[v3,06/16] libcamera: software_isp: Add SwStatsCpu class

19489 diff mbox series

Add a CPU based SwStats implementation for SoftwareISP / SoftIPA use.

This implementation offers a configure function + functions to gather
statistics on a line by line basis. This allows CPU based software
debayering to call into interlace debayering and statistics gathering
on a line by line bases while the input data is still hot in the cache.

This implementation also allows specifying a window over which to gather
statistics instead of processing the whole frame.

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>
Co-developed-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Co-developed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Co-developed-by: Dennis Bonke <admin@dennisbonke.com>
Signed-off-by: Dennis Bonke <admin@dennisbonke.com>
Co-developed-by: Marttico <g.martti@gmail.com>
Signed-off-by: Marttico <g.martti@gmail.com>
Co-developed-by: Toon Langendam <t.langendam@gmail.com>
Signed-off-by: Toon Langendam <t.langendam@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v3:
- Merge SwStats base-class into SwStatsCpu
- Move swstats_cpu.h to src/libcamera/software_isp/
- Move documentation to .cpp file and extend it
- Rename a bunch of foo_bar symbols to fooBar
- Change a couple of defines and hardcoded values to constexpr
- Remove statsBayer10P in swstats_cpu.cpp, instead move the loop to
  statsBGGR10PLine0 / statsGBRG10PLine0
- Make startFrame() and finishFrame() normal methods instead of
  using function pointers for these
---
 include/libcamera/internal/meson.build        |   1 +
 .../internal/software_isp/meson.build         |   5 +
 .../internal/software_isp/swisp_stats.h       |  38 ++++
 src/libcamera/meson.build                     |   1 +
 src/libcamera/software_isp/meson.build        |   5 +
 src/libcamera/software_isp/swstats_cpu.cpp    | 208 ++++++++++++++++++
 src/libcamera/software_isp/swstats_cpu.h      | 158 +++++++++++++
 7 files changed, 416 insertions(+)
 create mode 100644 include/libcamera/internal/software_isp/meson.build
 create mode 100644 include/libcamera/internal/software_isp/swisp_stats.h
 create mode 100644 src/libcamera/software_isp/meson.build
 create mode 100644 src/libcamera/software_isp/swstats_cpu.cpp
 create mode 100644 src/libcamera/software_isp/swstats_cpu.h

Hans de Goede <hdegoede@redhat.com> writes:

> Add a CPU based SwStats implementation for SoftwareISP / SoftIPA use.
>
> This implementation offers a configure function + functions to gather
> statistics on a line by line basis. This allows CPU based software
> debayering to call into interlace debayering and statistics gathering
> on a line by line bases while the input data is still hot in the cache.
>
> This implementation also allows specifying a window over which to gather
> statistics instead of processing the whole frame.
>
> 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>
> Co-developed-by: Andrey Konovalov <andrey.konovalov@linaro.org>
> Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
> Co-developed-by: Pavel Machek <pavel@ucw.cz>
> Signed-off-by: Pavel Machek <pavel@ucw.cz>
> Co-developed-by: Dennis Bonke <admin@dennisbonke.com>
> Signed-off-by: Dennis Bonke <admin@dennisbonke.com>
> Co-developed-by: Marttico <g.martti@gmail.com>
> Signed-off-by: Marttico <g.martti@gmail.com>
> Co-developed-by: Toon Langendam <t.langendam@gmail.com>
> Signed-off-by: Toon Langendam <t.langendam@gmail.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> Changes in v3:
> - Merge SwStats base-class into SwStatsCpu
> - Move swstats_cpu.h to src/libcamera/software_isp/
> - Move documentation to .cpp file and extend it
> - Rename a bunch of foo_bar symbols to fooBar
> - Change a couple of defines and hardcoded values to constexpr
> - Remove statsBayer10P in swstats_cpu.cpp, instead move the loop to
>   statsBGGR10PLine0 / statsGBRG10PLine0
> - Make startFrame() and finishFrame() normal methods instead of
>   using function pointers for these
> ---
>  include/libcamera/internal/meson.build        |   1 +
>  .../internal/software_isp/meson.build         |   5 +
>  .../internal/software_isp/swisp_stats.h       |  38 ++++
>  src/libcamera/meson.build                     |   1 +
>  src/libcamera/software_isp/meson.build        |   5 +
>  src/libcamera/software_isp/swstats_cpu.cpp    | 208 ++++++++++++++++++
>  src/libcamera/software_isp/swstats_cpu.h      | 158 +++++++++++++
>  7 files changed, 416 insertions(+)
>  create mode 100644 include/libcamera/internal/software_isp/meson.build
>  create mode 100644 include/libcamera/internal/software_isp/swisp_stats.h
>  create mode 100644 src/libcamera/software_isp/meson.build
>  create mode 100644 src/libcamera/software_isp/swstats_cpu.cpp
>  create mode 100644 src/libcamera/software_isp/swstats_cpu.h
>
> diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
> index 5807dfd9..160fdc37 100644
> --- a/include/libcamera/internal/meson.build
> +++ b/include/libcamera/internal/meson.build
> @@ -50,3 +50,4 @@ libcamera_internal_headers = files([
>  ])
>  
>  subdir('converter')
> +subdir('software_isp')
> diff --git a/include/libcamera/internal/software_isp/meson.build b/include/libcamera/internal/software_isp/meson.build
> new file mode 100644
> index 00000000..66c9c3fb
> --- /dev/null
> +++ b/include/libcamera/internal/software_isp/meson.build
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +libcamera_internal_headers += files([
> +    'swisp_stats.h',
> +])
> diff --git a/include/libcamera/internal/software_isp/swisp_stats.h b/include/libcamera/internal/software_isp/swisp_stats.h
> new file mode 100644
> index 00000000..afe42c9a
> --- /dev/null
> +++ b/include/libcamera/internal/software_isp/swisp_stats.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2023, Linaro Ltd
> + *
> + * swisp_stats.h - Statistics data format used by the software ISP and software IPA
> + */
> +
> +#pragma once
> +
> +namespace libcamera {
> +
> +/**
> + * \brief Struct that holds the statistics for the Software ISP.
> + */
> +struct SwIspStats {
> +	/**
> +	 * \brief Holds the sum of all sampled red pixels.
> +	 */
> +	unsigned long sumR_;
> +	/**
> +	 * \brief Holds the sum of all sampled green pixels.
> +	 */
> +	unsigned long sumG_;
> +	/**
> +	 * \brief Holds the sum of all sampled blue pixels.
> +	 */
> +	unsigned long sumB_;
> +	/**
> +	 * \brief Number of bins in the yHistogram.
> +	 */
> +	static constexpr unsigned int kYHistogramSize = 16;
> +	/**
> +	 * \brief A histogram of luminance values.
> +	 */
> +	std::array<unsigned int, kYHistogramSize> yHistogram;
> +};
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> index 94a95ae3..91e4cc60 100644
> --- a/src/libcamera/meson.build
> +++ b/src/libcamera/meson.build
> @@ -71,6 +71,7 @@ subdir('converter')
>  subdir('ipa')
>  subdir('pipeline')
>  subdir('proxy')
> +subdir('software_isp')
>  
>  null_dep = dependency('', required : false)
>  
> diff --git a/src/libcamera/software_isp/meson.build b/src/libcamera/software_isp/meson.build
> new file mode 100644
> index 00000000..e1fb8ccc
> --- /dev/null
> +++ b/src/libcamera/software_isp/meson.build
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +libcamera_sources += files([
> +    'swstats_cpu.cpp',
> +])
> diff --git a/src/libcamera/software_isp/swstats_cpu.cpp b/src/libcamera/software_isp/swstats_cpu.cpp
> new file mode 100644
> index 00000000..a3a2eb94
> --- /dev/null
> +++ b/src/libcamera/software_isp/swstats_cpu.cpp
> @@ -0,0 +1,208 @@
> +/* 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>
> + *
> + * swstats_cpu.cpp - CPU based software statistics implementation
> + */
> +
> +#include "swstats_cpu.h"
> +
> +#include <libcamera/base/log.h>
> +
> +#include <libcamera/stream.h>
> +
> +#include "libcamera/internal/bayer_format.h"
> +
> +namespace libcamera {
> +
> +/**
> + * \class SwStatsCpu
> + * \brief Class for gathering statistics on the CPU
> + *
> + * CPU based software ISP statistics implementation.
> + *
> + * This class offers a configure function + functions to gather statistics
> + * on a line by line basis. This allows CPU based software debayering to
> + * interlace debayering and statistics gathering on a line by line bases
                                                                      ^^^^^

