v4l: Add V4L2_PIX_FMT_NV24 and V4L2_PIX_FMT_NV42 formats

NV24 and NV42 are planar YCbCr 4:4:4 and YCrCb 4:4:4 formats with a
luma plane followed by an interleaved chroma plane.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 Documentation/DocBook/media/v4l/pixfmt-nv24.xml |  128 +++++++++++++++++++++++
 Documentation/DocBook/media/v4l/pixfmt.xml      |    1 +
 include/linux/videodev2.h                       |    2 +
 3 files changed, 131 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/DocBook/media/v4l/pixfmt-nv24.xml

This format will be used by an fbdev driver. I'm already posting the patch for
for review and will send a pull request later.
  

Hi Laurent,

Thanks for the patch.

On Fri, Aug 19, 2011 at 08:14:20AM +0200, Laurent Pinchart wrote:
> NV24 and NV42 are planar YCbCr 4:4:4 and YCrCb 4:4:4 formats with a
> luma plane followed by an interleaved chroma plane.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  Documentation/DocBook/media/v4l/pixfmt-nv24.xml |  128 +++++++++++++++++++++++
>  Documentation/DocBook/media/v4l/pixfmt.xml      |    1 +
>  include/linux/videodev2.h                       |    2 +
>  3 files changed, 131 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> 
> This format will be used by an fbdev driver. I'm already posting the patch for
> for review and will send a pull request later.
> 
> diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv24.xml b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> new file mode 100644
> index 0000000..e77301d
> --- /dev/null
> +++ b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> @@ -0,0 +1,128 @@
> +    <refentry>
> +      <refmeta>
> +	<refentrytitle>V4L2_PIX_FMT_NV24 ('NV24'), V4L2_PIX_FMT_NV42 ('NV42')</refentrytitle>
> +	&manvol;
> +      </refmeta>
> +      <refnamediv>
> +	<refname id="V4L2-PIX-FMT-NV24"><constant>V4L2_PIX_FMT_NV24</constant></refname>
> +	<refname id="V4L2-PIX-FMT-NV42"><constant>V4L2_PIX_FMT_NV42</constant></refname>
> +	<refpurpose>Formats with full horizontal and vertical
> +chroma resolutions, also known as YUV 4:4:4. One luminance and one
> +chrominance plane with alternating chroma samples as opposed to
> +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose>
> +      </refnamediv>
> +      <refsect1>
> +	<title>Description</title>
> +
> +	<para>These are two-plane versions of the YUV 4:4:4 format.
> +The three components are separated into two sub-images or planes. The
> +Y plane is first. The Y plane has one byte per pixel. For

Are all 8 bits being used per sample, or is there padding?

> +<constant>V4L2_PIX_FMT_NV24</constant>, a combined CbCr plane
> +immediately follows the Y plane in memory.  The CbCr plane is the same
> +width and height, in pixels, as the Y plane (and of the image).
> +Each line contains one CbCr pair per pixel.

How may bits / bytes per Cb / Cr sample? Perhaps you could mention this once
somewhere if all have the same.

> +<constant>V4L2_PIX_FMT_NV42</constant> is the same except the Cb and
> +Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para>
> +	<para>If the Y plane has pad bytes after each row, then the
> +CbCr plane has twice as many pad bytes after its rows.</para>

[clip]

Cheers,
  

Hi Sakari,

On Saturday 20 August 2011 07:26:17 Sakari Ailus wrote:
> Hi Laurent,
> 
> Thanks for the patch.

And thanks for the comments.

> On Fri, Aug 19, 2011 at 08:14:20AM +0200, Laurent Pinchart wrote:
> > NV24 and NV42 are planar YCbCr 4:4:4 and YCrCb 4:4:4 formats with a
> > luma plane followed by an interleaved chroma plane.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> > 
> >  Documentation/DocBook/media/v4l/pixfmt-nv24.xml |  128
> >  +++++++++++++++++++++++ Documentation/DocBook/media/v4l/pixfmt.xml     
> >  |    1 +
> >  include/linux/videodev2.h                       |    2 +
> >  3 files changed, 131 insertions(+), 0 deletions(-)
> >  create mode 100644 Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> > 
> > This format will be used by an fbdev driver. I'm already posting the
> > patch for for review and will send a pull request later.
> > 
> > diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> > b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml new file mode 100644
> > index 0000000..e77301d
> > --- /dev/null
> > +++ b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> > @@ -0,0 +1,128 @@
> > +    <refentry>
> > +      <refmeta>
> > +	<refentrytitle>V4L2_PIX_FMT_NV24 ('NV24'), V4L2_PIX_FMT_NV42
> > ('NV42')</refentrytitle> +	&manvol;
> > +      </refmeta>
> > +      <refnamediv>
> > +	<refname
> > id="V4L2-PIX-FMT-NV24"><constant>V4L2_PIX_FMT_NV24</constant></refname>
> > +	<refname
> > id="V4L2-PIX-FMT-NV42"><constant>V4L2_PIX_FMT_NV42</constant></refname>
> > +	<refpurpose>Formats with full horizontal and vertical
> > +chroma resolutions, also known as YUV 4:4:4. One luminance and one
> > +chrominance plane with alternating chroma samples as opposed to
> > +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose>
> > +      </refnamediv>
> > +      <refsect1>
> > +	<title>Description</title>
> > +
> > +	<para>These are two-plane versions of the YUV 4:4:4 format.
> > +The three components are separated into two sub-images or planes. The
> > +Y plane is first. The Y plane has one byte per pixel. For
> 
> Are all 8 bits being used per sample, or is there padding?

