Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="vidioc-enumstd"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_ENUMSTD</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_ENUMSTD</refname> 9 <refpurpose>Enumerate supported video standards</refpurpose> 10 </refnamediv> 11 12 <refsynopsisdiv> 13 <funcsynopsis> 14 <funcprototype> 15 <funcdef>int <function>ioctl</function></funcdef> 16 <paramdef>int <parameter>fd</parameter></paramdef> 17 <paramdef>int <parameter>request</parameter></paramdef> 18 <paramdef>struct v4l2_standard *<parameter>argp</parameter></paramdef> 19 </funcprototype> 20 </funcsynopsis> 21 </refsynopsisdiv> 22 23 <refsect1> 24 <title>Arguments</title> 25 26 <variablelist> 27 <varlistentry> 28 <term><parameter>fd</parameter></term> 29 <listitem> 30 <para>&fd;</para> 31 </listitem> 32 </varlistentry> 33 <varlistentry> 34 <term><parameter>request</parameter></term> 35 <listitem> 36 <para>VIDIOC_ENUMSTD</para> 37 </listitem> 38 </varlistentry> 39 <varlistentry> 40 <term><parameter>argp</parameter></term> 41 <listitem> 42 <para></para> 43 </listitem> 44 </varlistentry> 45 </variablelist> 46 </refsect1> 47 48 <refsect1> 49 <title>Description</title> 50 51 <para>To query the attributes of a video standard, 52 especially a custom (driver defined) one, applications initialize the 53 <structfield>index</structfield> field of &v4l2-standard; and call the 54 <constant>VIDIOC_ENUMSTD</constant> ioctl with a pointer to this 55 structure. Drivers fill the rest of the structure or return an 56 &EINVAL; when the index is out of bounds. To enumerate all standards 57 applications shall begin at index zero, incrementing by one until the 58 driver returns <errorcode>EINVAL</errorcode>. Drivers may enumerate a 59 different set of standards after switching the video input or 60 output.<footnote> 61 <para>The supported standards may overlap and we need an 62 unambiguous set to find the current standard returned by 63 <constant>VIDIOC_G_STD</constant>.</para> 64 </footnote></para> 65 66 <table pgwide="1" frame="none" id="v4l2-standard"> 67 <title>struct <structname>v4l2_standard</structname></title> 68 <tgroup cols="3"> 69 &cs-str; 70 <tbody valign="top"> 71 <row> 72 <entry>__u32</entry> 73 <entry><structfield>index</structfield></entry> 74 <entry>Number of the video standard, set by the 75 application.</entry> 76 </row> 77 <row> 78 <entry>&v4l2-std-id;</entry> 79 <entry><structfield>id</structfield></entry> 80 <entry>The bits in this field identify the standard as 81 one of the common standards listed in <xref linkend="v4l2-std-id" />, 82 or if bits 32 to 63 are set as custom standards. Multiple bits can be 83 set if the hardware does not distinguish between these standards, 84 however separate indices do not indicate the opposite. The 85 <structfield>id</structfield> must be unique. No other enumerated 86 <structname>v4l2_standard</structname> structure, for this input or 87 output anyway, can contain the same set of bits.</entry> 88 </row> 89 <row> 90 <entry>__u8</entry> 91 <entry><structfield>name</structfield>[24]</entry> 92 <entry>Name of the standard, a NUL-terminated ASCII 93 string, for example: "PAL-B/G", "NTSC Japan". This information is 94 intended for the user.</entry> 95 </row> 96 <row> 97 <entry>&v4l2-fract;</entry> 98 <entry><structfield>frameperiod</structfield></entry> 99 <entry>The frame period (not field period) is numerator 100 / denominator. For example M/NTSC has a frame period of 1001 / 101 30000 seconds.