[v3,01/19] ipa: rkisp1: Add basic compression algorithm

24111 diff mbox series

The i.MX8 M Plus has a compression curve inside the compand block.  This
curve is necessary to process HDR stitched data and is useful for other
aspects like applying a digital gain to the incoming sensor data.

Add a basic algorithm for the compression curve. This algorithm has a
hardcoded input width of 20bit and output width of 12bit which matches
the imx8mp pipeline. Only a static gain is supported in this version.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>

---

Changes in v3:
- Removed unused member
- Fixed comment referencing copy-paste source
- Ensure activeState.compress.supported stays false if unsupported
---
 src/ipa/rkisp1/algorithms/compress.cpp | 102 +++++++++++++++++++++++++
 src/ipa/rkisp1/algorithms/compress.h   |  30 ++++++++
 src/ipa/rkisp1/algorithms/meson.build  |   1 +
 src/ipa/rkisp1/ipa_context.h           |   9 +++
 4 files changed, 142 insertions(+)
 create mode 100644 src/ipa/rkisp1/algorithms/compress.cpp
 create mode 100644 src/ipa/rkisp1/algorithms/compress.h

Quoting Stefan Klug (2025-08-15 19:29:21)
> The i.MX8 M Plus has a compression curve inside the compand block.  This
> curve is necessary to process HDR stitched data and is useful for other
> aspects like applying a digital gain to the incoming sensor data.
> 
> Add a basic algorithm for the compression curve. This algorithm has a
> hardcoded input width of 20bit and output width of 12bit which matches
> the imx8mp pipeline. Only a static gain is supported in this version.
> 
> Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
> 
> ---
> 
> Changes in v3:
> - Removed unused member
> - Fixed comment referencing copy-paste source
> - Ensure activeState.compress.supported stays false if unsupported
> ---
>  src/ipa/rkisp1/algorithms/compress.cpp | 102 +++++++++++++++++++++++++
>  src/ipa/rkisp1/algorithms/compress.h   |  30 ++++++++
>  src/ipa/rkisp1/algorithms/meson.build  |   1 +
>  src/ipa/rkisp1/ipa_context.h           |   9 +++
>  4 files changed, 142 insertions(+)
>  create mode 100644 src/ipa/rkisp1/algorithms/compress.cpp
>  create mode 100644 src/ipa/rkisp1/algorithms/compress.h
> 
> diff --git a/src/ipa/rkisp1/algorithms/compress.cpp b/src/ipa/rkisp1/algorithms/compress.cpp
> new file mode 100644
> index 000000000000..e076727de4f1
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/compress.cpp
> @@ -0,0 +1,102 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2025, Ideas On Board
> + *
> + * RkISP1 Compression curve
> + */
> +#include "compress.h"
> +
> +#include <linux/videodev2.h>
> +
> +#include <libcamera/base/log.h>
> +#include <libcamera/base/utils.h>
> +
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "linux/rkisp1-config.h"
> +
> +/**
> + * \file compress.h
> + */
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +/**
> + * \class Compress
> + * \brief RkISP1 Compress curve
> + *
> + * This algorithm implements support for the compressions curve in the compand

s/compressions/compression/

> + * block available in the i.MX8 M Plus
> + *
> + * In its current version it only supports a static gain. This is useful for
> + * the agc algorithm to compensate for exposure/gain quantization effects.
> + *
> + * This algorithm doesn't have any configuration options. It needs to be
> + * configured per frame by other algorithms.
> + *
> + * Other algorithms can check activeState.compress.supported to see if
> + * compression is available. If it is available they can configure it per frame
> + * using frameContext.compress.enable and frameContext.compress.gain.
> + */
> +
> +LOG_DEFINE_CATEGORY(RkISP1Compress)
> +
> +constexpr static int kRkISP1CompressInBits = 20;
> +constexpr static int kRkISP1CompressOutBits = 12;
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::configure
> + */
> +int Compress::configure(IPAContext &context,
> +                       [[maybe_unused]] const IPACameraSensorInfo &configInfo)
> +{
> +       if (context.configuration.paramFormat != V4L2_META_FMT_RK_ISP1_EXT_PARAMS ||
> +           !context.hw->compand) {
> +               LOG(RkISP1Compress, Warning)
> +                       << "Compression is not supported by the hardware or kernel.";
> +               return 0;
> +       }
> +
> +       context.activeState.compress.supported = true;

imo this sounds like something that should be in the session configuration
instead of the active state.

