* [PATCH 2/3] Document 8-bit and 16-bit YCrCb media bus pixel codes
@ 2011-07-10 18:14 Christian Gmeiner
2011-07-11 10:58 ` Laurent Pinchart
0 siblings, 1 reply; 5+ messages in thread
From: Christian Gmeiner @ 2011-07-10 18:14 UTC (permalink / raw)
To: linux-media
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>
+ </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>
--
1.7.6
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH 2/3] Document 8-bit and 16-bit YCrCb media bus pixel codes
2011-07-10 18:14 [PATCH 2/3] Document 8-bit and 16-bit YCrCb media bus pixel codes Christian Gmeiner
@ 2011-07-11 10:58 ` Laurent Pinchart
2011-07-11 21:28 ` Christian Gmeiner
0 siblings, 1 reply; 5+ messages in thread
From: Laurent Pinchart @ 2011-07-11 10:58 UTC (permalink / raw)
To: Christian Gmeiner; +Cc: linux-media
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>
--
Regards,
Laurent Pinchart
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/3] Document 8-bit and 16-bit YCrCb media bus pixel codes
2011-07-11 10:58 ` Laurent Pinchart
@ 2011-07-11 21:28 ` Christian Gmeiner
2011-07-13 18:58 ` Christian Gmeiner
0 siblings, 1 reply; 5+ messages in thread
From: Christian Gmeiner @ 2011-07-11 21:28 UTC (permalink / raw)
To: Laurent Pinchart; +Cc: linux-media
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
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/3] Document 8-bit and 16-bit YCrCb media bus pixel codes
2011-07-11 21:28 ` Christian Gmeiner
@ 2011-07-13 18:58 ` Christian Gmeiner
2011-07-14 9:45 ` Laurent Pinchart
0 siblings, 1 reply; 5+ messages in thread
From: Christian Gmeiner @ 2011-07-13 18:58 UTC (permalink / raw)
To: Laurent Pinchart; +Cc: linux-media
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
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/3] Document 8-bit and 16-bit YCrCb media bus pixel codes
2011-07-13 18:58 ` Christian Gmeiner
@ 2011-07-14 9:45 ` Laurent Pinchart
0 siblings, 0 replies; 5+ messages in thread
From: Laurent Pinchart @ 2011-07-14 9:45 UTC (permalink / raw)
To: Christian Gmeiner; +Cc: linux-media
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.
--
Regards,
Laurent Pinchart
^ permalink raw reply [flat|nested] 5+ messages in thread
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2011-07-10 18:14 [PATCH 2/3] Document 8-bit and 16-bit YCrCb media bus pixel codes Christian Gmeiner
2011-07-11 10:58 ` Laurent Pinchart
2011-07-11 21:28 ` Christian Gmeiner
2011-07-13 18:58 ` Christian Gmeiner
2011-07-14 9:45 ` Laurent Pinchart
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