Documentation/DocBook/media/v4l/pixfmt.xml

   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. If <structfield>field</structfield> is
  29           one of <constant>V4L2_FIELD_TOP</constant>, <constant>V4L2_FIELD_BOTTOM</constant>
  30           or <constant>V4L2_FIELD_ALTERNATE</constant> then height refers to the
  31           number of lines in the field, otherwise it refers to the number of
  32           lines in the frame (which is twice the field height for interlaced
  33           formats).</entry>
  34         </row>
  35         <row>
  36           <entry spanname="hspan">Applications set these fields to
  37 request an image size, drivers return the closest possible values. In
  38 case of planar formats the <structfield>width</structfield> and
  39 <structfield>height</structfield> applies to the largest plane. To
  40 avoid ambiguities drivers must return values rounded up to a multiple
  41 of the scale factor of any smaller planes. For example when the image
  42 format is YUV 4:2:0, <structfield>width</structfield> and
  43 <structfield>height</structfield> must be multiples of two.</entry>
  44         </row>
  45         <row>
  46           <entry>__u32</entry>
  47           <entry><structfield>pixelformat</structfield></entry>
  48           <entry>The pixel format or type of compression, set by the
  49 application. This is a little endian <link
  50 linkend="v4l2-fourcc">four character code</link>. V4L2 defines
  51 standard RGB formats in <xref linkend="rgb-formats" />, YUV formats in <xref
  52 linkend="yuv-formats" />, and reserved codes in <xref
  53 linkend="reserved-formats" /></entry>
  54         </row>
  55         <row>
  56           <entry>&v4l2-field;</entry>
  57           <entry><structfield>field</structfield></entry>
  58           <entry>Video images are typically interlaced. Applications
  59 can request to capture or output only the top or bottom field, or both
  60 fields interlaced or sequentially stored in one buffer or alternating
  61 in separate buffers. Drivers return the actual field order selected.
  62 For more details on fields see <xref linkend="field-order" />.</entry>
  63         </row>
  64         <row>
  65           <entry>__u32</entry>
  66           <entry><structfield>bytesperline</structfield></entry>
  67           <entry>Distance in bytes between the leftmost pixels in two
  68 adjacent lines.</entry>
  69         </row>
  70         <row>
  71           <entry spanname="hspan"><para>Both applications and drivers
  72 can set this field to request padding bytes at the end of each line.
  73 Drivers however may ignore the value requested by the application,
  74 returning <structfield>width</structfield> times bytes per pixel or a
  75 larger value required by the hardware. That implies applications can
  76 just set this field to zero to get a reasonable
  77 default.</para><para>Video hardware may access padding bytes,
  78 therefore they must reside in accessible memory. Consider cases where
  79 padding bytes after the last line of an image cross a system page
  80 boundary. Input devices may write padding bytes, the value is
  81 undefined. Output devices ignore the contents of padding
  82 bytes.</para><para>When the image format is planar the
  83 <structfield>bytesperline</structfield> value applies to the largest
  84 plane and is divided by the same factor as the
  85 <structfield>width</structfield> field for any smaller planes. For
  86 example the Cb and Cr planes of a YUV 4:2:0 image have half as many
  87 padding bytes following each line as the Y plane. To avoid ambiguities
  88 drivers must return a <structfield>bytesperline</structfield> value
  89 rounded up to a multiple of the scale factor.</para>
  90 <para>For compressed formats the <structfield>bytesperline</structfield>
  91 value makes no sense. Applications and drivers must set this to 0 in
  92 that case.</para></entry>
  93         </row>
  94         <row>
  95           <entry>__u32</entry>
  96           <entry><structfield>sizeimage</structfield></entry>
  97           <entry>Size in bytes of the buffer to hold a complete image,
  98 set by the driver. Usually this is
  99 <structfield>bytesperline</structfield> times
 100 <structfield>height</structfield>. When the image consists of variable
 101 length compressed data this is the maximum number of bytes required to
 102 hold an image.</entry>
 103         </row>
 104         <row>
 105           <entry>&v4l2-colorspace;</entry>
 106           <entry><structfield>colorspace</structfield></entry>
 107           <entry>This information supplements the
 108 <structfield>pixelformat</structfield> and must be set by the driver for
 109 capture streams and by the application for output streams,
 110 see <xref linkend="colorspaces" />.</entry>
 111         </row>
 112         <row>
 113           <entry>__u32</entry>
 114           <entry><structfield>priv</structfield></entry>
 115           <entry><para>This field indicates whether the remaining fields of the
 116 <structname>v4l2_pix_format</structname> structure, also called the extended
 117 fields, are valid. When set to <constant>V4L2_PIX_FMT_PRIV_MAGIC</constant>, it
 118 indicates that the extended fields have been correctly initialized. When set to
 119 any other value it indicates that the extended fields contain undefined values.
 120 </para>
 121 <para>Applications that wish to use the pixel format extended fields must first
 122 ensure that the feature is supported by querying the device for the
 123 <link linkend="querycap"><constant>V4L2_CAP_EXT_PIX_FORMAT</constant></link>
 124 capability. If the capability isn't set the pixel format extended fields are not
 125 supported and using the extended fields will lead to undefined results.</para>
 126 <para>To use the extended fields, applications must set the
 127 <structfield>priv</structfield> field to
 128 <constant>V4L2_PIX_FMT_PRIV_MAGIC</constant>, initialize all the extended fields
 129 and zero the unused bytes of the <structname>v4l2_format</structname>
 130 <structfield>raw_data</structfield> field.</para>
 131 <para>When the <structfield>priv</structfield> field isn't set to
 132 <constant>V4L2_PIX_FMT_PRIV_MAGIC</constant> drivers must act as if all the
 133 extended fields were set to zero. On return drivers must set the
 134 <structfield>priv</structfield> field to
 135 <constant>V4L2_PIX_FMT_PRIV_MAGIC</constant> and all the extended fields to
 136 applicable values.</para></entry>
 137         </row>
 138         <row>
 139           <entry>__u32</entry>
 140           <entry><structfield>flags</structfield></entry>
 141             <entry>Flags set by the application or driver, see <xref
 142 linkend="format-flags" />.</entry>
 143         </row>
 144       </tbody>
 145     </tgroup>
 146   </table>
 147 </section>
 148
 149 <section>
 150   <title>Multi-planar format structures</title>
 151   <para>The <structname>v4l2_plane_pix_format</structname> structures define
 152     size and layout for each of the planes in a multi-planar format.
 153     The <structname>v4l2_pix_format_mplane</structname> structure contains
 154     information common to all planes (such as image width and height) and
 155     an array of <structname>v4l2_plane_pix_format</structname> structures,
 156     describing all planes of that format.</para>
 157   <table pgwide="1" frame="none" id="v4l2-plane-pix-format">
 158     <title>struct <structname>v4l2_plane_pix_format</structname></title>
 159     <tgroup cols="3">
 160       &cs-str;
 161       <tbody valign="top">
 162         <row>
 163           <entry>__u32</entry>
 164           <entry><structfield>sizeimage</structfield></entry>
 165           <entry>Maximum size in bytes required for image data in this plane.
