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@xxxxxxxxxxxxxxxx>
> > ---
> >
> > 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,
--
Regards,
Laurent Pinchart
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