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Based on kernel version 3.13. Page generated on 2014-01-20 22:02 EST.

1	  <title>Image Formats</title>
2	
3	  <para>The V4L2 API was primarily designed for devices exchanging
4	image data with applications. The
5	<structname>v4l2_pix_format</structname> and <structname>v4l2_pix_format_mplane
6	</structname> structures define the format and layout of an image in memory.
7	The former is used with the single-planar API, while the latter is used with the
8	multi-planar version (see <xref linkend="planar-apis"/>). Image formats are
9	negotiated with the &VIDIOC-S-FMT; ioctl. (The explanations here focus on video
10	capturing and output, for overlay frame buffer formats see also
11	&VIDIOC-G-FBUF;.)</para>
12	
13	<section>
14	  <title>Single-planar format structure</title>
15	  <table pgwide="1" frame="none" id="v4l2-pix-format">
16	    <title>struct <structname>v4l2_pix_format</structname></title>
17	    <tgroup cols="3">
18	      &cs-str;
19	      <tbody valign="top">
20		<row>
21		  <entry>__u32</entry>
22		  <entry><structfield>width</structfield></entry>
23		  <entry>Image width in pixels.</entry>
24		</row>
25		<row>
26		  <entry>__u32</entry>
27		  <entry><structfield>height</structfield></entry>
28		  <entry>Image height in pixels.</entry>
29		</row>
30		<row>
31		  <entry spanname="hspan">Applications set these fields to
32	request an image size, drivers return the closest possible values. In
33	case of planar formats the <structfield>width</structfield> and
34	<structfield>height</structfield> applies to the largest plane. To
35	avoid ambiguities drivers must return values rounded up to a multiple
36	of the scale factor of any smaller planes. For example when the image
37	format is YUV 4:2:0, <structfield>width</structfield> and
38	<structfield>height</structfield> must be multiples of two.</entry>
39		</row>
40		<row>
41		  <entry>__u32</entry>
42		  <entry><structfield>pixelformat</structfield></entry>
43		  <entry>The pixel format or type of compression, set by the
44	application. This is a little endian <link
45	linkend="v4l2-fourcc">four character code</link>. V4L2 defines
46	standard RGB formats in <xref linkend="rgb-formats" />, YUV formats in <xref
47	linkend="yuv-formats" />, and reserved codes in <xref
48	linkend="reserved-formats" /></entry>
49		</row>
50		<row>
51		  <entry>&v4l2-field;</entry>
52		  <entry><structfield>field</structfield></entry>
53		  <entry>Video images are typically interlaced. Applications
54	can request to capture or output only the top or bottom field, or both
55	fields interlaced or sequentially stored in one buffer or alternating
56	in separate buffers. Drivers return the actual field order selected.
57	For details see <xref linkend="field-order" />.</entry>
58		</row>
59		<row>
60		  <entry>__u32</entry>
61		  <entry><structfield>bytesperline</structfield></entry>
62		  <entry>Distance in bytes between the leftmost pixels in two
63	adjacent lines.</entry>
64		</row>
65		<row>
66		  <entry spanname="hspan"><para>Both applications and drivers
67	can set this field to request padding bytes at the end of each line.
68	Drivers however may ignore the value requested by the application,
69	returning <structfield>width</structfield> times bytes per pixel or a
70	larger value required by the hardware. That implies applications can
71	just set this field to zero to get a reasonable
72	default.</para><para>Video hardware may access padding bytes,
73	therefore they must reside in accessible memory. Consider cases where
74	padding bytes after the last line of an image cross a system page
75	boundary. Input devices may write padding bytes, the value is
76	undefined. Output devices ignore the contents of padding
77	bytes.</para><para>When the image format is planar the
78	<structfield>bytesperline</structfield> value applies to the largest
79	plane and is divided by the same factor as the
80	<structfield>width</structfield> field for any smaller planes. For
81	example the Cb and Cr planes of a YUV 4:2:0 image have half as many
82	padding bytes following each line as the Y plane. To avoid ambiguities
83	drivers must return a <structfield>bytesperline</structfield> value
84	rounded up to a multiple of the scale factor.</para></entry>
85		</row>
86		<row>
87		  <entry>__u32</entry>
88		  <entry><structfield>sizeimage</structfield></entry>
89		  <entry>Size in bytes of the buffer to hold a complete image,
90	set by the driver. Usually this is
91	<structfield>bytesperline</structfield> times
92	<structfield>height</structfield>. When the image consists of variable
93	length compressed data this is the maximum number of bytes required to
94	hold an image.</entry>
95		</row>
96		<row>
97		  <entry>&v4l2-colorspace;</entry>
98		  <entry><structfield>colorspace</structfield></entry>
99		  <entry>This information supplements the
100	<structfield>pixelformat</structfield> and must be set by the driver,
101	see <xref linkend="colorspaces" />.</entry>
102		</row>
103		<row>
104		  <entry>__u32</entry>
105		  <entry><structfield>priv</structfield></entry>
106		  <entry>Reserved for custom (driver defined) additional
107	information about formats. When not used drivers and applications must
108	set this field to zero.</entry>
109		</row>
110	      </tbody>
111	    </tgroup>
112	  </table>
113	</section>
114	
115	<section>
116	  <title>Multi-planar format structures</title>
117	  <para>The <structname>v4l2_plane_pix_format</structname> structures define
118	    size and layout for each of the planes in a multi-planar format.
119	    The <structname>v4l2_pix_format_mplane</structname> structure contains
120	    information common to all planes (such as image width and height) and
121	    an array of <structname>v4l2_plane_pix_format</structname> structures,
122	    describing all planes of that format.</para>
123	  <table pgwide="1" frame="none" id="v4l2-plane-pix-format">
124	    <title>struct <structname>v4l2_plane_pix_format</structname></title>
125	    <tgroup cols="3">
126	      &cs-str;
127	      <tbody valign="top">
128	        <row>
129	          <entry>__u32</entry>
130	          <entry><structfield>sizeimage</structfield></entry>
131	          <entry>Maximum size in bytes required for image data in this plane.
