Based on kernel version 3.0.4. Page generated on 2011-10-03 22:07 EST.
1 <title>DVB Demux Device</title> 2 3 <para>The DVB demux device controls the filters of the DVB hardware/software. It can be 4 accessed through <emphasis role="tt">/dev/adapter0/demux0</emphasis>. Data types and and ioctl definitions can be 5 accessed by including <emphasis role="tt">linux/dvb/dmx.h</emphasis> in your application. 6 </para> 7 <section id="dmx_types"> 8 <title>Demux Data Types</title> 9 10 <section id="dmx_output_t"> 11 <title>dmx_output_t</title> 12 <programlisting> 13 typedef enum 14 { 15 DMX_OUT_DECODER, 16 DMX_OUT_TAP, 17 DMX_OUT_TS_TAP 18 } dmx_output_t; 19 </programlisting> 20 <para><emphasis role="tt">DMX_OUT_TAP</emphasis> delivers the stream output to the demux device on which the ioctl is 21 called. 22 </para> 23 <para><emphasis role="tt">DMX_OUT_TS_TAP</emphasis> routes output to the logical DVR device <emphasis role="tt">/dev/dvb/adapter0/dvr0</emphasis>, 24 which delivers a TS multiplexed from all filters for which <emphasis role="tt">DMX_OUT_TS_TAP</emphasis> was 25 specified. 26 </para> 27 </section> 28 29 <section id="dmx_input_t"> 30 <title>dmx_input_t</title> 31 <programlisting> 32 typedef enum 33 { 34 DMX_IN_FRONTEND, 35 DMX_IN_DVR 36 } dmx_input_t; 37 </programlisting> 38 </section> 39 40 <section id="dmx_pes_type_t"> 41 <title>dmx_pes_type_t</title> 42 <programlisting> 43 typedef enum 44 { 45 DMX_PES_AUDIO, 46 DMX_PES_VIDEO, 47 DMX_PES_TELETEXT, 48 DMX_PES_SUBTITLE, 49 DMX_PES_PCR, 50 DMX_PES_OTHER 51 } dmx_pes_type_t; 52 </programlisting> 53 </section> 54 55 <section id="dmx_event_t"> 56 <title>dmx_event_t</title> 57 <programlisting> 58 typedef enum 59 { 60 DMX_SCRAMBLING_EV, 61 DMX_FRONTEND_EV 62 } dmx_event_t; 63 </programlisting> 64 </section> 65 66 <section id="dmx_scrambling_status_t"> 67 <title>dmx_scrambling_status_t</title> 68 <programlisting> 69 typedef enum 70 { 71 DMX_SCRAMBLING_OFF, 72 DMX_SCRAMBLING_ON 73 } dmx_scrambling_status_t; 74 </programlisting> 75 </section> 76 77 <section id="dmx_filter"> 78 <title>struct dmx_filter</title> 79 <programlisting> 80 typedef struct dmx_filter 81 { 82 uint8_t filter[DMX_FILTER_SIZE]; 83 uint8_t mask[DMX_FILTER_SIZE]; 84 } dmx_filter_t; 85 </programlisting> 86 </section> 87 88 <section id="dmx_sct_filter_params"> 89 <title>struct dmx_sct_filter_params</title> 90 <programlisting> 91 struct dmx_sct_filter_params 92 { 93 uint16_t pid; 94 dmx_filter_t filter; 95 uint32_t timeout; 96 uint32_t flags; 97 #define DMX_CHECK_CRC 1 98 #define DMX_ONESHOT 2 99 #define DMX_IMMEDIATE_START 4 100 }; 101 </programlisting> 102 </section> 103 104 <section id="dmx_pes_filter_params"> 105 <title>struct dmx_pes_filter_params</title> 106 <programlisting> 107 struct dmx_pes_filter_params 108 { 109 uint16_t pid; 110 dmx_input_t input; 111 dmx_output_t output; 112 dmx_pes_type_t pes_type; 113 uint32_t flags; 114 }; 115 </programlisting> 116 </section> 117 118 <section id="dmx_event"> 119 <title>struct dmx_event</title> 120 <programlisting> 121 struct dmx_event 122 { 123 dmx_event_t event; 124 time_t timeStamp; 125 union 126 { 127 dmx_scrambling_status_t scrambling; 128 } u; 129 }; 130 </programlisting> 131 </section> 132 133 <section id="dmx_stc"> 134 <title>struct dmx_stc</title> 135 <programlisting> 136 struct dmx_stc { 137 unsigned int num; /⋆ input : which STC? 0..N ⋆/ 138 unsigned int base; /⋆ output: divisor for stc to get 90 kHz clock ⋆/ 139 uint64_t stc; /⋆ output: stc in 'base'⋆90 kHz units ⋆/ 140 }; 141 </programlisting> 142 </section> 143 144 </section> 145 146 <section id="dmx_fcalls"> 147 <title>Demux Function Calls</title> 148 149 <section id="dmx_fopen"> 150 <title>open()</title> 151 <para>DESCRIPTION 152 </para> 153 <informaltable><tgroup cols="1"><tbody><row><entry 