[libcamera-devel] [PATCH 2/5] pipeline: raspberrypi: Set the ISP Output1 to 1/4 resolution if unused

[David Plowman]

Hi Naush

Thanks for this patch. Just one small tidiness thing...

On Wed, 20 Jan 2021 at 08:34, Naushir Patuck <naush at raspberrypi.com> wrote:
>
> In preparation for fast colour denoise, set the low resolution ISP
> output stream (Output1) to a 1/4 resolution of the application requested
> stream (Output0). This only happens if the application has not requested
> an additional YUV or RGB stream.
>
> We also constrain this 1/4 resolution to at most 1200 pixels in the
> largest dimension to avoid being too taxing on memory usage and system
> bandwidth.
>
> Also switch the default StreamRole::VideoRecording to YUV420 to allow
> fast colour denoise to run.
>
> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> ---
>  .../pipeline/raspberrypi/raspberrypi.cpp      | 42 ++++++++++++++++++-
>  1 file changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index e03bcb036f9f..282c4ba75d89 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -496,7 +496,7 @@ CameraConfiguration *PipelineHandlerRPi::generateConfiguration(Camera *camera,
>
>                 case StreamRole::VideoRecording:
>                         fmts = data->isp_[Isp::Output0].dev()->formats();
> -                       pixelFormat = formats::NV12;
> +                       pixelFormat = formats::YUV420;
>                         size = { 1920, 1080 };
>                         bufferCount = 4;
>                         outCount++;
> @@ -608,6 +608,7 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
>          * StreamConfiguration appropriately.
>          */
>         V4L2DeviceFormat format;
> +       bool output1Set = false;
>         for (unsigned i = 0; i < config->size(); i++) {
>                 StreamConfiguration &cfg = config->at(i);
>
> @@ -632,6 +633,9 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
>                 format.size = cfg.size;
>                 format.fourcc = fourcc;
>
> +               LOG(RPI, Info) << "Setting " << stream->name() << " to a resolution of "
> +                              << format.toString();
> +
>                 ret = stream->dev()->setFormat(&format);
>                 if (ret)
>                         return -EINVAL;
> @@ -645,6 +649,42 @@ int PipelineHandlerRPi::configure(Camera *camera, CameraConfiguration *config)
>
>                 cfg.setStream(stream);
>                 stream->setExternal(true);
> +
> +               if (i != maxIndex)
> +                       output1Set = true;
> +       }
> +
> +       /*
> +        * If ISP::Output1 stream has not been requested by the application, we
> +        * set it up for internal use now. This second stream will be used for
> +        * fast colour denoise, and must be a quarter resolution of the ISP::Output0
> +        * stream. However, also limit the maximum size to 1200 pixels in the
> +        * larger dimension, just to avoid being wasteful with buffer allocations
> +        * and memory bandwidth.
> +        */
> +       if (!output1Set) {
> +               V4L2DeviceFormat output1Format = format;
> +               constexpr unsigned int maxDimensions = 1200;
> +
> +               output1Format.size = format.size / 2;
> +               if (output1Format.size.width > maxDimensions) {
> +                       output1Format.size.height = maxDimensions * output1Format.size.height /
> +                                                   output1Format.size.width;
> +                       output1Format.size.height &= ~1;
> +                       output1Format.size.width = maxDimensions;
> +               } else if (output1Format.size.height > maxDimensions) {
> +                       output1Format.size.width = maxDimensions * output1Format.size.width /
> +                                                  output1Format.size.height;
> +                       output1Format.size.width &= ~1;
> +                       output1Format.size.height = maxDimensions;
> +               }

I wonder if we can tidy this up with those new(ish) Size methods?
Maybe along the lines of

const Size maxSize = Size(maxDimensions ,
maxDimensions).boundedToAspectRatio(format.size);
output1Format.size = (format.size / 2).boundedTo(maxSize).alignedDownTo(2, 2);

Thanks!
David

> +
> +               LOG(RPI, Info) << "Setting ISP Output 1 (internal) to a resolution of "
> +                              << output1Format.toString();
> +
> +               ret = data->isp_[Isp::Output1].dev()->setFormat(&output1Format);
> +               if (ret)
> +                       return -EINVAL;
>         }
>
>         /* ISP statistics output format. */
> --
> 2.25.1
>
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