[PATCH v6 09/18] libcamera: ipa: add Soft IPA

Laurent Pinchart laurent.pinchart at ideasonboard.com
Tue Apr 2 22:48:13 CEST 2024


Hi Andrei,

On Tue, Apr 02, 2024 at 11:34:13PM +0300, Andrei Konovalov wrote:
> On 28.03.2024 01:36, Andrei Konovalov wrote:
> > On 27.03.2024 19:38, Laurent Pinchart wrote:
> >> On Tue, Mar 19, 2024 at 01:35:56PM +0100, Milan Zamazal wrote:
> >>> From: Andrey Konovalov <andrey.konovalov at linaro.org>
> >>>
> >>> Define the Soft IPA main and event interfaces, add the Soft IPA
> >>> implementation.
> >>>
> >>> The current src/ipa/meson.build assumes the IPA name to match the
> >>> pipeline name. For this reason "-Dipas=simple" is used for the
> >>> Soft IPA module.
> >>
> >> This should be addressed, please record this as a \todo item somewhere.
> > 
> > Ack
> > 
> >>> Auto exposure/gain and AWB implementation by Dennis, Toon and Martti.
> >>>
> >>> Auto exposure/gain targets a Mean Sample Value of 2.5 following
> >>> the MSV calculation algorithm from:
> >>> https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf
> >>>
> >>> Tested-by: Bryan O'Donoghue <bryan.odonoghue at linaro.org> # sc8280xp Lenovo x13s
> >>> Tested-by: Pavel Machek <pavel at ucw.cz>
> >>> Reviewed-by: Pavel Machek <pavel at ucw.cz>
> >>> Signed-off-by: Andrey Konovalov <andrey.konovalov at linaro.org>
> >>> Co-developed-by: Dennis Bonke <admin at dennisbonke.com>
> >>> Signed-off-by: Dennis Bonke <admin at dennisbonke.com>
> >>> Co-developed-by: Marttico <g.martti at gmail.com>
> >>> Signed-off-by: Marttico <g.martti at gmail.com>
> >>> Co-developed-by: Toon Langendam <t.langendam at gmail.com>
> >>> Signed-off-by: Toon Langendam <t.langendam at gmail.com>
> >>> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> >>> ---
> >>>   Documentation/Doxyfile.in         |   1 +
> >>>   include/libcamera/ipa/meson.build |   1 +
> >>>   include/libcamera/ipa/soft.mojom  |  28 +++
> >>>   meson_options.txt                 |   2 +-
> >>>   src/ipa/simple/data/meson.build   |   9 +
> >>>   src/ipa/simple/data/soft.conf     |   3 +
> >>>   src/ipa/simple/meson.build        |  25 +++
> >>>   src/ipa/simple/soft_simple.cpp    | 326 ++++++++++++++++++++++++++++++
> >>>   8 files changed, 394 insertions(+), 1 deletion(-)
> >>>   create mode 100644 include/libcamera/ipa/soft.mojom
> >>>   create mode 100644 src/ipa/simple/data/meson.build
> >>>   create mode 100644 src/ipa/simple/data/soft.conf
> >>>   create mode 100644 src/ipa/simple/meson.build
> >>>   create mode 100644 src/ipa/simple/soft_simple.cpp
> >>>
> >>> diff --git a/Documentation/Doxyfile.in b/Documentation/Doxyfile.in
> >>> index a86ea6c1..2be8d47b 100644
> >>> --- a/Documentation/Doxyfile.in
> >>> +++ b/Documentation/Doxyfile.in
> >>> @@ -44,6 +44,7 @@ EXCLUDE                = @TOP_SRCDIR@/include/libcamera/base/span.h \
> >>>                            @TOP_SRCDIR@/src/libcamera/pipeline/ \
> >>>                            @TOP_SRCDIR@/src/libcamera/tracepoints.cpp \
> >>>                            @TOP_BUILDDIR@/include/libcamera/internal/tracepoints.h \
> >>> +                         @TOP_BUILDDIR@/include/libcamera/ipa/soft_ipa_interface.h \
> >>
> >> Why is this needed ?