 166           </entry>
 167         </row>
 168         <row>
 169           <entry>__u16</entry>
 170           <entry><structfield>bytesperline</structfield></entry>
 171           <entry>Distance in bytes between the leftmost pixels in two adjacent
 172             lines. See &v4l2-pix-format;.</entry>
 173         </row>
 174         <row>
 175           <entry>__u16</entry>
 176           <entry><structfield>reserved[7]</structfield></entry>
 177           <entry>Reserved for future extensions. Should be zeroed by the
 178            application.</entry>
 179         </row>
 180       </tbody>
 181     </tgroup>
 182   </table>
 183   <table pgwide="1" frame="none" id="v4l2-pix-format-mplane">
 184     <title>struct <structname>v4l2_pix_format_mplane</structname></title>
 185     <tgroup cols="3">
 186       &cs-str;
 187       <tbody valign="top">
 188         <row>
 189           <entry>__u32</entry>
 190           <entry><structfield>width</structfield></entry>
 191           <entry>Image width in pixels. See &v4l2-pix-format;.</entry>
 192         </row>
 193         <row>
 194           <entry>__u32</entry>
 195           <entry><structfield>height</structfield></entry>
 196           <entry>Image height in pixels. See &v4l2-pix-format;.</entry>
 197         </row>
 198         <row>
 199           <entry>__u32</entry>
 200           <entry><structfield>pixelformat</structfield></entry>
 201           <entry>The pixel format. Both single- and multi-planar four character
 202 codes can be used.</entry>
 203         </row>
 204         <row>
 205           <entry>&v4l2-field;</entry>
 206           <entry><structfield>field</structfield></entry>
 207           <entry>See &v4l2-pix-format;.</entry>
 208         </row>
 209         <row>
 210           <entry>&v4l2-colorspace;</entry>
 211           <entry><structfield>colorspace</structfield></entry>
 212           <entry>See &v4l2-pix-format;.</entry>
 213         </row>
 214         <row>
 215           <entry>&v4l2-plane-pix-format;</entry>
 216           <entry><structfield>plane_fmt[VIDEO_MAX_PLANES]</structfield></entry>
 217           <entry>An array of structures describing format of each plane this
 218           pixel format consists of. The number of valid entries in this array
 219           has to be put in the <structfield>num_planes</structfield>
 220           field.</entry>
 221         </row>
 222         <row>
 223           <entry>__u8</entry>
 224           <entry><structfield>num_planes</structfield></entry>
 225           <entry>Number of planes (i.e. separate memory buffers) for this format
 226           and the number of valid entries in the
 227           <structfield>plane_fmt</structfield> array.</entry>
 228         </row>
 229         <row>
 230           <entry>__u8</entry>
 231           <entry><structfield>flags</structfield></entry>
 232           <entry>Flags set by the application or driver, see <xref
 233 linkend="format-flags" />.</entry>
 234         </row>
 235         <row>
 236           <entry>__u8</entry>
 237           <entry><structfield>reserved[10]</structfield></entry>
 238           <entry>Reserved for future extensions. Should be zeroed by the
 239            application.</entry>
 240         </row>
 241       </tbody>
 242     </tgroup>
 243   </table>
 244 </section>
 245
 246   <section>
 247     <title>Standard Image Formats</title>
 248
 249     <para>In order to exchange images between drivers and
 250 applications, it is necessary to have standard image data formats
 251 which both sides will interpret the same way. V4L2 includes several
 252 such formats, and this section is intended to be an unambiguous
 253 specification of the standard image data formats in V4L2.</para>
 254
 255     <para>V4L2 drivers are not limited to these formats, however.
 256 Driver-specific formats are possible. In that case the application may
 257 depend on a codec to convert images to one of the standard formats
 258 when needed. But the data can still be stored and retrieved in the
 259 proprietary format. For example, a device may support a proprietary
 260 compressed format. Applications can still capture and save the data in
 261 the compressed format, saving much disk space, and later use a codec
 262 to convert the images to the X Windows screen format when the video is
 263 to be displayed.</para>
 264
 265     <para>Even so, ultimately, some standard formats are needed, so
 266 the V4L2 specification would not be complete without well-defined
 267 standard formats.</para>
 268
 269     <para>The V4L2 standard formats are mainly uncompressed formats. The
 270 pixels are always arranged in memory from left to right, and from top
 271 to bottom. The first byte of data in the image buffer is always for
 272 the leftmost pixel of the topmost row. Following that is the pixel
 273 immediately to its right, and so on until the end of the top row of
 274 pixels. Following the rightmost pixel of the row there may be zero or
 275 more bytes of padding to guarantee that each row of pixel data has a
 276 certain alignment. Following the pad bytes, if any, is data for the
 277 leftmost pixel of the second row from the top, and so on. The last row
 278 has just as many pad bytes after it as the other rows.</para>
 279
 280     <para>In V4L2 each format has an identifier which looks like
 281 <constant>PIX_FMT_XXX</constant>, defined in the <link
 282 linkend="videodev">videodev2.h</link> header file. These identifiers
 283 represent <link linkend="v4l2-fourcc">four character (FourCC) codes</link>
 284 which are also listed below, however they are not the same as those
 285 used in the Windows world.</para>
 286
 287     <para>For some formats, data is stored in separate, discontiguous
 288 memory buffers. Those formats are identified by a separate set of FourCC codes
 289 and are referred to as "multi-planar formats". For example, a YUV422 frame is
 290 normally stored in one memory buffer, but it can also be placed in two or three
 291 separate buffers, with Y component in one buffer and CbCr components in another
 292 in the 2-planar version or with each component in its own buffer in the
 293 3-planar case. Those sub-buffers are referred to as "planes".</para>
 294   </section>
 295
 296   <section id="colorspaces">
 297     <title>Colorspaces</title>
 298
 299     <para>[intro]</para>
