Re: [PATCH 4/8] media: Add P010 video format

[Nicolas Dufresne <nicolas@ndufresne.ca>]

Le lundi 07 juin 2021 à 13:31 +0200, Benjamin Gaignard a écrit :
> Le 04/06/2021 à 18:17, Nicolas Dufresne a écrit :
> > Le vendredi 04 juin 2021 à 15:06 +0200, Benjamin Gaignard a écrit :
> > > P010 is a YUV format with 10-bits per pixel with interleaved UV.
> > > 
> > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> > > ---
> > >   .../userspace-api/media/v4l/pixfmt-yuv-planar.rst         | 8 ++++++++
> > >   drivers/media/v4l2-core/v4l2-common.c                     | 1 +
> > >   drivers/media/v4l2-core/v4l2-ioctl.c                      | 1 +
> > >   include/uapi/linux/videodev2.h                            | 1 +
> > >   4 files changed, 11 insertions(+)
> > > 
> > > diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> > > index 090c091affd2..71fed70c03ec 100644
> > > --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> > > +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
> > > @@ -100,6 +100,13 @@ All components are stored with the same number of bits per component.
> > >         - Cb, Cr
> > >         - No
> > >         - 64x32 macroblocks
> > > +    * - V4L2_PIX_FMT_P010
> > > +      - 'P010'
> > > +      - 10
> > > +      - 4:2:0
> > > +      - Cb, Cr
> > > +      - No
> > > +      - Linear
> > >   
> > >           Horizontal Z order
> > >       * - V4L2_PIX_FMT_NV12MT_16X16
> > > @@ -171,6 +178,7 @@ horizontally.
> > >   .. _V4L2-PIX-FMT-NV21:
> > >   .. _V4L2-PIX-FMT-NV12M:
> > >   .. _V4L2-PIX-FMT-NV21M:
> > > +.. _V4L2-PIX-FMT-P010:
> > The NV12/21 documentation is not sufficient to describe this format. While it
> > shares the layout (two planes Y and interleaved UV), it does not share the
> > packing. In this case, assuming this is P010 (and not the P010 the Rockchip
> > tried to upstreamed previously), each 10bit worth of pixel data would be pakced
> > into 16 bits with the least significant 6 bit being padding bits.
> 
> Yes it 10 bits packed in 16 bits. I was think that the 'Bits per component' columns
> was referring to the number of encoded bits.
> So like this is it fine ? or does something else than the bit per component need to be changed ?
>   * - V4L2_PIX_FMT_P010
>        - 'P010'
>        - 16
>        - 4:2:0
>        - Cb, Cr
>        - No
>        - Linear

I believe we also need a table, similar to what we do for BGRx and other padded
format in order to document were the padding is located. Specially, with 16bit
formats, which could also have a big engian variants if handled per 16bit words.

> 
> Regards,
> Benjamin
> 
> > 
> > >   
> > >   NV12, NV21, NV12M and NV21M
> > >   ---------------------------
> > > diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> > > index 04af03285a20..37b5d82359dd 100644
> > > --- a/drivers/media/v4l2-core/v4l2-common.c
> > > +++ b/drivers/media/v4l2-core/v4l2-common.c
> > > @@ -266,6 +266,7 @@ const struct v4l2_format_info *v4l2_format_info(u32 format)
> > >   		{ .format = V4L2_PIX_FMT_NV61,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 2, .vdiv = 1 },
> > >   		{ .format = V4L2_PIX_FMT_NV24,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 1, .vdiv = 1 },
> > >   		{ .format = V4L2_PIX_FMT_NV42,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 1, 2, 0, 0 }, .hdiv = 1, .vdiv = 1 },
> > > +		{ .format = V4L2_PIX_FMT_P010,    .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 2, 2, 0, 0 }, .hdiv = 2, .vdiv = 1 },
> > >   
> > >   		{ .format = V4L2_PIX_FMT_YUV410,  .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 3, .bpp = { 1, 1, 1, 0 }, .hdiv = 4, .vdiv = 4 },
> > >   		{ .format = V4L2_PIX_FMT_YVU410,  .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 3, .bpp = { 1, 1, 1, 0 }, .hdiv = 4, .vdiv = 4 },
> > > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> > > index 2673f51aafa4..6404d5b6e350 100644
> > > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > > @@ -1282,6 +1282,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> > >   	case V4L2_PIX_FMT_NV61:		descr = "Y/CrCb 4:2:2"; break;
> > >   	case V4L2_PIX_FMT_NV24:		descr = "Y/CbCr 4:4:4"; break;
> > >   	case V4L2_PIX_FMT_NV42:		descr = "Y/CrCb 4:4:4"; break;
> > > +	case V4L2_PIX_FMT_P010:		descr = "10-bit Y/CrCb 4:2:0"; break;
> > >   	case V4L2_PIX_FMT_NV12M:	descr = "Y/CbCr 4:2:0 (N-C)"; break;
> > >   	case V4L2_PIX_FMT_NV21M:	descr = "Y/CrCb 4:2:0 (N-C)"; break;
> > >   	case V4L2_PIX_FMT_NV16M:	descr = "Y/CbCr 4:2:2 (N-C)"; break;
> > > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> > > index 9260791b8438..e5f7acde0730 100644
> > > --- a/include/uapi/linux/videodev2.h
> > > +++ b/include/uapi/linux/videodev2.h
> > > @@ -602,6 +602,7 @@ struct v4l2_pix_format {
> > >   #define V4L2_PIX_FMT_NV24    v4l2_fourcc('N', 'V', '2', '4') /* 24  Y/CbCr 4:4:4  */
> > >   #define V4L2_PIX_FMT_NV42    v4l2_fourcc('N', 'V', '4', '2') /* 24  Y/CrCb 4:4:4  */
> > >   #define V4L2_PIX_FMT_HM12    v4l2_fourcc('H', 'M', '1', '2') /*  8  YUV 4:2:0 16x16 macroblocks */
> > > +#define V4L2_PIX_FMT_P010    v4l2_fourcc('P', '0', '1', '0') /* 15  Y/CbCr 4:2:0 10-bit per pixel*/
> > >   
> > >   /* two non contiguous planes - one Y, one Cr + Cb interleaved  */
> > >   #define V4L2_PIX_FMT_NV12M   v4l2_fourcc('N', 'M', '1', '2') /* 12  Y/CbCr 4:2:0  */
> >