Documentation/DocBook/media/dvb/demux.xml

   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, /&#x22C6; Streaming directly to decoder. &#x22C6;/
  16         DMX_OUT_TAP,     /&#x22C6; Output going to a memory buffer &#x22C6;/
  17                          /&#x22C6; (to be retrieved via the read command).&#x22C6;/
  18         DMX_OUT_TS_TAP,  /&#x22C6; Output multiplexed into a new TS  &#x22C6;/
  19                          /&#x22C6; (to be retrieved by reading from the &#x22C6;/
  20                          /&#x22C6; logical DVR device).                 &#x22C6;/
  21         DMX_OUT_TSDEMUX_TAP /&#x22C6; Like TS_TAP but retrieved from the DMX device &#x22C6;/
  22 } dmx_output_t;
  23 </programlisting>
  24 <para><emphasis role="tt">DMX_OUT_TAP</emphasis> delivers the stream output to the demux device on which the ioctl is
  25 called.
  26 </para>
  27 <para><emphasis role="tt">DMX_OUT_TS_TAP</emphasis> routes output to the logical DVR device <emphasis role="tt">/dev/dvb/adapter0/dvr0</emphasis>,
  28 which delivers a TS multiplexed from all filters for which <emphasis role="tt">DMX_OUT_TS_TAP</emphasis> was
  29 specified.
  30 </para>
  31 </section>
  32
  33 <section id="dmx-input-t">
  34 <title>dmx_input_t</title>
  35 <programlisting>
  36 typedef enum
  37 {
  38         DMX_IN_FRONTEND, /&#x22C6; Input from a front-end device.  &#x22C6;/
  39         DMX_IN_DVR       /&#x22C6; Input from the logical DVR device.  &#x22C6;/
  40 } dmx_input_t;
  41 </programlisting>
  42 </section>
  43
  44 <section id="dmx-pes-type-t">
  45 <title>dmx_pes_type_t</title>
  46 <programlisting>
  47 typedef enum
  48 {
  49         DMX_PES_AUDIO0,
  50         DMX_PES_VIDEO0,
  51         DMX_PES_TELETEXT0,
  52         DMX_PES_SUBTITLE0,
  53         DMX_PES_PCR0,
  54
  55         DMX_PES_AUDIO1,
  56         DMX_PES_VIDEO1,
  57         DMX_PES_TELETEXT1,
  58         DMX_PES_SUBTITLE1,
  59         DMX_PES_PCR1,
  60
  61         DMX_PES_AUDIO2,
  62         DMX_PES_VIDEO2,
  63         DMX_PES_TELETEXT2,
  64         DMX_PES_SUBTITLE2,
  65         DMX_PES_PCR2,
  66
  67         DMX_PES_AUDIO3,
  68         DMX_PES_VIDEO3,
  69         DMX_PES_TELETEXT3,
  70         DMX_PES_SUBTITLE3,
  71         DMX_PES_PCR3,
  72
  73         DMX_PES_OTHER
  74 } dmx_pes_type_t;
  75 </programlisting>
  76 </section>
  77
  78 <section id="dmx-filter">
  79 <title>struct dmx_filter</title>
  80  <programlisting>
  81  typedef struct dmx_filter
  82 {
  83         __u8  filter[DMX_FILTER_SIZE];
  84         __u8  mask[DMX_FILTER_SIZE];
  85         __u8  mode[DMX_FILTER_SIZE];
  86 } dmx_filter_t;
  87 </programlisting>
  88 </section>
  89
  90 <section id="dmx-sct-filter-params">
  91 <title>struct dmx_sct_filter_params</title>
  92 <programlisting>
  93 struct dmx_sct_filter_params
  94 {
  95         __u16          pid;
  96         dmx_filter_t   filter;
  97         __u32          timeout;
  98         __u32          flags;
  99 #define DMX_CHECK_CRC       1
 100 #define DMX_ONESHOT         2
 101 #define DMX_IMMEDIATE_START 4
 102 #define DMX_KERNEL_CLIENT   0x8000
 103 };
 104 </programlisting>
 105 </section>
 106
 107 <section id="dmx-pes-filter-params">
 108 <title>struct dmx_pes_filter_params</title>
 109 <programlisting>
 110 struct dmx_pes_filter_params
 111 {
 112         __u16          pid;
 113         dmx_input_t    input;
 114         dmx_output_t   output;
 115         dmx_pes_type_t pes_type;
 116         __u32          flags;
 117 };
 118 </programlisting>
 119 </section>
 120
 121 <section id="dmx-event">
 122 <title>struct dmx_event</title>
 123  <programlisting>
 124  struct dmx_event
 125  {
 126          dmx_event_t          event;
 127          time_t               timeStamp;
 128          union
 129          {
 130                  dmx_scrambling_status_t scrambling;
 131          } u;
 132  };
 133 </programlisting>
 134 </section>
 135
 136 <section id="dmx-stc">
 137 <title>struct dmx_stc</title>
 138  <programlisting>
 139 struct dmx_stc {