154 align="char"> 155 <para>This system call, used with a device name of /dev/dvb/adapter0/demux0, 156 allocates a new filter and returns a handle which can be used for subsequent 157 control of that filter. This call has to be made for each filter to be used, i.e. every 158 returned file descriptor is a reference to a single filter. /dev/dvb/adapter0/dvr0 159 is a logical device to be used for retrieving Transport Streams for digital 160 video recording. When reading from this device a transport stream containing 161 the packets from all PES filters set in the corresponding demux device 162 (/dev/dvb/adapter0/demux0) having the output set to DMX_OUT_TS_TAP. A 163 recorded Transport Stream is replayed by writing to this device. </para> 164 <para>The significance of blocking or non-blocking mode is described in the 165 documentation for functions where there is a difference. It does not affect the 166 semantics of the open() call itself. A device opened in blocking mode can later 167 be put into non-blocking mode (and vice versa) using the F_SETFL command 168 of the fcntl system call.</para> 169 </entry> 170 </row></tbody></tgroup></informaltable> 171 <para>SYNOPSIS 172 </para> 173 <informaltable><tgroup cols="1"><tbody><row><entry 174 align="char"> 175 <para>int open(const char ⋆deviceName, int flags);</para> 176 </entry> 177 </row></tbody></tgroup></informaltable> 178 <para>PARAMETERS 179 </para> 180 <informaltable><tgroup cols="2"><tbody><row><entry 181 align="char"> 182 <para>const char 183 *deviceName</para> 184 </entry><entry 185 align="char"> 186 <para>Name of demux device.</para> 187 </entry> 188 </row><row><entry 189 align="char"> 190 <para>int flags</para> 191 </entry><entry 192 align="char"> 193 <para>A bit-wise OR of the following flags:</para> 194 </entry> 195 </row><row><entry 196 align="char"> 197 </entry><entry 198 align="char"> 199 <para>O_RDWR read/write access</para> 200 </entry> 201 </row><row><entry 202 align="char"> 203 </entry><entry 204 align="char"> 205 <para>O_NONBLOCK open in non-blocking mode</para> 206 </entry> 207 </row><row><entry 208 align="char"> 209 </entry><entry 210 align="char"> 211 <para>(blocking mode is the default)</para> 212 </entry> 213 </row></tbody></tgroup></informaltable> 214 <para>ERRORS 215 </para> 216 <informaltable><tgroup cols="2"><tbody><row><entry 217 align="char"> 218 <para>ENODEV</para> 219 </entry><entry 220 align="char"> 221 <para>Device driver not loaded/available.</para> 222 </entry> 223 </row><row><entry 224 align="char"> 225 <para>EINVAL</para> 226 </entry><entry 227 align="char"> 228 <para>Invalid argument.</para> 229 </entry> 230 </row><row><entry 231 align="char"> 232 <para>EMFILE</para> 233 </entry><entry 234 align="char"> 235 <para>“Too many open files”, i.e. no more filters available.</para> 236 </entry> 237 </row><row><entry 238 align="char"> 239 <para>ENOMEM</para> 240 </entry><entry 241 align="char"> 242 <para>The driver failed to allocate enough memory.</para> 243 </entry> 244 </row></tbody></tgroup></informaltable> 245 </section> 246 247 <section id="dmx_fclose"> 248 <title>close()</title> 249 <para>DESCRIPTION 250 </para> 251 <informaltable><tgroup cols="1"><tbody><row><entry 252 align="char"> 253 <para>This system call deactivates and deallocates a filter that was previously 254 allocated via the open() call.</para> 255 </entry> 256 </row></tbody></tgroup></informaltable> 257 <para>SYNOPSIS 258 </para> 259 <informaltable><tgroup cols="1"><tbody><row><entry 260 align="char"> 261 <para>int close(int fd);</para> 262 </entry> 263 </row></tbody></tgroup></informaltable> 264 <para>PARAMETERS 265 </para> 266 <informaltable><tgroup cols="2"><tbody><row><entry 267 align="char"> 268 <para>int fd</para> 269 </entry><entry 270 align="char"> 271 <para>File descriptor returned by a previous call to open().