1<refentry id="vidioc-g-tuner"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_G_TUNER, VIDIOC_S_TUNER</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_G_TUNER</refname> 9 <refname>VIDIOC_S_TUNER</refname> 10 <refpurpose>Get or set tuner attributes</refpurpose> 11 </refnamediv> 12 13 <refsynopsisdiv> 14 <funcsynopsis> 15 <funcprototype> 16 <funcdef>int <function>ioctl</function></funcdef> 17 <paramdef>int <parameter>fd</parameter></paramdef> 18 <paramdef>int <parameter>request</parameter></paramdef> 19 <paramdef>struct v4l2_tuner 20*<parameter>argp</parameter></paramdef> 21 </funcprototype> 22 </funcsynopsis> 23 <funcsynopsis> 24 <funcprototype> 25 <funcdef>int <function>ioctl</function></funcdef> 26 <paramdef>int <parameter>fd</parameter></paramdef> 27 <paramdef>int <parameter>request</parameter></paramdef> 28 <paramdef>const struct v4l2_tuner 29*<parameter>argp</parameter></paramdef> 30 </funcprototype> 31 </funcsynopsis> 32 </refsynopsisdiv> 33 34 <refsect1> 35 <title>Arguments</title> 36 37 <variablelist> 38 <varlistentry> 39 <term><parameter>fd</parameter></term> 40 <listitem> 41 <para>&fd;</para> 42 </listitem> 43 </varlistentry> 44 <varlistentry> 45 <term><parameter>request</parameter></term> 46 <listitem> 47 <para>VIDIOC_G_TUNER, VIDIOC_S_TUNER</para> 48 </listitem> 49 </varlistentry> 50 <varlistentry> 51 <term><parameter>argp</parameter></term> 52 <listitem> 53 <para></para> 54 </listitem> 55 </varlistentry> 56 </variablelist> 57 </refsect1> 58 59 <refsect1> 60 <title>Description</title> 61 62 <para>To query the attributes of a tuner applications initialize the 63<structfield>index</structfield> field and zero out the 64<structfield>reserved</structfield> array of a &v4l2-tuner; and call the 65<constant>VIDIOC_G_TUNER</constant> ioctl with a pointer to this 66structure. Drivers fill the rest of the structure or return an 67&EINVAL; when the index is out of bounds. To enumerate all tuners 68applications shall begin at index zero, incrementing by one until the 69driver returns <errorcode>EINVAL</errorcode>.</para> 70 71 <para>Tuners have two writable properties, the audio mode and 72the radio frequency. To change the audio mode, applications initialize 73the <structfield>index</structfield>, 74<structfield>audmode</structfield> and 75<structfield>reserved</structfield> fields and call the 76<constant>VIDIOC_S_TUNER</constant> ioctl. This will 77<emphasis>not</emphasis> change the current tuner, which is determined 78by the current video input. Drivers may choose a different audio mode 79if the requested mode is invalid or unsupported. Since this is a 80<!-- FIXME -->write-only ioctl, it does not return the actually 81selected audio mode.</para> 82 83 <para>To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl 84is available.</para> 85 86 <table pgwide="1" frame="none" id="v4l2-tuner"> 87 <title>struct <structname>v4l2_tuner</structname></title> 88 <tgroup cols="3"> 89 <colspec colname="c1" colwidth="1*" /> 90 <colspec colname="c2" colwidth="1*" /> 91 <colspec colname="c3" colwidth="1*" /> 92 <colspec colname="c4" colwidth="1*" /> 93 <spanspec spanname="hspan" namest="c3" nameend="c4" /> 94 <tbody valign="top"> 95 <row> 96 <entry>__u32</entry> 97 <entry><structfield>index</structfield></entry> 98 <entry spanname="hspan">Identifies the tuner, set by the 99application.</entry> 100 </row> 101 <row> 102 <entry>__u8</entry> 103 <entry><structfield>name</structfield>[32]</entry> 104 <entry spanname="hspan"><para>Name of the tuner, a 105NUL-terminated ASCII string. This information is intended for the 106user.<!-- FIXME Video inputs already have a name, the purpose of this 107field is not quite clear.--></para></entry> 108 </row> 109 <row> 110 <entry>&v4l2-tuner-type;</entry> 111 <entry><structfield>type</structfield></entry> 112 <entry spanname="hspan">Type of the tuner, see <xref 113 linkend="v4l2-tuner-type" />.