 140         unsigned int num;       /&#x22C6; input : which STC? 0..N &#x22C6;/
 141         unsigned int base;      /&#x22C6; output: divisor for stc to get 90 kHz clock &#x22C6;/
 142         __u64 stc;              /&#x22C6; output: stc in 'base'&#x22C6;90 kHz units &#x22C6;/
 143 };
 144 </programlisting>
 145  </section>
 146
 147 </section>
 148
 149 <section id="dmx_fcalls">
 150 <title>Demux Function Calls</title>
 151
 152 <section id="dmx_fopen">
 153 <title>open()</title>
 154 <para>DESCRIPTION
 155 </para>
 156 <informaltable><tgroup cols="1"><tbody><row><entry
 157  align="char">
 158 <para>This system call, used with a device name of /dev/dvb/adapter0/demux0,
 159  allocates a new filter and returns a handle which can be used for subsequent
 160  control of that filter. This call has to be made for each filter to be used, i.e. every
 161  returned file descriptor is a reference to a single filter. /dev/dvb/adapter0/dvr0
 162  is a logical device to be used for retrieving Transport Streams for digital
 163  video recording. When reading from this device a transport stream containing
 164  the packets from all PES filters set in the corresponding demux device
 165  (/dev/dvb/adapter0/demux0) having the output set to DMX_OUT_TS_TAP. A
 166  recorded Transport Stream is replayed by writing to this device. </para>
 167 <para>The significance of blocking or non-blocking mode is described in the
 168  documentation for functions where there is a difference. It does not affect the
 169  semantics of the open() call itself. A device opened in blocking mode can later
 170  be put into non-blocking mode (and vice versa) using the F_SETFL command
 171  of the fcntl system call.</para>
 172 </entry>
 173  </row></tbody></tgroup></informaltable>
 174 <para>SYNOPSIS
 175 </para>
 176 <informaltable><tgroup cols="1"><tbody><row><entry
 177  align="char">
 178 <para>int open(const char &#x22C6;deviceName, int flags);</para>
 179 </entry>
 180  </row></tbody></tgroup></informaltable>
 181 <para>PARAMETERS
 182 </para>
 183 <informaltable><tgroup cols="2"><tbody><row><entry
 184  align="char">
 185 <para>const char
 186  *deviceName</para>
 187 </entry><entry
 188  align="char">
 189 <para>Name of demux device.</para>
 190 </entry>
 191  </row><row><entry
 192  align="char">
 193 <para>int flags</para>
 194 </entry><entry
 195  align="char">
 196 <para>A bit-wise OR of the following flags:</para>
 197 </entry>
 198  </row><row><entry
 199  align="char">
 200 </entry><entry
 201  align="char">
 202 <para>O_RDWR read/write access</para>
 203 </entry>
 204  </row><row><entry
 205  align="char">
 206 </entry><entry
 207  align="char">
 208 <para>O_NONBLOCK open in non-blocking mode</para>
 209 </entry>
 210  </row><row><entry
 211  align="char">
 212 </entry><entry
 213  align="char">
 214 <para>(blocking mode is the default)</para>
 215 </entry>
 216  </row></tbody></tgroup></informaltable>
 217 <para>ERRORS
 218 </para>
 219 <informaltable><tgroup cols="2"><tbody><row><entry
 220  align="char">
 221 <para>ENODEV</para>
 222 </entry><entry
 223  align="char">
 224 <para>Device driver not loaded/available.</para>
 225 </entry>
 226  </row><row><entry
 227  align="char">
 228 <para>EINVAL</para>
 229 </entry><entry
 230  align="char">
 231 <para>Invalid argument.</para>
 232 </entry>
 233  </row><row><entry
 234  align="char">
 235 <para>EMFILE</para>
 236 </entry><entry
 237  align="char">
 238 <para>&#8220;Too many open files&#8221;, i.e. no more filters available.</para>
 239 </entry>
 240  </row><row><entry
 241  align="char">
 242 <para>ENOMEM</para>
 243 </entry><entry
 244  align="char">
 245 <para>The driver failed to allocate enough memory.</para>
 246 </entry>
 247  </row></tbody></tgroup></informaltable>
 248 </section>
 249
 250 <section id="dmx_fclose">
 251 <title>close()</title>
 252 <para>DESCRIPTION
 253 </para>
 254 <informaltable><tgroup cols="1"><tbody><row><entry
 255  align="char">
 256 <para>This system call deactivates and deallocates a filter that was previously
 257  allocated via the open() call.</para>