basis?

> + * while the input data is still hot in the cache.
> + *
> + * It is also possible to specify a window over which to gather
> + * statistics instead of processing the whole frame.
> + */
> +
> +LOG_DEFINE_CATEGORY(SwStatsCpu)
> +
> +SwStatsCpu::SwStatsCpu()
> +{
> +	sharedStats_ = SharedMemObject<SwIspStats>("softIsp_stats");
> +	if (!sharedStats_.fd().isValid())
> +		LOG(SwStatsCpu, Error)
> +			<< "Failed to create shared memory for statistics";
> +}
> +
> +static const unsigned int kRedYMul = 77; /* 0.299 * 256 */
> +static const unsigned int kGreenYMul = 150; /* 0.587 * 256 */
> +static const unsigned int kBlueYMul = 29; /* 0.114 * 256 */
> +
> +#define SWSTATS_START_LINE_STATS(pixel_t) \
> +	pixel_t r, g, g2, b;              \
> +	unsigned int yVal;                \
> +                                          \
> +	unsigned int sumR = 0;            \
> +	unsigned int sumG = 0;            \
> +	unsigned int sumB = 0;
> +
> +#define SWSTATS_ACCUMULATE_LINE_STATS(div) \
> +	sumR += r;                         \
> +	sumG += g;                         \
> +	sumB += b;                         \
> +                                           \
> +	yVal = r * kRedYMul;               \
> +	yVal += g * kGreenYMul;            \
> +	yVal += b * kBlueYMul;             \
> +	stats_.yHistogram[yVal / (256 * SwIspStats::kYHistogramSize * (div))]++;
> +
> +#define SWSTATS_FINISH_LINE_STATS() \
> +	stats_.sumR_ += sumR;       \
> +	stats_.sumG_ += sumG;       \
> +	stats_.sumB_ += sumB;
> +
> +void SwStatsCpu::statsBGGR10PLine0(const uint8_t *src[])
> +{
> +	const uint8_t *src0 = src[1] + window_.x * 5 / 4;
> +	const uint8_t *src1 = src[2] + window_.x * 5 / 4;
> +	const int widthInBytes = window_.width * 5 / 4;
> +
> +	if (swapLines_)
> +		std::swap(src0, src1);
> +
> +	SWSTATS_START_LINE_STATS(uint8_t)
> +
> +	/* x += 5 sample every other 2x2 block */
> +	for (int x = 0; x < widthInBytes; x += 5) {
> +		/* BGGR */
> +		b = src0[x];
> +		g = src0[x + 1];
> +		g2 = src1[x];
> +		r = src1[x + 1];
> +		g = (g + g2) / 2;
> +		/* Data is already 8 bits, divide by 1 */
> +		SWSTATS_ACCUMULATE_LINE_STATS(1)
> +	}
> +
> +	SWSTATS_FINISH_LINE_STATS()
> +}
> +
> +void SwStatsCpu::statsGBRG10PLine0(const uint8_t *src[])
> +{
> +	const uint8_t *src0 = src[1] + window_.x * 5 / 4;
> +	const uint8_t *src1 = src[2] + window_.x * 5 / 4;
> +	const int widthInBytes = window_.width * 5 / 4;
> +
> +	if (swapLines_)
> +		std::swap(src0, src1);
> +
> +	SWSTATS_START_LINE_STATS(uint8_t)
> +
> +	/* x += 5 sample every other 2x2 block */
> +	for (int x = 0; x < widthInBytes; x += 5) {
> +		/* GBRG */
> +		g = src0[x];
> +		b = src0[x + 1];
> +		r = src1[x];
> +		g2 = src1[x + 1];
> +		g = (g + g2) / 2;
> +		/* Data is already 8 bits, divide by 1 */
> +		SWSTATS_ACCUMULATE_LINE_STATS(1)
> +	}
> +
> +	SWSTATS_FINISH_LINE_STATS()
> +}
> +
> +/**
> + * \brief Reset state to start statistics gathering for a new frame.
> + *
> + * This may only be called after a successful setWindow() call.
> + */
> +void SwStatsCpu::startFrame(void)
> +{
> +	stats_.sumR_ = 0;
> +	stats_.sumB_ = 0;
> +	stats_.sumG_ = 0;
> +	stats_.yHistogram.fill(0);
> +}
> +
> +/**
> + * \brief Finish statistics calculation for the current frame.
> + *
> + * This may only be called after a successful setWindow() call.
> + */
> +void SwStatsCpu::finishFrame(void)
> +{
> +	*sharedStats_ = stats_;
> +	statsReady.emit(0);
> +}
> +
> +/**
> + * \brief Configure the statistics object for the passed in input format.
> + * \param[in] inputCfg The input format
> + *
> + * \return 0 on success, a negative errno value on failure
> + */
> +int SwStatsCpu::configure(const StreamConfiguration &inputCfg)
> +{
> +	BayerFormat bayerFormat =
> +		BayerFormat::fromPixelFormat(inputCfg.pixelFormat);
> +
> +	if (bayerFormat.bitDepth == 10 &&
> +	    bayerFormat.packing == BayerFormat::Packing::CSI2) {
> +		patternSize_.height = 2;
> +		patternSize_.width = 4; /* 5 bytes per *4* pixels */
> +		/* Skip every 3th and 4th line, sample every other 2x2 block */
> +		ySkipMask_ = 0x02;
> +		xShift_ = 0;
> +
> +		switch (bayerFormat.order) {
> +		case BayerFormat::BGGR:
> +		case BayerFormat::GRBG:
> +			stats0_ = (SwStatsCpu::statsProcessFn)&SwStatsCpu::statsBGGR10PLine0;
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Isn't the type cast superfluous?  (The same below.)

