context.h"
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(IPASoftAwb)
+
+namespace ipa::soft::algorithms {
+
+int Awb::configure(IPAContext &context,
+		   [[maybe_unused]] const IPAConfigInfo &configInfo)
+{
+	auto &gains = context.activeState.gains;
+	gains.red = gains.green = gains.blue = 1.0;
+
+	return 0;
+}
+
+void Awb::process(IPAContext &context,
+		  [[maybe_unused]] const uint32_t frame,
+		  [[maybe_unused]] IPAFrameContext &frameContext,
+		  const SwIspStats *stats,
+		  [[maybe_unused]] ControlList &metadata)
+{
+	const SwIspStats::Histogram &histogram = stats->yHistogram;
+	const uint8_t blackLevel = context.activeState.blc.level;
+
+	/*
+	 * Black level must be subtracted to get the correct AWB ratios, they
+	 * would be off if they were computed from the whole brightness range
+	 * rather than from the sensor range.
+	 */
+	const uint64_t nPixels = std::accumulate(
+		histogram.begin(), histogram.end(), 0);
+	const uint64_t offset = blackLevel * nPixels;
+	const uint64_t sumR = stats->sumR_ - offset / 4;
+	const uint64_t sumG = stats->sumG_ - offset / 2;
+	const uint64_t sumB = stats->sumB_ - offset / 4;
+
+	/*
+	 * Calculate red and blue gains for AWB.
+	 * Clamp max gain at 4.0, this also avoids 0 division.
+	 */
+	auto &gains = context.activeState.gains;
+	gains.red = sumR <= sumG / 4 ? 4.0 : static_cast<double>(sumG) / sumR;
+	gains.blue = sumB <= sumG / 4 ? 4.0 : static_cast<double>(sumG) / sumB;
+	/* Green gain is fixed to 1.0 */
+
+	LOG(IPASoftAwb, Debug) << "gain R/B " << gains.red << "/" << gains.blue;
+}
+
+REGISTER_IPA_ALGORITHM(Awb, "Awb")
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/awb.h b/src/ipa/simple/algorithms/awb.h
new file mode 100644
index 00000000..db1496cd
--- /dev/null
+++ b/src/ipa/simple/algorithms/awb.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Auto white balance
+ */
+
+#pragma once
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+class Awb : public Algorithm
+{
+public:
+	Awb() = default;
+	~Awb() = default;
+
+	int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
+	void process(IPAContext &context,
+		     const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     const SwIspStats *stats,
+		     ControlList &metadata) override;
+};
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/blc.cpp b/src/ipa/simple/algorithms/blc.cpp
new file mode 100644
index 00000000..b4e32fe1
--- /dev/null
+++ b/src/ipa/simple/algorithms/blc.cpp
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Black level handling
+ */
+
+#include "blc.h"
+
+#include <numeric>
+
+#include <libcamera/base/log.h>
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+LOG_DEFINE_CATEGORY(IPASoftBL)
+
+BlackLevel::BlackLevel()
+{
+}
+
+int BlackLevel::init(IPAContext &context, const YamlObject &tuningData)
+{
+	auto blackLevel = tuningData["blackLevel"].get<int16_t>();
+	if (blackLevel.has_value()) {
+		/*
+		 * Convert 16 bit values from the tuning file to 8 bit black
+		 * level for the SoftISP.
+		 */
+		context.configuration.black.level = blackLevel.value() >> 8;
+	}
+	return 0;
+}
+
+int BlackLevel::configure(IPAContext &context,
+			  [[maybe_unused]] const IPAConfigInfo &configInfo)
+{
+	context.activeState.blc.level =
+		context.configuration.black.level.value_or(255);
+	return 0;
+}
+
+void BlackLevel::process(IPAContext &context,
+			 [[maybe_unused]] const uint32_t frame,
+			 IPAFrameContext &frameContext,
+			 const SwIspStats *stats,
+			 [[maybe_unused]] ControlList &metadata)
+{
+	if (context.configuration.black.level.has_value())
+		return;
+
+	if (frameContext.sensor.exposure == exposure_ &&
+	    frameContext.sensor.gain == gain_) {
+		return;
+	}
+
+	const SwIspStats::Histogram &histogram = stats->yHistogram;
+
+	/*
+	 * The constant is selected to be "good enough", not overly
+	 * conservative or aggressive. There is no magic about the given value.
+	 */
+	constexpr float ignoredPercentage = 0.02;
+	const unsigned int total =
+		std::accumulate(begin(histogram), end(histogram), 0);
+	const unsigned int pixelThreshold = ignoredPercentage * total;
+	const unsigned int histogramRatio = 256 / SwIspStats::kYHistogramSize;
+	const unsigned int currentBlackIdx =
+		context.activeState.blc.level / histogramRatio;
+
+	for (unsigned int i = 0, seen = 0;
+	     i < currentBlackIdx && i < SwIspStats::kYHistogramSize;
+	     i++) {
+		seen += histogram[i];
+		if (seen >= pixelThreshold) {