> >>
> >>>                            @TOP_BUILDDIR@/src/libcamera/proxy/
> >>>   EXCLUDE_PATTERNS       = @TOP_BUILDDIR@/include/libcamera/ipa/*_serializer.h \
> >>> diff --git a/include/libcamera/ipa/meson.build b/include/libcamera/ipa/meson.build
> >>> index f3b4881c..3352d08f 100644
> >>> --- a/include/libcamera/ipa/meson.build
> >>> +++ b/include/libcamera/ipa/meson.build
> >>> @@ -65,6 +65,7 @@ pipeline_ipa_mojom_mapping = {
> >>>       'ipu3': 'ipu3.mojom',
> >>>       'rkisp1': 'rkisp1.mojom',
> >>>       'rpi/vc4': 'raspberrypi.mojom',
> >>> +    'simple': 'soft.mojom',
> >>>       'vimc': 'vimc.mojom',
> >>>   }
> >>> diff --git a/include/libcamera/ipa/soft.mojom b/include/libcamera/ipa/soft.mojom
> >>> new file mode 100644
> >>> index 00000000..c249bd75
> >>> --- /dev/null
> >>> +++ b/include/libcamera/ipa/soft.mojom
> >>> @@ -0,0 +1,28 @@
> >>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> >>> +
> >>> +/*
> >>> + * \todo Document the interface and remove the related EXCLUDE_PATTERNS entry.
> >>
> >> Ah that's why.
> > 
> > Yes, because, well... all the other IPAs were doing that...
> > 
> >> It doesn't have to be done before merging, but could you
> >> address this sooner than later ?
> > 
> > I can't promise a lot, but I'll look into that.
> > 
> >>> + */
> >>> +
> >>> +module ipa.soft;
> >>> +
> >>> +import "include/libcamera/ipa/core.mojom";
> >>> +
> >>> +interface IPASoftInterface {
> >>> +    init(libcamera.IPASettings settings,
> >>> +         libcamera.SharedFD fdStats,
> >>> +         libcamera.SharedFD fdParams,
> >>
> >> The IPA and soft ISP run in separate threads. How do you guarantee that
> >> the stats and params are not accessed concurrently by both ?
> > 
> > I tried avoiding using a pool of buffers for stats and params, and used just a
> > single chunk of shared memory to pass the stats from soft ISP (its worker thread)
> > to IPA, and the other chunk for params.
> > 
> > The soft ISP accumulates the stats in its member variable, and after all the stats
> > for the frame are calculated, the member variable is copyed to the shared memory and
> > statReady signal is emitted (so using the member var implements some kind of double
> > buffering). This way the write to the stats shared memory happens once per frame and
> > is short in time right before emitting the statReady signal.
> > The callback executed on receiving statReady signal invokes the IPA's processStats
> > function. So the IPA's processStats() is called soon after the statReady is emitted.
> > If the IPA finish processing the stats before the next frame is processed by the soft IPS
> > and the stats for the next frame are written into the shared memory, there is no concurrent
> > acess.
> > 
> > This doesn't strictly guarantee that the stats are not accessed concurrently by the IPA and
> > soft ISP. But unless the video stream from the camera sensor overloads the system this
> > scheme works OK. And if the load is high the concurrent access isn't impossible, and can harm
> > the image quality, but doesn't lead to critical problems like invalid pointers as the stats
> > structure only contains numbers and an array of fixed size.
> >
> >> Shouldn't
> >> you have a pool of buffers for each, mimicking what is done with
> >> hardware ISPs ?
> > 
> > This would definitely work, but is a more heavy wait implementation.
> > 
> > On the other side, the current implementation is less universal (isn't very scalable), more fragile,
> > and can't reliably associate the stats and the params with the given frame from the camera sensor.
> > 
> > So let me try to implement what you suggested ("a pool of buffers for each, mimicking what is done with
> > hardware ISPs").
> 
> I won't be able to do this particular part by tomorrow...
> So a branch I plan to publish tomorrow - with this patch updated to address the review comments
> and the [PATCH v6 18/18] "libcamera: Soft IPA: use CameraSensorHelper for analogue gain" merged
> into the earlier ones - would not use the pool of buffers for the stats and the params (yet).

That's fine. While I don't like relying on race windows being small, and
on hitting the race being harmless (as it's dangerous and not a very
good design), it doesn't have to be fixed to merge this series. It
should however be recorded as a TODO item in the next version, and be
addressed on top sooner than later, before adding more features.