> +			swapLines_ = bayerFormat.order == BayerFormat::GRBG;
> +			return 0;
> +		case BayerFormat::GBRG:
> +		case BayerFormat::RGGB:
> +			stats0_ = (SwStatsCpu::statsProcessFn)&SwStatsCpu::statsGBRG10PLine0;
> +			swapLines_ = bayerFormat.order == BayerFormat::RGGB;
> +			return 0;
> +		default:
> +			break;
> +		}
> +	}
> +
> +	LOG(SwStatsCpu, Info)
> +		<< "Unsupported input format " << inputCfg.pixelFormat.toString();
> +	return -EINVAL;
> +}
> +
> +/**
> + * \brief Specify window coordinates over which to gather statistics.
> + * \param[in] window The window object.
> + */
> +void SwStatsCpu::setWindow(Rectangle window)
> +{
> +	window_ = window;
> +
> +	window_.x &= ~(patternSize_.width - 1);
> +	window_.x += xShift_;
> +	window_.y &= ~(patternSize_.height - 1);
> +
> +	/* width_ - xShift_ to make sure the window fits */
> +	window_.width -= xShift_;
> +	window_.width &= ~(patternSize_.width - 1);
> +	window_.height &= ~(patternSize_.height - 1);
> +}
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/software_isp/swstats_cpu.h b/src/libcamera/software_isp/swstats_cpu.h
> new file mode 100644
> index 00000000..166ebe28
> --- /dev/null
> +++ b/src/libcamera/software_isp/swstats_cpu.h
> @@ -0,0 +1,158 @@
> +/* 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>
> + *
> + * swstats_cpu.h - CPU based software statistics implementation
> + */
> +
> +#pragma once
> +
> +#include <stdint.h>
> +
> +#include <libcamera/base/signal.h>
> +
> +#include <libcamera/geometry.h>
> +
> +#include "libcamera/internal/shared_mem_object.h"
> +#include "libcamera/internal/software_isp/swisp_stats.h"
> +
> +namespace libcamera {
> +
> +class PixelFormat;
> +struct StreamConfiguration;
> +
> +class SwStatsCpu
> +{
> +public:
> +	SwStatsCpu();
> +	~SwStatsCpu() = default;
> +
> +	/**
> +	 * \brief Gets wether the statistics object is valid.
> +	 *
> +	 * \return true if it's valid, false otherwise
> +	 */
> +	bool isValid() const { return sharedStats_.fd().isValid(); }
> +
> +	/**
> +	 * \brief Get the file descriptor for the statistics.
> +	 *
> +	 * \return the file descriptor
> +	 */
> +	const SharedFD &getStatsFD() { return sharedStats_.fd(); }
> +
> +	/**
> +	 * \brief Get the pattern size.
> +	 *
> +	 * For some input-formats, e.g. Bayer data, processing is done multiple lines
> +	 * and/or columns at a time. Get width and height at which the (bayer) pattern
> +	 * repeats. Window values are rounded down to a multiple of this and the height
> +	 * also indicates if processLine2() should be called or not.
> +	 * This may only be called after a successful configure() call.
> +	 *
> +	 * \return the pattern size
> +	 */
> +	const Size &patternSize() { return patternSize_; }
> +
> +	int configure(const StreamConfiguration &inputCfg);
> +	void setWindow(Rectangle window);
> +	void startFrame();
> +	void finishFrame();
> +
> +	/**
> +	 * \brief Process line 0.
> +	 * \param[in] y The y coordinate.
> +	 * \param[in] src The input data.
> +	 *
> +	 * This function processes line 0 for input formats with patternSize height == 1.
> +	 * It'll process line 0 and 1 for input formats with patternSize height >= 2.
> +	 * This function may only be called after a successful setWindow() call.
> +	 */
> +	void processLine0(unsigned int y, const uint8_t *src[])
> +	{
> +		if ((y & ySkipMask_) || y < (unsigned int)window_.y ||
> +		    y >= (window_.y + window_.height))
> +			return;
> +
> +		(this->*stats0_)(src);
> +	}
> +
> +	/**
> +	 * \brief Process line 2 and 3.
> +	 * \param[in] y The y coordinate.
> +	 * \param[in] src The input data.
> +	 *
> +	 * This function processes line 2 and 3 for input formats with patternSize height == 4.
> +	 * This function may only be called after a successful setWindow() call.
> +	 */
> +	void processLine2(unsigned int y, const uint8_t *src[])
> +	{
> +		if ((y & ySkipMask_) || y < (unsigned int)window_.y ||
> +		    y >= (window_.y + window_.height))
> +			return;
> +
> +		(this->*stats2_)(src);
> +	}
> +
> +	/**
> +	 * \brief Signals that the statistics are ready.
> +	 *
> +	 * The int parameter isn't actually used.
> +	 */
> +	Signal<int> statsReady;
> +private:
> +	/**
> +	 * \brief Called when there is data to get statistics from.
> +	 * \param[in] src The input data
> +	 *
> +	 * These functions take an array of (patternSize_.height + 1) src
> +	 * pointers each pointing to a line in the source image. The middle
> +	 * element of the array will point to the actual line being processed.
> +	 * Earlier element(s) will point to the previous line(s) and later
> +	 * element(s) to the next line(s).