 300
 301     <!-- See proposal by Billy Biggs, video4linux-list@redhat.com
 302 on 11 Oct 2002, subject: "Re: [V4L] Re: v4l2 api", and
 303 http://vektor.theorem.ca/graphics/ycbcr/ and
 304 http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html -->
 305
 306     <para>
 307       <variablelist>
 308         <varlistentry>
 309           <term>Gamma Correction</term>
 310           <listitem>
 311             <para>[to do]</para>
 312             <para>E'<subscript>R</subscript> = f(R)</para>
 313             <para>E'<subscript>G</subscript> = f(G)</para>
 314             <para>E'<subscript>B</subscript> = f(B)</para>
 315           </listitem>
 316         </varlistentry>
 317         <varlistentry>
 318           <term>Construction of luminance and color-difference
 319 signals</term>
 320           <listitem>
 321             <para>[to do]</para>
 322             <para>E'<subscript>Y</subscript> =
 323 Coeff<subscript>R</subscript> E'<subscript>R</subscript>
 324 + Coeff<subscript>G</subscript> E'<subscript>G</subscript>
 325 + Coeff<subscript>B</subscript> E'<subscript>B</subscript></para>
 326             <para>(E'<subscript>R</subscript> - E'<subscript>Y</subscript>) = E'<subscript>R</subscript>
 327 - Coeff<subscript>R</subscript> E'<subscript>R</subscript>
 328 - Coeff<subscript>G</subscript> E'<subscript>G</subscript>
 329 - Coeff<subscript>B</subscript> E'<subscript>B</subscript></para>
 330             <para>(E'<subscript>B</subscript> - E'<subscript>Y</subscript>) = E'<subscript>B</subscript>
 331 - Coeff<subscript>R</subscript> E'<subscript>R</subscript>
 332 - Coeff<subscript>G</subscript> E'<subscript>G</subscript>
 333 - Coeff<subscript>B</subscript> E'<subscript>B</subscript></para>
 334           </listitem>
 335         </varlistentry>
 336         <varlistentry>
 337           <term>Re-normalized color-difference signals</term>
 338           <listitem>
 339             <para>The color-difference signals are scaled back to unity
 340 range [-0.5;+0.5]:</para>
 341             <para>K<subscript>B</subscript> = 0.5 / (1 - Coeff<subscript>B</subscript>)</para>
 342             <para>K<subscript>R</subscript> = 0.5 / (1 - Coeff<subscript>R</subscript>)</para>
 343             <para>P<subscript>B</subscript> =
 344 K<subscript>B</subscript> (E'<subscript>B</subscript> - E'<subscript>Y</subscript>) =
 345   0.5 (Coeff<subscript>R</subscript> / Coeff<subscript>B</subscript>) E'<subscript>R</subscript>
 346 + 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>B</subscript>) E'<subscript>G</subscript>
 347 + 0.5 E'<subscript>B</subscript></para>
 348             <para>P<subscript>R</subscript> =
 349 K<subscript>R</subscript> (E'<subscript>R</subscript> - E'<subscript>Y</subscript>) =
 350   0.5 E'<subscript>R</subscript>
 351 + 0.5 (Coeff<subscript>G</subscript> / Coeff<subscript>R</subscript>) E'<subscript>G</subscript>
 352 + 0.5 (Coeff<subscript>B</subscript> / Coeff<subscript>R</subscript>) E'<subscript>B</subscript></para>
 353           </listitem>
 354         </varlistentry>
 355         <varlistentry>
 356           <term>Quantization</term>
 357           <listitem>
 358             <para>[to do]</para>
 359             <para>Y' = (Lum. Levels - 1) &middot; E'<subscript>Y</subscript> + Lum. Offset</para>
 360             <para>C<subscript>B</subscript> = (Chrom. Levels - 1)
 361 &middot; P<subscript>B</subscript> + Chrom. Offset</para>
 362             <para>C<subscript>R</subscript> = (Chrom. Levels - 1)
 363 &middot; P<subscript>R</subscript> + Chrom. Offset</para>
 364             <para>Rounding to the nearest integer and clamping to the range
 365 [0;255] finally yields the digital color components Y'CbCr
 366 stored in YUV images.</para>
 367           </listitem>
 368         </varlistentry>
 369       </variablelist>
 370     </para>
 371
 372     <example>
 373       <title>ITU-R Rec. BT.601 color conversion</title>
 374
 375       <para>Forward Transformation</para>
 376
 377       <programlisting>
 378 int ER, EG, EB;         /* gamma corrected RGB input [0;255] */
 379 int Y1, Cb, Cr;         /* 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 r = ER / 255.0;
 395 g = EG / 255.0;
 396 b = EB / 255.0;
 397
 398 y1  =  0.299  * r + 0.587 * g + 0.114  * b;
 399 pb  = -0.169  * r - 0.331 * g + 0.5    * b;
 400 pr  =  0.5    * r - 0.419 * g - 0.081  * b;
 401
 402 Y1 = clamp (219 * y1 + 16);
 403 Cb = clamp (224 * pb + 128);
 404 Cr = clamp (224 * pr + 128);
 405
 406 /* or shorter */
 407
 408 y1 = 0.299 * ER + 0.587 * EG + 0.114 * EB;
 409
 410 Y1 = clamp ( (219 / 255.0)                    *       y1  + 16);
 411 Cb = clamp (((224 / 255.0) / (2 - 2 * 0.114)) * (EB - y1) + 128);
 412 Cr = clamp (((224 / 255.0) / (2 - 2 * 0.299)) * (ER - y1) + 128);
 413       </programlisting>
 414
 415       <para>Inverse Transformation</para>
 416
 417       <programlisting>
 418 int Y1, Cb, Cr;         /* gamma pre-corrected input [0;255] */
 419 int ER, EG, EB;         /* output [0;255] */
 420
 421 double r, g, b;         /* temporaries */
 422 double y1, pb, pr;
 423
 424 int
 425 clamp (double x)
 426 {
 427         int r = x;      /* round to nearest */
 428
 429         if (r &lt; 0)         return 0;
 430         else if (r &gt; 255)  return 255;
 431         else               return r;
 432 }
 433
 434 y1 = (Y1 - 16) / 219.0;
 435 pb = (Cb - 128) / 224.0;
 436 pr = (Cr - 128) / 224.0;
 437
 438 r = 1.0 * y1 + 0     * pb + 1.402 * pr;
 439 g = 1.0 * y1 - 0.344 * pb - 0.714 * pr;
 440 b = 1.0 * y1 + 1.772 * pb + 0     * pr;
 441
 442 ER = clamp (r * 255); /* [ok? one should prob. limit y1,pb,pr] */
 443 EG = clamp (g * 255);
 444 EB = clamp (b * 255);
 445       </programlisting>
 446     </example>
 447
 448     <table pgwide="1" id="v4l2-colorspace" orient="land">
 449       <title>enum v4l2_colorspace</title>
 450       <tgroup cols="11" align="center">
 451         <colspec align="left" />
 452         <colspec align="center" />
 453         <colspec align="left" />
 454         <colspec colname="cr" />
 455         <colspec colname="cg" />
 456         <colspec colname="cb" />
 457         <colspec colname="wp" />
 458         <colspec colname="gc" />
 459         <colspec colname="lum" />
 460         <colspec colname="qy" />
 461         <colspec colname="qc" />
 462         <spanspec namest="cr" nameend="cb" spanname="chrom" />