+			context.activeState.blc.level = i * histogramRatio;
+			exposure_ = frameContext.sensor.exposure;
+			gain_ = frameContext.sensor.gain;
+			LOG(IPASoftBL, Debug)
+				<< "Auto-set black level: "
+				<< i << "/" << SwIspStats::kYHistogramSize
+				<< " (" << 100 * (seen - histogram[i]) / total << "% below, "
+				<< 100 * seen / total << "% at or below)";
+			break;
+		}
+	};
+}
+
+REGISTER_IPA_ALGORITHM(BlackLevel, "BlackLevel")
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/blc.h b/src/ipa/simple/algorithms/blc.h
new file mode 100644
index 00000000..2cf2a877
--- /dev/null
+++ b/src/ipa/simple/algorithms/blc.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Black level handling
+ */
+
+#pragma once
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+class BlackLevel : public Algorithm
+{
+public:
+	BlackLevel();
+	~BlackLevel() = default;
+
+	int init(IPAContext &context, const YamlObject &tuningData) override;
+	int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
+	void process(IPAContext &context, const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     const SwIspStats *stats,
+		     ControlList &metadata) override;
+
+private:
+	uint32_t exposure_;
+	double gain_;
+};
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/lut.cpp b/src/ipa/simple/algorithms/lut.cpp
new file mode 100644
index 00000000..9744e773
--- /dev/null
+++ b/src/ipa/simple/algorithms/lut.cpp
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Color lookup tables construction
+ */
+
+#include "lut.h"
+
+#include <algorithm>
+#include <cmath>
+#include <stdint.h>
+
+#include <libcamera/base/log.h>
+
+#include "simple/ipa_context.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+int Lut::configure(IPAContext &context,
+		   [[maybe_unused]] const IPAConfigInfo &configInfo)
+{
+	/* Gamma value is fixed */
+	context.configuration.gamma = 0.5;
+	updateGammaTable(context);
+
+	return 0;
+}
+
+void Lut::updateGammaTable(IPAContext &context)
+{
+	auto &gammaTable = context.activeState.gamma.gammaTable;
+	auto blackLevel = context.activeState.blc.level;
+	const unsigned int blackIndex = blackLevel * gammaTable.size() / 256;
+
+	std::fill(gammaTable.begin(), gammaTable.begin() + blackIndex, 0);
+	const float divisor = gammaTable.size() - blackIndex - 1.0;
+	for (unsigned int i = blackIndex; i < gammaTable.size(); i++)
+		gammaTable[i] = UINT8_MAX * std::pow((i - blackIndex) / divisor,
+						     context.configuration.gamma);
+
+	context.activeState.gamma.blackLevel = blackLevel;
+}
+
+void Lut::prepare(IPAContext &context,
+		  [[maybe_unused]] const uint32_t frame,
+		  [[maybe_unused]] IPAFrameContext &frameContext,
+		  [[maybe_unused]] DebayerParams *params)
+{
+	/*
+	 * Update the gamma table if needed. This means if black level changes
+	 * and since the black level gets updated only if a lower value is
+	 * observed, it's not permanently prone to minor fluctuations or
+	 * rounding errors.
+	 */
+	if (context.activeState.gamma.blackLevel != context.activeState.blc.level)
+		updateGammaTable(context);
+
+	auto &gains = context.activeState.gains;
+	auto &gammaTable = context.activeState.gamma.gammaTable;
+	const unsigned int gammaTableSize = gammaTable.size();
+
+	for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) {
+		const double div = static_cast<double>(DebayerParams::kRGBLookupSize) /
+				   gammaTableSize;
+		/* Apply gamma after gain! */
+		unsigned int idx;
+		idx = std::min({ static_cast<unsigned int>(i * gains.red / div),
+				 gammaTableSize - 1 });
+		params->red[i] = gammaTable[idx];
+		idx = std::min({ static_cast<unsigned int>(i * gains.green / div),
+				 gammaTableSize - 1 });
+		params->green[i] = gammaTable[idx];
+		idx = std::min({ static_cast<unsigned int>(i * gains.blue / div),
+				 gammaTableSize - 1 });
+		params->blue[i] = gammaTable[idx];
+	}
+}
+
+REGISTER_IPA_ALGORITHM(Lut, "Lut")
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/lut.h b/src/ipa/simple/algorithms/lut.h
new file mode 100644
index 00000000..b635987d
--- /dev/null
+++ b/src/ipa/simple/algorithms/lut.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Color lookup tables construction
+ */
+
+#pragma once
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+class Lut : public Algorithm
+{
+public:
+	Lut() = default;
+	~Lut() = default;
+
+	int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
+	void prepare(IPAContext &context,