> >>> +         libcamera.ControlInfoMap sensorCtrlInfoMap)
> >>> +        => (int32 ret);
> >>> +    start() => (int32 ret);
> >>> +    stop();
> >>> +    configure(libcamera.ControlInfoMap sensorCtrlInfoMap)
> >>> +        => (int32 ret);
> >>> +
> >>> +    [async] processStats(libcamera.ControlList sensorControls);
> >>> +};
> >>> +
> >>> +interface IPASoftEventInterface {
> >>> +    setSensorControls(libcamera.ControlList sensorControls);
> >>> +    setIspParams(int32 dummy);
> >>
> >> Drop the dummy value.
> > 
> > libcamera docs do allow signals with zero parameters.
> > But when I tried having zero parameters for an EventInterface function,
> > it didn't work for me iirc.
> > Let me double check.

Milan replied separately on this. It looks like we've never tested that,
I think Paul will be able to help.

> >>> +};
> >>> diff --git a/meson_options.txt b/meson_options.txt
> >>> index 99dab96d..2644bef0 100644
> >>> --- a/meson_options.txt
> >>> +++ b/meson_options.txt
> >>> @@ -27,7 +27,7 @@ option('gstreamer',
> >>>   option('ipas',
> >>>           type : 'array',
> >>> -        choices : ['ipu3', 'rkisp1', 'rpi/vc4', 'vimc'],
> >>> +        choices : ['ipu3', 'rkisp1', 'rpi/vc4', 'simple', 'vimc'],
> >>>           description : 'Select which IPA modules to build')
> >>>   option('lc-compliance',
> >>> diff --git a/src/ipa/simple/data/meson.build b/src/ipa/simple/data/meson.build
> >>> new file mode 100644
> >>> index 00000000..33548cc6
> >>> --- /dev/null
> >>> +++ b/src/ipa/simple/data/meson.build
> >>> @@ -0,0 +1,9 @@
> >>> +# SPDX-License-Identifier: CC0-1.0
> >>> +
> >>> +conf_files = files([
> >>> +    'soft.conf',
> >>> +])
> >>> +
> >>> +install_data(conf_files,
> >>> +             install_dir : ipa_data_dir / 'soft',
> >>> +             install_tag : 'runtime')
> >>> diff --git a/src/ipa/simple/data/soft.conf b/src/ipa/simple/data/soft.conf
> >>> new file mode 100644
> >>> index 00000000..0c70e7c0
> >>> --- /dev/null
> >>> +++ b/src/ipa/simple/data/soft.conf
> >>
> >> We use YAML files for all IPAs, could you do the same here ? It
> >> shouldn't be much extra work as the file is empty :-)
> > 
> > OK
> > 
> >>> @@ -0,0 +1,3 @@
> >>> +# SPDX-License-Identifier: LGPL-2.1-or-later
> >>> +#
> >>> +# Dummy configuration file for the soft IPA.
> >>> diff --git a/src/ipa/simple/meson.build b/src/ipa/simple/meson.build
> >>> new file mode 100644
> >>> index 00000000..3e863db7
> >>> --- /dev/null
> >>> +++ b/src/ipa/simple/meson.build
> >>> @@ -0,0 +1,25 @@
> >>> +# SPDX-License-Identifier: CC0-1.0
> >>> +
> >>> +ipa_name = 'ipa_soft_simple'
> >>> +
> >>> +mod = shared_module(ipa_name,
> >>> +                    ['soft_simple.cpp', libcamera_generated_ipa_headers],
> >>> +                    name_prefix : '',
> >>> +                    include_directories : [ipa_includes, libipa_includes],
> >>> +                    dependencies : libcamera_private,
> >>> +                    link_with : libipa,
> >>> +                    install : true,
> >>> +                    install_dir : ipa_install_dir)
> >>> +
> >>> +if ipa_sign_module
> >>> +    custom_target(ipa_name + '.so.sign',
> >>> +                  input : mod,
> >>> +                  output : ipa_name + '.so.sign',
> >>> +                  command : [ipa_sign, ipa_priv_key, '@INPUT@', '@OUTPUT@'],
> >>> +                  install : false,
> >>> +                  build_by_default : true)
> >>> +endif
> >>> +
> >>> +subdir('data')
> >>> +
> >>> +ipa_names += ipa_name
> >>> diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp
> >>> new file mode 100644
> >>> index 00000000..312df4ba
> >>> --- /dev/null
> >>> +++ b/src/ipa/simple/soft_simple.cpp
> >>> @@ -0,0 +1,326 @@
> >>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> >>> +/*
> >>> + * Copyright (C) 2023, Linaro Ltd
> >>> + *
> >>> + * soft_simple.cpp - Simple Software Image Processing Algorithm module
> >>> + */
> >>> +
> >>> +#include <sys/mman.h>
> >>> +
> >>> +#include <libcamera/base/file.h>
> >>> +#include <libcamera/base/log.h>
> >>> +#include <libcamera/base/shared_fd.h>
> >>> +
> >>> +#include <libcamera/control_ids.h>
> >>> +#include <libcamera/controls.h>
> >>> +
> >>> +#include <libcamera/ipa/ipa_interface.h>
> >>> +#include <libcamera/ipa/ipa_module_info.h>
> >>> +#include <libcamera/ipa/soft_ipa_interface.h>
> >>> +
> >>> +#include "libcamera/internal/camera_sensor.h"
> >>
> >> Not needed.
