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1<title>DVB Audio Device</title>
2<para>The DVB audio device controls the MPEG2 audio decoder of the DVB hardware. It
3can be accessed through <emphasis role="tt">/dev/dvb/adapter0/audio0</emphasis>. Data types and and
4ioctl definitions can be accessed by including <emphasis role="tt">linux/dvb/video.h</emphasis> in your
5application.
6</para>
7<para>Please note that some DVB cards don&#8217;t have their own MPEG decoder, which results in
8the omission of the audio and video device.
9</para>
10
11<section id="audio_data_types">
12<title>Audio Data Types</title>
13<para>This section describes the structures, data types and defines used when talking to the
14audio device.
15</para>
16
17<section id="audio-stream-source-t">
18<title>audio_stream_source_t</title>
19<para>The audio stream source is set through the AUDIO_SELECT_SOURCE call and can take
20the following values, depending on whether we are replaying from an internal (demux) or
21external (user write) source.
22</para>
23<programlisting>
24typedef enum {
25 AUDIO_SOURCE_DEMUX,
26 AUDIO_SOURCE_MEMORY
27} audio_stream_source_t;
28</programlisting>
29<para>AUDIO_SOURCE_DEMUX selects the demultiplexer (fed either by the frontend or the
30DVR device) as the source of the video stream. If AUDIO_SOURCE_MEMORY
31is selected the stream comes from the application through the <emphasis role="tt">write()</emphasis> system
32call.
33</para>
34
35</section>
36<section id="audio-play-state-t">
37<title>audio_play_state_t</title>
38<para>The following values can be returned by the AUDIO_GET_STATUS call representing the
39state of audio playback.
40</para>
41<programlisting>
42typedef enum {
43 AUDIO_STOPPED,
44 AUDIO_PLAYING,
45 AUDIO_PAUSED
46} audio_play_state_t;
47</programlisting>
48
49</section>
50<section id="audio-channel-select-t">
51<title>audio_channel_select_t</title>
52<para>The audio channel selected via AUDIO_CHANNEL_SELECT is determined by the
53following values.
54</para>
55<programlisting>
56typedef enum {
57 AUDIO_STEREO,
58 AUDIO_MONO_LEFT,
59 AUDIO_MONO_RIGHT,
60 AUDIO_MONO,
61 AUDIO_STEREO_SWAPPED
62} audio_channel_select_t;
63</programlisting>
64
65</section>
66<section id="audio-status">
67<title>struct audio_status</title>
68<para>The AUDIO_GET_STATUS call returns the following structure informing about various
69states of the playback operation.
70</para>
71<programlisting>
72typedef struct audio_status {
73 boolean AV_sync_state;
74 boolean mute_state;
75 audio_play_state_t play_state;
76 audio_stream_source_t stream_source;
77 audio_channel_select_t channel_select;
78 boolean bypass_mode;
79 audio_mixer_t mixer_state;
80} audio_status_t;
81</programlisting>
82
83</section>
84<section id="audio-mixer">
85<title>struct audio_mixer</title>
86<para>The following structure is used by the AUDIO_SET_MIXER call to set the audio
87volume.
88</para>
89<programlisting>
90typedef struct audio_mixer {
91 unsigned int volume_left;
92 unsigned int volume_right;
93} audio_mixer_t;
94</programlisting>
95
96</section>
97<section id="audio_encodings">
98<title>audio encodings</title>
99<para>A call to AUDIO_GET_CAPABILITIES returns an unsigned integer with the following
100bits set according to the hardwares capabilities.