</para> 272 </entry> 273 </row></tbody></tgroup></informaltable> 274 <para>ERRORS 275 </para> 276 <informaltable><tgroup cols="2"><tbody><row><entry 277 align="char"> 278 <para>EBADF</para> 279 </entry><entry 280 align="char"> 281 <para>fd is not a valid open file descriptor.</para> 282 </entry> 283 </row></tbody></tgroup></informaltable> 284 </section> 285 286 <section id="dmx_fread"> 287 <title>read()</title> 288 <para>DESCRIPTION 289 </para> 290 <informaltable><tgroup cols="1"><tbody><row><entry 291 align="char"> 292 <para>This system call returns filtered data, which might be section or PES data. The 293 filtered data is transferred from the driver’s internal circular buffer to buf. The 294 maximum amount of data to be transferred is implied by count.</para> 295 </entry> 296 </row><row><entry 297 align="char"> 298 <para>When returning section data the driver always tries to return a complete single 299 section (even though buf would provide buffer space for more data). If the size 300 of the buffer is smaller than the section as much as possible will be returned, 301 and the remaining data will be provided in subsequent calls.</para> 302 </entry> 303 </row><row><entry 304 align="char"> 305 <para>The size of the internal buffer is 2 * 4096 bytes (the size of two maximum 306 sized sections) by default. The size of this buffer may be changed by using the 307 DMX_SET_BUFFER_SIZE function. If the buffer is not large enough, or if 308 the read operations are not performed fast enough, this may result in a buffer 309 overflow error. In this case EOVERFLOW will be returned, and the circular 310 buffer will be emptied. This call is blocking if there is no data to return, i.e. the 311 process will be put to sleep waiting for data, unless the O_NONBLOCK flag 312 is specified.</para> 313 </entry> 314 </row><row><entry 315 align="char"> 316 <para>Note that in order to be able to read, the filtering process has to be started 317 by defining either a section or a PES filter by means of the ioctl functions, 318 and then starting the filtering process via the DMX_START ioctl function 319 or by setting the DMX_IMMEDIATE_START flag. If the reading is done 320 from a logical DVR demux device, the data will constitute a Transport Stream 321 including the packets from all PES filters in the corresponding demux device 322 /dev/dvb/adapter0/demux0 having the output set to DMX_OUT_TS_TAP.</para> 323 </entry> 324 </row></tbody></tgroup></informaltable> 325 <para>SYNOPSIS 326 </para> 327 <informaltable><tgroup cols="1"><tbody><row><entry 328 align="char"> 329 <para>size_t read(int fd, void ⋆buf, size_t count);</para> 330 </entry> 331 </row></tbody></tgroup></informaltable> 332 <para>PARAMETERS 333 </para> 334 <informaltable><tgroup cols="2"><tbody><row><entry 335 align="char"> 336 <para>int fd</para> 337 </entry><entry 338 align="char"> 339 <para>File descriptor returned by a previous call to open().</para> 340 </entry> 341 </row><row><entry 342 align="char"> 343 <para>void *buf</para> 344 </entry><entry 345 align="char"> 346 <para>Pointer to the buffer to be used for returned filtered data.</para> 347 </entry> 348 </row><row><entry 349 align="char"> 350 <para>size_t count</para> 351 </entry><entry 352 align="char"> 353 <para>Size of buf.</para> 354 </entry> 355 </row></tbody></tgroup></informaltable> 356 <para>ERRORS 357 </para> 358 <informaltable><tgroup cols="2"><tbody><row><entry 359 align="char"> 360 <para>EWOULDBLOCK</para> 361 </entry><entry 362 align="char"> 363 <para>No data to return and O_NONBLOCK was specified.</para> 364 </entry> 365 </row><row><entry 366 align="char"> 367 <para>EBADF</para> 368 </entry><entry 369 align="char"> 370 <para>fd is not a valid open file descriptor.