</entry> 114 </row> 115 <row> 116 <entry>__u32</entry> 117 <entry><structfield>capability</structfield></entry> 118 <entry spanname="hspan"><para>Tuner capability flags, see 119<xref linkend="tuner-capability" />. Audio flags indicate the ability 120to decode audio subprograms. They will <emphasis>not</emphasis> 121change, for example with the current video standard.</para><para>When 122the structure refers to a radio tuner only the 123<constant>V4L2_TUNER_CAP_LOW</constant>, 124<constant>V4L2_TUNER_CAP_STEREO</constant> and 125<constant>V4L2_TUNER_CAP_RDS</constant> flags can be set.</para></entry> 126 </row> 127 <row> 128 <entry>__u32</entry> 129 <entry><structfield>rangelow</structfield></entry> 130 <entry spanname="hspan">The lowest tunable frequency in 131units of 62.5 kHz, or if the <structfield>capability</structfield> 132flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 133Hz.</entry> 134 </row> 135 <row> 136 <entry>__u32</entry> 137 <entry><structfield>rangehigh</structfield></entry> 138 <entry spanname="hspan">The highest tunable frequency in 139units of 62.5 kHz, or if the <structfield>capability</structfield> 140flag <constant>V4L2_TUNER_CAP_LOW</constant> is set, in units of 62.5 141Hz.</entry> 142 </row> 143 <row> 144 <entry>__u32</entry> 145 <entry><structfield>rxsubchans</structfield></entry> 146 <entry spanname="hspan"><para>Some tuners or audio 147decoders can determine the received audio subprograms by analyzing 148audio carriers, pilot tones or other indicators. To pass this 149information drivers set flags defined in <xref 150 linkend="tuner-rxsubchans" /> in this field. For 151example:</para></entry> 152 </row> 153 <row> 154 <entry></entry> 155 <entry></entry> 156 <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> 157 <entry>receiving mono audio</entry> 158 </row> 159 <row> 160 <entry></entry> 161 <entry></entry> 162 <entry><constant>STEREO | SAP</constant></entry> 163 <entry>receiving stereo audio and a secondary audio 164program</entry> 165 </row> 166 <row> 167 <entry></entry> 168 <entry></entry> 169 <entry><constant>MONO | STEREO</constant></entry> 170 <entry>receiving mono or stereo audio, the hardware cannot 171distinguish</entry> 172 </row> 173 <row> 174 <entry></entry> 175 <entry></entry> 176 <entry><constant>LANG1 | LANG2</constant></entry> 177 <entry>receiving bilingual audio</entry> 178 </row> 179 <row> 180 <entry></entry> 181 <entry></entry> 182 <entry><constant>MONO | STEREO | LANG1 | LANG2</constant></entry> 183 <entry>receiving mono, stereo or bilingual 184audio</entry> 185 </row> 186 <row> 187 <entry></entry> 188 <entry></entry> 189 <entry spanname="hspan"><para>When the 190<constant>V4L2_TUNER_CAP_STEREO</constant>, 191<constant>_LANG1</constant>, <constant>_LANG2</constant> or 192<constant>_SAP</constant> flag is cleared in the 193<structfield>capability</structfield> field, the corresponding 194<constant>V4L2_TUNER_SUB_</constant> flag must not be set 195here.</para><para>This field is valid only if this is the tuner of the 196current video input, or when the structure refers to a radio 197tuner.</para></entry> 198 </row> 199 <row> 200 <entry>__u32</entry> 201 <entry><structfield>audmode</structfield></entry> 202 <entry spanname="hspan"><para>The selected audio mode, see 203<xref linkend="tuner-audmode" /> for valid values. The audio mode does 204not affect audio subprogram detection, and like a <link 205linkend="control">control</link> it does not automatically change 206unless the requested mode is invalid or unsupported. See <xref 207 linkend="tuner-matrix" /> for possible results when 208the selected and received audio programs do not 209match.</para><para>Currently this is the only field of struct 210<structname>v4l2_tuner</structname> applications can 211change.