> > 
> > OK
> > 
> >>> +#include "libcamera/internal/software_isp/debayer_params.h"
> >>> +#include "libcamera/internal/software_isp/swisp_stats.h"
> >>> +
> >>> +namespace libcamera {
> >>> +
> >>> +LOG_DEFINE_CATEGORY(IPASoft)
> >>> +
> >>> +namespace ipa::soft {
> >>> +
> >>> +class IPASoftSimple : public ipa::soft::IPASoftInterface
> >>> +{
> >>> +public:
> >>> +    IPASoftSimple()
> >>> +        : params_(static_cast<DebayerParams *>(MAP_FAILED)),
> >>
> >> Initialize this to nullptr, that's more standard, and will make the
> >> tests in the destructor nicer. init() will have to set the pointers to
> >> null if mmap() calls fail.
> > 
> > OK
> > 
> >>> +          stats_(static_cast<SwIspStats *>(MAP_FAILED)), ignore_updates_(0)
> >>
> >> s/ignore_updates_/ignoreUpdates_/
> > 
> > OK
> > 
> >>> +    {
> >>> +    }
> >>> +
> >>> +    ~IPASoftSimple()
> >>> +    {
> >>> +        if (stats_ != MAP_FAILED)
> >>> +            munmap(stats_, sizeof(SwIspStats));
> >>> +        if (params_ != MAP_FAILED)
> >>> +            munmap(params_, sizeof(DebayerParams));
> >>> +    }
> >>
> >> No need to inline this.
> > 
> > OK
> > 
> >>> +
> >>> +    int init(const IPASettings &settings,
> >>> +         const SharedFD &fdStats,
> >>> +         const SharedFD &fdParams,
> >>> +         const ControlInfoMap &sensorInfoMap) override;
> >>> +    int configure(const ControlInfoMap &sensorInfoMap) override;
> >>> +
> >>> +    int start() override;
> >>> +    void stop() override;
> >>> +
> >>> +    void processStats(const ControlList &sensorControls) override;
> >>> +
> >>> +private:
> >>> +    void updateExposure(double exposureMSV);
> >>> +
> >>> +    SharedFD fdStats_;
> >>> +    SharedFD fdParams_;
> >>> +    DebayerParams *params_;
> >>> +    SwIspStats *stats_;
> >>> +
> >>> +    int32_t exposure_min_, exposure_max_;
> >>> +    int32_t again_min_, again_max_;
> >>> +    int32_t again_, exposure_;
> >>> +    unsigned int ignore_updates_;
> >>> +};
> >>> +
> >>> +int IPASoftSimple::init([[maybe_unused]] const IPASettings &settings,
> >>> +            const SharedFD &fdStats,
> >>> +            const SharedFD &fdParams,
> >>> +            const ControlInfoMap &sensorInfoMap)
> >>> +{
> >>> +    fdStats_ = fdStats;
> >>
> >> As you never use fdStats_ and fdParams_ after this function returns,
> >> there's no need to store a copy.