+		     const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     DebayerParams *params) override;
+
+private:
+	void updateGammaTable(IPAContext &context);
+};
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/meson.build b/src/ipa/simple/algorithms/meson.build
new file mode 100644
index 00000000..37a2eb53
--- /dev/null
+++ b/src/ipa/simple/algorithms/meson.build
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: CC0-1.0
+
+soft_simple_ipa_algorithms = files([
+    'awb.cpp',
+    'agc.cpp',
+    'blc.cpp',
+    'lut.cpp',
+])
diff --git a/src/ipa/simple/black_level.cpp b/src/ipa/simple/black_level.cpp
deleted file mode 100644
index cc490eb5..00000000
--- a/src/ipa/simple/black_level.cpp
+++ /dev/null
@@ -1,88 +0,0 @@
-/* SPDX-License-Identifier: LGPL-2.1-or-later */
-/*
- * Copyright (C) 2024, Red Hat Inc.
- *
- * black level handling
- */
-
-#include "black_level.h"
-
-#include <numeric>
-
-#include <libcamera/base/log.h>
-
-namespace libcamera {
-
-LOG_DEFINE_CATEGORY(IPASoftBL)
-
-/**
- * \class BlackLevel
- * \brief Object providing black point level for software ISP
- *
- * Black level can be provided in hardware tuning files or, if no tuning file is
- * available for the given hardware, guessed automatically, with less accuracy.
- * As tuning files are not yet implemented for software ISP, BlackLevel
- * currently provides only guessed black levels.
- *
- * This class serves for tracking black level as a property of the underlying
- * hardware, not as means of enhancing a particular scene or image.
- *
- * The class is supposed to be instantiated for the given camera stream.
- * The black level can be retrieved using BlackLevel::get() method. It is
- * initially 0 and may change when updated using BlackLevel::update() method.
- */
-
-BlackLevel::BlackLevel()
-	: blackLevel_(255), blackLevelSet_(false)
-{
-}
-
-/**
- * \brief Return the current black level
- *
- * \return The black level, in the range from 0 (minimum) to 255 (maximum).
- * If the black level couldn't be determined yet, return 0.
- */
-uint8_t BlackLevel::get() const
-{
-	return blackLevelSet_ ? blackLevel_ : 0;
-}
-
-/**
- * \brief Update black level from the provided histogram
- * \param[in] yHistogram The histogram to be used for updating black level
- *
- * The black level is property of the given hardware, not image. It is updated
- * only if it has not been yet set or if it is lower than the lowest value seen
- * so far.
- */
-void BlackLevel::update(SwIspStats::Histogram &yHistogram)
-{
-	/*
-	 * The constant is selected to be "good enough", not overly conservative or
-	 * aggressive. There is no magic about the given value.
-	 */
-	constexpr float ignoredPercentage_ = 0.02;
-	const unsigned int total =
-		std::accumulate(begin(yHistogram), end(yHistogram), 0);
-	const unsigned int pixelThreshold = ignoredPercentage_ * total;
-	const unsigned int histogramRatio = 256 / SwIspStats::kYHistogramSize;
-	const unsigned int currentBlackIdx = blackLevel_ / histogramRatio;
-
-	for (unsigned int i = 0, seen = 0;
-	     i < currentBlackIdx && i < SwIspStats::kYHistogramSize;
-	     i++) {
-		seen += yHistogram[i];
-		if (seen >= pixelThreshold) {
-			blackLevel_ = i * histogramRatio;
-			blackLevelSet_ = true;
-			LOG(IPASoftBL, Debug)
-				<< "Auto-set black level: "
-				<< i << "/" << SwIspStats::kYHistogramSize
-				<< " (" << 100 * (seen - yHistogram[i]) / total << "% below, "
-				<< 100 * seen / total << "% at or below)";
-			break;
-		}
-	};
-}
-} /* namespace libcamera */
diff --git a/src/ipa/simple/black_level.h b/src/ipa/simple/black_level.h
deleted file mode 100644
index 5e032f9f..00000000
--- a/src/ipa/simple/black_level.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/* SPDX-License-Identifier: LGPL-2.1-or-later */
-/*
- * Copyright (C) 2024, Red Hat Inc.
- *
- * black level handling
- */
-
-#pragma once
-
-#include <array>
-#include <stdint.h>
-
-#include "libcamera/internal/software_isp/swisp_stats.h"
-
-namespace libcamera {
-
-class BlackLevel
-{
-public:
-	BlackLevel();
-	uint8_t get() const;
-	void update(SwIspStats::Histogram &yHistogram);
-
-private:
-	uint8_t blackLevel_;
-	bool blackLevelSet_;
-};
-
-} /* namespace libcamera */
diff --git a/src/ipa/simple/data/uncalibrated.yaml b/src/ipa/simple/data/uncalibrated.yaml
index ff981a1a..3f147112 100644
--- a/src/ipa/simple/data/uncalibrated.yaml
+++ b/src/ipa/simple/data/uncalibrated.yaml
@@ -2,4 +2,9 @@
 %YAML 1.1
 ---
 version: 1
+algorithms:
+  - BlackLevel:
