6 files changed, 244 insertions, 0 deletions
diff --git a/include/libcamera/internal/software_isp/debayer_params.h b/include/libcamera/internal/software_isp/debayer_params.h
new file mode 100644
index 00000000..c818ca3a
--- /dev/null
+++ b/include/libcamera/internal/software_isp/debayer_params.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2023, Red Hat Inc.
+ *
+ * Authors:
+ * Hans de Goede <hdegoede@redhat.com>
+ *
+ * debayer_params.h - DebayerParams header
+ */
+
+#pragma once
+
+namespace libcamera {
+
+struct DebayerParams {
+	static constexpr unsigned int kGain10 = 256;
+
+	unsigned int gainR;
+	unsigned int gainG;
+	unsigned int gainB;
+
+	float gamma;
+};
+
+} /* namespace libcamera */
diff --git a/include/libcamera/internal/software_isp/meson.build b/include/libcamera/internal/software_isp/meson.build
index 66c9c3fb..a620e16d 100644
--- a/include/libcamera/internal/software_isp/meson.build
+++ b/include/libcamera/internal/software_isp/meson.build
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: CC0-1.0
 
 libcamera_internal_headers += files([
+    'debayer_params.h',
     'swisp_stats.h',
 ])
diff --git a/src/libcamera/software_isp/TODO b/src/libcamera/software_isp/TODO
index 1c28fc36..7929e73e 100644
--- a/src/libcamera/software_isp/TODO
+++ b/src/libcamera/software_isp/TODO
@@ -69,3 +69,34 @@ Removing the signal and refactoring those classes doesn't have to be
 addressed now, I think it would be part of a larger refactoring
 (possibly also considering platforms that have no ISP but can produce
 stats in hardware, such as the i.MX7), but please keep it on your radar.
+
+---
+
+4. Hide internal representation of gains from callers
+
+> struct DebayerParams {
+> 	static constexpr unsigned int kGain10 = 256;
+
+Forcing the caller to deal with the internal representation of gains
+isn't nice, especially given that it precludes implementing gains of
+different precisions in different backend. Wouldn't it be better to pass
+the values as floating point numbers, and convert them to the internal
+representation in the implementation of process() before using them ?
+
+---
+
+5. Store ISP parameters in per-frame buffers
+
+> /**
+>  * \fn void Debayer::process(FrameBuffer *input, FrameBuffer *output, DebayerParams params)
+>  * \brief Process the bayer data into the requested format.
+>  * \param[in] input The input buffer.
+>  * \param[in] output The output buffer.
+>  * \param[in] params The parameters to be used in debayering.
+>  *
+>  * \note DebayerParams is passed by value deliberately so that a copy is passed
+>  * when this is run in another thread by invokeMethod().
+>  */
+
+Possibly something to address later, by storing ISP parameters in
+per-frame buffers like we do for hardware ISPs.
diff --git a/src/libcamera/software_isp/debayer.cpp b/src/libcamera/software_isp/debayer.cpp
new file mode 100644
index 00000000..1c035e9b
--- /dev/null
+++ b/src/libcamera/software_isp/debayer.cpp
@@ -0,0 +1,132 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2023, Linaro Ltd
+ * Copyright (C) 2023, Red Hat Inc.
+ *
+ * Authors:
+ * Hans de Goede <hdegoede@redhat.com>
+ *
+ * debayer.cpp - debayer base class
+ */
+
+#include "debayer.h"
+
+namespace libcamera {
+
+/**
+ * \struct DebayerParams
+ * \brief Struct to hold the debayer parameters.
+ */
+
+/**
+ * \var DebayerParams::kGain10
+ * \brief const value for 1.0 gain
+ */
+
+/**
+ * \var DebayerParams::gainR
+ * \brief Red gain
+ *
+ * 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
+ */
+
+/**
+ * \var DebayerParams::gainG
+ * \brief Green gain
+ *
+ * 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
+ */
+
+/**
+ * \var DebayerParams::gainB
+ * \brief Blue gain
+ *
+ * 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
+ */
+
+/**
+ * \var DebayerParams::gamma
+ * \brief Gamma correction, 1.0 is no correction
+ */
+
+/**
+ * \class Debayer
+ * \brief Base debayering class
+ *
+ * Base class that provides functions for setting up the debayering process.
+ */
+
+LOG_DEFINE_CATEGORY(Debayer)
+
+Debayer::~Debayer()
+{
+}
+
+/**
+ * \fn int Debayer::configure(const StreamConfiguration &inputCfg, const std::vector<std::reference_wrapper<StreamConfiguration>> &outputCfgs)
+ * \brief Configure the debayer object according to the passed in parameters.