</entry> 102 </row> 103 <row> 104 <entry>__u32</entry> 105 <entry><structfield>framelines</structfield></entry> 106 <entry>Total lines per frame including blanking, 107 e. g. 625 for B/PAL.</entry> 108 </row> 109 <row> 110 <entry>__u32</entry> 111 <entry><structfield>reserved</structfield>[4]</entry> 112 <entry>Reserved for future extensions. Drivers must set 113 the array to zero.</entry> 114 </row> 115 </tbody> 116 </tgroup> 117 </table> 118 119 <table pgwide="1" frame="none" id="v4l2-fract"> 120 <title>struct <structname>v4l2_fract</structname></title> 121 <tgroup cols="3"> 122 &cs-str; 123 <tbody valign="top"> 124 <row> 125 <entry>__u32</entry> 126 <entry><structfield>numerator</structfield></entry> 127 <entry></entry> 128 </row> 129 <row> 130 <entry>__u32</entry> 131 <entry><structfield>denominator</structfield></entry> 132 <entry></entry> 133 </row> 134 </tbody> 135 </tgroup> 136 </table> 137 138 <table pgwide="1" frame="none" id="v4l2-std-id"> 139 <title>typedef <structname>v4l2_std_id</structname></title> 140 <tgroup cols="3"> 141 &cs-str; 142 <tbody valign="top"> 143 <row> 144 <entry>__u64</entry> 145 <entry><structfield>v4l2_std_id</structfield></entry> 146 <entry>This type is a set, each bit representing another 147 video standard as listed below and in <xref 148 linkend="video-standards" />. The 32 most significant bits are reserved 149 for custom (driver defined) video standards.</entry> 150 </row> 151 </tbody> 152 </tgroup> 153 </table> 154 155 <para><programlisting> 156 #define V4L2_STD_PAL_B ((v4l2_std_id)0x00000001) 157 #define V4L2_STD_PAL_B1 ((v4l2_std_id)0x00000002) 158 #define V4L2_STD_PAL_G ((v4l2_std_id)0x00000004) 159 #define V4L2_STD_PAL_H ((v4l2_std_id)0x00000008) 160 #define V4L2_STD_PAL_I ((v4l2_std_id)0x00000010) 161 #define V4L2_STD_PAL_D ((v4l2_std_id)0x00000020) 162 #define V4L2_STD_PAL_D1 ((v4l2_std_id)0x00000040) 163 #define V4L2_STD_PAL_K ((v4l2_std_id)0x00000080) 164 165 #define V4L2_STD_PAL_M ((v4l2_std_id)0x00000100) 166 #define V4L2_STD_PAL_N ((v4l2_std_id)0x00000200) 167 #define V4L2_STD_PAL_Nc ((v4l2_std_id)0x00000400) 168 #define V4L2_STD_PAL_60 ((v4l2_std_id)0x00000800) 169 </programlisting></para><para><constant>V4L2_STD_PAL_60</constant> is 170 a hybrid standard with 525 lines, 60 Hz refresh rate, and PAL color 171 modulation with a 4.43 MHz color subcarrier. Some PAL video recorders 172 can play back NTSC tapes in this mode for display on a 50/60 Hz agnostic 173 PAL TV.</para><para><programlisting> 174 #define V4L2_STD_NTSC_M ((v4l2_std_id)0x00001000) 175 #define V4L2_STD_NTSC_M_JP ((v4l2_std_id)0x00002000) 176 #define V4L2_STD_NTSC_443 ((v4l2_std_id)0x00004000) 177 </programlisting></para><para><constant>V4L2_STD_NTSC_443</constant> 178 is a hybrid standard with 525 lines, 60 Hz refresh rate, and NTSC 179 color modulation with a 4.43 MHz color 180 subcarrier.</para><para><programlisting> 181 #define V4L2_STD_NTSC_M_KR ((v4l2_std_id)0x00008000) 182 183 #define V4L2_STD_SECAM_B ((v4l2_std_id)0x00010000) 184 #define V4L2_STD_SECAM_D ((v4l2_std_id)0x00020000) 185 #define V4L2_STD_SECAM_G ((v4l2_std_id)0x00040000) 186 #define V4L2_STD_SECAM_H ((v4l2_std_id)0x00080000) 187 #define V4L2_STD_SECAM_K ((v4l2_std_id)0x00100000) 188 #define V4L2_STD_SECAM_K1 ((v4l2_std_id)0x00200000) 189 #define V4L2_STD_SECAM_L ((v4l2_std_id)0x00400000) 190 #define V4L2_STD_SECAM_LC ((v4l2_std_id)0x00800000) 191 192 /* ATSC/HDTV */ 193 #define V4L2_STD_ATSC_8_VSB ((v4l2_std_id)0x01000000) 194 #define V4L2_STD_ATSC_16_VSB ((v4l2_std_id)0x02000000) 195 </programlisting></para><para><!