> > 
> > Good catch. OK
> > 
> >>> +    if (!fdStats_.isValid()) {
> >>> +        LOG(IPASoft, Error) << "Invalid Statistics handle";
> >>> +        return -ENODEV;
> >>> +    }
> >>> +
> >>> +    fdParams_ = fdParams;
> >>> +    if (!fdParams_.isValid()) {
> >>> +        LOG(IPASoft, Error) << "Invalid Parameters handle";
> >>> +        return -ENODEV;
> >>> +    }
> >>> +
> >>> +    params_ = static_cast<DebayerParams *>(mmap(nullptr, sizeof(DebayerParams),
> >>> +                            PROT_WRITE, MAP_SHARED,
> >>> +                            fdParams_.get(), 0));
> >>> +    if (params_ == MAP_FAILED) {
> >>> +        LOG(IPASoft, Error) << "Unable to map Parameters";
> >>> +        return -errno;
> >>> +    }
> >>
> >>     void *mem = mmap(nullptr, sizeof(DebayerParams), PROT_WRITE, MAP_SHARED,
> >>              fdParams_.get(), 0));
> >>     if (mem == MAP_FAILED) {
> >>         LOG(IPASoft, Error) << "Unable to map Parameters";
> >>         return -errno;
> >>     }
> >>
> >>     params_ = static_cast<DebayerParams *>(mem);
> > 
> > OK
> > 
> >>> +
> >>> +    stats_ = static_cast<SwIspStats *>(mmap(nullptr, sizeof(SwIspStats),
> >>> +                        PROT_READ, MAP_SHARED,
> >>> +                        fdStats_.get(), 0));
> >>> +    if (stats_ == MAP_FAILED) {
> >>> +        LOG(IPASoft, Error) << "Unable to map Statistics";
> >>> +        return -errno;
> >>> +    }
> >>> +
> >>> +    if (sensorInfoMap.find(V4L2_CID_EXPOSURE) == sensorInfoMap.end()) {
> >>> +        LOG(IPASoft, Error) << "Don't have exposure control";
> >>> +        return -EINVAL;
> >>> +    }
> >>> +
> >>> +    if (sensorInfoMap.find(V4L2_CID_ANALOGUE_GAIN) == sensorInfoMap.end()) {
> >>> +        LOG(IPASoft, Error) << "Don't have gain control";
> >>> +        return -EINVAL;
> >>> +    }
> >>> +
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +int IPASoftSimple::configure(const ControlInfoMap &sensorInfoMap)
> >>> +{
> >>> +    const ControlInfo &exposure_info = sensorInfoMap.find(V4L2_CID_EXPOSURE)->second;
> >>
> >> s/exposure_info/exposureInfo/
> >>
> >> I'll let you address the other snake_case to camelCase conversions in
> >> the series :-)
> > 
> > OK
> > 
> >>> +    const ControlInfo &gain_info = sensorInfoMap.find(V4L2_CID_ANALOGUE_GAIN)->second;
> >>> +
> >>> +    exposure_min_ = exposure_info.min().get<int32_t>();
> >>> +    exposure_max_ = exposure_info.max().get<int32_t>();
> >>> +    if (!exposure_min_) {
> >>> +        LOG(IPASoft, Warning) << "Minimum exposure is zero, that can't be linear";
> >>> +        exposure_min_ = 1;
> >>> +    }
> >>> +
> >>> +    again_min_ = gain_info.min().get<int32_t>();
> >>> +    again_max_ = gain_info.max().get<int32_t>();
> >>
> >> Add a blank line.
> > 
> > OK
> > 
> >>> +    /*
> >>> +     * The camera sensor gain (g) is usually not equal to the value written
> >>> +     * into the gain register (x). But the way how the AGC algorithm changes
> >>> +     * the gain value to make the total exposure closer to the optimum assumes
> >>> +     * that g(x) is not too far from linear function. If the minimal gain is 0,
> >>> +     * the g(x) is likely to be far from the linear, like g(x) = a / (b * x + c).
> >>> +     * To avoid unexpected changes to the gain by the AGC algorithm (abrupt near
> >>> +     * one edge, and very small near the other) we limit the range of the gain
> >>> +     * values used.