101</para>
102<programlisting>
103 #define AUDIO_CAP_DTS 1
104 #define AUDIO_CAP_LPCM 2
105 #define AUDIO_CAP_MP1 4
106 #define AUDIO_CAP_MP2 8
107 #define AUDIO_CAP_MP3 16
108 #define AUDIO_CAP_AAC 32
109 #define AUDIO_CAP_OGG 64
110 #define AUDIO_CAP_SDDS 128
111 #define AUDIO_CAP_AC3 256
112</programlisting>
113
114</section>
115<section id="audio-karaoke">
116<title>struct audio_karaoke</title>
117<para>The ioctl AUDIO_SET_KARAOKE uses the following format:
118</para>
119<programlisting>
120typedef
121struct audio_karaoke {
122 int vocal1;
123 int vocal2;
124 int melody;
125} audio_karaoke_t;
126</programlisting>
127<para>If Vocal1 or Vocal2 are non-zero, they get mixed into left and right t at 70% each. If both,
128Vocal1 and Vocal2 are non-zero, Vocal1 gets mixed into the left channel and Vocal2 into the
129right channel at 100% each. Ff Melody is non-zero, the melody channel gets mixed into left
130and right.
131</para>
132
133</section>
134<section id="audio-attributes-t">
135<title>audio attributes</title>
136<para>The following attributes can be set by a call to AUDIO_SET_ATTRIBUTES:
137</para>
138<programlisting>
139 typedef uint16_t audio_attributes_t;
140 /&#x22C6; bits: descr. &#x22C6;/
141 /&#x22C6; 15-13 audio coding mode (0=ac3, 2=mpeg1, 3=mpeg2ext, 4=LPCM, 6=DTS, &#x22C6;/
142 /&#x22C6; 12 multichannel extension &#x22C6;/
143 /&#x22C6; 11-10 audio type (0=not spec, 1=language included) &#x22C6;/
144 /&#x22C6; 9- 8 audio application mode (0=not spec, 1=karaoke, 2=surround) &#x22C6;/
145 /&#x22C6; 7- 6 Quantization / DRC (mpeg audio: 1=DRC exists)(lpcm: 0=16bit, &#x22C6;/
146 /&#x22C6; 5- 4 Sample frequency fs (0=48kHz, 1=96kHz) &#x22C6;/
147 /&#x22C6; 2- 0 number of audio channels (n+1 channels) &#x22C6;/
148</programlisting>
149 </section></section>
150<section id="audio_function_calls">
151<title>Audio Function Calls</title>
152
153
154<section id="audio_fopen">
155<title>open()</title>
156<para>DESCRIPTION
157</para>
158<informaltable><tgroup cols="1"><tbody><row><entry
159 align="char">
160<para>This system call opens a named audio device (e.g. /dev/dvb/adapter0/audio0)
161 for subsequent use. When an open() call has succeeded, the device will be ready
162 for use. The significance of blocking or non-blocking mode is described in the
163 documentation for functions where there is a difference. It does not affect the
164 semantics of the open() call itself. A device opened in blocking mode can later
165 be put into non-blocking mode (and vice versa) using the F_SETFL command
166 of the fcntl system call. This is a standard system call, documented in the Linux
167 manual page for fcntl. Only one user can open the Audio Device in O_RDWR
168 mode. All other attempts to open the device in this mode will fail, and an error
169 code will be returned. If the Audio Device is opened in O_RDONLY mode, the
170 only ioctl call that can be used is AUDIO_GET_STATUS. All other call will
171 return with an error code.</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 specific audio 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_RDONLY read-only access</para>
203</entry>
204 </row><row><entry
205 align="char">
206</entry><entry
207 align="char">
208<para>O_RDWR read/write access</para>
209</entry>
210 </row><row><entry
211 align="char">
212</entry><entry
213 align="char">
214<para>O_NONBLOCK open in non-blocking mode</para>
215</entry>
216 </row><row><entry
217 align="char">
218</entry><entry
219 align="char">
220<para>(blocking mode is the default)</para>
221</entry>
222 </row></tbody></tgroup></informaltable>
223<para>RETURN VALUE</para>
224<informaltable><tgroup cols="2"><tbody><row><entry
225 align="char">
226<para>ENODEV</para>