 258 </entry>
 259  </row></tbody></tgroup></informaltable>
 260 <para>SYNOPSIS
 261 </para>
 262 <informaltable><tgroup cols="1"><tbody><row><entry
 263  align="char">
 264 <para>int close(int fd);</para>
 265 </entry>
 266  </row></tbody></tgroup></informaltable>
 267 <para>PARAMETERS
 268 </para>
 269 <informaltable><tgroup cols="2"><tbody><row><entry
 270  align="char">
 271 <para>int fd</para>
 272 </entry><entry
 273  align="char">
 274 <para>File descriptor returned by a previous call to open().</para>
 275 </entry>
 276  </row></tbody></tgroup></informaltable>
 277 <para>ERRORS
 278 </para>
 279 <informaltable><tgroup cols="2"><tbody><row><entry
 280  align="char">
 281 <para>EBADF</para>
 282 </entry><entry
 283  align="char">
 284 <para>fd is not a valid open file descriptor.</para>
 285 </entry>
 286  </row></tbody></tgroup></informaltable>
 287 </section>
 288
 289 <section id="dmx_fread">
 290 <title>read()</title>
 291 <para>DESCRIPTION
 292 </para>
 293 <informaltable><tgroup cols="1"><tbody><row><entry
 294  align="char">
 295 <para>This system call returns filtered data, which might be section or PES data. The
 296  filtered data is transferred from the driver&#8217;s internal circular buffer to buf. The
 297  maximum amount of data to be transferred is implied by count.</para>
 298 </entry>
 299  </row><row><entry
 300  align="char">
 301 <para>When returning section data the driver always tries to return a complete single
 302  section (even though buf would provide buffer space for more data). If the size
 303  of the buffer is smaller than the section as much as possible will be returned,
 304  and the remaining data will be provided in subsequent calls.</para>
 305 </entry>
 306  </row><row><entry
 307  align="char">
 308 <para>The size of the internal buffer is 2 * 4096 bytes (the size of two maximum
 309  sized sections) by default. The size of this buffer may be changed by using the
 310  DMX_SET_BUFFER_SIZE function. If the buffer is not large enough, or if
 311  the read operations are not performed fast enough, this may result in a buffer
 312  overflow error. In this case EOVERFLOW will be returned, and the circular
 313  buffer will be emptied. This call is blocking if there is no data to return, i.e. the
 314  process will be put to sleep waiting for data, unless the O_NONBLOCK flag
 315  is specified.</para>
 316 </entry>
 317  </row><row><entry
 318  align="char">
 319 <para>Note that in order to be able to read, the filtering process has to be started
 320  by defining either a section or a PES filter by means of the ioctl functions,
 321  and then starting the filtering process via the DMX_START ioctl function
 322  or by setting the DMX_IMMEDIATE_START flag. If the reading is done
 323  from a logical DVR demux device, the data will constitute a Transport Stream
 324  including the packets from all PES filters in the corresponding demux device
 325  /dev/dvb/adapter0/demux0 having the output set to DMX_OUT_TS_TAP.</para>
 326 </entry>
 327  </row></tbody></tgroup></informaltable>
 328 <para>SYNOPSIS
 329 </para>
 330 <informaltable><tgroup cols="1"><tbody><row><entry
 331  align="char">
 332 <para>size_t read(int fd, void &#x22C6;buf, size_t count);</para>
 333 </entry>
 334  </row></tbody></tgroup></informaltable>
 335 <para>PARAMETERS
 336 </para>
 337 <informaltable><tgroup cols="2"><tbody><row><entry
 338  align="char">
 339 <para>int fd</para>
 340 </entry><entry
 341  align="char">
 342 <para>File descriptor returned by a previous call to open().</para>
 343 </entry>
 344  </row><row><entry
 345  align="char">
 346 <para>void *buf</para>
 347 </entry><entry
 348  align="char">
 349 <para>Pointer to the buffer to be used for returned filtered data.</para>
 350 </entry>
 351  </row><row><entry
 352  align="char">
 353 <para>size_t count</para>
 354 </entry><entry
 355  align="char">
 356 <para>Size of buf.</para>
 357 </entry>
 358  </row></tbody></tgroup></informaltable>
 359 <para>ERRORS
 360 </para>
 361 <informaltable><tgroup cols="2"><tbody><row><entry