132	          </entry>
133	        </row>
134	        <row>
135	          <entry>__u16</entry>
136	          <entry><structfield>bytesperline</structfield></entry>
137	          <entry>Distance in bytes between the leftmost pixels in two adjacent
138	            lines.</entry>
139	        </row>
140	        <row>
141	          <entry>__u16</entry>
142	          <entry><structfield>reserved[7]</structfield></entry>
143	          <entry>Reserved for future extensions. Should be zeroed by the
144	           application.</entry>
145	        </row>
146	      </tbody>
147	    </tgroup>
148	  </table>
149	  <table pgwide="1" frame="none" id="v4l2-pix-format-mplane">
150	    <title>struct <structname>v4l2_pix_format_mplane</structname></title>
151	    <tgroup cols="3">
152	      &cs-str;
153	      <tbody valign="top">
154	        <row>
155	          <entry>__u32</entry>
156	          <entry><structfield>width</structfield></entry>
157	          <entry>Image width in pixels.</entry>
158	        </row>
159	        <row>
160	          <entry>__u32</entry>
161	          <entry><structfield>height</structfield></entry>
162	          <entry>Image height in pixels.</entry>
163	        </row>
164	        <row>
165	          <entry>__u32</entry>
166	          <entry><structfield>pixelformat</structfield></entry>
167	          <entry>The pixel format. Both single- and multi-planar four character
168	codes can be used.</entry>
169	        </row>
170	        <row>
171	          <entry>&v4l2-field;</entry>
172	          <entry><structfield>field</structfield></entry>
173	          <entry>See &v4l2-pix-format;.</entry>
174	        </row>
175	        <row>
176	          <entry>&v4l2-colorspace;</entry>
177	          <entry><structfield>colorspace</structfield></entry>
178	          <entry>See &v4l2-pix-format;.</entry>
179	        </row>
180	        <row>
181	          <entry>&v4l2-plane-pix-format;</entry>
182	          <entry><structfield>plane_fmt[VIDEO_MAX_PLANES]</structfield></entry>
183	          <entry>An array of structures describing format of each plane this
184	          pixel format consists of. The number of valid entries in this array
185	          has to be put in the <structfield>num_planes</structfield>
186	          field.</entry>
187	        </row>
188	        <row>
189	          <entry>__u8</entry>
190	          <entry><structfield>num_planes</structfield></entry>
191	          <entry>Number of planes (i.e. separate memory buffers) for this format
192	          and the number of valid entries in the
193	          <structfield>plane_fmt</structfield> array.</entry>
194	        </row>
195	        <row>
196	          <entry>__u8</entry>
197	          <entry><structfield>reserved[11]</structfield></entry>
198	          <entry>Reserved for future extensions. Should be zeroed by the
199	           application.</entry>
200	        </row>
201	      </tbody>
202	    </tgroup>
203	  </table>
204	</section>
205	
206	  <section>
207	    <title>Standard Image Formats</title>
208	
209	    <para>In order to exchange images between drivers and
210	applications, it is necessary to have standard image data formats
211	which both sides will interpret the same way. V4L2 includes several
212	such formats, and this section is intended to be an unambiguous
213	specification of the standard image data formats in V4L2.</para>
214	
215	    <para>V4L2 drivers are not limited to these formats, however.
216	Driver-specific formats are possible. In that case the application may
217	depend on a codec to convert images to one of the standard formats
218	when needed. But the data can still be stored and retrieved in the
219	proprietary format. For example, a device may support a proprietary
220	compressed format. Applications can still capture and save the data in
221	the compressed format, saving much disk space, and later use a codec
222	to convert the images to the X Windows screen format when the video is
223	to be displayed.</para>
224	
225	    <para>Even so, ultimately, some standard formats are needed, so
226	the V4L2 specification would not be complete without well-defined
227	standard formats.</para>
228	
229	    <para>The V4L2 standard formats are mainly uncompressed formats. The
230	pixels are always arranged in memory from left to right, and from top
231	to bottom. The first byte of data in the image buffer is always for
232	the leftmost pixel of the topmost row. Following that is the pixel
233	immediately to its right, and so on until the end of the top row of
234	pixels. Following the rightmost pixel of the row there may be zero or
235	more bytes of padding to guarantee that each row of pixel data has a
236	certain alignment. Following the pad bytes, if any, is data for the
237	leftmost pixel of the second row from the top, and so on. The last row
238	has just as many pad bytes after it as the other rows.</para>
239	
240	    <para>In V4L2 each format has an identifier which looks like
241	<constant>PIX_FMT_XXX</constant>, defined in the <link
242	linkend="videodev">videodev.h</link> header file. These identifiers
243	represent <link linkend="v4l2-fourcc">four character (FourCC) codes</link>
244	which are also listed below, however they are not the same as those
245	used in the Windows world.</para>
246	
247	    <para>For some formats, data is stored in separate, discontiguous
248	memory buffers. Those formats are identified by a separate set of FourCC codes
249	and are referred to as "multi-planar formats". For example, a YUV422 frame is
250	normally stored in one memory buffer, but it can also be placed in two or three
