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linux/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml
Hans Verkuil f234a76e10 [media] DocBook media: clarify BGR666 
The documentation is not clear whether this is a three or four byte
format. Clarify this.

Also move the BGR666 format to the other 32 bit formats.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2015-04-02 21:05:15 -03:00

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<refentry id="packed-rgb">
<refmeta>
<refentrytitle>Packed RGB formats</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>Packed RGB formats</refname>
<refpurpose>Packed RGB formats</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>These formats are designed to match the pixel formats of
typical PC graphics frame buffers. They occupy 8, 16, 24 or 32 bits
per pixel. These are all packed-pixel formats, meaning all the data
for a pixel lie next to each other in memory.</para>
<table pgwide="1" frame="none" id="rgb-formats">
<title>Packed RGB Image Formats</title>
<tgroup cols="37" align="center">
<colspec colname="id" align="left" />
<colspec colname="fourcc" />
<colspec colname="bit" />
<colspec colnum="4" colname="b07" align="center" />
<colspec colnum="5" colname="b06" align="center" />
<colspec colnum="6" colname="b05" align="center" />
<colspec colnum="7" colname="b04" align="center" />
<colspec colnum="8" colname="b03" align="center" />
<colspec colnum="9" colname="b02" align="center" />
<colspec colnum="10" colname="b01" align="center" />
<colspec colnum="11" colname="b00" align="center" />
<colspec colnum="13" colname="b17" align="center" />
<colspec colnum="14" colname="b16" align="center" />
<colspec colnum="15" colname="b15" align="center" />
<colspec colnum="16" colname="b14" align="center" />
<colspec colnum="17" colname="b13" align="center" />
<colspec colnum="18" colname="b12" align="center" />
<colspec colnum="19" colname="b11" align="center" />
<colspec colnum="20" colname="b10" align="center" />
<colspec colnum="22" colname="b27" align="center" />
<colspec colnum="23" colname="b26" align="center" />
<colspec colnum="24" colname="b25" align="center" />
<colspec colnum="25" colname="b24" align="center" />
<colspec colnum="26" colname="b23" align="center" />
<colspec colnum="27" colname="b22" align="center" />
<colspec colnum="28" colname="b21" align="center" />
<colspec colnum="29" colname="b20" align="center" />
<colspec colnum="31" colname="b37" align="center" />
<colspec colnum="32" colname="b36" align="center" />
<colspec colnum="33" colname="b35" align="center" />
<colspec colnum="34" colname="b34" align="center" />
<colspec colnum="35" colname="b33" align="center" />
<colspec colnum="36" colname="b32" align="center" />
<colspec colnum="37" colname="b31" align="center" />
<colspec colnum="38" colname="b30" align="center" />
<spanspec namest="b07" nameend="b00" spanname="b0" />
<spanspec namest="b17" nameend="b10" spanname="b1" />
<spanspec namest="b27" nameend="b20" spanname="b2" />
<spanspec namest="b37" nameend="b30" spanname="b3" />
<thead>
<row>
<entry>Identifier</entry>
<entry>Code</entry>
<entry>&nbsp;</entry>
<entry spanname="b0">Byte&nbsp;0 in memory</entry>
<entry spanname="b1">Byte&nbsp;1</entry>
<entry spanname="b2">Byte&nbsp;2</entry>
<entry spanname="b3">Byte&nbsp;3</entry>
</row>
<row>
<entry>&nbsp;</entry>
<entry>&nbsp;</entry>
<entry>Bit</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
<entry>&nbsp;</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
<entry>&nbsp;</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
<entry>&nbsp;</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
</row>
</thead>
<tbody valign="top">
<row id="V4L2-PIX-FMT-RGB332">
<entry><constant>V4L2_PIX_FMT_RGB332</constant></entry>
<entry>'RGB1'</entry>
<entry></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-ARGB444">
<entry><constant>V4L2_PIX_FMT_ARGB444</constant></entry>
<entry>'AR12'</entry>
<entry></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>a<subscript>3</subscript></entry>
<entry>a<subscript>2</subscript></entry>
<entry>a<subscript>1</subscript></entry>
<entry>a<subscript>0</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-XRGB444">
<entry><constant>V4L2_PIX_FMT_XRGB444</constant></entry>
<entry>'XR12'</entry>
<entry></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-ARGB555">
<entry><constant>V4L2_PIX_FMT_ARGB555</constant></entry>
<entry>'AR15'</entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>a</entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-XRGB555">
