Re: [PATCH] media: uvcvideo: Add support for NV21 pixel format

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Sun, Oct 25, 2026 at 03:35:22PM +0100, Manuel Herrmann wrote:
> Add support for the NV21 (Y/VU 4:2:0) pixel format to the uvcvideo
> driver. This format is exposed by the color camera of the Creality Pika
> 3D scanner (2bc5:0c0b), next to YUYV and MJPEG. Without it, the driver

Could you please provide the USB descriptors for that device
(`lsusb -v -d 2bc5:0c0b`) ?

> skips the format as unknown.
> 
> NV21 only differs from NV12 in the order of the chroma samples, so
> bytesperline is wWidth, as for NV12.
> 
> Signed-off-by: Manuel Herrmann <m@manuel-herrmann.de>
> ---
> Tested on media next (d7e7bca71698) in a QEMU guest with the scanner passed
> through. Before the patch, the driver logs
> 
>   uvcvideo 2-1:1.3: Unknown video format 3132564e-0000-0010-8000-00aa00389b71
> 
> and the color node only offers YUYV and MJPG. With the patch, NV21 is
> listed, G_FMT reports a bytesperline of 1280 for 1280x960, and v4l2-ctl
> streams it at 30 fps. A frame captured in the guest has the right
> colors decoded as NV21, and red and blue swapped decoded as NV12.
> 
>  drivers/media/common/uvc.c       | 4 ++++
>  drivers/media/usb/uvc/uvc_v4l2.c | 1 +
>  include/linux/usb/uvc.h          | 3 +++
>  3 files changed, 8 insertions(+)
> 
> diff --git a/drivers/media/common/uvc.c b/drivers/media/common/uvc.c
> index 0107cedd0..7d918ba0e 100644
> --- a/drivers/media/common/uvc.c
> +++ b/drivers/media/common/uvc.c
> @@ -24,6 +24,10 @@ static const struct uvc_format_desc uvc_fmts[] = {
>  		.guid		= UVC_GUID_FORMAT_NV12,
>  		.fcc		= V4L2_PIX_FMT_NV12,
>  	},
> +	{
> +		.guid		= UVC_GUID_FORMAT_NV21,
> +		.fcc		= V4L2_PIX_FMT_NV21,
> +	},
>  	{
>  		.guid		= UVC_GUID_FORMAT_MJPEG,
>  		.fcc		= V4L2_PIX_FMT_MJPEG,
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 644c2f1cd..60732f5ac 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -232,6 +232,7 @@ static u32 uvc_v4l2_get_bytesperline(const struct uvc_format *format,
>  {
>  	switch (format->fcc) {
>  	case V4L2_PIX_FMT_NV12:
> +	case V4L2_PIX_FMT_NV21:
>  	case V4L2_PIX_FMT_YVU420:
>  	case V4L2_PIX_FMT_YUV420:
>  	case V4L2_PIX_FMT_M420:
> diff --git a/include/linux/usb/uvc.h b/include/linux/usb/uvc.h
> index 99b070ab8..48419a862 100644
> --- a/include/linux/usb/uvc.h
> +++ b/include/linux/usb/uvc.h
> @@ -85,6 +85,9 @@
>  #define UVC_GUID_FORMAT_NV12 \
>  	{ 'N',  'V',  '1',  '2', 0x00, 0x00, 0x10, 0x00, \
>  	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
> +#define UVC_GUID_FORMAT_NV21 \
> +	{ 'N',  'V',  '2',  '1', 0x00, 0x00, 0x10, 0x00, \
> +	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
>  #define UVC_GUID_FORMAT_YV12 \
>  	{ 'Y',  'V',  '1',  '2', 0x00, 0x00, 0x10, 0x00, \
>  	 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
> 
> base-commit: d7e7bca7169873b46e857c025c10f3336c1258d8

-- 
Regards,

Laurent Pinchart