251	separate buffers, with Y component in one buffer and CbCr components in another
252	in the 2-planar version or with each component in its own buffer in the
253	3-planar case. Those sub-buffers are referred to as "planes".</para>
254	  </section>
255	
256	  <section id="colorspaces">
257	    <title>Colorspaces</title>
258	
259	    <para>[intro]</para>
260	
261	    <!-- See proposal by Billy Biggs, video4linux-list@redhat.com
262	on 11 Oct 2002, subject: "Re: [V4L] Re: v4l2 api", and
263	http://vektor.theorem.ca/graphics/ycbcr/ and
264	http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html -->
265	
266	    <para>
267	      <variablelist>
268		<varlistentry>
269		  <term>Gamma Correction</term>
270		  <listitem>
271		    <para>[to do]</para>
272		    <para>E'<subscript>R</subscript> = f(R)</para>
273		    <para>E'<subscript>G</subscript> = f(G)</para>
274		    <para>E'<subscript>B</subscript> = f(B)</para>
275		  </listitem>
276		</varlistentry>
277		<varlistentry>
278		  <term>Construction of luminance and color-difference
279	signals</term>
280		  <listitem>
281		    <para>[to do]</para>
282		    <para>E'<subscript>Y</subscript> =
283	Coeff<subscript>R</subscript> E'<subscript>R</subscript>
284	+ Coeff<subscript>G</subscript> E'<subscript>G</subscript>
285	+ Coeff<subscript>B</subscript> E'<subscript>B</subscript></para>
286		    <para>(E'<subscript>R</subscript> - E'<subscript>Y</subscript>) = E'<subscript>R</subscript>
287	- Coeff<subscript>R</subscript> E'<subscript>R</subscript>
288	- Coeff<subscript>G</subscript> E'<subscript>G</subscript>
289	- Coeff<subscript>B</subscript> E'<subscript>B</subscript></para>
290		    <para>(E'<subscript>B</subscript> - E'<subscript>Y</subscript>) = E'<subscript>B</subscript>
291	- Coeff<subscript>R</subscript> E'<subscript>R</subscript>
292	- Coeff<subscript>G</subscript> E'<subscript>G</subscript>
293	- Coeff<subscript>B</subscript> E'<subscript>B</subscript></para>
294		  </listitem>
295		</varlistentry>
296		<varlistentry>
297		  <term>Re-normalized color-difference signals</term>
298		  <listitem>
299		    <para>The color-difference signals are scaled back to unity
300	range [-0.5;+0.5]:</para>
301		    <para>K<subscript>B</subscript> = 0.5 / (1 - Coeff<subscript>B</subscript>)</para>
302		    <para>K<subscript>R</subscript> = 0.5 / (1 - Coeff<subscript>R</subscript>)</para>
303		    <para>P<subscript>B</subscript> =
304	K<subscript>B</subscript> (E'<subscript>B</subscript> - E'<subscript>Y</subscript>) =
305	  0.5 (Coeff<subscript>R</subscript> / Coeff<subscript>B</subscript>) E'<subscript>R</subscript>
306	+ 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>B</subscript>) E'<subscript>G</subscript>
307	+ 0.5 E'<subscript>B</subscript></para>
308		    <para>P<subscript>R</subscript> =
309	K<subscript>R</subscript> (E'<subscript>R</subscript> - E'<subscript>Y</subscript>) =
310	  0.5 E'<subscript>R</subscript>
311	+ 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>R</subscript>) E'<subscript>G</subscript>
312	+ 0.5 (Coeff<subscript>B</subscript> / Coeff<subscript>R</subscript>) E'<subscript>B</subscript></para>
313		  </listitem>
314		</varlistentry>
315		<varlistentry>
316		  <term>Quantization</term>
317		  <listitem>
318		    <para>[to do]</para>
319		    <para>Y' = (Lum. Levels - 1) &middot; E'<subscript>Y</subscript> + Lum. Offset</para>
320		    <para>C<subscript>B</subscript> = (Chrom. Levels - 1)
321	&middot; P<subscript>B</subscript> + Chrom. Offset</para>
322		    <para>C<subscript>R</subscript> = (Chrom. Levels - 1)
323	&middot; P<subscript>R</subscript> + Chrom. Offset</para>
324		    <para>Rounding to the nearest integer and clamping to the range
325	[0;255] finally yields the digital color components Y'CbCr
326	stored in YUV images.</para>
327		  </listitem>
328		</varlistentry>
329	      </variablelist>
330	    </para>
331	
332	    <example>
333	      <title>ITU-R Rec. BT.601 color conversion</title>
334	
335	      <para>Forward Transformation</para>
336	
337	      <programlisting>
338	int ER, EG, EB;         /* gamma corrected RGB input [0;255] */
339	int Y1, Cb, Cr;         /* output [0;255] */
340	
341	double r, g, b;         /* temporaries */
342	double y1, pb, pr;
343	
344	int
345	clamp (double x)
346	{
347		int r = x;      /* round to nearest */
348	
349		if (r &lt; 0)         return 0;
350		else if (r &gt; 255)  return 255;
351		else               return r;
352	}
353	
354	r = ER / 255.0;
355	g = EG / 255.0;
356	b = EB / 255.0;
357	
358	y1  =  0.299  * r + 0.587 * g + 0.114  * b;
359	pb  = -0.169  * r - 0.331 * g + 0.5    * b;
360	pr  =  0.5    * r - 0.419 * g - 0.081  * b;
361	
362	Y1 = clamp (219 * y1 + 16);
363	Cb = clamp (224 * pb + 128);
364	Cr = clamp (224 * pr + 128);
365	
366	/* or shorter */
367	
368	y1 = 0.299 * ER + 0.587 * EG + 0.114 * EB;
369	
370	Y1 = clamp ( (219 / 255.0)                    *       y1  + 16);
371	Cb = clamp (((224 / 255.0) / (2 - 2 * 0.114)) * (EB - y1) + 128);
372	Cr = clamp (((224 / 255.0) / (2 - 2 * 0.299)) * (ER - y1) + 128);
373	      </programlisting>
374	
375	      <para>Inverse Transformation</para>
376	
377	      <programlisting>
378	int Y1, Cb, Cr;         /* gamma pre-corrected input [0;255] */
379	int ER, EG, EB;         /* output [0;255] */
380	
381	double r, g, b;         /* temporaries */
382	double y1, pb, pr;
383	
384	int
385	clamp (double x)
386	{
387		int r = x;      /* round to nearest */
388	
389		if (r &lt; 0)         return 0;
390		else if (r &gt; 255)  return 255;
391		else               return r;
392	}
393	