</para></entry> 212 </row> 213 <row> 214 <entry>__u32</entry> 215 <entry><structfield>signal</structfield></entry> 216 <entry spanname="hspan">The signal strength if known, ranging 217from 0 to 65535. Higher values indicate a better signal.</entry> 218 </row> 219 <row> 220 <entry>__s32</entry> 221 <entry><structfield>afc</structfield></entry> 222 <entry spanname="hspan">Automatic frequency control: When the 223<structfield>afc</structfield> value is negative, the frequency is too 224low, when positive too high.<!-- FIXME need example what to do when it never 225settles at zero, &ie; range is what? --></entry> 226 </row> 227 <row> 228 <entry>__u32</entry> 229 <entry><structfield>reserved</structfield>[4]</entry> 230 <entry spanname="hspan">Reserved for future extensions. Drivers and 231applications must set the array to zero.</entry> 232 </row> 233 </tbody> 234 </tgroup> 235 </table> 236 237 <table pgwide="1" frame="none" id="v4l2-tuner-type"> 238 <title>enum v4l2_tuner_type</title> 239 <tgroup cols="3"> 240 &cs-def; 241 <tbody valign="top"> 242 <row> 243 <entry><constant>V4L2_TUNER_RADIO</constant></entry> 244 <entry>1</entry> 245 <entry></entry> 246 </row> 247 <row> 248 <entry><constant>V4L2_TUNER_ANALOG_TV</constant></entry> 249 <entry>2</entry> 250 <entry></entry> 251 </row> 252 </tbody> 253 </tgroup> 254 </table> 255 256 <table pgwide="1" frame="none" id="tuner-capability"> 257 <title>Tuner and Modulator Capability Flags</title> 258 <tgroup cols="3"> 259 &cs-def; 260 <tbody valign="top"> 261 <row> 262 <entry><constant>V4L2_TUNER_CAP_LOW</constant></entry> 263 <entry>0x0001</entry> 264 <entry>When set, tuning frequencies are expressed in units of 26562.5 Hz, otherwise in units of 62.5 kHz.</entry> 266 </row> 267 <row> 268 <entry><constant>V4L2_TUNER_CAP_NORM</constant></entry> 269 <entry>0x0002</entry> 270 <entry>This is a multi-standard tuner; the video standard 271can or must be switched. (B/G PAL tuners for example are typically not 272 considered multi-standard because the video standard is automatically 273 determined from the frequency band.) The set of supported video 274 standards is available from the &v4l2-input; pointing to this tuner, 275 see the description of ioctl &VIDIOC-ENUMINPUT; for details. Only 276 <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> 277 </row> 278 <row> 279 <entry><constant>V4L2_TUNER_CAP_STEREO</constant></entry> 280 <entry>0x0010</entry> 281 <entry>Stereo audio reception is supported.</entry> 282 </row> 283 <row> 284 <entry><constant>V4L2_TUNER_CAP_LANG1</constant></entry> 285 <entry>0x0040</entry> 286 <entry>Reception of the primary language of a bilingual 287audio program is supported. Bilingual audio is a feature of 288two-channel systems, transmitting the primary language monaural on the 289main audio carrier and a secondary language monaural on a second 290carrier. Only 291 <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> 292 </row> 293 <row> 294 <entry><constant>V4L2_TUNER_CAP_LANG2</constant></entry> 295 <entry>0x0020</entry> 296 <entry>Reception of the secondary language of a bilingual 297audio program is supported. Only 298 <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</entry> 299 </row> 300 <row> 301 <entry><constant>V4L2_TUNER_CAP_SAP</constant></entry> 302 <entry>0x0020</entry> 303 <entry><para>Reception of a secondary audio program is 304supported. This is a feature of the BTSC system which accompanies the 305NTSC video standard. Two audio carriers are available for mono or 306stereo transmissions of a primary language, and an independent third 307carrier for a monaural secondary language. Only 308 <constant>V4L2_TUNER_ANALOG_TV</constant> tuners can have this capability.</para><para>Note the 309<constant>V4L2_TUNER_CAP_LANG2</constant> and 310<constant>V4L2_TUNER_CAP_SAP</constant> flags are synonyms. 311<constant>V4L2_TUNER_CAP_SAP</constant> applies when the tuner 312supports the <constant>V4L2_STD_NTSC_M</constant> video 313standard.