 362  align="char">
 363 <para>EWOULDBLOCK</para>
 364 </entry><entry
 365  align="char">
 366 <para>No data to return and O_NONBLOCK was specified.</para>
 367 </entry>
 368  </row><row><entry
 369  align="char">
 370 <para>EBADF</para>
 371 </entry><entry
 372  align="char">
 373 <para>fd is not a valid open file descriptor.</para>
 374 </entry>
 375  </row><row><entry
 376  align="char">
 377 <para>ECRC</para>
 378 </entry><entry
 379  align="char">
 380 <para>Last section had a CRC error - no data returned. The
 381  buffer is flushed.</para>
 382 </entry>
 383  </row><row><entry
 384  align="char">
 385 <para>EOVERFLOW</para>
 386 </entry><entry
 387  align="char">
 388 </entry>
 389  </row><row><entry
 390  align="char">
 391 </entry><entry
 392  align="char">
 393 <para>The filtered data was not read from the buffer in due
 394  time, resulting in non-read data being lost. The buffer is
 395  flushed.</para>
 396 </entry>
 397  </row><row><entry
 398  align="char">
 399 <para>ETIMEDOUT</para>
 400 </entry><entry
 401  align="char">
 402 <para>The section was not loaded within the stated timeout
 403  period. See ioctl DMX_SET_FILTER for how to set a
 404  timeout.</para>
 405 </entry>
 406  </row><row><entry
 407  align="char">
 408 <para>EFAULT</para>
 409 </entry><entry
 410  align="char">
 411 <para>The driver failed to write to the callers buffer due to an
 412  invalid *buf pointer.</para>
 413 </entry>
 414  </row></tbody></tgroup></informaltable>
 415 </section>
 416
 417 <section id="dmx_fwrite">
 418 <title>write()</title>
 419 <para>DESCRIPTION
 420 </para>
 421 <informaltable><tgroup cols="1"><tbody><row><entry
 422  align="char">
 423 <para>This system call is only provided by the logical device /dev/dvb/adapter0/dvr0,
 424  associated with the physical demux device that provides the actual DVR
 425  functionality. It is used for replay of a digitally recorded Transport Stream.
 426  Matching filters have to be defined in the corresponding physical demux
 427  device, /dev/dvb/adapter0/demux0. The amount of data to be transferred is
 428  implied by count.</para>
 429 </entry>
 430  </row></tbody></tgroup></informaltable>
 431 <para>SYNOPSIS
 432 </para>
 433 <informaltable><tgroup cols="1"><tbody><row><entry
 434  align="char">
 435 <para>ssize_t write(int fd, const void &#x22C6;buf, size_t
 436  count);</para>
 437 </entry>
 438  </row></tbody></tgroup></informaltable>
 439 <para>PARAMETERS
 440 </para>
 441 <informaltable><tgroup cols="2"><tbody><row><entry
 442  align="char">
 443 <para>int fd</para>
 444 </entry><entry
 445  align="char">
 446 <para>File descriptor returned by a previous call to open().</para>
 447 </entry>
 448  </row><row><entry
 449  align="char">
 450 <para>void *buf</para>
 451 </entry><entry
 452  align="char">
 453 <para>Pointer to the buffer containing the Transport Stream.</para>
 454 </entry>
 455  </row><row><entry
 456  align="char">
 457 <para>size_t count</para>
 458 </entry><entry
 459  align="char">
 460 <para>Size of buf.</para>
 461 </entry>
 462  </row></tbody></tgroup></informaltable>
 463 <para>ERRORS
 464 </para>
 465 <informaltable><tgroup cols="2"><tbody><row><entry
 466  align="char">
 467 <para>EWOULDBLOCK</para>
 468 </entry><entry
 469  align="char">
 470 <para>No data was written. This
 471  might happen if O_NONBLOCK was specified and there
 472  is no more buffer space available (if O_NONBLOCK is
 473  not specified the function will block until buffer space is
 474  available).</para>
 475 </entry>
 476  </row><row><entry
 477  align="char">
 478 <para>EBUSY</para>
 479 </entry><entry
 480  align="char">
 481 <para>This error code indicates that there are conflicting
 482  requests. The corresponding demux device is setup to
 483  receive data from the front- end. Make sure that these
 484  filters are stopped and that the filters with input set to
 485  DMX_IN_DVR are started.</para>
 486 </entry>
 487  </row><row><entry
 488  align="char">
 489 <para>EBADF</para>
 490 </entry><entry
 491  align="char">