> +       return 0;
> +}
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::prepare
> + */
> +void Compress::prepare([[maybe_unused]] IPAContext &context,
> +                      [[maybe_unused]] const uint32_t frame,
> +                      IPAFrameContext &frameContext,
> +                      RkISP1Params *params)
> +{
> +       auto comp = params->block<BlockType::CompandCompress>();
> +       comp.setEnabled(frameContext.compress.enable);

Should this be not enabled if not frameContext.compress.enable?

> +
> +       if (!frameContext.compress.enable)
> +               return;
> +
> +       int xmax = (1 << kRkISP1CompressInBits);
> +       int ymax = (1 << kRkISP1CompressOutBits);
> +       int inLogStep = std::log2(xmax / 64);

imo s/64/RKISP1_CIF_ISP_COMPAND_NUM_POINTS/ is clearer as to what the 64 means.


Paul

> +
> +       for (unsigned int i = 0; i < RKISP1_CIF_ISP_COMPAND_NUM_POINTS; i++) {
> +               double x = (i + 1) * (1.0 / RKISP1_CIF_ISP_COMPAND_NUM_POINTS);
> +               double y = x * frameContext.compress.gain;
> +
> +               comp->px[i] = inLogStep;
> +               comp->x[i] = std::min<int>(x * xmax, xmax - 1);
> +               comp->y[i] = std::min<int>(y * ymax, ymax - 1);
> +       }
> +
> +       LOG(RkISP1Compress, Debug) << "Compression: " << kRkISP1CompressInBits
> +                                  << " bits to " << kRkISP1CompressOutBits
> +                                  << " bits gain: " << frameContext.compress.gain;
> +}
> +
> +REGISTER_IPA_ALGORITHM(Compress, "Compress")
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/compress.h b/src/ipa/rkisp1/algorithms/compress.h
> new file mode 100644
> index 000000000000..87797b8ebcc5
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/compress.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2025, Ideas On Board
> + *
> + * RkISP1 Compression curve
> + */
> +
> +#pragma once
> +
> +#include "algorithm.h"
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +class Compress : public Algorithm
> +{
> +public:
> +       Compress() = default;
> +       ~Compress() = default;
> +
> +       int configure(IPAContext &context,
> +                     const IPACameraSensorInfo &configInfo) override;
> +       void prepare(IPAContext &context, const uint32_t frame,
> +                    IPAFrameContext &frameContext,
> +                    RkISP1Params *params) override;
> +};
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
> index c66b0b70b82f..2e42a80cf99d 100644
> --- a/src/ipa/rkisp1/algorithms/meson.build
> +++ b/src/ipa/rkisp1/algorithms/meson.build
> @@ -5,6 +5,7 @@ rkisp1_ipa_algorithms = files([
>      'awb.cpp',
>      'blc.cpp',
>      'ccm.cpp',
> +    'compress.cpp',
>      'cproc.cpp',
>      'dpcc.cpp',
>      'dpf.cpp',
> diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
> index 7ccc7b501aff..37a74215ce19 100644
> --- a/src/ipa/rkisp1/ipa_context.h
> +++ b/src/ipa/rkisp1/ipa_context.h
> @@ -106,6 +106,10 @@ struct IPAActiveState {
>                 Matrix<float, 3, 3> automatic;
>         } ccm;
>  
> +       struct {
> +               bool supported;
> +       } compress;
> +
>         struct {
>                 int8_t brightness;
>                 uint8_t contrast;
> @@ -158,6 +162,11 @@ struct IPAFrameContext : public FrameContext {
>                 bool update;
>         } cproc;
>  
> +       struct {
> +               bool enable;
> +               double gain;
> +       } compress;
> +
>         struct {
>                 bool denoise;
>                 bool update;
> -- 
> 2.48.1
>