[libcamera-devel] [PATCH v4 08/11] libcamera: v4l2_videodevice: Map V4L2_PIX_FMT_GREY to DRM FourCC

[Niklas Söderlund]

Hi Laurent,

Thanks for your work.

On 2020-04-04 03:44:35 +0300, Laurent Pinchart wrote:
> DRM has a format for 8-bit greyscale data, DRM_FORMAT_R8. Despite the
> 'R' name, which comes from GL/Vulkan to mean single-channel data, the
> format maps to greyscale for display. We can thus map it to
> V4L2_PIX_FMT_GREY.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>

> ---
> Changes since v2:
> 
> - Rebase on top of PixelFormat class
> ---
>  src/libcamera/v4l2_videodevice.cpp | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index 5208e5a47148..437e771d7fe4 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -1699,12 +1699,15 @@ PixelFormat V4L2VideoDevice::toPixelFormat(V4L2PixelFormat v4l2Fourcc)
>  	case V4L2_PIX_FMT_NV21M:
>  		return PixelFormat(DRM_FORMAT_NV21);
>  
> +	/* Greyscale formats. */
> +	case V4L2_PIX_FMT_GREY:
> +		return PixelFormat(DRM_FORMAT_R8);
> +
>  	/* Compressed formats. */
>  	case V4L2_PIX_FMT_MJPEG:
>  		return PixelFormat(DRM_FORMAT_MJPEG);
>  
>  	/* V4L2 formats not yet supported by DRM. */
> -	case V4L2_PIX_FMT_GREY:
>  	default:
>  		/*
>  		 * \todo We can't use LOG() in a static method of a Loggable
> @@ -1790,6 +1793,10 @@ V4L2PixelFormat V4L2VideoDevice::toV4L2PixelFormat(const PixelFormat &pixelForma
>  	case DRM_FORMAT_NV21:
>  		return V4L2PixelFormat(V4L2_PIX_FMT_NV21);
>  
> +	/* Greyscale formats. */
> +	case DRM_FORMAT_R8:
> +		return V4L2PixelFormat(V4L2_PIX_FMT_GREY);
> +
>  	/* Compressed formats. */
>  	case DRM_FORMAT_MJPEG:
>  		return V4L2PixelFormat(V4L2_PIX_FMT_MJPEG);
> -- 
> Regards,
> 
> Laurent Pinchart
> 
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> libcamera-devel at lists.libcamera.org
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-- 
Regards,
Niklas Söderlund