libcamera: software_isp: Add Debayer base class

Add a base class for debayer implementations. This is intended to be
suitable for both GPU (or otherwise) accelerated debayer implementations
as well as CPU based debayering.

Doxygen documentation by Dennis Bonke.

Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> # sc8280xp Lenovo x13s
Tested-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>
Co-developed-by: Dennis Bonke <admin@dennisbonke.com>
Signed-off-by: Dennis Bonke <admin@dennisbonke.com>
Co-developed-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

4 files changed, 218 insertions, 0 deletions

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',
 ])