 492 <para>fd is not a valid open file descriptor.</para>
 493 </entry>
 494  </row></tbody></tgroup></informaltable>
 495 </section>
 496
 497 <section id="DMX_START">
 498 <title>DMX_START</title>
 499 <para>DESCRIPTION
 500 </para>
 501 <informaltable><tgroup cols="1"><tbody><row><entry
 502  align="char">
 503 <para>This ioctl call is used to start the actual filtering operation defined via the ioctl
 504  calls DMX_SET_FILTER or DMX_SET_PES_FILTER.</para>
 505 </entry>
 506  </row></tbody></tgroup></informaltable>
 507 <para>SYNOPSIS
 508 </para>
 509 <informaltable><tgroup cols="1"><tbody><row><entry
 510  align="char">
 511 <para>int ioctl( int fd, int request = DMX_START);</para>
 512 </entry>
 513  </row></tbody></tgroup></informaltable>
 514 <para>PARAMETERS
 515 </para>
 516 <informaltable><tgroup cols="2"><tbody><row><entry
 517  align="char">
 518 <para>int fd</para>
 519 </entry><entry
 520  align="char">
 521 <para>File descriptor returned by a previous call to open().</para>
 522 </entry>
 523  </row><row><entry
 524  align="char">
 525 <para>int request</para>
 526 </entry><entry
 527  align="char">
 528 <para>Equals DMX_START for this command.</para>
 529 </entry>
 530  </row></tbody></tgroup></informaltable>
 531 <para>ERRORS
 532 </para>
 533 <informaltable><tgroup cols="2"><tbody><row><entry
 534  align="char">
 535 <para>EBADF</para>
 536 </entry><entry
 537  align="char">
 538 <para>fd is not a valid file descriptor.</para>
 539 </entry>
 540  </row><row><entry
 541  align="char">
 542 <para>EINVAL</para>
 543 </entry><entry
 544  align="char">
 545 <para>Invalid argument, i.e. no filtering parameters provided via
 546  the DMX_SET_FILTER or DMX_SET_PES_FILTER
 547  functions.</para>
 548 </entry>
 549  </row><row><entry
 550  align="char">
 551 <para>EBUSY</para>
 552 </entry><entry
 553  align="char">
 554 <para>This error code indicates that there are conflicting
 555  requests. There are active filters filtering data from
 556  another input source. Make sure that these filters are
 557  stopped before starting this filter.</para>
 558 </entry>
 559  </row></tbody></tgroup></informaltable>
 560 </section>
 561
 562 <section id="DMX_STOP">
 563 <title>DMX_STOP</title>
 564 <para>DESCRIPTION
 565 </para>
 566 <informaltable><tgroup cols="1"><tbody><row><entry
 567  align="char">
 568 <para>This ioctl call is used to stop the actual filtering operation defined via the
 569  ioctl calls DMX_SET_FILTER or DMX_SET_PES_FILTER and started via
 570  the DMX_START command.</para>
 571 </entry>
 572  </row></tbody></tgroup></informaltable>
 573 <para>SYNOPSIS
 574 </para>
 575 <informaltable><tgroup cols="1"><tbody><row><entry
 576  align="char">
 577 <para>int ioctl( int fd, int request = DMX_STOP);</para>
 578 </entry>
 579  </row></tbody></tgroup></informaltable>
 580 <para>PARAMETERS
 581 </para>
 582 <informaltable><tgroup cols="2"><tbody><row><entry
 583  align="char">
 584 <para>int fd</para>
 585 </entry><entry
 586  align="char">
 587 <para>File descriptor returned by a previous call to open().</para>
 588 </entry>
 589  </row><row><entry
 590  align="char">
 591 <para>int request</para>
 592 </entry><entry
 593  align="char">
 594 <para>Equals DMX_STOP for this command.</para>
 595 </entry>
 596  </row></tbody></tgroup></informaltable>
 597 <para>ERRORS
 598 </para>
 599 <informaltable><tgroup cols="2"><tbody><row><entry
 600  align="char">
 601 <para>EBADF</para>
 602 </entry><entry
 603  align="char">
 604 <para>fd is not a valid file descriptor.</para>
 605 </entry>
 606  </row></tbody></tgroup></informaltable>
 607 </section>
 608
 609 <section id="DMX_SET_FILTER">
 610 <title>DMX_SET_FILTER</title>
 611 <para>DESCRIPTION
 612 </para>
 613 <informaltable><tgroup cols="1"><tbody><row><entry
 614  align="char">
 615 <para>This ioctl call sets up a filter according to the filter and mask parameters
 616  provided. A timeout may be defined stating number of seconds to wait for a
 617  section to be loaded. A value of 0 means that no timeout should be applied.