-- ATSC proposal by Mark McClelland, 196 video4linux-list@redhat.com on 17 Oct 2002 197 --><constant>V4L2_STD_ATSC_8_VSB</constant> and 198 <constant>V4L2_STD_ATSC_16_VSB</constant> are U.S. terrestrial digital 199 TV standards. Presently the V4L2 API does not support digital TV. See 200 also the Linux DVB API at <ulink 201 url="https://linuxtv.org">https://linuxtv.org</ulink>.</para> 202 <para><programlisting> 203 #define V4L2_STD_PAL_BG (V4L2_STD_PAL_B |\ 204 V4L2_STD_PAL_B1 |\ 205 V4L2_STD_PAL_G) 206 #define V4L2_STD_B (V4L2_STD_PAL_B |\ 207 V4L2_STD_PAL_B1 |\ 208 V4L2_STD_SECAM_B) 209 #define V4L2_STD_GH (V4L2_STD_PAL_G |\ 210 V4L2_STD_PAL_H |\ 211 V4L2_STD_SECAM_G |\ 212 V4L2_STD_SECAM_H) 213 #define V4L2_STD_PAL_DK (V4L2_STD_PAL_D |\ 214 V4L2_STD_PAL_D1 |\ 215 V4L2_STD_PAL_K) 216 #define V4L2_STD_PAL (V4L2_STD_PAL_BG |\ 217 V4L2_STD_PAL_DK |\ 218 V4L2_STD_PAL_H |\ 219 V4L2_STD_PAL_I) 220 #define V4L2_STD_NTSC (V4L2_STD_NTSC_M |\ 221 V4L2_STD_NTSC_M_JP |\ 222 V4L2_STD_NTSC_M_KR) 223 #define V4L2_STD_MN (V4L2_STD_PAL_M |\ 224 V4L2_STD_PAL_N |\ 225 V4L2_STD_PAL_Nc |\ 226 V4L2_STD_NTSC) 227 #define V4L2_STD_SECAM_DK (V4L2_STD_SECAM_D |\ 228 V4L2_STD_SECAM_K |\ 229 V4L2_STD_SECAM_K1) 230 #define V4L2_STD_DK (V4L2_STD_PAL_DK |\ 231 V4L2_STD_SECAM_DK) 232 233 #define V4L2_STD_SECAM (V4L2_STD_SECAM_B |\ 234 V4L2_STD_SECAM_G |\ 235 V4L2_STD_SECAM_H |\ 236 V4L2_STD_SECAM_DK |\ 237 V4L2_STD_SECAM_L |\ 238 V4L2_STD_SECAM_LC) 239 240 #define V4L2_STD_525_60 (V4L2_STD_PAL_M |\ 241 V4L2_STD_PAL_60 |\ 242 V4L2_STD_NTSC |\ 243 V4L2_STD_NTSC_443) 244 #define V4L2_STD_625_50 (V4L2_STD_PAL |\ 245 V4L2_STD_PAL_N |\ 246 V4L2_STD_PAL_Nc |\ 247 V4L2_STD_SECAM) 248 249 #define V4L2_STD_UNKNOWN 0 250 #define V4L2_STD_ALL (V4L2_STD_525_60 |\ 251 V4L2_STD_625_50) 252 </programlisting></para> 253 254 <table pgwide="1" id="video-standards" orient="land"> 255 <title>Video Standards (based on [<xref linkend="itu470" />])</title> 256 <tgroup cols="12" colsep="1" rowsep="1" align="center"> 257 <colspec colname="c1" align="left" /> 258 <colspec colname="c2" /> 259 <colspec colname="c3" /> 260 <colspec colname="c4" /> 261 <colspec colname="c5" /> 262 <colspec colnum="7" colname="c7" /> 263 <colspec colnum="9" colname="c9" /> 264 <colspec colnum="12" colname="c12" /> 265 <spanspec namest="c2" nameend="c3" spanname="m" align="center" /> 266 <spanspec namest="c4" nameend="c12" spanname="x" align="center" /> 267 <spanspec namest="c5" nameend="c7" spanname="b" align="center" /> 268 <spanspec namest="c9" nameend="c12" spanname="s" align="center" /> 269 <thead> 270 <row> 271 <entry>Characteristics</entry> 272 <entry><para>M/NTSC<footnote><para>Japan uses a standard 273 similar to M/NTSC 274 (V4L2_STD_NTSC_M_JP).</para></footnote></para></entry> 275 <entry>M/PAL</entry> 276 <entry><para>N/PAL<footnote><para> The values in 277 brackets apply to the combination N/PAL a.k.a. 278 N<subscript>C</subscript> used in Argentina 279 (V4L2_STD_PAL_Nc).