394	y1 = (Y1 - 16) / 219.0;
395	pb = (Cb - 128) / 224.0;
396	pr = (Cr - 128) / 224.0;
397	
398	r = 1.0 * y1 + 0     * pb + 1.402 * pr;
399	g = 1.0 * y1 - 0.344 * pb - 0.714 * pr;
400	b = 1.0 * y1 + 1.772 * pb + 0     * pr;
401	
402	ER = clamp (r * 255); /* [ok? one should prob. limit y1,pb,pr] */
403	EG = clamp (g * 255);
404	EB = clamp (b * 255);
405	      </programlisting>
406	    </example>
407	
408	    <table pgwide="1" id="v4l2-colorspace" orient="land">
409	      <title>enum v4l2_colorspace</title>
410	      <tgroup cols="11" align="center">
411		<colspec align="left" />
412		<colspec align="center" />
413		<colspec align="left" />
414		<colspec colname="cr" />
415		<colspec colname="cg" />
416		<colspec colname="cb" />
417		<colspec colname="wp" />
418		<colspec colname="gc" />
419		<colspec colname="lum" />
420		<colspec colname="qy" />
421		<colspec colname="qc" />
422		<spanspec namest="cr" nameend="cb" spanname="chrom" />
423		<spanspec namest="qy" nameend="qc" spanname="quant" />
424		<spanspec namest="lum" nameend="qc" spanname="spam" />
425		<thead>
426		  <row>
427		    <entry morerows="1">Identifier</entry>
428		    <entry morerows="1">Value</entry>
429		    <entry morerows="1">Description</entry>
430		    <entry spanname="chrom">Chromaticities<footnote>
431			<para>The coordinates of the color primaries are
432	given in the CIE system (1931)</para>
433		      </footnote></entry>
434		    <entry morerows="1">White Point</entry>
435		    <entry morerows="1">Gamma Correction</entry>
436		    <entry morerows="1">Luminance E'<subscript>Y</subscript></entry>
437		    <entry spanname="quant">Quantization</entry>
438		  </row>
439		  <row>
440		    <entry>Red</entry>
441		    <entry>Green</entry>
442		    <entry>Blue</entry>
443		    <entry>Y'</entry>
444		    <entry>Cb, Cr</entry>
445		  </row>
446		</thead>
447		<tbody valign="top">
448		  <row>
449		    <entry><constant>V4L2_COLORSPACE_SMPTE170M</constant></entry>
450		    <entry>1</entry>
451		    <entry>NTSC/PAL according to <xref linkend="smpte170m" />,
452	<xref linkend="itu601" /></entry>
453		    <entry>x&nbsp;=&nbsp;0.630, y&nbsp;=&nbsp;0.340</entry>
454		    <entry>x&nbsp;=&nbsp;0.310, y&nbsp;=&nbsp;0.595</entry>
455		    <entry>x&nbsp;=&nbsp;0.155, y&nbsp;=&nbsp;0.070</entry>
456		    <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
457		    Illuminant D<subscript>65</subscript></entry>
458		    <entry>E' = 4.5&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.018,
459	1.099&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.099&nbsp;for&nbsp;0.018&nbsp;&lt;&nbsp;I</entry>
460		    <entry>0.299&nbsp;E'<subscript>R</subscript>
461	+&nbsp;0.587&nbsp;E'<subscript>G</subscript>
462	+&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
463		    <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
464		    <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
465		  </row>
466		  <row>
467		    <entry><constant>V4L2_COLORSPACE_SMPTE240M</constant></entry>
468		    <entry>2</entry>
469		    <entry>1125-Line (US) HDTV, see <xref
470	linkend="smpte240m" /></entry>
471		    <entry>x&nbsp;=&nbsp;0.630, y&nbsp;=&nbsp;0.340</entry>
472		    <entry>x&nbsp;=&nbsp;0.310, y&nbsp;=&nbsp;0.595</entry>
473		    <entry>x&nbsp;=&nbsp;0.155, y&nbsp;=&nbsp;0.070</entry>
474		    <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
475		    Illuminant D<subscript>65</subscript></entry>
476		    <entry>E' = 4&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.0228,
477	1.1115&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.1115&nbsp;for&nbsp;0.0228&nbsp;&lt;&nbsp;I</entry>
478		    <entry>0.212&nbsp;E'<subscript>R</subscript>
479	+&nbsp;0.701&nbsp;E'<subscript>G</subscript>
480	+&nbsp;0.087&nbsp;E'<subscript>B</subscript></entry>
481		    <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
482		    <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
483		  </row>
484		  <row>
485		    <entry><constant>V4L2_COLORSPACE_REC709</constant></entry>
486		    <entry>3</entry>
487		    <entry>HDTV and modern devices, see <xref
488	linkend="itu709" /></entry>
489		    <entry>x&nbsp;=&nbsp;0.640, y&nbsp;=&nbsp;0.330</entry>
490		    <entry>x&nbsp;=&nbsp;0.300, y&nbsp;=&nbsp;0.600</entry>
491		    <entry>x&nbsp;=&nbsp;0.150, y&nbsp;=&nbsp;0.060</entry>
492		    <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
493		    Illuminant D<subscript>65</subscript></entry>
494		    <entry>E' = 4.5&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.018,
495	1.099&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.099&nbsp;for&nbsp;0.018&nbsp;&lt;&nbsp;I</entry>
496		    <entry>0.2125&nbsp;E'<subscript>R</subscript>
497	+&nbsp;0.7154&nbsp;E'<subscript>G</subscript>
498	+&nbsp;0.0721&nbsp;E'<subscript>B</subscript></entry>
499		    <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
500		    <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
501		  </row>
502		  <row>
503		    <entry><constant>V4L2_COLORSPACE_BT878</constant></entry>
504		    <entry>4</entry>
505		    <entry>Broken Bt878 extents<footnote>
506			<para>The ubiquitous Bt878 video capture chip
507	quantizes E'<subscript>Y</subscript> to 238 levels, yielding a range
508	of Y' = 16 &hellip; 253, unlike Rec. 601 Y' = 16 &hellip;
509	235. This is not a typo in the Bt878 documentation, it has been
510	implemented in silicon. The chroma extents are unclear.</para>
511		      </footnote>, <xref linkend="itu601" /></entry>
512		    <entry>?</entry>
513		    <entry>?</entry>
514		    <entry>?</entry>
515		    <entry>?</entry>
516		    <entry>?</entry>