 463         <spanspec namest="qy" nameend="qc" spanname="quant" />
 464         <spanspec namest="lum" nameend="qc" spanname="spam" />
 465         <thead>
 466           <row>
 467             <entry morerows="1">Identifier</entry>
 468             <entry morerows="1">Value</entry>
 469             <entry morerows="1">Description</entry>
 470             <entry spanname="chrom">Chromaticities<footnote>
 471                 <para>The coordinates of the color primaries are
 472 given in the CIE system (1931)</para>
 473               </footnote></entry>
 474             <entry morerows="1">White Point</entry>
 475             <entry morerows="1">Gamma Correction</entry>
 476             <entry morerows="1">Luminance E'<subscript>Y</subscript></entry>
 477             <entry spanname="quant">Quantization</entry>
 478           </row>
 479           <row>
 480             <entry>Red</entry>
 481             <entry>Green</entry>
 482             <entry>Blue</entry>
 483             <entry>Y'</entry>
 484             <entry>Cb, Cr</entry>
 485           </row>
 486         </thead>
 487         <tbody valign="top">
 488           <row>
 489             <entry><constant>V4L2_COLORSPACE_SMPTE170M</constant></entry>
 490             <entry>1</entry>
 491             <entry>NTSC/PAL according to <xref linkend="smpte170m" />,
 492 <xref linkend="itu601" /></entry>
 493             <entry>x&nbsp;=&nbsp;0.630, y&nbsp;=&nbsp;0.340</entry>
 494             <entry>x&nbsp;=&nbsp;0.310, y&nbsp;=&nbsp;0.595</entry>
 495             <entry>x&nbsp;=&nbsp;0.155, y&nbsp;=&nbsp;0.070</entry>
 496             <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
 497             Illuminant D<subscript>65</subscript></entry>
 498             <entry>E' = 4.5&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.018,
 499 1.099&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.099&nbsp;for&nbsp;0.018&nbsp;&lt;&nbsp;I</entry>
 500             <entry>0.299&nbsp;E'<subscript>R</subscript>
 501 +&nbsp;0.587&nbsp;E'<subscript>G</subscript>
 502 +&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
 503             <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
 504             <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
 505           </row>
 506           <row>
 507             <entry><constant>V4L2_COLORSPACE_SMPTE240M</constant></entry>
 508             <entry>2</entry>
 509             <entry>1125-Line (US) HDTV, see <xref
 510 linkend="smpte240m" /></entry>
 511             <entry>x&nbsp;=&nbsp;0.630, y&nbsp;=&nbsp;0.340</entry>
 512             <entry>x&nbsp;=&nbsp;0.310, y&nbsp;=&nbsp;0.595</entry>
 513             <entry>x&nbsp;=&nbsp;0.155, y&nbsp;=&nbsp;0.070</entry>
 514             <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
 515             Illuminant D<subscript>65</subscript></entry>
 516             <entry>E' = 4&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.0228,
 517 1.1115&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.1115&nbsp;for&nbsp;0.0228&nbsp;&lt;&nbsp;I</entry>
 518             <entry>0.212&nbsp;E'<subscript>R</subscript>
 519 +&nbsp;0.701&nbsp;E'<subscript>G</subscript>
 520 +&nbsp;0.087&nbsp;E'<subscript>B</subscript></entry>
 521             <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
 522             <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
 523           </row>
 524           <row>
 525             <entry><constant>V4L2_COLORSPACE_REC709</constant></entry>
 526             <entry>3</entry>
 527             <entry>HDTV and modern devices, see <xref
 528 linkend="itu709" /></entry>
 529             <entry>x&nbsp;=&nbsp;0.640, y&nbsp;=&nbsp;0.330</entry>
 530             <entry>x&nbsp;=&nbsp;0.300, y&nbsp;=&nbsp;0.600</entry>
 531             <entry>x&nbsp;=&nbsp;0.150, y&nbsp;=&nbsp;0.060</entry>
 532             <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
 533             Illuminant D<subscript>65</subscript></entry>
 534             <entry>E' = 4.5&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.018,
 535 1.099&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.099&nbsp;for&nbsp;0.018&nbsp;&lt;&nbsp;I</entry>
 536             <entry>0.2125&nbsp;E'<subscript>R</subscript>
 537 +&nbsp;0.7154&nbsp;E'<subscript>G</subscript>
 538 +&nbsp;0.0721&nbsp;E'<subscript>B</subscript></entry>
 539             <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
 540             <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
 541           </row>
 542           <row>
 543             <entry><constant>V4L2_COLORSPACE_BT878</constant></entry>
 544             <entry>4</entry>
 545             <entry>Broken Bt878 extents<footnote>
 546                 <para>The ubiquitous Bt878 video capture chip
 547 quantizes E'<subscript>Y</subscript> to 238 levels, yielding a range
 548 of Y' = 16 &hellip; 253, unlike Rec. 601 Y' = 16 &hellip;
 549 235. This is not a typo in the Bt878 documentation, it has been
 550 implemented in silicon. The chroma extents are unclear.</para>
 551               </footnote>, <xref linkend="itu601" /></entry>
 552             <entry>?</entry>
 553             <entry>?</entry>
 554             <entry>?</entry>
 555             <entry>?</entry>
 556             <entry>?</entry>
 557             <entry>0.299&nbsp;E'<subscript>R</subscript>
 558 +&nbsp;0.587&nbsp;E'<subscript>G</subscript>
 559 +&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
 560             <entry><emphasis>237</emphasis>&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
 561             <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128 (probably)</entry>
 562           </row>
 563           <row>
 564             <entry><constant>V4L2_COLORSPACE_470_SYSTEM_M</constant></entry>
 565             <entry>5</entry>
 566             <entry>M/NTSC<footnote>
 567                 <para>No identifier exists for M/PAL which uses
 568 the chromaticities of M/NTSC, the remaining parameters are equal to B and
 569 G/PAL.</para>
 570               </footnote> according to <xref linkend="itu470" />, <xref
 571                 linkend="itu601" /></entry>
 572             <entry>x&nbsp;=&nbsp;0.67, y&nbsp;=&nbsp;0.33</entry>
 573             <entry>x&nbsp;=&nbsp;0.21, y&nbsp;=&nbsp;0.71</entry>
 574             <entry>x&nbsp;=&nbsp;0.14, y&nbsp;=&nbsp;0.08</entry>