+  - Awb:
+  - Lut:
+  - Agc:
 ...
diff --git a/src/ipa/simple/ipa_context.cpp b/src/ipa/simple/ipa_context.cpp
new file mode 100644
index 00000000..3f94bbeb
--- /dev/null
+++ b/src/ipa/simple/ipa_context.cpp
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Google Inc.
+ * Copyright (C) 2024 Red Hat Inc.
+ *
+ * Software ISP IPA Context
+ */
+
+#include "ipa_context.h"
+
+/**
+ * \file ipa_context.h
+ * \brief Context and state information shared between the algorithms
+ */
+
+namespace libcamera::ipa::soft {
+
+/**
+ * \struct IPASessionConfiguration
+ * \brief Session configuration for the IPA module
+ *
+ * The session configuration contains all IPA configuration parameters that
+ * remain constant during the capture session, from IPA module start to stop.
+ * It is typically set during the configure() operation of the IPA module, but
+ * may also be updated in the start() operation.
+ */
+
+/**
+ * \struct IPAActiveState
+ * \brief The active state of the IPA algorithms
+ *
+ * The IPA is fed with the statistics generated from the latest frame processed.
+ * The statistics are then processed by the IPA algorithms to compute parameters
+ * required for the next frame capture and processing. The current state of the
+ * algorithms is reflected through the IPAActiveState to store the values most
+ * recently computed by the IPA algorithms.
+ */
+
+/**
+ * \struct IPAContext
+ * \brief Global IPA context data shared between all algorithms
+ *
+ * \var IPAContext::configuration
+ * \brief The IPA session configuration, immutable during the session
+ *
+ * \var IPAContext::frameContexts
+ * \brief Ring buffer of the IPAFrameContext(s)
+ *
+ * \var IPAContext::activeState
+ * \brief The current state of IPA algorithms
+ */
+
+/**
+ * \var IPASessionConfiguration::gamma
+ * \brief Gamma value to be used in the raw image processing
+ */
+
+/**
+ * \var IPAActiveState::black
+ * \brief Context for the Black Level algorithm
+ *
+ * \var IPAActiveState::black.level
+ * \brief Current determined black level
+ */
+
+/**
+ * \var IPAActiveState::gains
+ * \brief Context for gains in the Colors algorithm
+ *
+ * \var IPAActiveState::gains.red
+ * \brief Gain of red color
+ *
+ * \var IPAActiveState::gains.green
+ * \brief Gain of green color
+ *
+ * \var IPAActiveState::gains.blue
+ * \brief Gain of blue color
+ */
+
+/**
+ * \var IPAActiveState::agc
+ * \brief Context for the AGC algorithm
+ *
+ * \var IPAActiveState::agc.exposure
+ * \brief Current exposure value
+ *
+ * \var IPAActiveState::agc.again
+ * \brief Current analog gain value
+ */
+
+/**
+ * \var IPAActiveState::gamma
+ * \brief Context for gamma in the Colors algorithm
+ *
+ * \var IPAActiveState::gamma.gammaTable
+ * \brief Computed gamma table
+ *
+ * \var IPAActiveState::gamma.blackLevel
+ * \brief Black level used for the gamma table computation
+ */
+
+} /* namespace libcamera::ipa::soft */
diff --git a/src/ipa/simple/ipa_context.h b/src/ipa/simple/ipa_context.h
new file mode 100644
index 00000000..fd121eeb
--- /dev/null
+++ b/src/ipa/simple/ipa_context.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024 Red Hat, Inc.
+ *
+ * Simple pipeline IPA Context
+ */
+
+#pragma once
+
+#include <array>
+#include <optional>
+#include <stdint.h>
+
+#include <libipa/fc_queue.h>
+
+namespace libcamera {
+
+namespace ipa::soft {
+
+struct IPASessionConfiguration {
+	float gamma;
+	struct {
+		int32_t exposureMin, exposureMax;
+		double againMin, againMax, againMinStep;
+	} agc;
+	struct {
+		std::optional<uint8_t> level;
+	} black;
+};
+
+struct IPAActiveState {
+	struct {
+		uint8_t level;
+	} blc;
+
+	struct {
+		double red;
+		double green;
+		double blue;
+	} gains;
+
+	struct {
+		int32_t exposure;
+		double again;
+	} agc;
+
+	static constexpr unsigned int kGammaLookupSize = 1024;
+	struct {
+		std::array<double, kGammaLookupSize> gammaTable;
+		uint8_t blackLevel;
+	} gamma;
+};
+
+struct IPAFrameContext : public FrameContext {
+	struct {
+		uint32_t exposure;
+		double gain;
+	} sensor;
+};
+
+struct IPAContext {
+	IPASessionConfiguration configuration;
+	IPAActiveState activeState;
+	FCQueue<IPAFrameContext> frameContexts;
+};
+
+} /* namespace ipa::soft */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/meson.build b/src/ipa/simple/meson.build
index 33d1c96a..2f9f15f4 100644
--- a/src/ipa/simple/meson.build
+++ b/src/ipa/simple/meson.build
@@ -1,14 +1,18 @@
 # SPDX-License-Identifier: CC0-1.0
 