517		    <entry>0.299&nbsp;E'<subscript>R</subscript>
518	+&nbsp;0.587&nbsp;E'<subscript>G</subscript>
519	+&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
520		    <entry><emphasis>237</emphasis>&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
521		    <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128 (probably)</entry>
522		  </row>
523		  <row>
524		    <entry><constant>V4L2_COLORSPACE_470_SYSTEM_M</constant></entry>
525		    <entry>5</entry>
526		    <entry>M/NTSC<footnote>
527			<para>No identifier exists for M/PAL which uses
528	the chromaticities of M/NTSC, the remaining parameters are equal to B and
529	G/PAL.</para>
530		      </footnote> according to <xref linkend="itu470" />, <xref
531			linkend="itu601" /></entry>
532		    <entry>x&nbsp;=&nbsp;0.67, y&nbsp;=&nbsp;0.33</entry>
533		    <entry>x&nbsp;=&nbsp;0.21, y&nbsp;=&nbsp;0.71</entry>
534		    <entry>x&nbsp;=&nbsp;0.14, y&nbsp;=&nbsp;0.08</entry>
535		    <entry>x&nbsp;=&nbsp;0.310, y&nbsp;=&nbsp;0.316, Illuminant C</entry>
536		    <entry>?</entry>
537		    <entry>0.299&nbsp;E'<subscript>R</subscript>
538	+&nbsp;0.587&nbsp;E'<subscript>G</subscript>
539	+&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
540		    <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
541		    <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
542		  </row>
543		  <row>
544		    <entry><constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant></entry>
545		    <entry>6</entry>
546		    <entry>625-line PAL and SECAM systems according to <xref
547	linkend="itu470" />, <xref linkend="itu601" /></entry>
548		    <entry>x&nbsp;=&nbsp;0.64, y&nbsp;=&nbsp;0.33</entry>
549		    <entry>x&nbsp;=&nbsp;0.29, y&nbsp;=&nbsp;0.60</entry>
550		    <entry>x&nbsp;=&nbsp;0.15, y&nbsp;=&nbsp;0.06</entry>
551		    <entry>x&nbsp;=&nbsp;0.313, y&nbsp;=&nbsp;0.329,
552	Illuminant D<subscript>65</subscript></entry>
553		    <entry>?</entry>
554		    <entry>0.299&nbsp;E'<subscript>R</subscript>
555	+&nbsp;0.587&nbsp;E'<subscript>G</subscript>
556	+&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
557		    <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
558		    <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
559		  </row>
560		  <row>
561		    <entry><constant>V4L2_COLORSPACE_JPEG</constant></entry>
562		    <entry>7</entry>
563		    <entry>JPEG Y'CbCr, see <xref linkend="jfif" />, <xref linkend="itu601" /></entry>
564		    <entry>?</entry>
565		    <entry>?</entry>
566		    <entry>?</entry>
567		    <entry>?</entry>
568		    <entry>?</entry>
569		    <entry>0.299&nbsp;E'<subscript>R</subscript>
570	+&nbsp;0.587&nbsp;E'<subscript>G</subscript>
571	+&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
572		    <entry>256&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16<footnote>
573			<para>Note JFIF quantizes
574	Y'P<subscript>B</subscript>P<subscript>R</subscript> in range [0;+1] and
575	[-0.5;+0.5] to <emphasis>257</emphasis> levels, however Y'CbCr signals
576	are still clamped to [0;255].</para>
577		      </footnote></entry>
578		    <entry>256&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
579		  </row>
580		  <row>
581		    <entry><constant>V4L2_COLORSPACE_SRGB</constant></entry>
582		    <entry>8</entry>
583		    <entry>[?]</entry>
584		    <entry>x&nbsp;=&nbsp;0.640, y&nbsp;=&nbsp;0.330</entry>
585		    <entry>x&nbsp;=&nbsp;0.300, y&nbsp;=&nbsp;0.600</entry>
586		    <entry>x&nbsp;=&nbsp;0.150, y&nbsp;=&nbsp;0.060</entry>
587		    <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
588		    Illuminant D<subscript>65</subscript></entry>
589		    <entry>E' = 4.5&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.018,
590	1.099&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.099&nbsp;for&nbsp;0.018&nbsp;&lt;&nbsp;I</entry>
591		    <entry spanname="spam">n/a</entry>
592		  </row>
593		</tbody>
594	      </tgroup>
595	    </table>
596	  </section>
597	
598	  <section id="pixfmt-indexed">
599	    <title>Indexed Format</title>
600	
601	    <para>In this format each pixel is represented by an 8 bit index
602	into a 256 entry ARGB palette. It is intended for <link
603	linkend="osd">Video Output Overlays</link> only. There are no ioctls to
604	access the palette, this must be done with ioctls of the Linux framebuffer API.</para>
605	
606	    <table pgwide="0" frame="none">
607	      <title>Indexed Image Format</title>
608	      <tgroup cols="37" align="center">
609		<colspec colname="id" align="left" />
610		<colspec colname="fourcc" />
611		<colspec colname="bit" />
612	
613		<colspec colnum="4" colname="b07" align="center" />
614		<colspec colnum="5" colname="b06" align="center" />
615		<colspec colnum="6" colname="b05" align="center" />
616		<colspec colnum="7" colname="b04" align="center" />
617		<colspec colnum="8" colname="b03" align="center" />
618		<colspec colnum="9" colname="b02" align="center" />
619		<colspec colnum="10" colname="b01" align="center" />
620		<colspec colnum="11" colname="b00" align="center" />
621	
622		<spanspec namest="b07" nameend="b00" spanname="b0" />
623		<spanspec namest="b17" nameend="b10" spanname="b1" />
624		<spanspec namest="b27" nameend="b20" spanname="b2" />
625		<spanspec namest="b37" nameend="b30" spanname="b3" />
626		<thead>
627		  <row>
628		    <entry>Identifier</entry>
629		    <entry>Code</entry>
630		    <entry>&nbsp;</entry>
631		    <entry spanname="b0">Byte&nbsp;0</entry>
632		  </row>
633		  <row>
634		    <entry>&nbsp;</entry>
635		    <entry>&nbsp;</entry>
636		    <entry>Bit</entry>
637		    <entry>7</entry>
638		    <entry>6</entry>