 618  Finally there is a flag field where it is possible to state whether a section should
 619  be CRC-checked, whether the filter should be a &#8221;one-shot&#8221; filter, i.e. if the
 620  filtering operation should be stopped after the first section is received, and
 621  whether the filtering operation should be started immediately (without waiting
 622  for a DMX_START ioctl call). If a filter was previously set-up, this filter will
 623  be canceled, and the receive buffer will be flushed.</para>
 624 </entry>
 625  </row></tbody></tgroup></informaltable>
 626 <para>SYNOPSIS
 627 </para>
 628 <informaltable><tgroup cols="1"><tbody><row><entry
 629  align="char">
 630 <para>int ioctl( int fd, int request = DMX_SET_FILTER,
 631  struct dmx_sct_filter_params &#x22C6;params);</para>
 632 </entry>
 633  </row></tbody></tgroup></informaltable>
 634 <para>PARAMETERS
 635 </para>
 636 <informaltable><tgroup cols="2"><tbody><row><entry
 637  align="char">
 638 <para>int fd</para>
 639 </entry><entry
 640  align="char">
 641 <para>File descriptor returned by a previous call to open().</para>
 642 </entry>
 643  </row><row><entry
 644  align="char">
 645 <para>int request</para>
 646 </entry><entry
 647  align="char">
 648 <para>Equals DMX_SET_FILTER for this command.</para>
 649 </entry>
 650  </row><row><entry
 651  align="char">
 652 <para>struct
 653  dmx_sct_filter_params
 654  *params</para>
 655 </entry><entry
 656  align="char">
 657 <para>Pointer to structure containing filter parameters.</para>
 658 </entry>
 659  </row></tbody></tgroup></informaltable>
 660 <para>ERRORS
 661 </para>
 662 <informaltable><tgroup cols="2"><tbody><row><entry
 663  align="char">
 664 <para>EBADF</para>
 665 </entry><entry
 666  align="char">
 667 <para>fd is not a valid file descriptor.</para>
 668 </entry>
 669  </row><row><entry
 670  align="char">
 671 <para>EINVAL</para>
 672 </entry><entry
 673  align="char">
 674 <para>Invalid argument.</para>
 675 </entry>
 676  </row></tbody></tgroup></informaltable>
 677 </section>
 678
 679 <section id="DMX_SET_PES_FILTER">
 680 <title>DMX_SET_PES_FILTER</title>
 681 <para>DESCRIPTION
 682 </para>
 683 <informaltable><tgroup cols="1"><tbody><row><entry
 684  align="char">
 685 <para>This ioctl call sets up a PES filter according to the parameters provided. By a
 686  PES filter is meant a filter that is based just on the packet identifier (PID), i.e.
 687  no PES header or payload filtering capability is supported.</para>
 688 </entry>
 689  </row><row><entry
 690  align="char">
 691 <para>The transport stream destination for the filtered output may be set. Also the
 692  PES type may be stated in order to be able to e.g. direct a video stream directly
 693  to the video decoder. Finally there is a flag field where it is possible to state
 694  whether the filtering operation should be started immediately (without waiting
 695  for a DMX_START ioctl call). If a filter was previously set-up, this filter will
 696  be cancelled, and the receive buffer will be flushed.</para>
 697 </entry>
 698  </row></tbody></tgroup></informaltable>
 699 <para>SYNOPSIS
 700 </para>
 701 <informaltable><tgroup cols="1"><tbody><row><entry
 702  align="char">
 703 <para>int ioctl( int fd, int request = DMX_SET_PES_FILTER,
 704  struct dmx_pes_filter_params &#x22C6;params);</para>
 705 </entry>
 706  </row></tbody></tgroup></informaltable>
 707 <para>PARAMETERS
 708 </para>
 709 <informaltable><tgroup cols="2"><tbody><row><entry
 710  align="char">
 711 <para>int fd</para>
 712 </entry><entry
 713  align="char">
 714 <para>File descriptor returned by a previous call to open().</para>
 715 </entry>
 716  </row><row><entry
 717  align="char">
 718 <para>int request</para>
 719 </entry><entry
 720  align="char">
 721 <para>Equals DMX_SET_PES_FILTER for this command.</para>
 722 </entry>
 723  </row><row><entry
 724  align="char">
 725 <para>struct
 726  dmx_pes_filter_params
 727  *params</para>