 575             <entry>x&nbsp;=&nbsp;0.310, y&nbsp;=&nbsp;0.316, Illuminant C</entry>
 576             <entry>?</entry>
 577             <entry>0.299&nbsp;E'<subscript>R</subscript>
 578 +&nbsp;0.587&nbsp;E'<subscript>G</subscript>
 579 +&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
 580             <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
 581             <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
 582           </row>
 583           <row>
 584             <entry><constant>V4L2_COLORSPACE_470_SYSTEM_BG</constant></entry>
 585             <entry>6</entry>
 586             <entry>625-line PAL and SECAM systems according to <xref
 587 linkend="itu470" />, <xref linkend="itu601" /></entry>
 588             <entry>x&nbsp;=&nbsp;0.64, y&nbsp;=&nbsp;0.33</entry>
 589             <entry>x&nbsp;=&nbsp;0.29, y&nbsp;=&nbsp;0.60</entry>
 590             <entry>x&nbsp;=&nbsp;0.15, y&nbsp;=&nbsp;0.06</entry>
 591             <entry>x&nbsp;=&nbsp;0.313, y&nbsp;=&nbsp;0.329,
 592 Illuminant D<subscript>65</subscript></entry>
 593             <entry>?</entry>
 594             <entry>0.299&nbsp;E'<subscript>R</subscript>
 595 +&nbsp;0.587&nbsp;E'<subscript>G</subscript>
 596 +&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
 597             <entry>219&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16</entry>
 598             <entry>224&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
 599           </row>
 600           <row>
 601             <entry><constant>V4L2_COLORSPACE_JPEG</constant></entry>
 602             <entry>7</entry>
 603             <entry>JPEG Y'CbCr, see <xref linkend="jfif" />, <xref linkend="itu601" /></entry>
 604             <entry>?</entry>
 605             <entry>?</entry>
 606             <entry>?</entry>
 607             <entry>?</entry>
 608             <entry>?</entry>
 609             <entry>0.299&nbsp;E'<subscript>R</subscript>
 610 +&nbsp;0.587&nbsp;E'<subscript>G</subscript>
 611 +&nbsp;0.114&nbsp;E'<subscript>B</subscript></entry>
 612             <entry>256&nbsp;E'<subscript>Y</subscript>&nbsp;+&nbsp;16<footnote>
 613                 <para>Note JFIF quantizes
 614 Y'P<subscript>B</subscript>P<subscript>R</subscript> in range [0;+1] and
 615 [-0.5;+0.5] to <emphasis>257</emphasis> levels, however Y'CbCr signals
 616 are still clamped to [0;255].</para>
 617               </footnote></entry>
 618             <entry>256&nbsp;P<subscript>B,R</subscript>&nbsp;+&nbsp;128</entry>
 619           </row>
 620           <row>
 621             <entry><constant>V4L2_COLORSPACE_SRGB</constant></entry>
 622             <entry>8</entry>
 623             <entry>[?]</entry>
 624             <entry>x&nbsp;=&nbsp;0.640, y&nbsp;=&nbsp;0.330</entry>
 625             <entry>x&nbsp;=&nbsp;0.300, y&nbsp;=&nbsp;0.600</entry>
 626             <entry>x&nbsp;=&nbsp;0.150, y&nbsp;=&nbsp;0.060</entry>
 627             <entry>x&nbsp;=&nbsp;0.3127, y&nbsp;=&nbsp;0.3290,
 628             Illuminant D<subscript>65</subscript></entry>
 629             <entry>E' = 4.5&nbsp;I&nbsp;for&nbsp;I&nbsp;&le;0.018,
 630 1.099&nbsp;I<superscript>0.45</superscript>&nbsp;-&nbsp;0.099&nbsp;for&nbsp;0.018&nbsp;&lt;&nbsp;I</entry>
 631             <entry spanname="spam">n/a</entry>
 632           </row>
 633         </tbody>
 634       </tgroup>
 635     </table>
 636   </section>
 637
 638   <section id="pixfmt-indexed">
 639     <title>Indexed Format</title>
 640
 641     <para>In this format each pixel is represented by an 8 bit index
 642 into a 256 entry ARGB palette. It is intended for <link
 643 linkend="osd">Video Output Overlays</link> only. There are no ioctls to
 644 access the palette, this must be done with ioctls of the Linux framebuffer API.</para>
 645
 646     <table pgwide="0" frame="none">
 647       <title>Indexed Image Format</title>
 648       <tgroup cols="37" align="center">
 649         <colspec colname="id" align="left" />
 650         <colspec colname="fourcc" />
 651         <colspec colname="bit" />
 652
 653         <colspec colnum="4" colname="b07" align="center" />
 654         <colspec colnum="5" colname="b06" align="center" />
 655         <colspec colnum="6" colname="b05" align="center" />
 656         <colspec colnum="7" colname="b04" align="center" />
 657         <colspec colnum="8" colname="b03" align="center" />
 658         <colspec colnum="9" colname="b02" align="center" />
 659         <colspec colnum="10" colname="b01" align="center" />
 660         <colspec colnum="11" colname="b00" align="center" />
 661
 662         <spanspec namest="b07" nameend="b00" spanname="b0" />
 663         <spanspec namest="b17" nameend="b10" spanname="b1" />
 664         <spanspec namest="b27" nameend="b20" spanname="b2" />
 665         <spanspec namest="b37" nameend="b30" spanname="b3" />
 666         <thead>
 667           <row>
 668             <entry>Identifier</entry>
 669             <entry>Code</entry>
 670             <entry>&nbsp;</entry>
 671             <entry spanname="b0">Byte&nbsp;0</entry>
 672           </row>
 673           <row>
 674             <entry>&nbsp;</entry>
 675             <entry>&nbsp;</entry>
 676             <entry>Bit</entry>
 677             <entry>7</entry>
 678             <entry>6</entry>
 679             <entry>5</entry>
 680             <entry>4</entry>
 681             <entry>3</entry>
 682             <entry>2</entry>
 683             <entry>1</entry>
 684             <entry>0</entry>
 685           </row>
 686         </thead>
 687         <tbody valign="top">
 688           <row id="V4L2-PIX-FMT-PAL8">
 689             <entry><constant>V4L2_PIX_FMT_PAL8</constant></entry>
 690             <entry>'PAL8'</entry>
 691             <entry></entry>
 692             <entry>i<subscript>7</subscript></entry>
 693             <entry>i<subscript>6</subscript></entry>
 694             <entry>i<subscript>5</subscript></entry>
 695             <entry>i<subscript>4</subscript></entry>
 696             <entry>i<subscript>3</subscript></entry>
 697             <entry>i<subscript>2</subscript></entry>
 698             <entry>i<subscript>1</subscript></entry>
 699             <entry>i<subscript>0</subscript></entry>
 700           </row>
 701         </tbody>
 702       </tgroup>
 703     </table>
 704   </section>
 705
 706   <section id="pixfmt-rgb">
 707     <title>RGB Formats</title>
 708
 709     &sub-packed-rgb;
 710     &sub-sbggr8;