All 8 bits are used, as in all YUV planar formats. Do you think that's worth 
mentioning ?

> > +<constant>V4L2_PIX_FMT_NV24</constant>, a combined CbCr plane
> > +immediately follows the Y plane in memory.  The CbCr plane is the same
> > +width and height, in pixels, as the Y plane (and of the image).
> > +Each line contains one CbCr pair per pixel.
> 
> How may bits / bytes per Cb / Cr sample? Perhaps you could mention this
> once somewhere if all have the same.

All YUV planar formats use 8 bits for each Cb and Cr samples. I will clarify 
this.

> > +<constant>V4L2_PIX_FMT_NV42</constant> is the same except the Cb and
> > +Cr bytes are swapped, the CrCb plane starts with a Cr byte.</para>
> > +	<para>If the Y plane has pad bytes after each row, then the
> > +CbCr plane has twice as many pad bytes after its rows.</para>
> 
> [clip]
> 
> Cheers,
  

On Mon, Aug 22, 2011 at 01:17:16AM +0200, Laurent Pinchart wrote:
> Hi Sakari,
> 
> On Saturday 20 August 2011 07:26:17 Sakari Ailus wrote:
> > Hi Laurent,
> > 
> > Thanks for the patch.
> 
> And thanks for the comments.
> 
> > On Fri, Aug 19, 2011 at 08:14:20AM +0200, Laurent Pinchart wrote:
> > > NV24 and NV42 are planar YCbCr 4:4:4 and YCrCb 4:4:4 formats with a
> > > luma plane followed by an interleaved chroma plane.
> > > 
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > ---
> > > 
> > >  Documentation/DocBook/media/v4l/pixfmt-nv24.xml |  128
> > >  +++++++++++++++++++++++ Documentation/DocBook/media/v4l/pixfmt.xml     
> > >  |    1 +
> > >  include/linux/videodev2.h                       |    2 +
> > >  3 files changed, 131 insertions(+), 0 deletions(-)
> > >  create mode 100644 Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> > > 
> > > This format will be used by an fbdev driver. I'm already posting the
> > > patch for for review and will send a pull request later.
> > > 
> > > diff --git a/Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> > > b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml new file mode 100644
> > > index 0000000..e77301d
> > > --- /dev/null
> > > +++ b/Documentation/DocBook/media/v4l/pixfmt-nv24.xml
> > > @@ -0,0 +1,128 @@
> > > +    <refentry>
> > > +      <refmeta>
> > > +	<refentrytitle>V4L2_PIX_FMT_NV24 ('NV24'), V4L2_PIX_FMT_NV42
> > > ('NV42')</refentrytitle> +	&manvol;
> > > +      </refmeta>
> > > +      <refnamediv>
> > > +	<refname
> > > id="V4L2-PIX-FMT-NV24"><constant>V4L2_PIX_FMT_NV24</constant></refname>
> > > +	<refname
> > > id="V4L2-PIX-FMT-NV42"><constant>V4L2_PIX_FMT_NV42</constant></refname>
> > > +	<refpurpose>Formats with full horizontal and vertical
> > > +chroma resolutions, also known as YUV 4:4:4. One luminance and one
> > > +chrominance plane with alternating chroma samples as opposed to
> > > +<constant>V4L2_PIX_FMT_YVU420</constant></refpurpose>
> > > +      </refnamediv>
> > > +      <refsect1>
> > > +	<title>Description</title>
> > > +
> > > +	<para>These are two-plane versions of the YUV 4:4:4 format.
> > > +The three components are separated into two sub-images or planes. The
> > > +Y plane is first. The Y plane has one byte per pixel. For
> > 
> > Are all 8 bits being used per sample, or is there padding?
> 
> All 8 bits are used, as in all YUV planar formats. Do you think that's worth 
> mentioning ?

I think this should definitely be mentioned, but if the same issue touches
all the YUV formats, I guess it doesn't need to be in this patch.

E.g. many (if not most) raw bayer formats contain padding.

> > > +<constant>V4L2_PIX_FMT_NV24</constant>, a combined CbCr plane
> > > +immediately follows the Y plane in memory.  The CbCr plane is the same
> > > +width and height, in pixels, as the Y plane (and of the image).
> > > +Each line contains one CbCr pair per pixel.
> > 
> > How may bits / bytes per Cb / Cr sample? Perhaps you could mention this
> > once somewhere if all have the same.
> 
> All YUV planar formats use 8 bits for each Cb and Cr samples. I will clarify 
> this.

Yes, I think the size per sample is important.