</para><!-- FIXME what if PAL+NTSC and Bi but not SAP? --></entry> 314 </row> 315 <row> 316 <entry><constant>V4L2_TUNER_CAP_RDS</constant></entry> 317 <entry>0x0080</entry> 318 <entry>RDS capture is supported. This capability is only valid for 319radio tuners.</entry> 320 </row> 321 </tbody> 322 </tgroup> 323 </table> 324 325 <table pgwide="1" frame="none" id="tuner-rxsubchans"> 326 <title>Tuner Audio Reception Flags</title> 327 <tgroup cols="3"> 328 &cs-def; 329 <tbody valign="top"> 330 <row> 331 <entry><constant>V4L2_TUNER_SUB_MONO</constant></entry> 332 <entry>0x0001</entry> 333 <entry>The tuner receives a mono audio signal.</entry> 334 </row> 335 <row> 336 <entry><constant>V4L2_TUNER_SUB_STEREO</constant></entry> 337 <entry>0x0002</entry> 338 <entry>The tuner receives a stereo audio signal.</entry> 339 </row> 340 <row> 341 <entry><constant>V4L2_TUNER_SUB_LANG1</constant></entry> 342 <entry>0x0008</entry> 343 <entry>The tuner receives the primary language of a 344bilingual audio signal. Drivers must clear this flag when the current 345video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> 346 </row> 347 <row> 348 <entry><constant>V4L2_TUNER_SUB_LANG2</constant></entry> 349 <entry>0x0004</entry> 350 <entry>The tuner receives the secondary language of a 351bilingual audio signal (or a second audio program).</entry> 352 </row> 353 <row> 354 <entry><constant>V4L2_TUNER_SUB_SAP</constant></entry> 355 <entry>0x0004</entry> 356 <entry>The tuner receives a Second Audio Program. Note the 357<constant>V4L2_TUNER_SUB_LANG2</constant> and 358<constant>V4L2_TUNER_SUB_SAP</constant> flags are synonyms. The 359<constant>V4L2_TUNER_SUB_SAP</constant> flag applies when the 360current video standard is <constant>V4L2_STD_NTSC_M</constant>.</entry> 361 </row> 362 <row> 363 <entry><constant>V4L2_TUNER_SUB_RDS</constant></entry> 364 <entry>0x0010</entry> 365 <entry>The tuner receives an RDS channel.</entry> 366 </row> 367 </tbody> 368 </tgroup> 369 </table> 370 371 <table pgwide="1" frame="none" id="tuner-audmode"> 372 <title>Tuner Audio Modes</title> 373 <tgroup cols="3"> 374 &cs-def; 375 <tbody valign="top"> 376 <row> 377 <entry><constant>V4L2_TUNER_MODE_MONO</constant></entry> 378 <entry>0</entry> 379 <entry>Play mono audio. When the tuner receives a stereo 380signal this a down-mix of the left and right channel. When the tuner 381receives a bilingual or SAP signal this mode selects the primary 382language.</entry> 383 </row> 384 <row> 385 <entry><constant>V4L2_TUNER_MODE_STEREO</constant></entry> 386 <entry>1</entry> 387 <entry><para>Play stereo audio. When the tuner receives 388bilingual audio it may play different languages on the left and right 389channel or the primary language is played on both channels.</para><para>Playing 390different languages in this mode is 391deprecated. New drivers should do this only in 392<constant>MODE_LANG1_LANG2</constant>.</para><para>When the tuner 393receives no stereo signal or does not support stereo reception the 394driver shall fall back to <constant>MODE_MONO</constant>.</para></entry> 395 </row> 396 <row> 397 <entry><constant>V4L2_TUNER_MODE_LANG1</constant></entry> 398 <entry>3</entry> 399 <entry>Play the primary language, mono or stereo. Only 400<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this 401mode.</entry> 402 </row> 403 <row> 404 <entry><constant>V4L2_TUNER_MODE_LANG2</constant></entry> 405 <entry>2</entry> 406 <entry>Play the secondary language, mono. When the tuner 407receives no bilingual audio or SAP, or their reception is not 408supported the driver shall fall back to mono or stereo mode. Only 409<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this 410mode.