 711     &sub-sgbrg8;
 712     &sub-sgrbg8;
 713     &sub-srggb8;
 714     &sub-sbggr16;
 715     &sub-srggb10;
 716     &sub-srggb10alaw8;
 717     &sub-srggb10dpcm8;
 718     &sub-srggb12;
 719   </section>
 720
 721   <section id="yuv-formats">
 722     <title>YUV Formats</title>
 723
 724     <para>YUV is the format native to TV broadcast and composite video
 725 signals. It separates the brightness information (Y) from the color
 726 information (U and V or Cb and Cr). The color information consists of
 727 red and blue <emphasis>color difference</emphasis> signals, this way
 728 the green component can be reconstructed by subtracting from the
 729 brightness component. See <xref linkend="colorspaces" /> for conversion
 730 examples. YUV was chosen because early television would only transmit
 731 brightness information. To add color in a way compatible with existing
 732 receivers a new signal carrier was added to transmit the color
 733 difference signals. Secondary in the YUV format the U and V components
 734 usually have lower resolution than the Y component. This is an analog
 735 video compression technique taking advantage of a property of the
 736 human visual system, being more sensitive to brightness
 737 information.</para>
 738
 739     &sub-packed-yuv;
 740     &sub-grey;
 741     &sub-y10;
 742     &sub-y12;
 743     &sub-y10b;
 744     &sub-y16;
 745     &sub-uv8;
 746     &sub-yuyv;
 747     &sub-uyvy;
 748     &sub-yvyu;
 749     &sub-vyuy;
 750     &sub-y41p;
 751     &sub-yuv420;
 752     &sub-yuv420m;
 753     &sub-yvu420m;
 754     &sub-yuv410;
 755     &sub-yuv422p;
 756     &sub-yuv411p;
 757     &sub-nv12;
 758     &sub-nv12m;
 759     &sub-nv12mt;
 760     &sub-nv16;
 761     &sub-nv16m;
 762     &sub-nv24;
 763     &sub-m420;
 764   </section>
 765
 766   <section>
 767     <title>Compressed Formats</title>
 768
 769     <table pgwide="1" frame="none" id="compressed-formats">
 770       <title>Compressed Image Formats</title>
 771       <tgroup cols="3" align="left">
 772         &cs-def;
 773         <thead>
 774           <row>
 775             <entry>Identifier</entry>
 776             <entry>Code</entry>
 777             <entry>Details</entry>
 778           </row>
 779         </thead>
 780         <tbody valign="top">
 781          <row id="V4L2-PIX-FMT-JPEG">
 782             <entry><constant>V4L2_PIX_FMT_JPEG</constant></entry>
 783             <entry>'JPEG'</entry>
 784             <entry>TBD. See also &VIDIOC-G-JPEGCOMP;,
 785             &VIDIOC-S-JPEGCOMP;.</entry>
 786           </row>
 787           <row id="V4L2-PIX-FMT-MPEG">
 788             <entry><constant>V4L2_PIX_FMT_MPEG</constant></entry>
 789             <entry>'MPEG'</entry>
 790             <entry>MPEG multiplexed stream. The actual format is determined by
 791 extended control <constant>V4L2_CID_MPEG_STREAM_TYPE</constant>, see
 792 <xref linkend="mpeg-control-id" />.</entry>
 793           </row>
 794           <row id="V4L2-PIX-FMT-H264">
 795                 <entry><constant>V4L2_PIX_FMT_H264</constant></entry>
 796                 <entry>'H264'</entry>
 797                 <entry>H264 video elementary stream with start codes.</entry>
 798           </row>
 799           <row id="V4L2-PIX-FMT-H264-NO-SC">
 800                 <entry><constant>V4L2_PIX_FMT_H264_NO_SC</constant></entry>
 801                 <entry>'AVC1'</entry>
 802                 <entry>H264 video elementary stream without start codes.</entry>
 803           </row>
 804           <row id="V4L2-PIX-FMT-H264-MVC">
 805                 <entry><constant>V4L2_PIX_FMT_H264_MVC</constant></entry>
 806                 <entry>'M264'</entry>
 807                 <entry>H264 MVC video elementary stream.</entry>
 808           </row>
 809           <row id="V4L2-PIX-FMT-H263">
 810                 <entry><constant>V4L2_PIX_FMT_H263</constant></entry>
 811                 <entry>'H263'</entry>
 812                 <entry>H263 video elementary stream.</entry>
 813           </row>
 814           <row id="V4L2-PIX-FMT-MPEG1">
 815                 <entry><constant>V4L2_PIX_FMT_MPEG1</constant></entry>
 816                 <entry>'MPG1'</entry>
 817                 <entry>MPEG1 video elementary stream.</entry>
 818           </row>
 819           <row id="V4L2-PIX-FMT-MPEG2">
 820                 <entry><constant>V4L2_PIX_FMT_MPEG2</constant></entry>
 821                 <entry>'MPG2'</entry>
 822                 <entry>MPEG2 video elementary stream.</entry>
 823           </row>
 824           <row id="V4L2-PIX-FMT-MPEG4">
 825                 <entry><constant>V4L2_PIX_FMT_MPEG4</constant></entry>
 826                 <entry>'MPG4'</entry>
 827                 <entry>MPEG4 video elementary stream.</entry>
 828           </row>
 829           <row id="V4L2-PIX-FMT-XVID">
 830                 <entry><constant>V4L2_PIX_FMT_XVID</constant></entry>
 831                 <entry>'XVID'</entry>
 832                 <entry>Xvid video elementary stream.</entry>
 833           </row>
 834           <row id="V4L2-PIX-FMT-VC1-ANNEX-G">
 835                 <entry><constant>V4L2_PIX_FMT_VC1_ANNEX_G</constant></entry>
 836                 <entry>'VC1G'</entry>
 837                 <entry>VC1, SMPTE 421M Annex G compliant stream.</entry>
 838           </row>
 839           <row id="V4L2-PIX-FMT-VC1-ANNEX-L">
 840                 <entry><constant>V4L2_PIX_FMT_VC1_ANNEX_L</constant></entry>
 841                 <entry>'VC1L'</entry>
 842                 <entry>VC1, SMPTE 421M Annex L compliant stream.</entry>
 843           </row>
 844           <row id="V4L2-PIX-FMT-VP8">
 845                 <entry><constant>V4L2_PIX_FMT_VP8</constant></entry>
 846                 <entry>'VP80'</entry>
 847                 <entry>VP8 video elementary stream.</entry>
 848           </row>
 849         </tbody>
 850       </tgroup>
 851     </table>
 852   </section>
 853
 854   <section id="sdr-formats">
 855     <title>SDR Formats</title>
 856
 857     <para>These formats are used for <link linkend="sdr">SDR Capture</link>
 858 interface only.</para>
 859
 860     &sub-sdr-cu08;
 861     &sub-sdr-cu16le;
 862     &sub-sdr-cs08;
 863     &sub-sdr-cs14le;
 864     &sub-sdr-ru12le;
 865
 866   </section>
 867
 868   <section id="pixfmt-reserved">
 869     <title>Reserved Format Identifiers</title>
 870
 871     <para>These formats are not defined by this specification, they