</para> 371 </entry> 372 </row><row><entry 373 align="char"> 374 <para>ECRC</para> 375 </entry><entry 376 align="char"> 377 <para>Last section had a CRC error - no data returned. The 378 buffer is flushed.</para> 379 </entry> 380 </row><row><entry 381 align="char"> 382 <para>EOVERFLOW</para> 383 </entry><entry 384 align="char"> 385 </entry> 386 </row><row><entry 387 align="char"> 388 </entry><entry 389 align="char"> 390 <para>The filtered data was not read from the buffer in due 391 time, resulting in non-read data being lost. The buffer is 392 flushed.</para> 393 </entry> 394 </row><row><entry 395 align="char"> 396 <para>ETIMEDOUT</para> 397 </entry><entry 398 align="char"> 399 <para>The section was not loaded within the stated timeout 400 period. See ioctl DMX_SET_FILTER for how to set a 401 timeout.</para> 402 </entry> 403 </row><row><entry 404 align="char"> 405 <para>EFAULT</para> 406 </entry><entry 407 align="char"> 408 <para>The driver failed to write to the callers buffer due to an 409 invalid *buf pointer.</para> 410 </entry> 411 </row></tbody></tgroup></informaltable> 412 </section> 413 414 <section id="dmx_fwrite"> 415 <title>write()</title> 416 <para>DESCRIPTION 417 </para> 418 <informaltable><tgroup cols="1"><tbody><row><entry 419 align="char"> 420 <para>This system call is only provided by the logical device /dev/dvb/adapter0/dvr0, 421 associated with the physical demux device that provides the actual DVR 422 functionality. It is used for replay of a digitally recorded Transport Stream. 423 Matching filters have to be defined in the corresponding physical demux 424 device, /dev/dvb/adapter0/demux0. The amount of data to be transferred is 425 implied by count.</para> 426 </entry> 427 </row></tbody></tgroup></informaltable> 428 <para>SYNOPSIS 429 </para> 430 <informaltable><tgroup cols="1"><tbody><row><entry 431 align="char"> 432 <para>ssize_t write(int fd, const void ⋆buf, size_t 433 count);</para> 434 </entry> 435 </row></tbody></tgroup></informaltable> 436 <para>PARAMETERS 437 </para> 438 <informaltable><tgroup cols="2"><tbody><row><entry 439 align="char"> 440 <para>int fd</para> 441 </entry><entry 442 align="char"> 443 <para>File descriptor returned by a previous call to open().</para> 444 </entry> 445 </row><row><entry 446 align="char"> 447 <para>void *buf</para> 448 </entry><entry 449 align="char"> 450 <para>Pointer to the buffer containing the Transport Stream.</para> 451 </entry> 452 </row><row><entry 453 align="char"> 454 <para>size_t count</para> 455 </entry><entry 456 align="char"> 457 <para>Size of buf.</para> 458 </entry> 459 </row></tbody></tgroup></informaltable> 460 <para>ERRORS 461 </para> 462 <informaltable><tgroup cols="2"><tbody><row><entry 463 align="char"> 464 <para>EWOULDBLOCK</para> 465 </entry><entry 466 align="char"> 467 <para>No data was written. This 468 might happen if O_NONBLOCK was specified and there 469 is no more buffer space available (if O_NONBLOCK is 470 not specified the function will block until buffer space is 471 available).</para> 472 </entry> 473 </row><row><entry 474 align="char"> 475 <para>EBUSY</para> 476 </entry><entry 477 align="char"> 478 <para>This error code indicates that there are conflicting 479 requests. The corresponding demux device is setup to 480 receive data from the front- end. Make sure that these 481 filters are stopped and that the filters with input set to 482 DMX_IN_DVR are started.</para> 483 </entry> 484 </row><row><entry 485 align="char"> 486 <para>EBADF</para> 487 </entry><entry 488 align="char"> 489 <para>fd is not a valid open file descriptor.