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@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 ?
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.
--
Sakari Ailus
sakari.ailus@xxxxxx
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