| Message ID | CAH9NwWc+zLqPyBcC99wbsbNkdjzMFfn2zuGm1VfmZctgpOGMew@mail.gmail.com (mailing list archive) |
|---|---|
| State | Under Review |
| Headers | show |
Hi Christian, On Sunday 10 July 2011 20:14:21 Christian Gmeiner wrote: > Signed-off-by: Christian Gmeiner > --- > diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml > b/Documentation/DocBook/media/v4l/subdev-formats.xml > index 49c532e..18e30b0 100644 > --- a/Documentation/DocBook/media/v4l/subdev-formats.xml > +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml > @@ -2565,5 +2565,43 @@ > </tgroup> > </table> > </section> > + > + <section> > + <title>YCrCb Formats</title> > + > + <para>YCbCr represents colors as a combination of three values: > + <itemizedlist> > + <listitem><para>Y - the luminosity (roughly the > brightness)</para></listitem> > + <listitem><para>Cb - the chrominance of the blue > primary</para></listitem> > + <listitem><para>Cr - the chrominance of the red > primary</para></listitem> How does that differ from YUV ? > + </itemizedlist> > + </para> > + > + <para>The following table lists existing YCrCb compressed > formats.</para> + > + <table pgwide="0" frame="none" id="v4l2-mbus-pixelcode-ycrcb"> > + <title>YCrCb Formats</title> > + <tgroup cols="2"> > + <colspec colname="id" align="left" /> > + <colspec colname="code" align="left"/> > + <thead> > + <row> > + <entry>Identifier</entry> > + <entry>Code</entry> > + </row> > + </thead> > + <tbody valign="top"> > + <row id="V4L2_MBUS_FMT_YCRCB_1X8"> > + <entry>V4L2_MBUS_FMT_YCRCB_1X8</entry> > + <entry>0x5001</entry> > + </row> > + <row id="V4L2_MBUS_FMT_YCRCB_1X16"> > + <entry>V4L2_MBUS_FMT_YCRCB_1X16</entry> > + <entry>0x5002</entry> > + </row> > + </tbody> > + </tgroup> > + </table> > + </section> > </section> > </section>
Hi Laurent, 2011/7/11 Laurent Pinchart <laurent.pinchart@ideasonboard.com>: > Hi Christian, > > On Sunday 10 July 2011 20:14:21 Christian Gmeiner wrote: >> Signed-off-by: Christian Gmeiner >> --- >> diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml >> b/Documentation/DocBook/media/v4l/subdev-formats.xml >> index 49c532e..18e30b0 100644 >> --- a/Documentation/DocBook/media/v4l/subdev-formats.xml >> +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml >> @@ -2565,5 +2565,43 @@ >> </tgroup> >> </table> >> </section> >> + >> + <section> >> + <title>YCrCb Formats</title> >> + >> + <para>YCbCr represents colors as a combination of three values: >> + <itemizedlist> >> + <listitem><para>Y - the luminosity (roughly the >> brightness)</para></listitem> >> + <listitem><para>Cb - the chrominance of the blue >> primary</para></listitem> >> + <listitem><para>Cr - the chrominance of the red >> primary</para></listitem> > > How does that differ from YUV ? I need to say that I am very new to this whole format stuff and so I am not really sure. In the data sheet http://dxr3.sourceforge.net/download/hardware/ADV7175A_6A.pdf there is on the first page a FUNCTIONAL BLOCK DIAGRAM which shows that there is a "YCrCb to YUV Matrix" stage in the pipeline. I am also fine to use a YUV format for the media bus. Any suggestions? Greets, -- Christian Gmeiner, MSc -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
2011/7/11 Christian Gmeiner <christian.gmeiner@gmail.com>: > Hi Laurent, > > 2011/7/11 Laurent Pinchart <laurent.pinchart@ideasonboard.com>: >> Hi Christian, >> >> On Sunday 10 July 2011 20:14:21 Christian Gmeiner wrote: >>> Signed-off-by: Christian Gmeiner >>> --- >>> diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml >>> b/Documentation/DocBook/media/v4l/subdev-formats.xml >>> index 49c532e..18e30b0 100644 >>> --- a/Documentation/DocBook/media/v4l/subdev-formats.xml >>> +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml >>> @@ -2565,5 +2565,43 @@ >>> </tgroup> >>> </table> >>> </section> >>> + >>> + <section> >>> + <title>YCrCb Formats</title> >>> + >>> + <para>YCbCr represents colors as a combination of three values: >>> + <itemizedlist> >>> + <listitem><para>Y - the luminosity (roughly the >>> brightness)</para></listitem> >>> + <listitem><para>Cb - the chrominance of the blue >>> primary</para></listitem> >>> + <listitem><para>Cr - the chrominance of the red >>> primary</para></listitem> >> >> How does that differ from YUV ? > > > I need to say that I am very new to this whole format stuff and so I > am not really sure. > In the data sheet > http://dxr3.sourceforge.net/download/hardware/ADV7175A_6A.pdf there is > on the > first page a FUNCTIONAL BLOCK DIAGRAM which shows that there is a > "YCrCb to YUV Matrix" > stage in the pipeline. I am also fine to use a YUV format for the media bus. > Any suggestions? Okay I think I have found the difference between YUV and YCrCb - see [1] YCbCr 4:2:2 (Redirected from YUV 4:2:2) FourCCs: YUY2, UYVY, YUV2 (Apple Component Video stored in MOV files) Samples: http://samples.mplayerhq.hu/V-codecs/YUV2/ (These FourCC names