<entry><constant>V4L2_PIX_FMT_XRGB555</constant></entry>
<entry>'XR15'</entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>-</entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-RGB565">
<entry><constant>V4L2_PIX_FMT_RGB565</constant></entry>
<entry>'RGBP'</entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-ARGB555X">
<entry><constant>V4L2_PIX_FMT_ARGB555X</constant></entry>
<entry>'AR15' | (1 &lt;&lt; 31)</entry>
<entry></entry>
<entry>a</entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-XRGB555X">
<entry><constant>V4L2_PIX_FMT_XRGB555X</constant></entry>
<entry>'XR15' | (1 &lt;&lt; 31)</entry>
<entry></entry>
<entry>-</entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-RGB565X">
<entry><constant>V4L2_PIX_FMT_RGB565X</constant></entry>
<entry>'RGBR'</entry>
<entry></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-BGR24">
<entry><constant>V4L2_PIX_FMT_BGR24</constant></entry>
<entry>'BGR3'</entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-RGB24">
<entry><constant>V4L2_PIX_FMT_RGB24</constant></entry>
<entry>'RGB3'</entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-BGR666">
<entry><constant>V4L2_PIX_FMT_BGR666</constant></entry>
<entry>'BGRH'</entry>
<entry></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry></entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
</row>
<row id="V4L2-PIX-FMT-ABGR32">
<entry><constant>V4L2_PIX_FMT_ABGR32</constant></entry>
<entry>'AR24'</entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry>a<subscript>7</subscript></entry>
<entry>a<subscript>6</subscript></entry>
<entry>a<subscript>5</subscript></entry>
<entry>a<subscript>4</subscript></entry>
<entry>a<subscript>3</subscript></entry>
<entry>a<subscript>2</subscript></entry>
<entry>a<subscript>1</subscript></entry>
<entry>a<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-XBGR32">
<entry><constant>V4L2_PIX_FMT_XBGR32</constant></entry>
<entry>'XR24'</entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
</row>
<row id="V4L2-PIX-FMT-ARGB32">
<entry><constant>V4L2_PIX_FMT_ARGB32</constant></entry>
<entry>'BA24'</entry>
<entry></entry>
<entry>a<subscript>7</subscript></entry>
<entry>a<subscript>6</subscript></entry>
<entry>a<subscript>5</subscript></entry>
<entry>a<subscript>4</subscript></entry>
<entry>a<subscript>3</subscript></entry>
<entry>a<subscript>2</subscript></entry>
<entry>a<subscript>1</subscript></entry>
<entry>a<subscript>0</subscript></entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-XRGB32">
<entry><constant>V4L2_PIX_FMT_XRGB32</constant></entry>
<entry>'BX24'</entry>
<entry></entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry>-</entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
</tbody>
</tgroup>
</table>
<para>Bit 7 is the most significant bit.</para>
<para>The usage and value of the alpha bits (a) in the ARGB and ABGR formats
(collectively referred to as alpha formats) depend on the device type and
hardware operation. <link linkend="capture">Capture</link> devices
(including capture queues of mem-to-mem devices) fill the alpha component in
memory. When the device outputs an alpha channel the alpha component will
have a meaningful value. Otherwise, when the device doesn't output an alpha
channel but can set the alpha bit to a user-configurable value, the <link
linkend="v4l2-alpha-component"><constant>V4L2_CID_ALPHA_COMPONENT</constant>
</link> control is used to specify that alpha value, and the alpha component
of all pixels will be set to the value specified by that control. Otherwise
a corresponding format without an alpha component (XRGB or XBGR) must be
used instead of an alpha format.</para>
<para><link linkend="output">Output</link> devices (including output queues
of mem-to-mem devices and <link linkend="osd">video output overlay</link>
devices) read the alpha component from memory. When the device processes the
alpha channel the alpha component must be filled with meaningful values by
applications. Otherwise a corresponding format without an alpha component
(XRGB or XBGR) must be used instead of an alpha format.</para>
<para>The XRGB and XBGR formats contain undefined bits (-). Applications,
devices and drivers must ignore those bits, for both <link
linkend="capture">capture</link> and <link linkend="output">output</link>
devices.</para>
<example>
<title><constant>V4L2_PIX_FMT_BGR24</constant> 4 &times; 4 pixel
image</title>
<formalpara>
<title>Byte Order.</title>
<para>Each cell is one byte.
