[PATCH v2 4/6] ipa: rkisp1: blc: Report sensor black levels in metadata

[Kieran Bingham]

Quoting Stefan Klug (2024-07-03 11:39:51)
> Add sensor black levels to the metadata of the rkisp1 pipeline.
> 
> Additionally enable raw support for this algorithm and add it to
> uncalibrated.yaml, so that black levels get reported when capturing
> tuning images. This is a bit of a hack, because no actual black level
> correction is taking place in raw mode, but it is the easiest way to get
> blacklevel reported for raw streams.
> 
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
> ---
>  src/ipa/rkisp1/algorithms/blc.cpp     | 28 +++++++++++++++++++++++++++
>  src/ipa/rkisp1/algorithms/blc.h       |  5 ++++-
>  src/ipa/rkisp1/data/uncalibrated.yaml |  1 +
>  3 files changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/src/ipa/rkisp1/algorithms/blc.cpp b/src/ipa/rkisp1/algorithms/blc.cpp
> index 87025e4f8c72..71c62b009707 100644
> --- a/src/ipa/rkisp1/algorithms/blc.cpp
> +++ b/src/ipa/rkisp1/algorithms/blc.cpp
> @@ -9,6 +9,8 @@
>  
>  #include <libcamera/base/log.h>
>  
> +#include <libcamera/control_ids.h>
> +
>  #include "libcamera/internal/yaml_parser.h"
>  
>  /**
> @@ -38,6 +40,13 @@ LOG_DEFINE_CATEGORY(RkISP1Blc)
>  BlackLevelCorrection::BlackLevelCorrection()
>         : tuningParameters_(false)
>  {
> +       /*
> +        * This is a bit of a hack. In raw mode no black level correction
> +        * happens. This flag is used to ensure the metadata gets populated with
> +        * the black level which is needed to capture proper raw images for
> +        * tuning.
> +        */
> +       supportsRaw_ = true;
>  }
>  
>  /**
> @@ -107,6 +116,9 @@ void BlackLevelCorrection::prepare([[maybe_unused]] IPAContext &context,
>                                    [[maybe_unused]] IPAFrameContext &frameContext,
>                                    rkisp1_params_cfg *params)
>  {
> +       if (context.configuration.raw)
> +               return;
> +
>         if (frame > 0)
>                 return;
>  
> @@ -125,6 +137,22 @@ void BlackLevelCorrection::prepare([[maybe_unused]] IPAContext &context,
>         params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_BLS;
>  }
>  
> +/**
> + * \copydoc libcamera::ipa::Algorithm::process
> + */
> +void BlackLevelCorrection::process([[maybe_unused]] IPAContext &context,
> +                                  [[maybe_unused]] const uint32_t frame,
> +                                  [[maybe_unused]] IPAFrameContext &frameContext,
> +                                  [[maybe_unused]] const rkisp1_stat_buffer *stats,
> +                                  [[maybe_unused]] ControlList &metadata)
> +{

Hrm. ... now ... should we report SensorBlackLevels at a bit-depth that
matches the bit-depth of the image?

I.e ... do we need to scale these 16 bit numbers to 8,10,12 bit
depending on the sensor configuration and output file bit-depth?

> +       metadata.set(controls::SensorBlackLevels,
> +                    { static_cast<int32_t>(blackLevelRed_),
> +                      static_cast<int32_t>(blackLevelGreenR_),
> +                      static_cast<int32_t>(blackLevelGreenB_),
> +                      static_cast<int32_t>(blackLevelBlue_) });
> +}
> +
>  REGISTER_IPA_ALGORITHM(BlackLevelCorrection, "BlackLevelCorrection")
>  
>  } /* namespace ipa::rkisp1::algorithms */
> diff --git a/src/ipa/rkisp1/algorithms/blc.h b/src/ipa/rkisp1/algorithms/blc.h
> index 460ebcc15739..4ecac233f88b 100644
> --- a/src/ipa/rkisp1/algorithms/blc.h
> +++ b/src/ipa/rkisp1/algorithms/blc.h
> @@ -23,7 +23,10 @@ public:
>         void prepare(IPAContext &context, const uint32_t frame,
>                      IPAFrameContext &frameContext,
>                      rkisp1_params_cfg *params) override;
> -
> +       void process(IPAContext &context, const uint32_t frame,
> +                    IPAFrameContext &frameContext,
> +                    const rkisp1_stat_buffer *stats,
> +                    ControlList &metadata) override;
>  private:
>         bool tuningParameters_;
>         int16_t blackLevelRed_;
> diff --git a/src/ipa/rkisp1/data/uncalibrated.yaml b/src/ipa/rkisp1/data/uncalibrated.yaml
> index a7bbd8d84263..609012967e02 100644
> --- a/src/ipa/rkisp1/data/uncalibrated.yaml
> +++ b/src/ipa/rkisp1/data/uncalibrated.yaml
> @@ -5,4 +5,5 @@ version: 1
>  algorithms:
>    - Agc:
>    - Awb:
> +  - BlackLevelCorrection:
>  ...
> -- 
> 2.43.0
>