 872 are just listed for reference and to avoid naming conflicts. If you
 873 want to register your own format, send an e-mail to the linux-media mailing
 874 list &v4l-ml; for inclusion in the <filename>videodev2.h</filename>
 875 file. If you want to share your format with other developers add a
 876 link to your documentation and send a copy to the linux-media mailing list
 877 for inclusion in this section. If you think your format should be listed
 878 in a standard format section please make a proposal on the linux-media mailing
 879 list.</para>
 880
 881     <table pgwide="1" frame="none" id="reserved-formats">
 882       <title>Reserved Image Formats</title>
 883       <tgroup cols="3" align="left">
 884         &cs-def;
 885         <thead>
 886           <row>
 887             <entry>Identifier</entry>
 888             <entry>Code</entry>
 889             <entry>Details</entry>
 890           </row>
 891         </thead>
 892         <tbody valign="top">
 893           <row id="V4L2-PIX-FMT-DV">
 894             <entry><constant>V4L2_PIX_FMT_DV</constant></entry>
 895             <entry>'dvsd'</entry>
 896             <entry>unknown</entry>
 897           </row>
 898           <row id="V4L2-PIX-FMT-ET61X251">
 899             <entry><constant>V4L2_PIX_FMT_ET61X251</constant></entry>
 900             <entry>'E625'</entry>
 901             <entry>Compressed format of the ET61X251 driver.</entry>
 902           </row>
 903           <row id="V4L2-PIX-FMT-HI240">
 904             <entry><constant>V4L2_PIX_FMT_HI240</constant></entry>
 905             <entry>'HI24'</entry>
 906             <entry><para>8 bit RGB format used by the BTTV driver.</para></entry>
 907           </row>
 908           <row id="V4L2-PIX-FMT-HM12">
 909             <entry><constant>V4L2_PIX_FMT_HM12</constant></entry>
 910             <entry>'HM12'</entry>
 911             <entry><para>YUV 4:2:0 format used by the
 912 IVTV driver, <ulink url="http://www.ivtvdriver.org/">
 913 http://www.ivtvdriver.org/</ulink></para><para>The format is documented in the
 914 kernel sources in the file <filename>Documentation/video4linux/cx2341x/README.hm12</filename>
 915 </para></entry>
 916           </row>
 917           <row id="V4L2-PIX-FMT-CPIA1">
 918             <entry><constant>V4L2_PIX_FMT_CPIA1</constant></entry>
 919             <entry>'CPIA'</entry>
 920             <entry>YUV format used by the gspca cpia1 driver.</entry>
 921           </row>
 922           <row id="V4L2-PIX-FMT-JPGL">
 923             <entry><constant>V4L2_PIX_FMT_JPGL</constant></entry>
 924             <entry>'JPGL'</entry>
 925             <entry>JPEG-Light format (Pegasus Lossless JPEG)
 926                         used in Divio webcams NW 80x.</entry>
 927           </row>
 928           <row id="V4L2-PIX-FMT-SPCA501">
 929             <entry><constant>V4L2_PIX_FMT_SPCA501</constant></entry>
 930             <entry>'S501'</entry>
 931             <entry>YUYV per line used by the gspca driver.</entry>
 932           </row>
 933           <row id="V4L2-PIX-FMT-SPCA505">
 934             <entry><constant>V4L2_PIX_FMT_SPCA505</constant></entry>
 935             <entry>'S505'</entry>
 936             <entry>YYUV per line used by the gspca driver.</entry>
 937           </row>
 938           <row id="V4L2-PIX-FMT-SPCA508">
 939             <entry><constant>V4L2_PIX_FMT_SPCA508</constant></entry>
 940             <entry>'S508'</entry>
 941             <entry>YUVY per line used by the gspca driver.</entry>
 942           </row>
 943           <row id="V4L2-PIX-FMT-SPCA561">
 944             <entry><constant>V4L2_PIX_FMT_SPCA561</constant></entry>
 945             <entry>'S561'</entry>
 946             <entry>Compressed GBRG Bayer format used by the gspca driver.</entry>
 947           </row>
 948           <row id="V4L2-PIX-FMT-PAC207">
 949             <entry><constant>V4L2_PIX_FMT_PAC207</constant></entry>
 950             <entry>'P207'</entry>
 951             <entry>Compressed BGGR Bayer format used by the gspca driver.</entry>
 952           </row>
 953           <row id="V4L2-PIX-FMT-MR97310A">
 954             <entry><constant>V4L2_PIX_FMT_MR97310A</constant></entry>
 955             <entry>'M310'</entry>
 956             <entry>Compressed BGGR Bayer format used by the gspca driver.</entry>
 957           </row>
 958           <row id="V4L2-PIX-FMT-JL2005BCD">
 959             <entry><constant>V4L2_PIX_FMT_JL2005BCD</constant></entry>
 960             <entry>'JL20'</entry>
 961             <entry>JPEG compressed RGGB Bayer format used by the gspca driver.</entry>
 962           </row>
 963           <row id="V4L2-PIX-FMT-OV511">
 964             <entry><constant>V4L2_PIX_FMT_OV511</constant></entry>
 965             <entry>'O511'</entry>
 966             <entry>OV511 JPEG format used by the gspca driver.</entry>
 967           </row>
 968           <row id="V4L2-PIX-FMT-OV518">
 969             <entry><constant>V4L2_PIX_FMT_OV518</constant></entry>
 970             <entry>'O518'</entry>
 971             <entry>OV518 JPEG format used by the gspca driver.</entry>
 972           </row>
 973           <row id="V4L2-PIX-FMT-PJPG">
 974             <entry><constant>V4L2_PIX_FMT_PJPG</constant></entry>
 975             <entry>'PJPG'</entry>
 976             <entry>Pixart 73xx JPEG format used by the gspca driver.</entry>
 977           </row>
 978           <row id="V4L2-PIX-FMT-SE401">
 979             <entry><constant>V4L2_PIX_FMT_SE401</constant></entry>
 980             <entry>'S401'</entry>
 981             <entry>Compressed RGB format used by the gspca se401 driver</entry>
 982           </row>
 983           <row id="V4L2-PIX-FMT-SQ905C">
 984             <entry><constant>V4L2_PIX_FMT_SQ905C</constant></entry>
 985             <entry>'905C'</entry>
 986             <entry>Compressed RGGB bayer format used by the gspca driver.</entry>
 987           </row>
 988           <row id="V4L2-PIX-FMT-MJPEG">
 989             <entry><constant>V4L2_PIX_FMT_MJPEG</constant></entry>
 990             <entry>'MJPG'</entry>
 991             <entry>Compressed format used by the Zoran driver</entry>
 992           </row>
 993           <row id="V4L2-PIX-FMT-PWC1">
 994             <entry><constant>V4L2_PIX_FMT_PWC1</constant></entry>
 995             <entry>'PWC1'</entry>
 996             <entry>Compressed format of the PWC driver.</entry>