</para> 490 </entry> 491 </row></tbody></tgroup></informaltable> 492 </section> 493 494 <section id="dmx_start"> 495 <title>DMX_START</title> 496 <para>DESCRIPTION 497 </para> 498 <informaltable><tgroup cols="1"><tbody><row><entry 499 align="char"> 500 <para>This ioctl call is used to start the actual filtering operation defined via the ioctl 501 calls DMX_SET_FILTER or DMX_SET_PES_FILTER.</para> 502 </entry> 503 </row></tbody></tgroup></informaltable> 504 <para>SYNOPSIS 505 </para> 506 <informaltable><tgroup cols="1"><tbody><row><entry 507 align="char"> 508 <para>int ioctl( int fd, int request = DMX_START);</para> 509 </entry> 510 </row></tbody></tgroup></informaltable> 511 <para>PARAMETERS 512 </para> 513 <informaltable><tgroup cols="2"><tbody><row><entry 514 align="char"> 515 <para>int fd</para> 516 </entry><entry 517 align="char"> 518 <para>File descriptor returned by a previous call to open().</para> 519 </entry> 520 </row><row><entry 521 align="char"> 522 <para>int request</para> 523 </entry><entry 524 align="char"> 525 <para>Equals DMX_START for this command.</para> 526 </entry> 527 </row></tbody></tgroup></informaltable> 528 <para>ERRORS 529 </para> 530 <informaltable><tgroup cols="2"><tbody><row><entry 531 align="char"> 532 <para>EBADF</para> 533 </entry><entry 534 align="char"> 535 <para>fd is not a valid file descriptor.</para> 536 </entry> 537 </row><row><entry 538 align="char"> 539 <para>EINVAL</para> 540 </entry><entry 541 align="char"> 542 <para>Invalid argument, i.e. no filtering parameters provided via 543 the DMX_SET_FILTER or DMX_SET_PES_FILTER 544 functions.</para> 545 </entry> 546 </row><row><entry 547 align="char"> 548 <para>EBUSY</para> 549 </entry><entry 550 align="char"> 551 <para>This error code indicates that there are conflicting 552 requests. There are active filters filtering data from 553 another input source. Make sure that these filters are 554 stopped before starting this filter.</para> 555 </entry> 556 </row></tbody></tgroup></informaltable> 557 </section> 558 559 <section id="dmx_stop"> 560 <title>DMX_STOP</title> 561 <para>DESCRIPTION 562 </para> 563 <informaltable><tgroup cols="1"><tbody><row><entry 564 align="char"> 565 <para>This ioctl call is used to stop the actual filtering operation defined via the 566 ioctl calls DMX_SET_FILTER or DMX_SET_PES_FILTER and started via 567 the DMX_START command.</para> 568 </entry> 569 </row></tbody></tgroup></informaltable> 570 <para>SYNOPSIS 571 </para> 572 <informaltable><tgroup cols="1"><tbody><row><entry 573 align="char"> 574 <para>int ioctl( int fd, int request = DMX_STOP);</para> 575 </entry> 576 </row></tbody></tgroup></informaltable> 577 <para>PARAMETERS 578 </para> 579 <informaltable><tgroup cols="2"><tbody><row><entry 580 align="char"> 581 <para>int fd</para> 582 </entry><entry 583 align="char"> 584 <para>File descriptor returned by a previous call to open().</para> 585 </entry> 586 </row><row><entry 587 align="char"> 588 <para>int request</para> 589 </entry><entry 590 align="char"> 591 <para>Equals DMX_STOP for this command.</para> 592 </entry> 593 </row></tbody></tgroup></informaltable> 594 <para>ERRORS 595 </para> 596 <informaltable><tgroup cols="2"><tbody><row><entry 597 align="char"> 598 <para>EBADF</para> 599 </entry><entry 600 align="char"> 601 <para>fd is not a valid file descriptor.</para> 602 </entry> 603 </row></tbody></tgroup></informaltable> 604 </section> 605 606 <section id="dmx_set_filter"> 607 <title>DMX_SET_FILTER</title> 608 <para>DESCRIPTION 609 </para> 610 <informaltable><tgroup cols="1"><tbody><row><entry 611 align="char"> 612 <para>This ioctl call sets up a filter according to the filter and mask parameters 613 provided. A timeout may be defined stating number of seconds to wait for a 614 section to be loaded. A value of 0 means that no timeout should be applied. 