</para></footnote></para></entry> 280 <entry align="center">B, B1, G/PAL</entry> 281 <entry align="center">D, D1, K/PAL</entry> 282 <entry align="center">H/PAL</entry> 283 <entry align="center">I/PAL</entry> 284 <entry align="center">B, G/SECAM</entry> 285 <entry align="center">D, K/SECAM</entry> 286 <entry align="center">K1/SECAM</entry> 287 <entry align="center">L/SECAM</entry> 288 </row> 289 </thead> 290 <tbody valign="top"> 291 <row> 292 <entry>Frame lines</entry> 293 <entry spanname="m">525</entry> 294 <entry spanname="x">625</entry> 295 </row> 296 <row> 297 <entry>Frame period (s)</entry> 298 <entry spanname="m">1001/30000</entry> 299 <entry spanname="x">1/25</entry> 300 </row> 301 <row> 302 <entry>Chrominance sub-carrier frequency (Hz)</entry> 303 <entry>3579545 ± 10</entry> 304 <entry>3579611.49 ± 10</entry> 305 <entry>4433618.75 ± 5 (3582056.25 306 ± 5)</entry> 307 <entry spanname="b">4433618.75 ± 5</entry> 308 <entry>4433618.75 ± 1</entry> 309 <entry spanname="s">f<subscript>OR</subscript> = 310 4406250 ± 2000, f<subscript>OB</subscript> = 4250000 311 ± 2000</entry> 312 </row> 313 <row> 314 <entry>Nominal radio-frequency channel bandwidth 315 (MHz)</entry> 316 <entry>6</entry> 317 <entry>6</entry> 318 <entry>6</entry> 319 <entry>B: 7; B1, G: 8</entry> 320 <entry>8</entry> 321 <entry>8</entry> 322 <entry>8</entry> 323 <entry>8</entry> 324 <entry>8</entry> 325 <entry>8</entry> 326 <entry>8</entry> 327 </row> 328 <row> 329 <entry>Sound carrier relative to vision carrier 330 (MHz)</entry> 331 <entry>+ 4.5</entry> 332 <entry>+ 4.5</entry> 333 <entry>+ 4.5</entry> 334 <entry><para>+ 5.5 ± 0.001 335 <footnote><para>In the Federal Republic of Germany, Austria, Italy, 336 the Netherlands, Slovakia and Switzerland a system of two sound 337 carriers is used, the frequency of the second carrier being 338 242.1875 kHz above the frequency of the first sound carrier. For 339 stereophonic sound transmissions a similar system is used in 340 Australia.</para></footnote> <footnote><para>New Zealand uses a sound 341 carrier displaced 5.4996 ± 0.0005 MHz from the vision 342 carrier.</para></footnote> <footnote><para>In Denmark, Finland, New 343 Zealand, Sweden and Spain a system of two sound carriers is used. In 344 Iceland, Norway and Poland the same system is being introduced. The 345 second carrier is 5.85 MHz above the vision carrier and is DQPSK 346 modulated with 728 kbit/s sound and data multiplex. (NICAM 347 system)</para></footnote> <footnote><para>In the United Kingdom, a 348 system of two sound carriers is used. The second sound carrier is 349 6.552 MHz above the vision carrier and is DQPSK modulated with a 350 728 kbit/s sound and data multiplex able to carry two sound 351 channels. (NICAM system)</para></footnote></para></entry> 352 <entry>+ 6.5 ± 0.001</entry> 353 <entry>+ 5.5</entry> 354 <entry>+ 5.9996 ± 0.0005</entry> 355 <entry>+ 5.5 ± 0.001</entry> 356 <entry>+ 6.5 ± 0.001</entry> 357 <entry>+ 6.5</entry> 358 <entry><para>+ 6.5 <footnote><para>In France, a 359 digital carrier 5.85 MHz away from the vision carrier may be used in 360 addition to the main sound carrier. It is modulated in differentially 361 encoded QPSK with a 728 kbit/s sound and data multiplexer capable of 362 carrying two sound channels. (NICAM 363 system)</para></footnote></para></entry> 364 </row> 365 </tbody> 366 </tgroup> 367 </table> 368 </refsect1> 369 370 <refsect1> 371 &return-value; 372 373 <variablelist> 374 <varlistentry> 375 <term><errorcode>EINVAL</errorcode></term> 376 <listitem> 377 <para>The &v4l2-standard; <structfield>index</structfield> 378 is out of bounds.</para> 379 </listitem> 380 </varlistentry> 381 <varlistentry> 382 <term><errorcode>ENODATA</errorcode></term> 383 <listitem> 384 <para>Standard video timings are not supported for this input or output.</para> 385 </listitem> 386 </varlistentry> 387 </variablelist> 388 </refsect1> 389 </refentry>
