[libcamera-devel] [PATCH v4 2/4] libcamera: rkisp1: Crop on ISP before downscaling

[Umang Jain]

Hi Jacopo,

Thank you for the patch.

On 3/21/23 10:50 PM, Jacopo Mondi via libcamera-devel wrote:
> Crop on the resizer sink pad before downscaling to the aspect ratio
> of the desired output size.
>
> Cropping the input frame to the output aspect ratio allows to maintain
> the correct picture proportions, as otherwise downscaling would change
> the image geometry.
>
> Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>

The code indeed makes sense to me.

Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>

> ---
>   src/libcamera/pipeline/rkisp1/rkisp1_path.cpp | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
> index 5079b268c464..5547cc32b6ca 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
> @@ -314,7 +314,10 @@ int RkISP1Path::configure(const StreamConfiguration &config,
>   	if (ret < 0)
>   		return ret;
>   
> -	Rectangle rect(0, 0, ispFormat.size);
> +	/* Crop on the resizer input to maintain FOV before downscaling */
> +	Size ispCrop = inputFormat.size.boundedToAspectRatio(config.size)
> +				       .alignedUpTo(2, 2);
> +	Rectangle rect(ispCrop);
>   	ret = resizer_->setSelection(0, V4L2_SEL_TGT_CROP, &rect);
>   	if (ret < 0)
>   		return ret;