615 Finally there is a flag field where it is possible to state whether a section should 616 be CRC-checked, whether the filter should be a ”one-shot” filter, i.e. if the 617 filtering operation should be stopped after the first section is received, and 618 whether the filtering operation should be started immediately (without waiting 619 for a DMX_START ioctl call). If a filter was previously set-up, this filter will 620 be canceled, and the receive buffer will be flushed.</para> 621 </entry> 622 </row></tbody></tgroup></informaltable> 623 <para>SYNOPSIS 624 </para> 625 <informaltable><tgroup cols="1"><tbody><row><entry 626 align="char"> 627 <para>int ioctl( int fd, int request = DMX_SET_FILTER, 628 struct dmx_sct_filter_params ⋆params);</para> 629 </entry> 630 </row></tbody></tgroup></informaltable> 631 <para>PARAMETERS 632 </para> 633 <informaltable><tgroup cols="2"><tbody><row><entry 634 align="char"> 635 <para>int fd</para> 636 </entry><entry 637 align="char"> 638 <para>File descriptor returned by a previous call to open().</para> 639 </entry> 640 </row><row><entry 641 align="char"> 642 <para>int request</para> 643 </entry><entry 644 align="char"> 645 <para>Equals DMX_SET_FILTER for this command.</para> 646 </entry> 647 </row><row><entry 648 align="char"> 649 <para>struct 650 dmx_sct_filter_params 651 *params</para> 652 </entry><entry 653 align="char"> 654 <para>Pointer to structure containing filter parameters.</para> 655 </entry> 656 </row></tbody></tgroup></informaltable> 657 <para>ERRORS 658 </para> 659 <informaltable><tgroup cols="2"><tbody><row><entry 660 align="char"> 661 <para>EBADF</para> 662 </entry><entry 663 align="char"> 664 <para>fd is not a valid file descriptor.</para> 665 </entry> 666 </row><row><entry 667 align="char"> 668 <para>EINVAL</para> 669 </entry><entry 670 align="char"> 671 <para>Invalid argument.</para> 672 </entry> 673 </row></tbody></tgroup></informaltable> 674 </section> 675 676 <section id="dmx_set_pes_filter"> 677 <title>DMX_SET_PES_FILTER</title> 678 <para>DESCRIPTION 679 </para> 680 <informaltable><tgroup cols="1"><tbody><row><entry 681 align="char"> 682 <para>This ioctl call sets up a PES filter according to the parameters provided. By a 683 PES filter is meant a filter that is based just on the packet identifier (PID), i.e. 684 no PES header or payload filtering capability is supported.</para> 685 </entry> 686 </row><row><entry 687 align="char"> 688 <para>The transport stream destination for the filtered output may be set. Also the 689 PES type may be stated in order to be able to e.g. direct a video stream directly 690 to the video decoder. Finally there is a flag field where it is possible to state 691 whether the filtering operation should be started immediately (without waiting 692 for a DMX_START ioctl call). If a filter was previously set-up, this filter will 693 be cancelled, and the receive buffer will be flushed.</para> 694 </entry> 695 </row></tbody></tgroup></informaltable> 696 <para>SYNOPSIS 697 </para> 698 <informaltable><tgroup cols="1"><tbody><row><entry 699 align="char"> 700 <para>int ioctl( int fd, int request = DMX_SET_PES_FILTER, 701 struct dmx_pes_filter_params ⋆params);</para> 702 </entry> 703 </row></tbody></tgroup></informaltable> 704 <para>PARAMETERS 705 </para> 706 <informaltable><tgroup cols="2"><tbody><row><entry 707 align="char"> 708 <para>int fd</para> 709 </entry><entry 710 align="char"> 711 <para>File descriptor returned by a previous call to open().</para> 712 </entry> 713 </row><row><entry 714 align="char"> 715 <para>int request</para> 716 </entry><entry 717 align="char"> 718 <para>Equals DMX_SET_PES_FILTER for this command.</para> 719 </entry> 720 </row><row><entry 721 align="char"> 722 <para>struct 723 dmx_pes_filter_params 724 *params</para> 725 </entry><entry 726 align="char"> 727 <para>Pointer to structure containing filter parameters.