<informaltable frame="none">
<tgroup cols="13" align="center">
<colspec align="left" colwidth="2*" />
<tbody valign="top">
<row>
<entry>start&nbsp;+&nbsp;0:</entry>
<entry>B<subscript>00</subscript></entry>
<entry>G<subscript>00</subscript></entry>
<entry>R<subscript>00</subscript></entry>
<entry>B<subscript>01</subscript></entry>
<entry>G<subscript>01</subscript></entry>
<entry>R<subscript>01</subscript></entry>
<entry>B<subscript>02</subscript></entry>
<entry>G<subscript>02</subscript></entry>
<entry>R<subscript>02</subscript></entry>
<entry>B<subscript>03</subscript></entry>
<entry>G<subscript>03</subscript></entry>
<entry>R<subscript>03</subscript></entry>
</row>
<row>
<entry>start&nbsp;+&nbsp;12:</entry>
<entry>B<subscript>10</subscript></entry>
<entry>G<subscript>10</subscript></entry>
<entry>R<subscript>10</subscript></entry>
<entry>B<subscript>11</subscript></entry>
<entry>G<subscript>11</subscript></entry>
<entry>R<subscript>11</subscript></entry>
<entry>B<subscript>12</subscript></entry>
<entry>G<subscript>12</subscript></entry>
<entry>R<subscript>12</subscript></entry>
<entry>B<subscript>13</subscript></entry>
<entry>G<subscript>13</subscript></entry>
<entry>R<subscript>13</subscript></entry>
</row>
<row>
<entry>start&nbsp;+&nbsp;24:</entry>
<entry>B<subscript>20</subscript></entry>
<entry>G<subscript>20</subscript></entry>
<entry>R<subscript>20</subscript></entry>
<entry>B<subscript>21</subscript></entry>
<entry>G<subscript>21</subscript></entry>
<entry>R<subscript>21</subscript></entry>
<entry>B<subscript>22</subscript></entry>
<entry>G<subscript>22</subscript></entry>
<entry>R<subscript>22</subscript></entry>
<entry>B<subscript>23</subscript></entry>
<entry>G<subscript>23</subscript></entry>
<entry>R<subscript>23</subscript></entry>
</row>
<row>
<entry>start&nbsp;+&nbsp;36:</entry>
<entry>B<subscript>30</subscript></entry>
<entry>G<subscript>30</subscript></entry>
<entry>R<subscript>30</subscript></entry>
<entry>B<subscript>31</subscript></entry>
<entry>G<subscript>31</subscript></entry>
<entry>R<subscript>31</subscript></entry>
<entry>B<subscript>32</subscript></entry>
<entry>G<subscript>32</subscript></entry>
<entry>R<subscript>32</subscript></entry>
<entry>B<subscript>33</subscript></entry>
<entry>G<subscript>33</subscript></entry>
<entry>R<subscript>33</subscript></entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</formalpara>
</example>
<para>Formats defined in <xref linkend="rgb-formats-deprecated"/> are
deprecated and must not be used by new drivers. They are documented here for
reference. The meaning of their alpha bits (a) is ill-defined and
interpreted as in either the corresponding ARGB or XRGB format, depending on
the driver.</para>
<table pgwide="1" frame="none" id="rgb-formats-deprecated">
<title>Deprecated Packed RGB Image Formats</title>
<tgroup cols="37" align="center">
<colspec colname="id" align="left" />
<colspec colname="fourcc" />
<colspec colname="bit" />
<colspec colnum="4" colname="b07" align="center" />
<colspec colnum="5" colname="b06" align="center" />
<colspec colnum="6" colname="b05" align="center" />
<colspec colnum="7" colname="b04" align="center" />
<colspec colnum="8" colname="b03" align="center" />
<colspec colnum="9" colname="b02" align="center" />
<colspec colnum="10" colname="b01" align="center" />
<colspec colnum="11" colname="b00" align="center" />
<colspec colnum="13" colname="b17" align="center" />
<colspec colnum="14" colname="b16" align="center" />
<colspec colnum="15" colname="b15" align="center" />
<colspec colnum="16" colname="b14" align="center" />
<colspec colnum="17" colname="b13" align="center" />
<colspec colnum="18" colname="b12" align="center" />
<colspec colnum="19" colname="b11" align="center" />
<colspec colnum="20" colname="b10" align="center" />
<colspec colnum="22" colname="b27" align="center" />
<colspec colnum="23" colname="b26" align="center" />
<colspec colnum="24" colname="b25" align="center" />
<colspec colnum="25" colname="b24" align="center" />
<colspec colnum="26" colname="b23" align="center" />
<colspec colnum="27" colname="b22" align="center" />
<colspec colnum="28" colname="b21" align="center" />
<colspec colnum="29" colname="b20" align="center" />
<colspec colnum="31" colname="b37" align="center" />