</entry> 411 </row> 412 <row> 413 <entry><constant>V4L2_TUNER_MODE_SAP</constant></entry> 414 <entry>2</entry> 415 <entry>Play the Second Audio Program. When the tuner 416receives no bilingual audio or SAP, or their reception is not 417supported the driver shall fall back to mono or stereo mode. Only 418<constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this mode. 419Note the <constant>V4L2_TUNER_MODE_LANG2</constant> and 420<constant>V4L2_TUNER_MODE_SAP</constant> are synonyms.</entry> 421 </row> 422 <row> 423 <entry><constant>V4L2_TUNER_MODE_LANG1_LANG2</constant></entry> 424 <entry>4</entry> 425 <entry>Play the primary language on the left channel, the 426secondary language on the right channel. When the tuner receives no 427bilingual audio or SAP, it shall fall back to 428<constant>MODE_LANG1</constant> or <constant>MODE_MONO</constant>. 429Only <constant>V4L2_TUNER_ANALOG_TV</constant> tuners support this 430mode.</entry> 431 </row> 432 </tbody> 433 </tgroup> 434 </table> 435 436 <table pgwide="1" frame="all" id="tuner-matrix"> 437 <title>Tuner Audio Matrix</title> 438 <tgroup cols="6" align="center"> 439 <colspec align="left" /> 440 <colspec colname="c2" colwidth="1*" /> 441 <colspec colwidth="1*" /> 442 <colspec colwidth="1*" /> 443 <colspec colnum="6" colname="c6" colwidth="1*" /> 444 <spanspec namest="c2" nameend="c6" spanname="hspan" align="center" /> 445 <thead> 446 <row> 447 <entry></entry> 448 <entry spanname="hspan">Selected 449<constant>V4L2_TUNER_MODE_</constant></entry> 450 </row> 451 <row> 452 <entry>Received <constant>V4L2_TUNER_SUB_</constant></entry> 453 <entry><constant>MONO</constant></entry> 454 <entry><constant>STEREO</constant></entry> 455 <entry><constant>LANG1</constant></entry> 456 <entry><constant>LANG2 = SAP</constant></entry> 457 <entry><constant>LANG1_LANG2</constant><footnote><para>This 458mode has been added in Linux 2.6.17 and may not be supported by older 459drivers.</para></footnote></entry> 460 </row> 461 </thead> 462 <tbody valign="top"> 463 <row> 464 <entry><constant>MONO</constant></entry> 465 <entry>Mono</entry> 466 <entry>Mono/Mono</entry> 467 <entry>Mono</entry> 468 <entry>Mono</entry> 469 <entry>Mono/Mono</entry> 470 </row> 471 <row> 472 <entry><constant>MONO | SAP</constant></entry> 473 <entry>Mono</entry> 474 <entry>Mono/Mono</entry> 475 <entry>Mono</entry> 476 <entry>SAP</entry> 477 <entry>Mono/SAP (preferred) or Mono/Mono</entry> 478 </row> 479 <row> 480 <entry><constant>STEREO</constant></entry> 481 <entry>L+R</entry> 482 <entry>L/R</entry> 483 <entry>Stereo L/R (preferred) or Mono L+R</entry> 484 <entry>Stereo L/R (preferred) or Mono L+R</entry> 485 <entry>L/R (preferred) or L+R/L+R</entry> 486 </row> 487 <row> 488 <entry><constant>STEREO | SAP</constant></entry> 489 <entry>L+R</entry> 490 <entry>L/R</entry> 491 <entry>Stereo L/R (preferred) or Mono L+R</entry> 492 <entry>SAP</entry> 493 <entry>L+R/SAP (preferred) or L/R or L+R/L+R</entry> 494 </row> 495 <row> 496 <entry><constant>LANG1 | LANG2</constant></entry> 497 <entry>Language 1</entry> 498 <entry>Lang1/Lang2 (deprecated<footnote><para>Playback of 499both languages in <constant>MODE_STEREO</constant> is deprecated. In 500the future drivers should produce only the primary language in this 501mode. Applications should request 502<constant>MODE_LANG1_LANG2</constant> to record both languages or a 503stereo signal.</para></footnote>) or 504Lang1/Lang1</entry> 505 <entry>Language 1</entry> 506 <entry>Language 2</entry> 507 <entry>Lang1/Lang2 (preferred) or Lang1/Lang1</entry> 508 </row> 509 </tbody> 510 </tgroup> 511 </table> 512 </refsect1> 513 514 <refsect1> 515 &return-value; 516 517 <variablelist> 518 <varlistentry> 519 <term><errorcode>EINVAL</errorcode></term> 520 <listitem> 521 <para>The &v4l2-tuner; <structfield>index</structfield> is 522out of bounds.</para> 523 </listitem> 524 </varlistentry> 525 </variablelist> 526 </refsect1> 527</refentry> 528 529<!-- 530Local Variables: 531mode: sgml 532sgml-parent-document: "v4l2.sgml" 533indent-tabs-mode: nil 534End: 535--> 536