</para> 728 </entry> 729 </row></tbody></tgroup></informaltable> 730 <para>ERRORS 731 </para> 732 <informaltable><tgroup cols="2"><tbody><row><entry 733 align="char"> 734 <para>EBADF</para> 735 </entry><entry 736 align="char"> 737 <para>fd is not a valid file descriptor.</para> 738 </entry> 739 </row><row><entry 740 align="char"> 741 <para>EINVAL</para> 742 </entry><entry 743 align="char"> 744 <para>Invalid argument.</para> 745 </entry> 746 </row><row><entry 747 align="char"> 748 <para>EBUSY</para> 749 </entry><entry 750 align="char"> 751 <para>This error code indicates that there are conflicting 752 requests. There are active filters filtering data from 753 another input source. Make sure that these filters are 754 stopped before starting this filter.</para> 755 </entry> 756 </row></tbody></tgroup></informaltable> 757 </section> 758 759 <section id="dms_set_buffer_size"> 760 <title>DMX_SET_BUFFER_SIZE</title> 761 <para>DESCRIPTION 762 </para> 763 <informaltable><tgroup cols="1"><tbody><row><entry 764 align="char"> 765 <para>This ioctl call is used to set the size of the circular buffer used for filtered data. 766 The default size is two maximum sized sections, i.e. if this function is not called 767 a buffer size of 2 * 4096 bytes will be used.</para> 768 </entry> 769 </row></tbody></tgroup></informaltable> 770 <para>SYNOPSIS 771 </para> 772 <informaltable><tgroup cols="1"><tbody><row><entry 773 align="char"> 774 <para>int ioctl( int fd, int request = 775 DMX_SET_BUFFER_SIZE, unsigned long size);</para> 776 </entry> 777 </row></tbody></tgroup></informaltable> 778 <para>PARAMETERS 779 </para> 780 <informaltable><tgroup cols="2"><tbody><row><entry 781 align="char"> 782 <para>int fd</para> 783 </entry><entry 784 align="char"> 785 <para>File descriptor returned by a previous call to open().</para> 786 </entry> 787 </row><row><entry 788 align="char"> 789 <para>int request</para> 790 </entry><entry 791 align="char"> 792 <para>Equals DMX_SET_BUFFER_SIZE for this command.</para> 793 </entry> 794 </row><row><entry 795 align="char"> 796 <para>unsigned long size</para> 797 </entry><entry 798 align="char"> 799 <para>Size of circular buffer.</para> 800 </entry> 801 </row></tbody></tgroup></informaltable> 802 <para>ERRORS 803 </para> 804 <informaltable><tgroup cols="2"><tbody><row><entry 805 align="char"> 806 <para>EBADF</para> 807 </entry><entry 808 align="char"> 809 <para>fd is not a valid file descriptor.</para> 810 </entry> 811 </row><row><entry 812 align="char"> 813 <para>ENOMEM</para> 814 </entry><entry 815 align="char"> 816 <para>The driver was not able to allocate a buffer of the 817 requested size.</para> 818 </entry> 819 </row></tbody></tgroup></informaltable> 820 </section> 821 822 <section id="dmx_get_event"> 823 <title>DMX_GET_EVENT</title> 824 <para>DESCRIPTION 825 </para> 826 <informaltable><tgroup cols="1"><tbody><row><entry 827 align="char"> 828 <para>This ioctl call returns an event if available. If an event is not available, 829 the behavior depends on whether the device is in blocking or non-blocking 830 mode. In the latter case, the call fails immediately with errno set to 831 EWOULDBLOCK. In the former case, the call blocks until an event becomes 832 available.</para> 833 </entry> 834 </row><row><entry 835 align="char"> 836 <para>The standard Linux poll() and/or select() system calls can be used with the 837 device file descriptor to watch for new events. For select(), the file descriptor 838 should be included in the exceptfds argument, and for poll(), POLLPRI should 839 be specified as the wake-up condition. Only the latest event for each filter is 840 saved.