> >>> +     */
> >>> +    if (!again_min_) {
> >>> +        LOG(IPASoft, Warning) << "Minimum gain is zero, that can't be linear";
> >>> +        again_min_ = std::min(100, again_min_ / 2 + again_max_ / 2);
> >>> +    }
> >>
> >> A patch further in the series addresses this by using
> >> CameraSensorHelper. It should be squashed with this patch.
> > 
> > OK
> > 
> >>> +
> >>> +    LOG(IPASoft, Info) << "Exposure " << exposure_min_ << "-" << exposure_max_
> >>> +               << ", gain " << again_min_ << "-" << again_max_;
> >>> +
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +int IPASoftSimple::start()
> >>> +{
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +void IPASoftSimple::stop()
> >>> +{
> >>> +}
> >>> +
> >>> +/*
> >>> + * The number of bins to use for the optimal exposure calculations.
> >>> + */
> >>> +static constexpr unsigned int kExposureBinsCount = 5;
> >>
> >> Missing blank line. Same below.
> > 
> > OK
> > 
> >>> +/*
> >>> + * 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;
> >>
> >> Move these to the beginning of the file, just before the IPASoftSimple
> >> definition.
> > 
> > OK
> > 
> >>> +
> >>> +void IPASoftSimple::processStats(const ControlList &sensorControls)
> >>> +{
> >>> +    /*
> >>> +     * Calculate red and blue gains for AWB.
> >>> +     * Clamp max gain at 4.0, this also avoids 0 division.
> >>> +     */
> >>> +    if (stats_->sumR_ <= stats_->sumG_ / 4)
> >>> +        params_->gainR = 1024;
> >>> +    else
> >>> +        params_->gainR = 256 * stats_->sumG_ / stats_->sumR_;
> >>> +
> >>> +    if (stats_->sumB_ <= stats_->sumG_ / 4)
> >>> +        params_->gainB = 1024;
> >>> +    else
> >>> +        params_->gainB = 256 * stats_->sumG_ / stats_->sumB_;
> >>> +
> >>> +    /* Green gain and gamma values are fixed */
> >>> +    params_->gainG = 256;
> >>> +    params_->gamma = 0.5;
> >>> +
> >>> +    setIspParams.emit(0);
> >>
> >> Do you envision switching to the libipa/algorithm.h API at some point ?
> >> If so, it would be nice to record it somewhere.
> > 
> > At some point, yes.
> > Will mention that.
> > 
> >>> +
> >>> +    /*
> >>> +     * AE / AGC, use 2 frames delay to make sure that the exposure and
> >>> +     * the gain set have applied to the camera sensor.
> >>> +     */
> >>> +    if (ignore_updates_ > 0) {
> >>> +        --ignore_updates_;
> >>> +        return;
> >>> +    }
> >>
> >> Also something that could be improved and that should be recorded
> >> somewhere.
> > 
> > OK
> > 
> >>> +
> >>> +    /*
> >>> +     * Calculate Mean Sample Value (MSV) according to formula from:
> >>> +     * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf
> >>> +     */
> >>> +    constexpr unsigned int yHistValsPerBin =
> >>> +        SwIspStats::kYHistogramSize / kExposureBinsCount;
> >>> +    constexpr unsigned int yHistValsPerBinMod =
> >>> +        SwIspStats::kYHistogramSize /
> >>> +        (SwIspStats::kYHistogramSize % kExposureBinsCount + 1);
> >>> +    int ExposureBins[kExposureBinsCount] = {};
> >>
> >> s/ExposureBins/exposureBins/
> > 
> > OK
> > 
> >>> +    unsigned int denom = 0;
> >>> +    unsigned int num = 0;
> >>> +
> >>> +    for (unsigned int i = 0; i < SwIspStats::kYHistogramSize; i++) {
> >>> +        unsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin;
> >>> +        ExposureBins[idx] += stats_->yHistogram[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 = (float)num / denom;
> >>
> >> C++ casts.
> > 
> > OK
> > 
> >>> +
> >>> +    /* sanity check */
> >>
> >> s/sanity/Sanity/
> > 
> > OK
> > 
> >>> +    if (!sensorControls.contains(V4L2_CID_EXPOSURE) ||
> >>> +        !sensorControls.contains(V4L2_CID_ANALOGUE_GAIN)) {
> >>> +        LOG(IPASoft, Error) << "Control(s) missing";
> >>> +        return;
> >>> +    }
> >>> +
> >>> +    ControlList ctrls(sensorControls);
> >>
> >> You shouldn't copy the control list, but instead create one from the
> >> ControlInfoMap that you get in init() (and that you then need to stored
> >> in the IPA class).
