[RFC,v2,3/3] ipa: mali-c55: agc: Ignore invalid statistics

28788 diff mbox series

It is possible that, for example, the first frame has no valid statistics
yet. In that case the histograms are empty. This is problematic because
e.g. `interQuantileMean()` may return NaN, which causes issues in the
calculations (this affects both the color temperature calculation and
`AgcTraits::estimanteLuminance()` as well).

Previously this has not manifested itself because implementation details in
`AgcMeanLuminance` prevented the NaNs from propagating, but 25cb6cd274d3
("libipa: agc_mean_luminance: Improve inital gain estimation") has changed that.

So ignore statistics if any of the color histograms are empty.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
---
 src/ipa/mali-c55/algorithms/agc.cpp | 19 +++++++++++++------
 src/ipa/mali-c55/algorithms/agc.h   |  5 +++++
 2 files changed, 18 insertions(+), 6 deletions(-)

Quoting Barnabás Pőcze (2026-11-06 12:58:07)
> It is possible that, for example, the first frame has no valid statistics
> yet. In that case the histograms are empty. This is problematic because
> e.g. `interQuantileMean()` may return NaN, which causes issues in the
> calculations (this affects both the color temperature calculation and
> `AgcTraits::estimanteLuminance()` as well).
> 
> Previously this has not manifested itself because implementation details in
> `AgcMeanLuminance` prevented the NaNs from propagating, but 25cb6cd274d3
> ("libipa: agc_mean_luminance: Improve inital gain estimation") has changed that.
> 
> So ignore statistics if any of the color histograms are empty.
> 
> Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

> ---
>  src/ipa/mali-c55/algorithms/agc.cpp | 19 +++++++++++++------
>  src/ipa/mali-c55/algorithms/agc.h   |  5 +++++
>  2 files changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/src/ipa/mali-c55/algorithms/agc.cpp b/src/ipa/mali-c55/algorithms/agc.cpp
> index bf9d3f7d4a..1b7687e723 100644
> --- a/src/ipa/mali-c55/algorithms/agc.cpp
> +++ b/src/ipa/mali-c55/algorithms/agc.cpp
> @@ -257,13 +257,20 @@ void Agc::process(IPAContext &context,
>         }
>  
>         statistics_.parseStatistics(stats);
> +       if (!statistics_.isValid()) {
> +               LOG(MaliC55Agc, Debug) << "Ignoring invalid statistics";
> +               agc_.process(context.configuration.agc, context.activeState.agc, frameContext.agc, {}, metadata);
> +               return;
> +       }
>  
> -       agc_.process(context.configuration.agc, context.activeState.agc, frameContext.agc, {{
> -               .traits = AgcTraits(statistics_),
> -               .yHist = statistics_.yHist,
> -               .exposure = frameContext.sensor.exposure,
> -               .gain = frameContext.sensor.gain,
> -       }}, metadata);
> +       agc_.process(context.configuration.agc, context.activeState.agc, frameContext.agc,
> +                    { {
> +                            .traits = AgcTraits(statistics_),
> +                            .yHist = statistics_.yHist,
> +                            .exposure = frameContext.sensor.exposure,
> +                            .gain = frameContext.sensor.gain,
> +                    } },
> +                    metadata);
>  }
>  
>  REGISTER_IPA_ALGORITHM(Agc, "Agc")
> diff --git a/src/ipa/mali-c55/algorithms/agc.h b/src/ipa/mali-c55/algorithms/agc.h
> index 809a57c53a..998ef57210 100644
> --- a/src/ipa/mali-c55/algorithms/agc.h
> +++ b/src/ipa/mali-c55/algorithms/agc.h
> @@ -32,6 +32,11 @@ public:
>         uint32_t decodeBinValue(uint16_t binVal);
>         void parseStatistics(const mali_c55_stats_buffer *stats);
>  
> +       bool isValid() const
> +       {
> +               return !rHist.empty() && !gHist.empty() && !bHist.empty();
> +       }
> +
>         Histogram rHist;
>         Histogram gHist;
>         Histogram bHist;
> -- 
> 2.56.0
>