+subdir('algorithms')
+subdir('data')
+
 ipa_name = 'ipa_soft_simple'
 
 soft_simple_sources = files([
+    'ipa_context.cpp',
     'soft_simple.cpp',
-    'black_level.cpp',
 ])
 
-mod = shared_module(ipa_name,
-                    [soft_simple_sources, libcamera_generated_ipa_headers],
+soft_simple_sources += soft_simple_ipa_algorithms
+
+mod = shared_module(ipa_name, soft_simple_sources,
                     name_prefix : '',
                     include_directories : [ipa_includes],
                     dependencies : [libcamera_private, libipa_dep],
@@ -24,6 +28,4 @@ if ipa_sign_module
                   build_by_default : true)
 endif
 
-subdir('data')
-
 ipa_names += ipa_name
diff --git a/src/ipa/simple/module.h b/src/ipa/simple/module.h
new file mode 100644
index 00000000..8d4d53fb
--- /dev/null
+++ b/src/ipa/simple/module.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024 Red Hat, Inc.
+ *
+ * Software ISP IPA Module
+ */
+
+#pragma once
+
+#include <libcamera/controls.h>
+
+#include <libcamera/ipa/soft_ipa_interface.h>
+
+#include "libcamera/internal/software_isp/debayer_params.h"
+#include "libcamera/internal/software_isp/swisp_stats.h"
+
+#include <libipa/module.h>
+
+#include "ipa_context.h"
+
+namespace libcamera {
+
+namespace ipa::soft {
+
+using Module = ipa::Module<IPAContext, IPAFrameContext, IPAConfigInfo,
+			   DebayerParams, SwIspStats>;
+
+} /* namespace ipa::soft */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp
index b7746ce0..ac2a9421 100644
--- a/src/ipa/simple/soft_simple.cpp
+++ b/src/ipa/simple/soft_simple.cpp
@@ -5,8 +5,6 @@
  * Simple Software Image Processing Algorithm module
  */
 
-#include <cmath>
-#include <numeric>
 #include <stdint.h>
 #include <sys/mman.h>
 
@@ -29,37 +27,21 @@
 
 #include "libipa/camera_sensor_helper.h"
 
-#include "black_level.h"
+#include "module.h"
 
 namespace libcamera {
 LOG_DEFINE_CATEGORY(IPASoft)
 
 namespace ipa::soft {
 
-/*
- * The number of bins to use for the optimal exposure calculations.
- */
-static constexpr unsigned int kExposureBinsCount = 5;
-
-/*
- * The exposure is optimal when the mean sample value of the histogram is
- * in the middle of the range.
- */
-static constexpr float kExposureOptimal = kExposureBinsCount / 2.0;
-
-/*
- * The below value implements the hysteresis for the exposure adjustment.
- * It is small enough to have the exposure close to the optimal, and is big
- * enough to prevent the exposure from wobbling around the optimal value.
- */
-static constexpr float kExposureSatisfactory = 0.2;
+/* Maximum number of frame contexts to be held */
+static constexpr uint32_t kMaxFrameContexts = 16;
 
-class IPASoftSimple : public ipa::soft::IPASoftInterface
+class IPASoftSimple : public ipa::soft::IPASoftInterface, public Module
 {
 public:
 	IPASoftSimple()
-		: params_(nullptr), stats_(nullptr), blackLevel_(BlackLevel()),
-		  ignoreUpdates_(0)
+		: context_({ {}, {}, { kMaxFrameContexts } })
 	{
 	}
 
@@ -69,12 +51,18 @@ public:
 		 const SharedFD &fdStats,
 		 const SharedFD &fdParams,
 		 const ControlInfoMap &sensorInfoMap) override;
-	int configure(const ControlInfoMap &sensorInfoMap) override;
+	int configure(const IPAConfigInfo &configInfo) override;
 
 	int start() override;
 	void stop() override;
 
-	void processStats(const ControlList &sensorControls) override;
+	void queueRequest(const uint32_t frame, const ControlList &controls) override;
+	void computeParams(const uint32_t frame) override;
+	void processStats(const uint32_t frame, const uint32_t bufferId,
+			  const ControlList &sensorControls) override;
+
+protected:
+	std::string logPrefix() const override;
 
 private:
 	void updateExposure(double exposureMSV);
@@ -83,17 +71,9 @@ private:
 	SwIspStats *stats_;
 	std::unique_ptr<CameraSensorHelper> camHelper_;
 	ControlInfoMap sensorInfoMap_;
-	BlackLevel blackLevel_;
 