And are there previous lines processed anywhere?  If not, what happens to the
very first line, must it be always excluded by the specified window?  It looks
hard to track what is what and whether we hit the right place for the given
pattern.  But I don't have any bright idea how to make it clearer so I can live
with it as it is, unless somebody else has a good suggestion.

> +	 *
> +	 * See the documentation of DebayerCpu::debayerFn for more details.
> +	 */
> +	typedef void (SwStatsCpu::*statsProcessFn)(const uint8_t *src[]);

`using' should be apparently used instead of `typedef'.

> +	void statsBGGR10PLine0(const uint8_t *src[]);
> +	void statsGBRG10PLine0(const uint8_t *src[]);
> +
> +	/* Variables set by configure(), used every line */
> +	statsProcessFn stats0_;
> +	statsProcessFn stats2_;
> +	bool swapLines_;
> +
> +	/**
> +	 * \brief Skip lines where this bitmask is set in y.
> +	 */
> +	unsigned int ySkipMask_;
> +
> +	/**
> +	 * \brief Statistics window, set by setWindow(), used ever line.
> +	 */
> +	Rectangle window_;
> +
> +	/**
> +	 * \brief The size of the bayer pattern.
> +	 *
> +	 * Valid sizes are: 2x2, 4x2 or 4x4.
> +	 */
> +	Size patternSize_;
> +
> +	/**
> +	 * \brief The offset of x, applied to window_.x for bayer variants.
> +	 *
> +	 * This can either be 0 or 1.
> +	 */
> +	unsigned int xShift_;
> +
> +	SharedMemObject<SwIspStats> sharedStats_;
> +	SwIspStats stats_;
> +};
> +
> +} /* namespace libcamera */

Hans de Goede <hdegoede@redhat.com> writes:

> Add a CPU based SwStats implementation for SoftwareISP / SoftIPA use.
>
> This implementation offers a configure function + functions to gather
> statistics on a line by line basis. This allows CPU based software
> debayering to call into interlace debayering and statistics gathering
> on a line by line bases while the input data is still hot in the cache.
>
> This implementation also allows specifying a window over which to gather
> statistics instead of processing the whole frame.
>
> 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>
> Co-developed-by: Andrey Konovalov <andrey.konovalov@linaro.org>
> Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
> Co-developed-by: Pavel Machek <pavel@ucw.cz>
> Signed-off-by: Pavel Machek <pavel@ucw.cz>
> Co-developed-by: Dennis Bonke <admin@dennisbonke.com>
> Signed-off-by: Dennis Bonke <admin@dennisbonke.com>
> Co-developed-by: Marttico <g.martti@gmail.com>
> Signed-off-by: Marttico <g.martti@gmail.com>
> Co-developed-by: Toon Langendam <t.langendam@gmail.com>
> Signed-off-by: Toon Langendam <t.langendam@gmail.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> Changes in v3:
> - Merge SwStats base-class into SwStatsCpu
> - Move swstats_cpu.h to src/libcamera/software_isp/
> - Move documentation to .cpp file and extend it
> - Rename a bunch of foo_bar symbols to fooBar
> - Change a couple of defines and hardcoded values to constexpr
> - Remove statsBayer10P in swstats_cpu.cpp, instead move the loop to
>   statsBGGR10PLine0 / statsGBRG10PLine0
> - Make startFrame() and finishFrame() normal methods instead of
>   using function pointers for these
> ---
>  include/libcamera/internal/meson.build        |   1 +
>  .../internal/software_isp/meson.build         |   5 +
>  .../internal/software_isp/swisp_stats.h       |  38 ++++
>  src/libcamera/meson.build                     |   1 +
>  src/libcamera/software_isp/meson.build        |   5 +
>  src/libcamera/software_isp/swstats_cpu.cpp    | 208 ++++++++++++++++++
>  src/libcamera/software_isp/swstats_cpu.h      | 158 +++++++++++++
>  7 files changed, 416 insertions(+)
>  create mode 100644 include/libcamera/internal/software_isp/meson.build
>  create mode 100644 include/libcamera/internal/software_isp/swisp_stats.h
>  create mode 100644 src/libcamera/software_isp/meson.build
>  create mode 100644 src/libcamera/software_isp/swstats_cpu.cpp
>  create mode 100644 src/libcamera/software_isp/swstats_cpu.h
>
> diff --git a/include/libcamera/internal/meson.build b/include/libcamera/internal/meson.build
> index 5807dfd9..160fdc37 100644
> --- a/include/libcamera/internal/meson.build
> +++ b/include/libcamera/internal/meson.build
> @@ -50,3 +50,4 @@ libcamera_internal_headers = files([
>  ])
>  
>  subdir('converter')
> +subdir('software_isp')
> diff --git a/include/libcamera/internal/software_isp/meson.build b/include/libcamera/internal/software_isp/meson.build
> new file mode 100644
> index 00000000..66c9c3fb
> --- /dev/null
> +++ b/include/libcamera/internal/software_isp/meson.build
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +libcamera_internal_headers += files([
> +    'swisp_stats.h',
> +])
> diff --git a/include/libcamera/internal/software_isp/swisp_stats.h b/include/libcamera/internal/software_isp/swisp_stats.h
> new file mode 100644
> index 00000000..afe42c9a
> --- /dev/null
> +++ b/include/libcamera/internal/software_isp/swisp_stats.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2023, Linaro Ltd
> + *
> + * swisp_stats.h - Statistics data format used by the software ISP and software IPA
> + */
> +
> +#pragma once
> +
> +namespace libcamera {
> +
> +/**
> + * \brief Struct that holds the statistics for the Software ISP.
> + */
> +struct SwIspStats {
> +	/**
> +	 * \brief Holds the sum of all sampled red pixels.
> +	 */
> +	unsigned long sumR_;
> +	/**
> +	 * \brief Holds the sum of all sampled green pixels.
> +	 */
> +	unsigned long sumG_;
> +	/**
> +	 * \brief Holds the sum of all sampled blue pixels.
> +	 */
> +	unsigned long sumB_;
> +	/**
> +	 * \brief Number of bins in the yHistogram.
> +	 */
> +	static constexpr unsigned int kYHistogramSize = 16;
> +	/**
> +	 * \brief A histogram of luminance values.
> +	 */
> +	std::array<unsigned int, kYHistogramSize> yHistogram;
> +};
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> index 94a95ae3..91e4cc60 100644
> --- a/src/libcamera/meson.build
> +++ b/src/libcamera/meson.build
> @@ -71,6 +71,7 @@ subdir('converter')
>  subdir('ipa')
>  subdir('pipeline')
>  subdir('proxy')
> +subdir('software_isp')
>  
>  null_dep = dependency('', required : false)
>  
> diff --git a/src/libcamera/software_isp/meson.build b/src/libcamera/software_isp/meson.build
> new file mode 100644
> index 00000000..e1fb8ccc
> --- /dev/null
> +++ b/src/libcamera/software_isp/meson.build
> @@ -0,0 +1,5 @@
> +# SPDX-License-Identifier: CC0-1.0
> +
> +libcamera_sources += files([
> +    'swstats_cpu.cpp',
> +])
> diff --git a/src/libcamera/software_isp/swstats_cpu.cpp b/src/libcamera/software_isp/swstats_cpu.cpp
> new file mode 100644
> index 00000000..a3a2eb94
> --- /dev/null
> +++ b/src/libcamera/software_isp/swstats_cpu.cpp
> @@ -0,0 +1,208 @@
> +/* 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>
> + *
> + * swstats_cpu.cpp - CPU based software statistics implementation
> + */
> +
> +#include "swstats_cpu.h"
> +
> +#include <libcamera/base/log.h>
> +
> +#include <libcamera/stream.h>
> +
> +#include "libcamera/internal/bayer_format.h"
> +
> +namespace libcamera {
> +
> +/**
> + * \class SwStatsCpu
> + * \brief Class for gathering statistics on the CPU
> + *
> + * CPU based software ISP statistics implementation.
> + *
> + * This class offers a configure function + functions to gather statistics
> + * on a line by line basis. This allows CPU based software debayering to
> + * interlace debayering and statistics gathering on a line by line bases
> + * while the input data is still hot in the cache.
> + *
> + * It is also possible to specify a window over which to gather
> + * statistics instead of processing the whole frame.
> + */
> +
> +LOG_DEFINE_CATEGORY(SwStatsCpu)
> +
> +SwStatsCpu::SwStatsCpu()
> +{
> +	sharedStats_ = SharedMemObject<SwIspStats>("softIsp_stats");
> +	if (!sharedStats_.fd().isValid())
> +		LOG(SwStatsCpu, Error)
> +			<< "Failed to create shared memory for statistics";
> +}
> +
> +static const unsigned int kRedYMul = 77; /* 0.299 * 256 */
> +static const unsigned int kGreenYMul = 150; /* 0.587 * 256 */
> +static const unsigned int kBlueYMul = 29; /* 0.114 * 256 */
> +
> +#define SWSTATS_START_LINE_STATS(pixel_t) \
> +	pixel_t r, g, g2, b;              \
> +	unsigned int yVal;                \
> +                                          \
> +	unsigned int sumR = 0;            \
> +	unsigned int sumG = 0;            \
> +	unsigned int sumB = 0;
> +
> +#define SWSTATS_ACCUMULATE_LINE_STATS(div) \
> +	sumR += r;                         \
> +	sumG += g;                         \
> +	sumB += b;                         \
> +                                           \
> +	yVal = r * kRedYMul;               \
> +	yVal += g * kGreenYMul;            \
> +	yVal += b * kBlueYMul;             \
> +	stats_.yHistogram[yVal / (256 * SwIspStats::kYHistogramSize * (div))]++;

This formula is wrong.  I think it should be

  stats_.yHistogram[yVal * SwIspStats::kYHistogramSize / (256 * 256 * (div))]++;

(The maximum yVal is 255 * 256 and the size of the array is
SwIspStats::kYHistogramSize.)

It works for kYHistogramSize == 16 by coincidence as in this case the two
versions are the same.