 728 </entry><entry
 729  align="char">
 730 <para>Pointer to structure containing filter parameters.</para>
 731 </entry>
 732  </row></tbody></tgroup></informaltable>
 733 <para>ERRORS
 734 </para>
 735 <informaltable><tgroup cols="2"><tbody><row><entry
 736  align="char">
 737 <para>EBADF</para>
 738 </entry><entry
 739  align="char">
 740 <para>fd is not a valid file descriptor.</para>
 741 </entry>
 742  </row><row><entry
 743  align="char">
 744 <para>EINVAL</para>
 745 </entry><entry
 746  align="char">
 747 <para>Invalid argument.</para>
 748 </entry>
 749  </row><row><entry
 750  align="char">
 751 <para>EBUSY</para>
 752 </entry><entry
 753  align="char">
 754 <para>This error code indicates that there are conflicting
 755  requests. There are active filters filtering data from
 756  another input source. Make sure that these filters are
 757  stopped before starting this filter.</para>
 758 </entry>
 759  </row></tbody></tgroup></informaltable>
 760 </section>
 761
 762 <section id="DMX_SET_BUFFER_SIZE">
 763 <title>DMX_SET_BUFFER_SIZE</title>
 764 <para>DESCRIPTION
 765 </para>
 766 <informaltable><tgroup cols="1"><tbody><row><entry
 767  align="char">
 768 <para>This ioctl call is used to set the size of the circular buffer used for filtered data.
 769  The default size is two maximum sized sections, i.e. if this function is not called
 770  a buffer size of 2 * 4096 bytes will be used.</para>
 771 </entry>
 772  </row></tbody></tgroup></informaltable>
 773 <para>SYNOPSIS
 774 </para>
 775 <informaltable><tgroup cols="1"><tbody><row><entry
 776  align="char">
 777 <para>int ioctl( int fd, int request =
 778  DMX_SET_BUFFER_SIZE, unsigned long size);</para>
 779 </entry>
 780  </row></tbody></tgroup></informaltable>
 781 <para>PARAMETERS
 782 </para>
 783 <informaltable><tgroup cols="2"><tbody><row><entry
 784  align="char">
 785 <para>int fd</para>
 786 </entry><entry
 787  align="char">
 788 <para>File descriptor returned by a previous call to open().</para>
 789 </entry>
 790  </row><row><entry
 791  align="char">
 792 <para>int request</para>
 793 </entry><entry
 794  align="char">
 795 <para>Equals DMX_SET_BUFFER_SIZE for this command.</para>
 796 </entry>
 797  </row><row><entry
 798  align="char">
 799 <para>unsigned long size</para>
 800 </entry><entry
 801  align="char">
 802 <para>Size of circular buffer.</para>
 803 </entry>
 804  </row></tbody></tgroup></informaltable>
 805 <para>ERRORS
 806 </para>
 807 <informaltable><tgroup cols="2"><tbody><row><entry
 808  align="char">
 809 <para>EBADF</para>
 810 </entry><entry
 811  align="char">
 812 <para>fd is not a valid file descriptor.</para>
 813 </entry>
 814  </row><row><entry
 815  align="char">
 816 <para>ENOMEM</para>
 817 </entry><entry
 818  align="char">
 819 <para>The driver was not able to allocate a buffer of the
 820  requested size.</para>
 821 </entry>
 822  </row></tbody></tgroup></informaltable>
 823 </section>
 824
 825 <section id="DMX_GET_EVENT">
 826 <title>DMX_GET_EVENT</title>
 827 <para>DESCRIPTION
 828 </para>
 829 <informaltable><tgroup cols="1"><tbody><row><entry
 830  align="char">
 831 <para>This ioctl call returns an event if available. If an event is not available,
 832  the behavior depends on whether the device is in blocking or non-blocking
 833  mode. In the latter case, the call fails immediately with errno set to
 834  EWOULDBLOCK. In the former case, the call blocks until an event becomes
 835  available.</para>
 836 </entry>
 837  </row><row><entry
 838  align="char">
 839 <para>The standard Linux poll() and/or select() system calls can be used with the
 840  device file descriptor to watch for new events. For select(), the file descriptor
 841  should be included in the exceptfds argument, and for poll(), POLLPRI should
 842  be specified as the wake-up condition. Only the latest event for each filter is
 843  saved.</para>
 844 </entry>
 845  </row></tbody></tgroup></informaltable>
 846 <para>SYNOPSIS