only reflect that the YCbCr of digital media is often falsely mixed up with analog PAL's YUV color space.) YCbCr 4:2:2 is a packed YCbCr format in which a pair of consecutive pixels is represented by 1 Y sample each but share a Cb sample and a Cr sample. This type of data may be packaged in a container format with a a FourCC of YUY2 which indicates the following byte formatting: [1] http://wiki.multimedia.cx/index.php?title=YUV_4:2:2 Greets, -- Christian Gmeiner, MSc -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Christian, On Wednesday 13 July 2011 20:58:12 Christian Gmeiner wrote: > 2011/7/11 Christian Gmeiner <christian.gmeiner@gmail.com>: > > 2011/7/11 Laurent Pinchart <laurent.pinchart@ideasonboard.com>: > >> On Sunday 10 July 2011 20:14:21 Christian Gmeiner wrote: > >>> Signed-off-by: Christian Gmeiner > >>> --- > >>> diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml > >>> b/Documentation/DocBook/media/v4l/subdev-formats.xml > >>> index 49c532e..18e30b0 100644 > >>> --- a/Documentation/DocBook/media/v4l/subdev-formats.xml > >>> +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml > >>> @@ -2565,5 +2565,43 @@ > >>> </tgroup> > >>> </table> > >>> </section> > >>> + > >>> + <section> > >>> + <title>YCrCb Formats</title> > >>> + > >>> + <para>YCbCr represents colors as a combination of three values: > >>> + <itemizedlist> > >>> + <listitem><para>Y - the luminosity (roughly the > >>> brightness)</para></listitem> > >>> + <listitem><para>Cb - the chrominance of the blue > >>> primary</para></listitem> > >>> + <listitem><para>Cr - the chrominance of the red > >>> primary</para></listitem> > >> > >> How does that differ from YUV ? > > > > I need to say that I am very new to this whole format stuff and so I > > am not really sure. > > In the data sheet > > http://dxr3.sourceforge.net/download/hardware/ADV7175A_6A.pdf there is > > on the > > first page a FUNCTIONAL BLOCK DIAGRAM which shows that there is a > > "YCrCb to YUV Matrix" > > stage in the pipeline. I am also fine to use a YUV format for the media > > bus. Any suggestions? > > Okay I think I have found the difference between YUV and YCrCb - see [1] > > YCbCr 4:2:2 > (Redirected from YUV 4:2:2) > > FourCCs: YUY2, UYVY, YUV2 (Apple Component Video stored in MOV files) > Samples: http://samples.mplayerhq.hu/V-codecs/YUV2/ > > (These FourCC names only reflect that the YCbCr of digital media is > often falsely mixed up with analog PAL's YUV color space.) > > YCbCr 4:2:2 is a packed YCbCr format in which a pair of consecutive > pixels is represented by 1 Y sample each but share a Cb sample and a > Cr sample. > > This type of data may be packaged in a container format with a a > FourCC of YUY2 which indicates the following byte formatting: > > > [1] http://wiki.multimedia.cx/index.php?title=YUV_4:2:2 According to http://en.wikipedia.org/wiki/Yuv, "Historically, the terms YUV and Y'UV were used for a specific analog encoding of color information in television systems, while YCbCr was used for digital encoding of color information suited for video and still-image compression and transmission such as MPEG and JPEG. Today, the term YUV is commonly used in the computer industry to describe file-formats that are encoded using YCbCr." V4L2 seems to suffer from the ambiguity, as we use YUV as generic term to mean a digital luma/chroma format. I thus think your driver should use the existing YUV pixel codes.
diff --git a/Documentation/DocBook/media/v4l/subdev-formats.xml b/Documentation/DocBook/media/v4l/subdev-formats.xml index 49c532e..18e30b0 100644 --- a/Documentation/DocBook/media/v4l/subdev-formats.xml +++ b/Documentation/DocBook/media/v4l/subdev-formats.xml @@ -2565,5 +2565,43 @@ </tgroup> </table> </section> + + <section> + <title>YCrCb Formats</title> + + <para>YCbCr represents colors as a combination of three values: + <itemizedlist> + <listitem><para>Y - the luminosity (roughly the brightness)</para></listitem> + <listitem><para>Cb - the chrominance of the blue primary</para></listitem> + <listitem><para>Cr - the chrominance of the red primary</para></listitem> + </itemizedlist> + </para> + + <para>The following table lists existing YCrCb compressed formats.</para> + + <table pgwide="0" frame="none" id="v4l2-mbus-pixelcode-ycrcb"> + <title>YCrCb Formats</title> + <tgroup cols="2"> + <colspec colname="id" align="left" /> + <colspec colname="code" align="left"/> + <thead> + <row> + <entry>Identifier</entry> + <entry>Code</entry> + </row> + </thead> + <tbody valign="top"> + <row id="V4L2_MBUS_FMT_YCRCB_1X8"> + <entry>V4L2_MBUS_FMT_YCRCB_1X8</entry> + <entry>0x5001</entry> + </row> + <row id="V4L2_MBUS_FMT_YCRCB_1X16"> + <entry>V4L2_MBUS_FMT_YCRCB_1X16</entry> + <entry>0x5002</entry> + </row> + </tbody> + </tgroup> + </table>
Signed-off-by: Christian Gmeiner --- + </section> </section> </section> -- 1.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html