+ * \param[in] inputCfg The input configuration.
+ * \param[in] outputCfgs The output configurations.
+ *
+ * \return 0 on success, a negative errno on failure.
+ */
+
+/**
+ * \fn Size Debayer::patternSize(PixelFormat inputFormat)
+ * \brief Get the width and height at which the bayer pattern repeats.
+ * \param[in] inputFormat The input format.
+ *
+ * Valid sizes are: 2x2, 4x2 or 4x4.
+ *
+ * \return Pattern size or an empty size for unsupported inputFormats.
+ */
+
+/**
+ * \fn std::vector<PixelFormat> Debayer::formats(PixelFormat inputFormat)
+ * \brief Get the supported output formats.
+ * \param[in] inputFormat The input format.
+ *
+ * \return All supported output formats or an empty vector if there are none.
+ */
+
+/**
+ * \fn std::tuple<unsigned int, unsigned int> Debayer::strideAndFrameSize(const PixelFormat &outputFormat, const Size &size)
+ * \brief Get the stride and the frame size.
+ * \param[in] outputFormat The output format.
+ * \param[in] size The output size.
+ *
+ * \return A tuple of the stride and the frame size, or a tuple with 0,0 if
+ *    there is no valid output config.
+ */
+
+/**
+ * \fn void Debayer::process(FrameBuffer *input, FrameBuffer *output, DebayerParams params)
+ * \brief Process the bayer data into the requested format.
+ * \param[in] input The input buffer.
+ * \param[in] output The output buffer.
+ * \param[in] params The parameters to be used in debayering.
+ *
+ * \note DebayerParams is passed by value deliberately so that a copy is passed
+ * when this is run in another thread by invokeMethod().
+ */
+
+/**
+ * \fn virtual SizeRange Debayer::sizes(PixelFormat inputFormat, const Size &inputSize)
+ * \brief Get the supported output sizes for the given input format and size.
+ * \param[in] inputFormat The input format.
+ * \param[in] inputSize The input size.
+ *
+ * \return The valid size ranges or an empty range if there are none.
+ */
+
+/**
+ * \var Signal<FrameBuffer *> Debayer::inputBufferReady
+ * \brief Signals when the input buffer is ready.
+ */
+
+/**
+ * \var Signal<FrameBuffer *> Debayer::outputBufferReady
+ * \brief Signals when the output buffer is ready.
+ */
+
+} /* namespace libcamera */
diff --git a/src/libcamera/software_isp/debayer.h b/src/libcamera/software_isp/debayer.h
new file mode 100644
index 00000000..42ae58ab
--- /dev/null
+++ b/src/libcamera/software_isp/debayer.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2023, Linaro Ltd
+ * Copyright (C) 2023, Red Hat Inc.
+ *
+ * Authors:
+ * Hans de Goede <hdegoede@redhat.com>
+ *
+ * debayer.h - debayering base class
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/signal.h>
+
+#include <libcamera/geometry.h>
+#include <libcamera/stream.h>
+
+#include "libcamera/internal/software_isp/debayer_params.h"
+
+namespace libcamera {
+
+class FrameBuffer;
+
+LOG_DECLARE_CATEGORY(Debayer)
+
+class Debayer
+{
+public:
+	virtual ~Debayer() = 0;
+
+	virtual int configure(const StreamConfiguration &inputCfg,
+			      const std::vector<std::reference_wrapper<StreamConfiguration>> &outputCfgs) = 0;
+
+	virtual std::vector<PixelFormat> formats(PixelFormat inputFormat) = 0;
+
+	virtual std::tuple<unsigned int, unsigned int>
+	strideAndFrameSize(const PixelFormat &outputFormat, const Size &size) = 0;
+
+	virtual void process(FrameBuffer *input, FrameBuffer *output, DebayerParams params) = 0;
+
+	virtual SizeRange sizes(PixelFormat inputFormat, const Size &inputSize) = 0;
+
+	Signal<FrameBuffer *> inputBufferReady;
+	Signal<FrameBuffer *> outputBufferReady;
+
+private:
+	virtual Size patternSize(PixelFormat inputFormat) = 0;
+};
+
+} /* namespace libcamera */
diff --git a/src/libcamera/software_isp/meson.build b/src/libcamera/software_isp/meson.build
index 281bbf0e..6068a418 100644
--- a/src/libcamera/software_isp/meson.build
+++ b/src/libcamera/software_isp/meson.build
@@ -8,5 +8,6 @@ if not softisp_enabled
 endif
 
 libcamera_sources += files([
+    'debayer.cpp',
     'swstats_cpu.cpp',
 ])