639		    <entry>5</entry>
640		    <entry>4</entry>
641		    <entry>3</entry>
642		    <entry>2</entry>
643		    <entry>1</entry>
644		    <entry>0</entry>
645		  </row>
646		</thead>
647		<tbody valign="top">
648		  <row id="V4L2-PIX-FMT-PAL8">
649		    <entry><constant>V4L2_PIX_FMT_PAL8</constant></entry>
650		    <entry>'PAL8'</entry>
651		    <entry></entry>
652		    <entry>i<subscript>7</subscript></entry>
653		    <entry>i<subscript>6</subscript></entry>
654		    <entry>i<subscript>5</subscript></entry>
655		    <entry>i<subscript>4</subscript></entry>
656		    <entry>i<subscript>3</subscript></entry>
657		    <entry>i<subscript>2</subscript></entry>
658		    <entry>i<subscript>1</subscript></entry>
659		    <entry>i<subscript>0</subscript></entry>
660		  </row>
661		</tbody>
662	      </tgroup>
663	    </table>
664	  </section>
665	
666	  <section id="pixfmt-rgb">
667	    <title>RGB Formats</title>
668	
669	    &sub-packed-rgb;
670	    &sub-sbggr8;
671	    &sub-sgbrg8;
672	    &sub-sgrbg8;
673	    &sub-srggb8;
674	    &sub-sbggr16;
675	    &sub-srggb10;
676	    &sub-srggb10alaw8;
677	    &sub-srggb10dpcm8;
678	    &sub-srggb12;
679	  </section>
680	
681	  <section id="yuv-formats">
682	    <title>YUV Formats</title>
683	
684	    <para>YUV is the format native to TV broadcast and composite video
685	signals. It separates the brightness information (Y) from the color
686	information (U and V or Cb and Cr). The color information consists of
687	red and blue <emphasis>color difference</emphasis> signals, this way
688	the green component can be reconstructed by subtracting from the
689	brightness component. See <xref linkend="colorspaces" /> for conversion
690	examples. YUV was chosen because early television would only transmit
691	brightness information. To add color in a way compatible with existing
692	receivers a new signal carrier was added to transmit the color
693	difference signals. Secondary in the YUV format the U and V components
694	usually have lower resolution than the Y component. This is an analog
695	video compression technique taking advantage of a property of the
696	human visual system, being more sensitive to brightness
697	information.</para>
698	
699	    &sub-packed-yuv;
700	    &sub-grey;
701	    &sub-y10;
702	    &sub-y12;
703	    &sub-y10b;
704	    &sub-y16;
705	    &sub-uv8;
706	    &sub-yuyv;
707	    &sub-uyvy;
708	    &sub-yvyu;
709	    &sub-vyuy;
710	    &sub-y41p;
711	    &sub-yuv420;
712	    &sub-yuv420m;
713	    &sub-yvu420m;
714	    &sub-yuv410;
715	    &sub-yuv422p;
716	    &sub-yuv411p;
717	    &sub-nv12;
718	    &sub-nv12m;
719	    &sub-nv12mt;
720	    &sub-nv16;
721	    &sub-nv16m;
722	    &sub-nv24;
723	    &sub-m420;
724	  </section>
725	
726	  <section>
727	    <title>Compressed Formats</title>
728	
729	    <table pgwide="1" frame="none" id="compressed-formats">
730	      <title>Compressed Image Formats</title>
731	      <tgroup cols="3" align="left">
732		&cs-def;
733		<thead>
734		  <row>
735		    <entry>Identifier</entry>
736		    <entry>Code</entry>
737		    <entry>Details</entry>
738		  </row>
739		</thead>
740		<tbody valign="top">
741		 <row id="V4L2-PIX-FMT-JPEG">
742		    <entry><constant>V4L2_PIX_FMT_JPEG</constant></entry>
743		    <entry>'JPEG'</entry>
744		    <entry>TBD. See also &VIDIOC-G-JPEGCOMP;,
745		    &VIDIOC-S-JPEGCOMP;.</entry>
746		  </row>
747		  <row id="V4L2-PIX-FMT-MPEG">
748		    <entry><constant>V4L2_PIX_FMT_MPEG</constant></entry>
749		    <entry>'MPEG'</entry>
750		    <entry>MPEG multiplexed stream. The actual format is determined by
751	extended control <constant>V4L2_CID_MPEG_STREAM_TYPE</constant>, see
752	<xref linkend="mpeg-control-id" />.</entry>
753		  </row>
754		  <row id="V4L2-PIX-FMT-H264">
755			<entry><constant>V4L2_PIX_FMT_H264</constant></entry>
756			<entry>'H264'</entry>
757			<entry>H264 video elementary stream with start codes.</entry>
758		  </row>
759		  <row id="V4L2-PIX-FMT-H264-NO-SC">
760			<entry><constant>V4L2_PIX_FMT_H264_NO_SC</constant></entry>
761			<entry>'AVC1'</entry>
762			<entry>H264 video elementary stream without start codes.</entry>
763		  </row>
764		  <row id="V4L2-PIX-FMT-H264-MVC">
765			<entry><constant>V4L2_PIX_FMT_H264_MVC</constant></entry>
766			<entry>'MVC'</entry>
767			<entry>H264 MVC video elementary stream.</entry>
768		  </row>
769		  <row id="V4L2-PIX-FMT-H263">
770			<entry><constant>V4L2_PIX_FMT_H263</constant></entry>
771			<entry>'H263'</entry>
772			<entry>H263 video elementary stream.</entry>
773		  </row>
774		  <row id="V4L2-PIX-FMT-MPEG1">
775			<entry><constant>V4L2_PIX_FMT_MPEG1</constant></entry>
776			<entry>'MPG1'</entry>
777			<entry>MPEG1 video elementary stream.</entry>
778		  </row>
779		  <row id="V4L2-PIX-FMT-MPEG2">
780			<entry><constant>V4L2_PIX_FMT_MPEG2</constant></entry>
781			<entry>'MPG2'</entry>
782			<entry>MPEG2 video elementary stream.</entry>
783		  </row>
784		  <row id="V4L2-PIX-FMT-MPEG4">
785			<entry><constant>V4L2_PIX_FMT_MPEG4</constant></entry>
786			<entry>'MPG4'</entry>
787			<entry>MPEG4 video elementary stream.</entry>
788		  </row>
789		  <row id="V4L2-PIX-FMT-XVID">
790			<entry><constant>V4L2_PIX_FMT_XVID</constant></entry>
791			<entry>'XVID'</entry>
792			<entry>Xvid video elementary stream.</entry>
793		  </row>
794		  <row id="V4L2-PIX-FMT-VC1-ANNEX-G">
795			<entry><constant>V4L2_PIX_FMT_VC1_ANNEX_G</constant></entry>
796			<entry>'VC1G'</entry>
797			<entry>VC1, SMPTE 421M Annex G compliant stream.</entry>
798		  </row>
799		  <row id="V4L2-PIX-FMT-VC1-ANNEX-L">