 847 </para>
 848 <informaltable><tgroup cols="1"><tbody><row><entry
 849  align="char">
 850 <para>int ioctl( int fd, int request = DMX_GET_EVENT,
 851  struct dmx_event &#x22C6;ev);</para>
 852 </entry>
 853  </row></tbody></tgroup></informaltable>
 854 <para>PARAMETERS
 855 </para>
 856 <informaltable><tgroup cols="2"><tbody><row><entry
 857  align="char">
 858 <para>int fd</para>
 859 </entry><entry
 860  align="char">
 861 <para>File descriptor returned by a previous call to open().</para>
 862 </entry>
 863  </row><row><entry
 864  align="char">
 865 <para>int request</para>
 866 </entry><entry
 867  align="char">
 868 <para>Equals DMX_GET_EVENT for this command.</para>
 869 </entry>
 870  </row><row><entry
 871  align="char">
 872 <para>struct dmx_event *ev</para>
 873 </entry><entry
 874  align="char">
 875 <para>Pointer to the location where the event is to be stored.</para>
 876 </entry>
 877  </row></tbody></tgroup></informaltable>
 878 <para>ERRORS
 879 </para>
 880 <informaltable><tgroup cols="2"><tbody><row><entry
 881  align="char">
 882 <para>EBADF</para>
 883 </entry><entry
 884  align="char">
 885 <para>fd is not a valid file descriptor.</para>
 886 </entry>
 887  </row><row><entry
 888  align="char">
 889 <para>EFAULT</para>
 890 </entry><entry
 891  align="char">
 892 <para>ev points to an invalid address.</para>
 893 </entry>
 894  </row><row><entry
 895  align="char">
 896 <para>EWOULDBLOCK</para>
 897 </entry><entry
 898  align="char">
 899 <para>There is no event pending, and the device is in
 900  non-blocking mode.</para>
 901 </entry>
 902  </row></tbody></tgroup></informaltable>
 903 </section>
 904
 905 <section id="DMX_GET_STC">
 906 <title>DMX_GET_STC</title>
 907 <para>DESCRIPTION
 908 </para>
 909 <informaltable><tgroup cols="1"><tbody><row><entry
 910  align="char">
 911 <para>This ioctl call returns the current value of the system time counter (which is driven
 912  by a PES filter of type DMX_PES_PCR). Some hardware supports more than one
 913  STC, so you must specify which one by setting the num field of stc before the ioctl
 914  (range 0...n). The result is returned in form of a ratio with a 64 bit numerator
 915  and a 32 bit denominator, so the real 90kHz STC value is stc-&#x003E;stc /
 916  stc-&#x003E;base
 917  .</para>
 918 </entry>
 919  </row></tbody></tgroup></informaltable>
 920 <para>SYNOPSIS
 921 </para>
 922 <informaltable><tgroup cols="1"><tbody><row><entry
 923  align="char">
 924 <para>int ioctl( int fd, int request = DMX_GET_STC, struct
 925  dmx_stc &#x22C6;stc);</para>
 926 </entry>
 927  </row></tbody></tgroup></informaltable>
 928 <para>PARAMETERS
 929 </para>
 930 <informaltable><tgroup cols="2"><tbody><row><entry
 931  align="char">
 932 <para>int fd</para>
 933 </entry><entry
 934  align="char">
 935 <para>File descriptor returned by a previous call to open().</para>
 936 </entry>
 937  </row><row><entry
 938  align="char">
 939 <para>int request</para>
 940 </entry><entry
 941  align="char">
 942 <para>Equals DMX_GET_STC for this command.</para>
 943 </entry>
 944  </row><row><entry
 945  align="char">
 946 <para>struct dmx_stc *stc</para>
 947 </entry><entry
 948  align="char">
 949 <para>Pointer to the location where the stc is to be stored.</para>
 950 </entry>
 951  </row></tbody></tgroup></informaltable>
 952 <para>ERRORS
 953 </para>
 954 <informaltable><tgroup cols="2"><tbody><row><entry
 955  align="char">
 956 <para>EBADF</para>
 957 </entry><entry
 958  align="char">
 959 <para>fd is not a valid file descriptor.</para>
 960 </entry>
 961  </row><row><entry
 962  align="char">
 963 <para>EFAULT</para>
 964 </entry><entry
 965  align="char">
 966 <para>stc points to an invalid address.</para>
 967 </entry>
 968  </row><row><entry
 969  align="char">
 970 <para>EINVAL</para>
 971 </entry><entry
 972  align="char">
 973 <para>Invalid stc number.</para>
 974 </entry>
 975  </row></tbody></tgroup></informaltable>
 976  </section></section>