-	static constexpr unsigned int kGammaLookupSize = 1024;
-	std::array<uint8_t, kGammaLookupSize> gammaTable_;
-	int lastBlackLevel_ = -1;
-
-	int32_t exposureMin_, exposureMax_;
-	int32_t exposure_;
-	double againMin_, againMax_, againMinStep_;
-	double again_;
-	unsigned int ignoreUpdates_;
+	/* Local parameter storage */
+	struct IPAContext context_;
 };
 
 IPASoftSimple::~IPASoftSimple()
@@ -134,6 +114,15 @@ int IPASoftSimple::init(const IPASettings &settings,
 	unsigned int version = (*data)["version"].get<uint32_t>(0);
 	LOG(IPASoft, Debug) << "Tuning file version " << version;
 
+	if (!data->contains("algorithms")) {
+		LOG(IPASoft, Error) << "Tuning file doesn't contain algorithms";
+		return -EINVAL;
+	}
+
+	int ret = createAlgorithms(context_, (*data)["algorithms"]);
+	if (ret)
+		return ret;
+
 	params_ = nullptr;
 	stats_ = nullptr;
 
@@ -188,27 +177,46 @@ int IPASoftSimple::init(const IPASettings &settings,
 	return 0;
 }
 
-int IPASoftSimple::configure(const ControlInfoMap &sensorInfoMap)
+int IPASoftSimple::configure(const IPAConfigInfo &configInfo)
 {
-	sensorInfoMap_ = sensorInfoMap;
+	sensorInfoMap_ = configInfo.sensorControls;
 
 	const ControlInfo &exposureInfo = sensorInfoMap_.find(V4L2_CID_EXPOSURE)->second;
 	const ControlInfo &gainInfo = sensorInfoMap_.find(V4L2_CID_ANALOGUE_GAIN)->second;
 
-	exposureMin_ = exposureInfo.min().get<int32_t>();
-	exposureMax_ = exposureInfo.max().get<int32_t>();
-	if (!exposureMin_) {
+	/* Clear the IPA context before the streaming session. */
+	context_.configuration = {};
+	context_.activeState = {};
+	context_.frameContexts.clear();
+
+	context_.configuration.agc.exposureMin = exposureInfo.min().get<int32_t>();
+	context_.configuration.agc.exposureMax = exposureInfo.max().get<int32_t>();
+	if (!context_.configuration.agc.exposureMin) {
 		LOG(IPASoft, Warning) << "Minimum exposure is zero, that can't be linear";
-		exposureMin_ = 1;
+		context_.configuration.agc.exposureMin = 1;
 	}
 
 	int32_t againMin = gainInfo.min().get<int32_t>();
 	int32_t againMax = gainInfo.max().get<int32_t>();
 
 	if (camHelper_) {
-		againMin_ = camHelper_->gain(againMin);
-		againMax_ = camHelper_->gain(againMax);
-		againMinStep_ = (againMax_ - againMin_) / 100.0;
+		context_.configuration.agc.againMin = camHelper_->gain(againMin);
+		context_.configuration.agc.againMax = camHelper_->gain(againMax);
+		context_.configuration.agc.againMinStep =
+			(context_.configuration.agc.againMax -
+			 context_.configuration.agc.againMin) /
+			100.0;
+		if (!context_.configuration.black.level.has_value() &&
+		    camHelper_->blackLevel().has_value()) {
+			/*
+			 * The black level from camHelper_ is a 16 bit value, software ISP
+			 * works with 8 bit pixel values, both regardless of the actual
+			 * sensor pixel width. Hence we obtain the pixel-based black value
+			 * by dividing the value from the helper by 256.
+			 */
+			context_.configuration.black.level =
+				camHelper_->blackLevel().value() / 256;
+		}
 	} else {
 		/*
 		 * The camera sensor gain (g) is usually not equal to the value written
@@ -220,18 +228,28 @@ int IPASoftSimple::configure(const ControlInfoMap &sensorInfoMap)
 		 * the AGC algorithm (abrupt near one edge, and very small near the
 		 * other) we limit the range of the gain values used.
 		 */
-		againMax_ = againMax;
+		context_.configuration.agc.againMax = againMax;
 		if (!againMin) {
 			LOG(IPASoft, Warning)
 				<< "Minimum gain is zero, that can't be linear";
-			againMin_ = std::min(100, againMin / 2 + againMax / 2);
+			context_.configuration.agc.againMin =
+				std::min(100, againMin / 2 + againMax / 2);
 		}
-		againMinStep_ = 1.0;
+		context_.configuration.agc.againMinStep = 1.0;
 	}
 