> +
> +#define SWSTATS_FINISH_LINE_STATS() \
> +	stats_.sumR_ += sumR;       \
> +	stats_.sumG_ += sumG;       \
> +	stats_.sumB_ += sumB;
> +
> +void SwStatsCpu::statsBGGR10PLine0(const uint8_t *src[])
> +{
> +	const uint8_t *src0 = src[1] + window_.x * 5 / 4;
> +	const uint8_t *src1 = src[2] + window_.x * 5 / 4;
> +	const int widthInBytes = window_.width * 5 / 4;
> +
> +	if (swapLines_)
> +		std::swap(src0, src1);
> +
> +	SWSTATS_START_LINE_STATS(uint8_t)
> +
> +	/* x += 5 sample every other 2x2 block */
> +	for (int x = 0; x < widthInBytes; x += 5) {
> +		/* BGGR */
> +		b = src0[x];
> +		g = src0[x + 1];
> +		g2 = src1[x];
> +		r = src1[x + 1];
> +		g = (g + g2) / 2;
> +		/* Data is already 8 bits, divide by 1 */
> +		SWSTATS_ACCUMULATE_LINE_STATS(1)
> +	}
> +
> +	SWSTATS_FINISH_LINE_STATS()
> +}
> +
> +void SwStatsCpu::statsGBRG10PLine0(const uint8_t *src[])
> +{
> +	const uint8_t *src0 = src[1] + window_.x * 5 / 4;
> +	const uint8_t *src1 = src[2] + window_.x * 5 / 4;
> +	const int widthInBytes = window_.width * 5 / 4;
> +
> +	if (swapLines_)
> +		std::swap(src0, src1);
> +
> +	SWSTATS_START_LINE_STATS(uint8_t)
> +
> +	/* x += 5 sample every other 2x2 block */
> +	for (int x = 0; x < widthInBytes; x += 5) {
> +		/* GBRG */
> +		g = src0[x];
> +		b = src0[x + 1];
> +		r = src1[x];
> +		g2 = src1[x + 1];
> +		g = (g + g2) / 2;
> +		/* Data is already 8 bits, divide by 1 */
> +		SWSTATS_ACCUMULATE_LINE_STATS(1)
> +	}
> +
> +	SWSTATS_FINISH_LINE_STATS()
> +}
> +
> +/**
> + * \brief Reset state to start statistics gathering for a new frame.
> + *
> + * This may only be called after a successful setWindow() call.
> + */
> +void SwStatsCpu::startFrame(void)
> +{
> +	stats_.sumR_ = 0;
> +	stats_.sumB_ = 0;
> +	stats_.sumG_ = 0;
> +	stats_.yHistogram.fill(0);
> +}
> +
> +/**
> + * \brief Finish statistics calculation for the current frame.
> + *
> + * This may only be called after a successful setWindow() call.
> + */
> +void SwStatsCpu::finishFrame(void)
> +{
> +	*sharedStats_ = stats_;
> +	statsReady.emit(0);
> +}
> +
> +/**
> + * \brief Configure the statistics object for the passed in input format.
> + * \param[in] inputCfg The input format
> + *
> + * \return 0 on success, a negative errno value on failure
> + */
> +int SwStatsCpu::configure(const StreamConfiguration &inputCfg)
> +{
> +	BayerFormat bayerFormat =
> +		BayerFormat::fromPixelFormat(inputCfg.pixelFormat);
> +
> +	if (bayerFormat.bitDepth == 10 &&
> +	    bayerFormat.packing == BayerFormat::Packing::CSI2) {
> +		patternSize_.height = 2;
> +		patternSize_.width = 4; /* 5 bytes per *4* pixels */
> +		/* Skip every 3th and 4th line, sample every other 2x2 block */
> +		ySkipMask_ = 0x02;
> +		xShift_ = 0;
> +
> +		switch (bayerFormat.order) {
> +		case BayerFormat::BGGR:
> +		case BayerFormat::GRBG:
> +			stats0_ = (SwStatsCpu::statsProcessFn)&SwStatsCpu::statsBGGR10PLine0;
> +			swapLines_ = bayerFormat.order == BayerFormat::GRBG;
> +			return 0;
> +		case BayerFormat::GBRG:
> +		case BayerFormat::RGGB:
> +			stats0_ = (SwStatsCpu::statsProcessFn)&SwStatsCpu::statsGBRG10PLine0;
> +			swapLines_ = bayerFormat.order == BayerFormat::RGGB;
> +			return 0;
> +		default:
> +			break;
> +		}
> +	}
> +
> +	LOG(SwStatsCpu, Info)
> +		<< "Unsupported input format " << inputCfg.pixelFormat.toString();
> +	return -EINVAL;
> +}
> +
> +/**
> + * \brief Specify window coordinates over which to gather statistics.
> + * \param[in] window The window object.
> + */
> +void SwStatsCpu::setWindow(Rectangle window)
> +{
> +	window_ = window;
> +
> +	window_.x &= ~(patternSize_.width - 1);
> +	window_.x += xShift_;
> +	window_.y &= ~(patternSize_.height - 1);
> +
> +	/* width_ - xShift_ to make sure the window fits */
> +	window_.width -= xShift_;
> +	window_.width &= ~(patternSize_.width - 1);
> +	window_.height &= ~(patternSize_.height - 1);
> +}
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/software_isp/swstats_cpu.h b/src/libcamera/software_isp/swstats_cpu.h
> new file mode 100644
> index 00000000..166ebe28
> --- /dev/null
> +++ b/src/libcamera/software_isp/swstats_cpu.h
> @@ -0,0 +1,158 @@
> +/* 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>
> + *
> + * swstats_cpu.h - CPU based software statistics implementation
> + */
> +
> +#pragma once
> +
> +#include <stdint.h>
> +
> +#include <libcamera/base/signal.h>
> +
> +#include <libcamera/geometry.h>
> +
> +#include "libcamera/internal/shared_mem_object.h"
> +#include "libcamera/internal/software_isp/swisp_stats.h"
> +
> +namespace libcamera {
> +
> +class PixelFormat;
> +struct StreamConfiguration;
> +
> +class SwStatsCpu
> +{
> +public:
> +	SwStatsCpu();
> +	~SwStatsCpu() = default;
> +
> +	/**
> +	 * \brief Gets wether the statistics object is valid.
> +	 *
> +	 * \return true if it's valid, false otherwise
> +	 */
> +	bool isValid() const { return sharedStats_.fd().isValid(); }
> +
> +	/**
> +	 * \brief Get the file descriptor for the statistics.
> +	 *
> +	 * \return the file descriptor
> +	 */
> +	const SharedFD &getStatsFD() { return sharedStats_.fd(); }
> +
> +	/**
> +	 * \brief Get the pattern size.
> +	 *
> +	 * For some input-formats, e.g. Bayer data, processing is done multiple lines
> +	 * and/or columns at a time. Get width and height at which the (bayer) pattern
> +	 * repeats. Window values are rounded down to a multiple of this and the height
> +	 * also indicates if processLine2() should be called or not.
> +	 * This may only be called after a successful configure() call.
> +	 *
> +	 * \return the pattern size
> +	 */
> +	const Size &patternSize() { return patternSize_; }
> +
> +	int configure(const StreamConfiguration &inputCfg);
> +	void setWindow(Rectangle window);
> +	void startFrame();
> +	void finishFrame();
> +
> +	/**
> +	 * \brief Process line 0.
> +	 * \param[in] y The y coordinate.
> +	 * \param[in] src The input data.
> +	 *
> +	 * This function processes line 0 for input formats with patternSize height == 1.
> +	 * It'll process line 0 and 1 for input formats with patternSize height >= 2.
> +	 * This function may only be called after a successful setWindow() call.
> +	 */
> +	void processLine0(unsigned int y, const uint8_t *src[])
> +	{
> +		if ((y & ySkipMask_) || y < (unsigned int)window_.y ||
> +		    y >= (window_.y + window_.height))
> +			return;
> +
> +		(this->*stats0_)(src);
> +	}
> +
> +	/**
> +	 * \brief Process line 2 and 3.
> +	 * \param[in] y The y coordinate.
> +	 * \param[in] src The input data.
> +	 *
> +	 * This function processes line 2 and 3 for input formats with patternSize height == 4.
> +	 * This function may only be called after a successful setWindow() call.
> +	 */
> +	void processLine2(unsigned int y, const uint8_t *src[])
> +	{
> +		if ((y & ySkipMask_) || y < (unsigned int)window_.y ||
> +		    y >= (window_.y + window_.height))
> +			return;
> +
> +		(this->*stats2_)(src);
> +	}
> +
> +	/**
> +	 * \brief Signals that the statistics are ready.
> +	 *
> +	 * The int parameter isn't actually used.
> +	 */
> +	Signal<int> statsReady;
> +private:
> +	/**
> +	 * \brief Called when there is data to get statistics from.
> +	 * \param[in] src The input data
> +	 *
> +	 * These functions take an array of (patternSize_.height + 1) src
> +	 * pointers each pointing to a line in the source image. The middle
> +	 * element of the array will point to the actual line being processed.
> +	 * Earlier element(s) will point to the previous line(s) and later
> +	 * element(s) to the next line(s).
> +	 *
> +	 * See the documentation of DebayerCpu::debayerFn for more details.
> +	 */
> +	typedef void (SwStatsCpu::*statsProcessFn)(const uint8_t *src[]);
> +
> +	void statsBGGR10PLine0(const uint8_t *src[]);
> +	void statsGBRG10PLine0(const uint8_t *src[]);
> +
> +	/* Variables set by configure(), used every line */
> +	statsProcessFn stats0_;
> +	statsProcessFn stats2_;
> +	bool swapLines_;
> +
> +	/**
> +	 * \brief Skip lines where this bitmask is set in y.
> +	 */
> +	unsigned int ySkipMask_;
> +
> +	/**
> +	 * \brief Statistics window, set by setWindow(), used ever line.
> +	 */
> +	Rectangle window_;
> +
> +	/**
> +	 * \brief The size of the bayer pattern.
> +	 *
> +	 * Valid sizes are: 2x2, 4x2 or 4x4.
> +	 */
> +	Size patternSize_;
> +
> +	/**
> +	 * \brief The offset of x, applied to window_.x for bayer variants.
> +	 *
> +	 * This can either be 0 or 1.
> +	 */
> +	unsigned int xShift_;
> +
> +	SharedMemObject<SwIspStats> sharedStats_;
> +	SwIspStats stats_;
> +};
> +
> +} /* namespace libcamera */