> > 
> > OK, thanks
> > 
> >>> +
> >>> +    exposure_ = ctrls.get(V4L2_CID_EXPOSURE).get<int32_t>();
> >>> +    again_ = ctrls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>();
> >>
> >>     exposure_ = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
> >>     again_ = sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>();
> > 
> > OK
> > 
> >>> +
> >>> +    updateExposure(exposureMSV);
> >>> +
> >>> +    ctrls.set(V4L2_CID_EXPOSURE, exposure_);
> >>> +    ctrls.set(V4L2_CID_ANALOGUE_GAIN, again_);
> >>> +
> >>> +    ignore_updates_ = 2;
> >>> +
> >>> +    setSensorControls.emit(ctrls);
> >>> +
> >>> +    LOG(IPASoft, Debug) << "exposureMSV " << exposureMSV
> >>> +                << " exp " << exposure_ << " again " << again_
> >>> +                << " gain R/B " << params_->gainR << "/" << params_->gainB;
> >>> +}
> >>> +
> >>> +void IPASoftSimple::updateExposure(double exposureMSV)
> >>> +{
> >>> +    /* DENOMINATOR of 10 gives ~10% increment/decrement; DENOMINATOR of 5 - about ~20% */
> >>
> >> Line wrap, and the DENOMINATOR needs to be renamed to kExpDenominator.
> > 
> > OK
> > 
> > Thanks for the review,
> > Andrei
> > 
> >>> +    static constexpr uint8_t kExpDenominator = 10;
> >>> +    static constexpr uint8_t kExpNumeratorUp = kExpDenominator + 1;
> >>> +    static constexpr uint8_t kExpNumeratorDown = kExpDenominator - 1;
> >>> +
> >>> +    int next;
> >>> +
> >>> +    if (exposureMSV < kExposureOptimal - kExposureSatisfactory) {
> >>> +        next = exposure_ * kExpNumeratorUp / kExpDenominator;
> >>> +        if (next - exposure_ < 1)
> >>> +            exposure_ += 1;
> >>> +        else
> >>> +            exposure_ = next;
> >>> +        if (exposure_ >= exposure_max_) {
> >>> +            next = again_ * kExpNumeratorUp / kExpDenominator;
> >>> +            if (next - again_ < 1)
> >>> +                again_ += 1;
> >>> +            else
> >>> +                again_ = next;
> >>> +        }
> >>> +    }
> >>> +
> >>> +    if (exposureMSV > kExposureOptimal + kExposureSatisfactory) {
> >>> +        if (exposure_ == exposure_max_ && again_ != again_min_) {
> >>> +            next = again_ * kExpNumeratorDown / kExpDenominator;
> >>> +            if (again_ - next < 1)
> >>> +                again_ -= 1;
> >>> +            else
> >>> +                again_ = next;
> >>> +        } else {
> >>> +            next = exposure_ * kExpNumeratorDown / kExpDenominator;
> >>> +            if (exposure_ - next < 1)
> >>> +                exposure_ -= 1;
> >>> +            else
> >>> +                exposure_ = next;
> >>> +        }
> >>> +    }
> >>> +
> >>> +    exposure_ = std::clamp(exposure_, exposure_min_, exposure_max_);
> >>> +    again_ = std::clamp(again_, again_min_, again_max_);
> >>> +}
> >>> +
> >>> +} /* namespace ipa::soft */
> >>> +
> >>> +/*
> >>> + * External IPA module interface
> >>> + */
> >>> +extern "C" {
> >>> +const struct IPAModuleInfo ipaModuleInfo = {
> >>> +    IPA_MODULE_API_VERSION,
> >>> +    0,
> >>> +    "SimplePipelineHandler",
> >>> +    "simple",
> >>> +};
> >>> +
> >>> +IPAInterface *ipaCreate()
> >>> +{
> >>> +    return new ipa::soft::IPASoftSimple();
> >>> +}
> >>> +
> >>> +} /* extern "C" */
> >>> +
> >>> +} /* namespace libcamera */

-- 
Regards,

Laurent Pinchart


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