-	LOG(IPASoft, Info) << "Exposure " << exposureMin_ << "-" << exposureMax_
-			   << ", gain " << againMin_ << "-" << againMax_
-			   << " (" << againMinStep_ << ")";
+	for (auto const &algo : algorithms()) {
+		int ret = algo->configure(context_, configInfo);
+		if (ret)
+			return ret;
+	}
+
+	LOG(IPASoft, Info)
+		<< "Exposure " << context_.configuration.agc.exposureMin << "-"
+		<< context_.configuration.agc.exposureMax
+		<< ", gain " << context_.configuration.agc.againMin << "-"
+		<< context_.configuration.agc.againMax
+		<< " (" << context_.configuration.agc.againMinStep << ")";
 
 	return 0;
 }
@@ -243,107 +261,45 @@ int IPASoftSimple::start()
 
 void IPASoftSimple::stop()
 {
+	context_.frameContexts.clear();
 }
 
-void IPASoftSimple::processStats(const ControlList &sensorControls)
+void IPASoftSimple::queueRequest(const uint32_t frame, const ControlList &controls)
 {
-	SwIspStats::Histogram histogram = stats_->yHistogram;
-	if (ignoreUpdates_ > 0)
-		blackLevel_.update(histogram);
-	const uint8_t blackLevel = blackLevel_.get();
-
-	/*
-	 * Black level must be subtracted to get the correct AWB ratios, they
-	 * would be off if they were computed from the whole brightness range
-	 * rather than from the sensor range.
-	 */
-	const uint64_t nPixels = std::accumulate(
-		histogram.begin(), histogram.end(), 0);
-	const uint64_t offset = blackLevel * nPixels;
-	const uint64_t sumR = stats_->sumR_ - offset / 4;
-	const uint64_t sumG = stats_->sumG_ - offset / 2;
-	const uint64_t sumB = stats_->sumB_ - offset / 4;
-
-	/*
-	 * Calculate red and blue gains for AWB.
-	 * Clamp max gain at 4.0, this also avoids 0 division.
-	 * Gain: 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
-	 */
-	const unsigned int gainR = sumR <= sumG / 4 ? 1024 : 256 * sumG / sumR;
-	const unsigned int gainB = sumB <= sumG / 4 ? 1024 : 256 * sumG / sumB;
-	/* Green gain and gamma values are fixed */
-	constexpr unsigned int gainG = 256;
-
-	/* Update the gamma table if needed */
-	if (blackLevel != lastBlackLevel_) {
-		constexpr float gamma = 0.5;
-		const unsigned int blackIndex = blackLevel * kGammaLookupSize / 256;
-		std::fill(gammaTable_.begin(), gammaTable_.begin() + blackIndex, 0);
-		const float divisor = kGammaLookupSize - blackIndex - 1.0;
-		for (unsigned int i = blackIndex; i < kGammaLookupSize; i++)
-			gammaTable_[i] = UINT8_MAX *
-					 std::pow((i - blackIndex) / divisor, gamma);
-
-		lastBlackLevel_ = blackLevel;
-	}
-
-	for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) {
-		constexpr unsigned int div =
-			DebayerParams::kRGBLookupSize * 256 / kGammaLookupSize;
-		unsigned int idx;
-
-		/* Apply gamma after gain! */
-		idx = std::min({ i * gainR / div, (kGammaLookupSize - 1) });
-		params_->red[i] = gammaTable_[idx];
+	IPAFrameContext &frameContext = context_.frameContexts.alloc(frame);
 
-		idx = std::min({ i * gainG / div, (kGammaLookupSize - 1) });
-		params_->green[i] = gammaTable_[idx];
-
-		idx = std::min({ i * gainB / div, (kGammaLookupSize - 1) });
-		params_->blue[i] = gammaTable_[idx];
-	}
+	for (auto const &algo : algorithms())
+		algo->queueRequest(context_, frame, frameContext, controls);
+}
 
+void IPASoftSimple::computeParams(const uint32_t frame)
+{
+	IPAFrameContext &frameContext = context_.frameContexts.get(frame);
+	for (auto const &algo : algorithms())
+		algo->prepare(context_, frame, frameContext, params_);
 	setIspParams.emit();
+}
 
-	/* \todo Switch to the libipa/algorithm.h API someday. */
+void IPASoftSimple::processStats(const uint32_t frame,
+				 [[maybe_unused]] const uint32_t bufferId,
+				 const ControlList &sensorControls)
+{
+	IPAFrameContext &frameContext = context_.frameContexts.get(frame);
 
-	/*
-	 * AE / AGC, use 2 frames delay to make sure that the exposure and
-	 * the gain set have applied to the camera sensor.
-	 * \todo This could be handled better with DelayedControls.
-	 */
-	if (ignoreUpdates_ > 0) {
-		--ignoreUpdates_;
-		return;
-	}
+	frameContext.sensor.exposure =
+		sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
+	int32_t again = sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>();
+	frameContext.sensor.gain = camHelper_ ? camHelper_->gain(again) : again;
 