 997           </row>
 998           <row id="V4L2-PIX-FMT-PWC2">
 999             <entry><constant>V4L2_PIX_FMT_PWC2</constant></entry>
1000             <entry>'PWC2'</entry>
1001             <entry>Compressed format of the PWC driver.</entry>
1002           </row>
1003           <row id="V4L2-PIX-FMT-SN9C10X">
1004             <entry><constant>V4L2_PIX_FMT_SN9C10X</constant></entry>
1005             <entry>'S910'</entry>
1006             <entry>Compressed format of the SN9C102 driver.</entry>
1007           </row>
1008           <row id="V4L2-PIX-FMT-SN9C20X-I420">
1009             <entry><constant>V4L2_PIX_FMT_SN9C20X_I420</constant></entry>
1010             <entry>'S920'</entry>
1011             <entry>YUV 4:2:0 format of the gspca sn9c20x driver.</entry>
1012           </row>
1013           <row id="V4L2-PIX-FMT-SN9C2028">
1014             <entry><constant>V4L2_PIX_FMT_SN9C2028</constant></entry>
1015             <entry>'SONX'</entry>
1016             <entry>Compressed GBRG bayer format of the gspca sn9c2028 driver.</entry>
1017           </row>
1018           <row id="V4L2-PIX-FMT-STV0680">
1019             <entry><constant>V4L2_PIX_FMT_STV0680</constant></entry>
1020             <entry>'S680'</entry>
1021             <entry>Bayer format of the gspca stv0680 driver.</entry>
1022           </row>
1023           <row id="V4L2-PIX-FMT-WNVA">
1024             <entry><constant>V4L2_PIX_FMT_WNVA</constant></entry>
1025             <entry>'WNVA'</entry>
1026             <entry><para>Used by the Winnov Videum driver, <ulink
1027 url="http://www.thedirks.org/winnov/">
1028 http://www.thedirks.org/winnov/</ulink></para></entry>
1029           </row>
1030           <row id="V4L2-PIX-FMT-TM6000">
1031             <entry><constant>V4L2_PIX_FMT_TM6000</constant></entry>
1032             <entry>'TM60'</entry>
1033             <entry><para>Used by Trident tm6000</para></entry>
1034           </row>
1035           <row id="V4L2-PIX-FMT-CIT-YYVYUY">
1036             <entry><constant>V4L2_PIX_FMT_CIT_YYVYUY</constant></entry>
1037             <entry>'CITV'</entry>
1038             <entry><para>Used by xirlink CIT, found at IBM webcams.</para>
1039                    <para>Uses one line of Y then 1 line of VYUY</para>
1040             </entry>
1041           </row>
1042           <row id="V4L2-PIX-FMT-KONICA420">
1043             <entry><constant>V4L2_PIX_FMT_KONICA420</constant></entry>
1044             <entry>'KONI'</entry>
1045             <entry><para>Used by Konica webcams.</para>
1046                    <para>YUV420 planar in blocks of 256 pixels.</para>
1047             </entry>
1048           </row>
1049           <row id="V4L2-PIX-FMT-YYUV">
1050             <entry><constant>V4L2_PIX_FMT_YYUV</constant></entry>
1051             <entry>'YYUV'</entry>
1052             <entry>unknown</entry>
1053           </row>
1054           <row id="V4L2-PIX-FMT-Y4">
1055             <entry><constant>V4L2_PIX_FMT_Y4</constant></entry>
1056             <entry>'Y04 '</entry>
1057             <entry>Old 4-bit greyscale format. Only the most significant 4 bits of each byte are used,
1058 the other bits are set to 0.</entry>
1059           </row>
1060           <row id="V4L2-PIX-FMT-Y6">
1061             <entry><constant>V4L2_PIX_FMT_Y6</constant></entry>
1062             <entry>'Y06 '</entry>
1063             <entry>Old 6-bit greyscale format. Only the most significant 6 bits of each byte are used,
1064 the other bits are set to 0.</entry>
1065           </row>
1066           <row id="V4L2-PIX-FMT-S5C-UYVY-JPG">
1067             <entry><constant>V4L2_PIX_FMT_S5C_UYVY_JPG</constant></entry>
1068             <entry>'S5CI'</entry>
1069             <entry>Two-planar format used by Samsung S5C73MX cameras. The
1070 first plane contains interleaved JPEG and UYVY image data, followed by meta data
1071 in form of an array of offsets to the UYVY data blocks. The actual pointer array
1072 follows immediately the interleaved JPEG/UYVY data, the number of entries in
1073 this array equals the height of the UYVY image. Each entry is a 4-byte unsigned
1074 integer in big endian order and it's an offset to a single pixel line of the
1075 UYVY image. The first plane can start either with JPEG or UYVY data chunk. The
1076 size of a single UYVY block equals the UYVY image's width multiplied by 2. The
1077 size of a JPEG chunk depends on the image and can vary with each line.
1078 <para>The second plane, at an offset of 4084 bytes, contains a 4-byte offset to
1079 the pointer array in the first plane. This offset is followed by a 4-byte value
1080 indicating size of the pointer array. All numbers in the second plane are also
1081 in big endian order. Remaining data in the second plane is undefined. The
1082 information in the second plane allows to easily find location of the pointer
1083 array, which can be different for each frame. The size of the pointer array is
1084 constant for given UYVY image height.</para>
1085 <para>In order to extract UYVY and JPEG frames an application can initially set
1086 a data pointer to the start of first plane and then add an offset from the first
1087 entry of the pointers table. Such a pointer indicates start of an UYVY image
1088 pixel line. Whole UYVY line can be copied to a separate buffer. These steps
1089 should be repeated for each line, i.e. the number of entries in the pointer
1090 array. Anything what's in between the UYVY lines is JPEG data and should be
1091 concatenated to form the JPEG stream. </para>
1092 </entry>
1093           </row>
1094         </tbody>
1095       </tgroup>
1096     </table>
1097
1098     <table frame="none" pgwide="1" id="format-flags">
1099       <title>Format Flags</title>
1100       <tgroup cols="3">
1101         &cs-def;
1102         <tbody valign="top">
1103           <row>
1104             <entry><constant>V4L2_PIX_FMT_FLAG_PREMUL_ALPHA</constant></entry>
1105             <entry>0x00000001</entry>
1106             <entry>The color values are premultiplied by the alpha channel
1107 value. For example, if a light blue pixel with 50% transparency was described by
1108 RGBA values (128, 192, 255, 128), the same pixel described with premultiplied
1109 colors would be described by RGBA values (64, 96, 128, 128) </entry>
1110           </row>
1111         </tbody>
1112       </tgroup>
1113     </table>
1114   </section>