Hi Milan,

On 2/16/24 10:43, Milan Zamazal wrote:
> Hans de Goede <hdegoede@redhat.com> writes:

<snip>

>> +static const unsigned int kRedYMul = 77; /* 0.299 * 256 */
>> +static const unsigned int kGreenYMul = 150; /* 0.587 * 256 */
>> +static const unsigned int kBlueYMul = 29; /* 0.114 * 256 */
>> +
>> +#define SWSTATS_START_LINE_STATS(pixel_t) \
>> +	pixel_t r, g, g2, b;              \
>> +	unsigned int yVal;                \
>> +                                          \
>> +	unsigned int sumR = 0;            \
>> +	unsigned int sumG = 0;            \
>> +	unsigned int sumB = 0;
>> +
>> +#define SWSTATS_ACCUMULATE_LINE_STATS(div) \
>> +	sumR += r;                         \
>> +	sumG += g;                         \
>> +	sumB += b;                         \
>> +                                           \
>> +	yVal = r * kRedYMul;               \
>> +	yVal += g * kGreenYMul;            \
>> +	yVal += b * kBlueYMul;             \
>> +	stats_.yHistogram[yVal / (256 * SwIspStats::kYHistogramSize * (div))]++;
> 
> This formula is wrong.  I think it should be
> 
>   stats_.yHistogram[yVal * SwIspStats::kYHistogramSize / (256 * 256 * (div))]++;
> 
> (The maximum yVal is 255 * 256 and the size of the array is
> SwIspStats::kYHistogramSize.)
> 
> It works for kYHistogramSize == 16 by coincidence as in this case the two
> versions are the same.

You are right, thank you for catching this.

I have pushed fixup patch (to be squashed later) to:

https://github.com/jwrdegoede/libcamera/commits/SoftwareISP-v06

So that I don't forget to fix this for the next version.

Regards,

Hans

Hi,

Thank you for the review.

One kind request for future reviews can you please remove
(<snip>) parts of the patch which you are not replying too ?

Quoting the entire patch makes it somewhat hard to
find the bits which you are actually commenting on.


On 2/15/24 15:20, Milan Zamazal wrote:
> Hans de Goede <hdegoede@redhat.com> writes:

<snip>

>> --- /dev/null
>> +++ b/src/libcamera/software_isp/swstats_cpu.cpp
>> @@ -0,0 +1,208 @@

<snip>

>> +/**
>> + * \class SwStatsCpu
>> + * \brief Class for gathering statistics on the CPU
>> + *
>> + * CPU based software ISP statistics implementation.
>> + *
>> + * This class offers a configure function + functions to gather statistics
>> + * on a line by line basis. This allows CPU based software debayering to
>> + * interlace debayering and statistics gathering on a line by line bases
>                                                                       ^^^^^
> 
> basis?

Ack, fixed in my personal tree now.

<snip>

>> +/**
>> + * \brief Configure the statistics object for the passed in input format.
>> + * \param[in] inputCfg The input format
>> + *
>> + * \return 0 on success, a negative errno value on failure
>> + */
>> +int SwStatsCpu::configure(const StreamConfiguration &inputCfg)
>> +{
>> +	BayerFormat bayerFormat =
>> +		BayerFormat::fromPixelFormat(inputCfg.pixelFormat);
>> +
>> +	if (bayerFormat.bitDepth == 10 &&
>> +	    bayerFormat.packing == BayerFormat::Packing::CSI2) {
>> +		patternSize_.height = 2;
>> +		patternSize_.width = 4; /* 5 bytes per *4* pixels */
>> +		/* Skip every 3th and 4th line, sample every other 2x2 block */
>> +		ySkipMask_ = 0x02;
>> +		xShift_ = 0;
>> +
>> +		switch (bayerFormat.order) {
>> +		case BayerFormat::BGGR:
>> +		case BayerFormat::GRBG:
>> +			stats0_ = (SwStatsCpu::statsProcessFn)&SwStatsCpu::statsBGGR10PLine0;
>                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 
> Isn't the type cast superfluous?  (The same below.)