</para> 841 </entry> 842 </row></tbody></tgroup></informaltable> 843 <para>SYNOPSIS 844 </para> 845 <informaltable><tgroup cols="1"><tbody><row><entry 846 align="char"> 847 <para>int ioctl( int fd, int request = DMX_GET_EVENT, 848 struct dmx_event ⋆ev);</para> 849 </entry> 850 </row></tbody></tgroup></informaltable> 851 <para>PARAMETERS 852 </para> 853 <informaltable><tgroup cols="2"><tbody><row><entry 854 align="char"> 855 <para>int fd</para> 856 </entry><entry 857 align="char"> 858 <para>File descriptor returned by a previous call to open().</para> 859 </entry> 860 </row><row><entry 861 align="char"> 862 <para>int request</para> 863 </entry><entry 864 align="char"> 865 <para>Equals DMX_GET_EVENT for this command.</para> 866 </entry> 867 </row><row><entry 868 align="char"> 869 <para>struct dmx_event *ev</para> 870 </entry><entry 871 align="char"> 872 <para>Pointer to the location where the event is to be stored.</para> 873 </entry> 874 </row></tbody></tgroup></informaltable> 875 <para>ERRORS 876 </para> 877 <informaltable><tgroup cols="2"><tbody><row><entry 878 align="char"> 879 <para>EBADF</para> 880 </entry><entry 881 align="char"> 882 <para>fd is not a valid file descriptor.</para> 883 </entry> 884 </row><row><entry 885 align="char"> 886 <para>EFAULT</para> 887 </entry><entry 888 align="char"> 889 <para>ev points to an invalid address.</para> 890 </entry> 891 </row><row><entry 892 align="char"> 893 <para>EWOULDBLOCK</para> 894 </entry><entry 895 align="char"> 896 <para>There is no event pending, and the device is in 897 non-blocking mode.</para> 898 </entry> 899 </row></tbody></tgroup></informaltable> 900 </section> 901 902 <section id="dmx_get_stc"> 903 <title>DMX_GET_STC</title> 904 <para>DESCRIPTION 905 </para> 906 <informaltable><tgroup cols="1"><tbody><row><entry 907 align="char"> 908 <para>This ioctl call returns the current value of the system time counter (which is driven 909 by a PES filter of type DMX_PES_PCR). Some hardware supports more than one 910 STC, so you must specify which one by setting the num field of stc before the ioctl 911 (range 0...n). The result is returned in form of a ratio with a 64 bit numerator 912 and a 32 bit denominator, so the real 90kHz STC value is stc->stc / 913 stc->base 914 .</para> 915 </entry> 916 </row></tbody></tgroup></informaltable> 917 <para>SYNOPSIS 918 </para> 919 <informaltable><tgroup cols="1"><tbody><row><entry 920 align="char"> 921 <para>int ioctl( int fd, int request = DMX_GET_STC, struct 922 dmx_stc ⋆stc);</para> 923 </entry> 924 </row></tbody></tgroup></informaltable> 925 <para>PARAMETERS 926 </para> 927 <informaltable><tgroup cols="2"><tbody><row><entry 928 align="char"> 929 <para>int fd</para> 930 </entry><entry 931 align="char"> 932 <para>File descriptor returned by a previous call to open().</para> 933 </entry> 934 </row><row><entry 935 align="char"> 936 <para>int request</para> 937 </entry><entry 938 align="char"> 939 <para>Equals DMX_GET_STC for this command.</para> 940 </entry> 941 </row><row><entry 942 align="char"> 943 <para>struct dmx_stc *stc</para> 944 </entry><entry 945 align="char"> 946 <para>Pointer to the location where the stc is to be stored.</para> 947 </entry> 948 </row></tbody></tgroup></informaltable> 949 <para>ERRORS 950 </para> 951 <informaltable><tgroup cols="2"><tbody><row><entry 952 align="char"> 953 <para>EBADF</para> 954 </entry><entry 955 align="char"> 956 <para>fd is not a valid file descriptor.</para> 957 </entry> 958 </row><row><entry 959 align="char"> 960 <para>EFAULT</para> 961 </entry><entry 962 align="char"> 963 <para>stc points to an invalid address.</para> 964 </entry> 965 </row><row><entry 966 align="char"> 967 <para>EINVAL</para> 968 </entry><entry 969 align="char"> 970 <para>Invalid stc number.</para> 971 </entry> 972 </row></tbody></tgroup></informaltable> 973 </section></section>