800			<entry><constant>V4L2_PIX_FMT_VC1_ANNEX_L</constant></entry>
801			<entry>'VC1L'</entry>
802			<entry>VC1, SMPTE 421M Annex L compliant stream.</entry>
803		  </row>
804		  <row id="V4L2-PIX-FMT-VP8">
805			<entry><constant>V4L2_PIX_FMT_VP8</constant></entry>
806			<entry>'VP8'</entry>
807			<entry>VP8 video elementary stream.</entry>
808		  </row>
809		</tbody>
810	      </tgroup>
811	    </table>
812	  </section>
813	
814	  <section id="pixfmt-reserved">
815	    <title>Reserved Format Identifiers</title>
816	
817	    <para>These formats are not defined by this specification, they
818	are just listed for reference and to avoid naming conflicts. If you
819	want to register your own format, send an e-mail to the linux-media mailing
820	list &v4l-ml; for inclusion in the <filename>videodev2.h</filename>
821	file. If you want to share your format with other developers add a
822	link to your documentation and send a copy to the linux-media mailing list
823	for inclusion in this section. If you think your format should be listed
824	in a standard format section please make a proposal on the linux-media mailing
825	list.</para>
826	
827	    <table pgwide="1" frame="none" id="reserved-formats">
828	      <title>Reserved Image Formats</title>
829	      <tgroup cols="3" align="left">
830		&cs-def;
831		<thead>
832		  <row>
833		    <entry>Identifier</entry>
834		    <entry>Code</entry>
835		    <entry>Details</entry>
836		  </row>
837		</thead>
838		<tbody valign="top">
839		  <row id="V4L2-PIX-FMT-DV">
840		    <entry><constant>V4L2_PIX_FMT_DV</constant></entry>
841		    <entry>'dvsd'</entry>
842		    <entry>unknown</entry>
843		  </row>
844		  <row id="V4L2-PIX-FMT-ET61X251">
845		    <entry><constant>V4L2_PIX_FMT_ET61X251</constant></entry>
846		    <entry>'E625'</entry>
847		    <entry>Compressed format of the ET61X251 driver.</entry>
848		  </row>
849		  <row id="V4L2-PIX-FMT-HI240">
850		    <entry><constant>V4L2_PIX_FMT_HI240</constant></entry>
851		    <entry>'HI24'</entry>
852		    <entry><para>8 bit RGB format used by the BTTV driver.</para></entry>
853		  </row>
854		  <row id="V4L2-PIX-FMT-HM12">
855		    <entry><constant>V4L2_PIX_FMT_HM12</constant></entry>
856		    <entry>'HM12'</entry>
857		    <entry><para>YUV 4:2:0 format used by the
858	IVTV driver, <ulink url="http://www.ivtvdriver.org/">
859	http://www.ivtvdriver.org/</ulink></para><para>The format is documented in the
860	kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.hm12</filename>
861	</para></entry>
862		  </row>
863		  <row id="V4L2-PIX-FMT-CPIA1">
864		    <entry><constant>V4L2_PIX_FMT_CPIA1</constant></entry>
865		    <entry>'CPIA'</entry>
866		    <entry>YUV format used by the gspca cpia1 driver.</entry>
867		  </row>
868		  <row id="V4L2-PIX-FMT-JPGL">
869		    <entry><constant>V4L2_PIX_FMT_JPGL</constant></entry>
870		    <entry>'JPGL'</entry>
871		    <entry>JPEG-Light format (Pegasus Lossless JPEG)
872				used in Divio webcams NW 80x.</entry>
873		  </row>
874		  <row id="V4L2-PIX-FMT-SPCA501">
875		    <entry><constant>V4L2_PIX_FMT_SPCA501</constant></entry>
876		    <entry>'S501'</entry>
877		    <entry>YUYV per line used by the gspca driver.</entry>
878		  </row>
879		  <row id="V4L2-PIX-FMT-SPCA505">
880		    <entry><constant>V4L2_PIX_FMT_SPCA505</constant></entry>
881		    <entry>'S505'</entry>
882		    <entry>YYUV per line used by the gspca driver.</entry>
883		  </row>
884		  <row id="V4L2-PIX-FMT-SPCA508">
885		    <entry><constant>V4L2_PIX_FMT_SPCA508</constant></entry>
886		    <entry>'S508'</entry>
887		    <entry>YUVY per line used by the gspca driver.</entry>
888		  </row>
889		  <row id="V4L2-PIX-FMT-SPCA561">
890		    <entry><constant>V4L2_PIX_FMT_SPCA561</constant></entry>
891		    <entry>'S561'</entry>
892		    <entry>Compressed GBRG Bayer format used by the gspca driver.</entry>
893		  </row>
894		  <row id="V4L2-PIX-FMT-PAC207">
895		    <entry><constant>V4L2_PIX_FMT_PAC207</constant></entry>
896		    <entry>'P207'</entry>
897		    <entry>Compressed BGGR Bayer format used by the gspca driver.</entry>
898		  </row>
899		  <row id="V4L2-PIX-FMT-MR97310A">
900		    <entry><constant>V4L2_PIX_FMT_MR97310A</constant></entry>
901		    <entry>'M310'</entry>
902		    <entry>Compressed BGGR Bayer format used by the gspca driver.</entry>
903		  </row>
904		  <row id="V4L2-PIX-FMT-JL2005BCD">
905		    <entry><constant>V4L2_PIX_FMT_JL2005BCD</constant></entry>
906		    <entry>'JL20'</entry>
907		    <entry>JPEG compressed RGGB Bayer format used by the gspca driver.</entry>
908		  </row>
909		  <row id="V4L2-PIX-FMT-OV511">
910		    <entry><constant>V4L2_PIX_FMT_OV511</constant></entry>
911		    <entry>'O511'</entry>
912		    <entry>OV511 JPEG format used by the gspca driver.</entry>
913		  </row>
914		  <row id="V4L2-PIX-FMT-OV518">
915		    <entry><constant>V4L2_PIX_FMT_OV518</constant></entry>
916		    <entry>'O518'</entry>
917		    <entry>OV518 JPEG format used by the gspca driver.</entry>
918		  </row>
919		  <row id="V4L2-PIX-FMT-PJPG">
920		    <entry><constant>V4L2_PIX_FMT_PJPG</constant></entry>
921		    <entry>'PJPG'</entry>
922		    <entry>Pixart 73xx JPEG format used by the gspca driver.</entry>
923		  </row>
924		  <row id="V4L2-PIX-FMT-SE401">
925		    <entry><constant>V4L2_PIX_FMT_SE401</constant></entry>
926		    <entry>'S401'</entry>
927		    <entry>Compressed RGB format used by the gspca se401 driver</entry>
928		  </row>
929		  <row id="V4L2-PIX-FMT-SQ905C">
930		    <entry><constant>V4L2_PIX_FMT_SQ905C</constant></entry>
931		    <entry>'905C'</entry>
932		    <entry>Compressed RGGB bayer format used by the gspca driver.</entry>