You would think so but gcc enforces this for c++ when assigning
function pointers. I tried removing the cast when reworking
Andrey's original code and gcc gave an error without the cast.


<snip>

>> +private:
>> +	/**
>> +	 * \brief Called when there is data to get statistics from.
>> +	 * \param[in] src The input data
>> +	 *
>> +	 * These functions take an array of (patternSize_.height + 1) src
>> +	 * pointers each pointing to a line in the source image. The middle
>> +	 * element of the array will point to the actual line being processed.
>> +	 * Earlier element(s) will point to the previous line(s) and later
>> +	 * element(s) to the next line(s).
> 
> And are there previous lines processed anywhere?

For debayering yes they are and since the swstats code is called from
the debayering code (to process the line while it is still in cache),
the debayer code is simply passing in the same array of line pointers
it gets passed. This is the main reason why the swstats code processLine
function prototype takes the same array of line pointers.

> If not, what happens to the
> very first line, must it be always excluded by the specified window?

In your reply to the DebayerCpu class you have some remarks about
the border which gets enforced there. That border ensures that the very
first line of the raw bayer data indeed is always excluded by the window.

Note the window inside the debayer code that is. The swstats window can
then be used to select a sub-area of the debayered area to gather stats
over, but atm it is simply set to the entire debayered area.

Regards,

Hans

Hi


2024. február 27., kedd 14:07 keltezéssel, Hans de Goede <hdegoede@redhat.com> írta:

> [...]
> >> +/**
> >> + * \brief Configure the statistics object for the passed in input format.
> >> + * \param[in] inputCfg The input format
> >> + *
> >> + * \return 0 on success, a negative errno value on failure
> >> + */
> >> +int SwStatsCpu::configure(const StreamConfiguration &inputCfg)
> >> +{
> >> +	BayerFormat bayerFormat =
> >> +		BayerFormat::fromPixelFormat(inputCfg.pixelFormat);
> >> +
> >> +	if (bayerFormat.bitDepth == 10 &&
> >> +	    bayerFormat.packing == BayerFormat::Packing::CSI2) {
> >> +		patternSize_.height = 2;
> >> +		patternSize_.width = 4; /* 5 bytes per *4* pixels */
> >> +		/* Skip every 3th and 4th line, sample every other 2x2 block */
> >> +		ySkipMask_ = 0x02;
> >> +		xShift_ = 0;
> >> +
> >> +		switch (bayerFormat.order) {
> >> +		case BayerFormat::BGGR:
> >> +		case BayerFormat::GRBG:
> >> +			stats0_ = (SwStatsCpu::statsProcessFn)&SwStatsCpu::statsBGGR10PLine0;
> >                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> > Isn't the type cast superfluous?  (The same below.)
> 
> You would think so but gcc enforces this for c++ when assigning
> function pointers. I tried removing the cast when reworking
> Andrey's original code and gcc gave an error without the cast.
> [...]

Is the code in this patchset different from what's on gitlab? Because I tested
the SoftwareISP-v06{,-ynk,-pdm} branches from https://gitlab.freedesktop.org/camera/libcamera-softisp
and they all seemed to compile without the cast.

I think the reason why it was needed is because in the previous version inheritance
was used (SwStatsCpu -> SwStats), i.e. you cast a "pointer-to-member-function of derived"
to "pointer-to-member-function of base". But now there is no inheritance, so the
implicit conversion should work.


Regards,
Barnabás Pőcze

Hi,

On 2/27/24 17:23, Barnabás Pőcze wrote:
> Hi
> 
> 
> 2024. február 27., kedd 14:07 keltezéssel, Hans de Goede <hdegoede@redhat.com> írta:
> 
>> [...]
>>>> +/**
>>>> + * \brief Configure the statistics object for the passed in input format.
>>>> + * \param[in] inputCfg The input format
>>>> + *
>>>> + * \return 0 on success, a negative errno value on failure
>>>> + */
>>>> +int SwStatsCpu::configure(const StreamConfiguration &inputCfg)
>>>> +{
>>>> +	BayerFormat bayerFormat =
>>>> +		BayerFormat::fromPixelFormat(inputCfg.pixelFormat);
>>>> +
>>>> +	if (bayerFormat.bitDepth == 10 &&
>>>> +	    bayerFormat.packing == BayerFormat::Packing::CSI2) {
>>>> +		patternSize_.height = 2;
>>>> +		patternSize_.width = 4; /* 5 bytes per *4* pixels */
>>>> +		/* Skip every 3th and 4th line, sample every other 2x2 block */
>>>> +		ySkipMask_ = 0x02;
>>>> +		xShift_ = 0;
>>>> +
>>>> +		switch (bayerFormat.order) {
>>>> +		case BayerFormat::BGGR:
>>>> +		case BayerFormat::GRBG:
>>>> +			stats0_ = (SwStatsCpu::statsProcessFn)&SwStatsCpu::statsBGGR10PLine0;
>>>                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>
>>> Isn't the type cast superfluous?  (The same below.)
>>
>> You would think so but gcc enforces this for c++ when assigning
>> function pointers. I tried removing the cast when reworking
>> Andrey's original code and gcc gave an error without the cast.
>> [...]
> 
> Is the code in this patchset different from what's on gitlab? Because I tested
> the SoftwareISP-v06{,-ynk,-pdm} branches from https://gitlab.freedesktop.org/camera/libcamera-softisp
> and they all seemed to compile without the cast.
> 
> I think the reason why it was needed is because in the previous version inheritance
> was used (SwStatsCpu -> SwStats), i.e. you cast a "pointer-to-member-function of derived"
> to "pointer-to-member-function of base". But now there is no inheritance, so the
> implicit conversion should work.

You are right I have dropped the casts for v4 of the series which I will
post real soon.

Regards,

Hans