 	/*
-	 * Calculate Mean Sample Value (MSV) according to formula from:
-	 * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf
+	 * Software ISP currently does not produce any metadata. Use an empty
+	 * ControlList for now.
+	 *
+	 * \todo Implement proper metadata handling
 	 */
-	const unsigned int blackLevelHistIdx =
-		blackLevel / (256 / SwIspStats::kYHistogramSize);
-	const unsigned int histogramSize =
-		SwIspStats::kYHistogramSize - blackLevelHistIdx;
-	const unsigned int yHistValsPerBin = histogramSize / kExposureBinsCount;
-	const unsigned int yHistValsPerBinMod =
-		histogramSize / (histogramSize % kExposureBinsCount + 1);
-	int exposureBins[kExposureBinsCount] = {};
-	unsigned int denom = 0;
-	unsigned int num = 0;
-
-	for (unsigned int i = 0; i < histogramSize; i++) {
-		unsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin;
-		exposureBins[idx] += stats_->yHistogram[blackLevelHistIdx + i];
-	}
-
-	for (unsigned int i = 0; i < kExposureBinsCount; i++) {
-		LOG(IPASoft, Debug) << i << ": " << exposureBins[i];
-		denom += exposureBins[i];
-		num += exposureBins[i] * (i + 1);
-	}
-
-	float exposureMSV = static_cast<float>(num) / denom;
+	ControlList metadata(controls::controls);
+	for (auto const &algo : algorithms())
+		algo->process(context_, frame, frameContext, stats_, metadata);
 
 	/* Sanity check */
 	if (!sensorControls.contains(V4L2_CID_EXPOSURE) ||
@@ -352,73 +308,19 @@ void IPASoftSimple::processStats(const ControlList &sensorControls)
 		return;
 	}
 
-	exposure_ = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
-	int32_t again = sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>();
-	again_ = camHelper_ ? camHelper_->gain(again) : again;
-
-	updateExposure(exposureMSV);
-
 	ControlList ctrls(sensorInfoMap_);
 
-	ctrls.set(V4L2_CID_EXPOSURE, exposure_);
+	auto &againNew = context_.activeState.agc.again;
+	ctrls.set(V4L2_CID_EXPOSURE, context_.activeState.agc.exposure);
 	ctrls.set(V4L2_CID_ANALOGUE_GAIN,
-		  static_cast<int32_t>(camHelper_ ? camHelper_->gainCode(again_) : again_));
-
-	ignoreUpdates_ = 2;
+		  static_cast<int32_t>(camHelper_ ? camHelper_->gainCode(againNew) : againNew));
 
 	setSensorControls.emit(ctrls);
-
-	LOG(IPASoft, Debug) << "exposureMSV " << exposureMSV
-			    << " exp " << exposure_ << " again " << again_
-			    << " gain R/B " << gainR << "/" << gainB
-			    << " black level " << static_cast<unsigned int>(blackLevel);
 }
 
-void IPASoftSimple::updateExposure(double exposureMSV)
+std::string IPASoftSimple::logPrefix() const
 {
-	/*
-	 * kExpDenominator of 10 gives ~10% increment/decrement;
-	 * kExpDenominator of 5 - about ~20%
-	 */
-	static constexpr uint8_t kExpDenominator = 10;
-	static constexpr uint8_t kExpNumeratorUp = kExpDenominator + 1;
-	static constexpr uint8_t kExpNumeratorDown = kExpDenominator - 1;
-
-	double next;
-
-	if (exposureMSV < kExposureOptimal - kExposureSatisfactory) {
-		next = exposure_ * kExpNumeratorUp / kExpDenominator;
-		if (next - exposure_ < 1)
-			exposure_ += 1;
-		else
-			exposure_ = next;
-		if (exposure_ >= exposureMax_) {
-			next = again_ * kExpNumeratorUp / kExpDenominator;
-			if (next - again_ < againMinStep_)
-				again_ += againMinStep_;
-			else
-				again_ = next;
-		}
-	}
-
-	if (exposureMSV > kExposureOptimal + kExposureSatisfactory) {
-		if (exposure_ == exposureMax_ && again_ > againMin_) {
-			next = again_ * kExpNumeratorDown / kExpDenominator;
-			if (again_ - next < againMinStep_)
-				again_ -= againMinStep_;
-			else
-				again_ = next;
-		} else {
-			next = exposure_ * kExpNumeratorDown / kExpDenominator;
-			if (exposure_ - next < 1)
-				exposure_ -= 1;
-			else
-				exposure_ = next;
-		}
-	}
-
-	exposure_ = std::clamp(exposure_, exposureMin_, exposureMax_);
-	again_ = std::clamp(again_, againMin_, againMax_);
+	return "IPASoft";
 }
 
 } /* namespace ipa::soft */