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

[Ricardo Ribalda]

Hi Manuel

On Sun, 25 Oct 2026 at 21:07, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
>
> 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.
> >
Reviewed-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> > Signed-off-by: Manuel Herrmann <m@xxxxxxxxxxxxxxxxxx>
> > ---
> > 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
>


-- 
Ricardo Ribalda