933		  </row>
934		  <row id="V4L2-PIX-FMT-MJPEG">
935		    <entry><constant>V4L2_PIX_FMT_MJPEG</constant></entry>
936		    <entry>'MJPG'</entry>
937		    <entry>Compressed format used by the Zoran driver</entry>
938		  </row>
939		  <row id="V4L2-PIX-FMT-PWC1">
940		    <entry><constant>V4L2_PIX_FMT_PWC1</constant></entry>
941		    <entry>'PWC1'</entry>
942		    <entry>Compressed format of the PWC driver.</entry>
943		  </row>
944		  <row id="V4L2-PIX-FMT-PWC2">
945		    <entry><constant>V4L2_PIX_FMT_PWC2</constant></entry>
946		    <entry>'PWC2'</entry>
947		    <entry>Compressed format of the PWC driver.</entry>
948		  </row>
949		  <row id="V4L2-PIX-FMT-SN9C10X">
950		    <entry><constant>V4L2_PIX_FMT_SN9C10X</constant></entry>
951		    <entry>'S910'</entry>
952		    <entry>Compressed format of the SN9C102 driver.</entry>
953		  </row>
954		  <row id="V4L2-PIX-FMT-SN9C20X-I420">
955		    <entry><constant>V4L2_PIX_FMT_SN9C20X_I420</constant></entry>
956		    <entry>'S920'</entry>
957		    <entry>YUV 4:2:0 format of the gspca sn9c20x driver.</entry>
958		  </row>
959		  <row id="V4L2-PIX-FMT-SN9C2028">
960		    <entry><constant>V4L2_PIX_FMT_SN9C2028</constant></entry>
961		    <entry>'SONX'</entry>
962		    <entry>Compressed GBRG bayer format of the gspca sn9c2028 driver.</entry>
963		  </row>
964		  <row id="V4L2-PIX-FMT-STV0680">
965		    <entry><constant>V4L2_PIX_FMT_STV0680</constant></entry>
966		    <entry>'S680'</entry>
967		    <entry>Bayer format of the gspca stv0680 driver.</entry>
968		  </row>
969		  <row id="V4L2-PIX-FMT-WNVA">
970		    <entry><constant>V4L2_PIX_FMT_WNVA</constant></entry>
971		    <entry>'WNVA'</entry>
972		    <entry><para>Used by the Winnov Videum driver, <ulink
973	url="http://www.thedirks.org/winnov/">
974	http://www.thedirks.org/winnov/</ulink></para></entry>
975		  </row>
976		  <row id="V4L2-PIX-FMT-TM6000">
977		    <entry><constant>V4L2_PIX_FMT_TM6000</constant></entry>
978		    <entry>'TM60'</entry>
979		    <entry><para>Used by Trident tm6000</para></entry>
980		  </row>
981		  <row id="V4L2-PIX-FMT-CIT-YYVYUY">
982		    <entry><constant>V4L2_PIX_FMT_CIT_YYVYUY</constant></entry>
983		    <entry>'CITV'</entry>
984		    <entry><para>Used by xirlink CIT, found at IBM webcams.</para>
985		           <para>Uses one line of Y then 1 line of VYUY</para>
986		    </entry>
987		  </row>
988		  <row id="V4L2-PIX-FMT-KONICA420">
989		    <entry><constant>V4L2_PIX_FMT_KONICA420</constant></entry>
990		    <entry>'KONI'</entry>
991		    <entry><para>Used by Konica webcams.</para>
992		           <para>YUV420 planar in blocks of 256 pixels.</para>
993		    </entry>
994		  </row>
995		  <row id="V4L2-PIX-FMT-YYUV">
996		    <entry><constant>V4L2_PIX_FMT_YYUV</constant></entry>
997		    <entry>'YYUV'</entry>
998		    <entry>unknown</entry>
999		  </row>
1000		  <row id="V4L2-PIX-FMT-Y4">
1001		    <entry><constant>V4L2_PIX_FMT_Y4</constant></entry>
1002		    <entry>'Y04 '</entry>
1003		    <entry>Old 4-bit greyscale format. Only the most significant 4 bits of each byte are used,
1004	the other bits are set to 0.</entry>
1005		  </row>
1006		  <row id="V4L2-PIX-FMT-Y6">
1007		    <entry><constant>V4L2_PIX_FMT_Y6</constant></entry>
1008		    <entry>'Y06 '</entry>
1009		    <entry>Old 6-bit greyscale format. Only the most significant 6 bits of each byte are used,
1010	the other bits are set to 0.</entry>
1011		  </row>
1012		  <row id="V4L2-PIX-FMT-S5C-UYVY-JPG">
1013		    <entry><constant>V4L2_PIX_FMT_S5C_UYVY_JPG</constant></entry>
1014		    <entry>'S5CI'</entry>
1015		    <entry>Two-planar format used by Samsung S5C73MX cameras. The
1016	first plane contains interleaved JPEG and UYVY image data, followed by meta data
1017	in form of an array of offsets to the UYVY data blocks. The actual pointer array
1018	follows immediately the interleaved JPEG/UYVY data, the number of entries in
1019	this array equals the height of the UYVY image. Each entry is a 4-byte unsigned
1020	integer in big endian order and it's an offset to a single pixel line of the
1021	UYVY image. The first plane can start either with JPEG or UYVY data chunk. The
1022	size of a single UYVY block equals the UYVY image's width multiplied by 2. The
1023	size of a JPEG chunk depends on the image and can vary with each line.
1024	<para>The second plane, at an offset of 4084 bytes, contains a 4-byte offset to
1025	the pointer array in the first plane. This offset is followed by a 4-byte value
1026	indicating size of the pointer array. All numbers in the second plane are also
1027	in big endian order. Remaining data in the second plane is undefined. The
1028	information in the second plane allows to easily find location of the pointer
1029	array, which can be different for each frame. The size of the pointer array is
1030	constant for given UYVY image height.</para>
1031	<para>In order to extract UYVY and JPEG frames an application can initially set
1032	a data pointer to the start of first plane and then add an offset from the first
1033	entry of the pointers table. Such a pointer indicates start of an UYVY image
1034	pixel line. Whole UYVY line can be copied to a separate buffer. These steps
1035	should be repeated for each line, i.e. the number of entries in the pointer
1036	array. Anything what's in between the UYVY lines is JPEG data and should be
1037	concatenated to form the JPEG stream. </para>
1038	</entry>
1039		  </row>
1040		</tbody>
1041	      </tgroup>
1042	    </table>
1043	  </section>
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