<colspec colnum="32" colname="b36" align="center" />
<colspec colnum="33" colname="b35" align="center" />
<colspec colnum="34" colname="b34" align="center" />
<colspec colnum="35" colname="b33" align="center" />
<colspec colnum="36" colname="b32" align="center" />
<colspec colnum="37" colname="b31" align="center" />
<colspec colnum="38" colname="b30" align="center" />
<spanspec namest="b07" nameend="b00" spanname="b0" />
<spanspec namest="b17" nameend="b10" spanname="b1" />
<spanspec namest="b27" nameend="b20" spanname="b2" />
<spanspec namest="b37" nameend="b30" spanname="b3" />
<thead>
<row>
<entry>Identifier</entry>
<entry>Code</entry>
<entry>&nbsp;</entry>
<entry spanname="b0">Byte&nbsp;0 in memory</entry>
<entry spanname="b1">Byte&nbsp;1</entry>
<entry spanname="b2">Byte&nbsp;2</entry>
<entry spanname="b3">Byte&nbsp;3</entry>
</row>
<row>
<entry>&nbsp;</entry>
<entry>&nbsp;</entry>
<entry>Bit</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
<entry>&nbsp;</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
<entry>&nbsp;</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
<entry>&nbsp;</entry>
<entry>7</entry>
<entry>6</entry>
<entry>5</entry>
<entry>4</entry>
<entry>3</entry>
<entry>2</entry>
<entry>1</entry>
<entry>0</entry>
</row>
</thead>
<tbody>
<row id="V4L2-PIX-FMT-RGB444">
<entry><constant>V4L2_PIX_FMT_RGB444</constant></entry>
<entry>'R444'</entry>
<entry></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>a<subscript>3</subscript></entry>
<entry>a<subscript>2</subscript></entry>
<entry>a<subscript>1</subscript></entry>
<entry>a<subscript>0</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-RGB555">
<entry><constant>V4L2_PIX_FMT_RGB555</constant></entry>
<entry>'RGBO'</entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>a</entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-RGB555X">
<entry><constant>V4L2_PIX_FMT_RGB555X</constant></entry>
<entry>'RGBQ'</entry>
<entry></entry>
<entry>a</entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-BGR32">
<entry><constant>V4L2_PIX_FMT_BGR32</constant></entry>
<entry>'BGR4'</entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry>a<subscript>7</subscript></entry>
<entry>a<subscript>6</subscript></entry>
<entry>a<subscript>5</subscript></entry>
<entry>a<subscript>4</subscript></entry>
<entry>a<subscript>3</subscript></entry>
<entry>a<subscript>2</subscript></entry>
<entry>a<subscript>1</subscript></entry>
<entry>a<subscript>0</subscript></entry>
</row>
<row id="V4L2-PIX-FMT-RGB32">
<entry><constant>V4L2_PIX_FMT_RGB32</constant></entry>
<entry>'RGB4'</entry>
<entry></entry>
<entry>a<subscript>7</subscript></entry>
<entry>a<subscript>6</subscript></entry>
<entry>a<subscript>5</subscript></entry>
<entry>a<subscript>4</subscript></entry>
<entry>a<subscript>3</subscript></entry>
<entry>a<subscript>2</subscript></entry>
<entry>a<subscript>1</subscript></entry>
<entry>a<subscript>0</subscript></entry>
<entry></entry>
<entry>r<subscript>7</subscript></entry>
<entry>r<subscript>6</subscript></entry>
<entry>r<subscript>5</subscript></entry>
<entry>r<subscript>4</subscript></entry>
<entry>r<subscript>3</subscript></entry>
<entry>r<subscript>2</subscript></entry>
<entry>r<subscript>1</subscript></entry>
<entry>r<subscript>0</subscript></entry>
<entry></entry>
<entry>g<subscript>7</subscript></entry>
<entry>g<subscript>6</subscript></entry>
<entry>g<subscript>5</subscript></entry>
<entry>g<subscript>4</subscript></entry>
<entry>g<subscript>3</subscript></entry>
<entry>g<subscript>2</subscript></entry>
<entry>g<subscript>1</subscript></entry>
<entry>g<subscript>0</subscript></entry>
<entry></entry>
<entry>b<subscript>7</subscript></entry>
<entry>b<subscript>6</subscript></entry>
<entry>b<subscript>5</subscript></entry>
<entry>b<subscript>4</subscript></entry>
<entry>b<subscript>3</subscript></entry>
<entry>b<subscript>2</subscript></entry>
<entry>b<subscript>1</subscript></entry>
<entry>b<subscript>0</subscript></entry>
</row>
</tbody>
</tgroup>
</table>
<para>A test utility to determine which RGB formats a driver
actually supports is available from the LinuxTV v4l-dvb repository.
See &v4l-dvb; for access instructions.</para>
</refsect1>
</refentry>
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