227</entry><entry
228 align="char">
229<para>Device driver not loaded/available.</para>
230</entry>
231 </row><row><entry
232 align="char">
233<para>EBUSY</para>
234</entry><entry
235 align="char">
236<para>Device or resource busy.</para>
237</entry>
238 </row><row><entry
239 align="char">
240<para>EINVAL</para>
241</entry><entry
242 align="char">
243<para>Invalid argument.</para>
244</entry>
245 </row></tbody></tgroup></informaltable>
246
247</section>
248<section id="audio_fclose">
249<title>close()</title>
250<para>DESCRIPTION
251</para>
252<informaltable><tgroup cols="1"><tbody><row><entry
253 align="char">
254<para>This system call closes a previously opened audio device.</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>RETURN VALUE</para>
275<informaltable><tgroup cols="2"><tbody><row><entry
276 align="char">
277<para>EBADF</para>
278</entry><entry
279 align="char">
280<para>fd is not a valid open file descriptor.</para>
281</entry>
282 </row></tbody></tgroup></informaltable>
283
284</section>
285<section id="audio_fwrite">
286<title>write()</title>
287<para>DESCRIPTION
288</para>
289<informaltable><tgroup cols="1"><tbody><row><entry
290 align="char">
291<para>This system call can only be used if AUDIO_SOURCE_MEMORY is selected
292 in the ioctl call AUDIO_SELECT_SOURCE. The data provided shall be in
293 PES format. If O_NONBLOCK is not specified the function will block until
294 buffer space is available. The amount of data to be transferred is implied by
295 count.</para>
296</entry>
297 </row></tbody></tgroup></informaltable>
298<para>SYNOPSIS
299</para>
300<informaltable><tgroup cols="1"><tbody><row><entry
301 align="char">
302<para>size_t write(int fd, const void &#x22C6;buf, size_t count);</para>
303</entry>
304 </row></tbody></tgroup></informaltable>
305<para>PARAMETERS
306</para>
307<informaltable><tgroup cols="2"><tbody><row><entry
308 align="char">
309<para>int fd</para>
310</entry><entry
311 align="char">
312<para>File descriptor returned by a previous call to open().</para>
313</entry>
314 </row><row><entry
315 align="char">
316<para>void *buf</para>
317</entry><entry
318 align="char">
319<para>Pointer to the buffer containing the PES data.</para>
320</entry>
321 </row><row><entry
322 align="char">
323<para>size_t count</para>
324</entry><entry
325 align="char">
326<para>Size of buf.</para>
327</entry>
328 </row></tbody></tgroup></informaltable>
329<para>RETURN VALUE</para>
330<informaltable><tgroup cols="2"><tbody><row><entry
331 align="char">
332<para>EPERM</para>
333</entry><entry
334 align="char">
335<para>Mode AUDIO_SOURCE_MEMORY not selected.</para>
336</entry>
337 </row><row><entry
338 align="char">
339<para>ENOMEM</para>
340</entry><entry
341 align="char">
342<para>Attempted to write more data than the internal buffer can
343 hold.</para>
344</entry>
345 </row><row><entry
346 align="char">
347<para>EBADF</para>
348</entry><entry
349 align="char">
350<para>fd is not a valid open file descriptor.</para>
351</entry>
352 </row></tbody></tgroup></informaltable>
353
354</section><section id="AUDIO_STOP"
355role="subsection"><title>AUDIO_STOP</title>
356<para>DESCRIPTION
357</para>
358<informaltable><tgroup cols="1"><tbody><row><entry
359 align="char">
360<para>This ioctl call asks the Audio Device to stop playing the current stream.</para>
361</entry>
362 </row></tbody></tgroup></informaltable>
363<para>SYNOPSIS
364</para>
365<informaltable><tgroup cols="1"><tbody><row><entry
366 align="char">
367<para>int ioctl(int fd, int request = AUDIO_STOP);</para>
368</entry>
369 </row></tbody></tgroup></informaltable>
370<para>PARAMETERS
371</para>
372<informaltable><tgroup cols="2"><tbody><row><entry
373 align="char">
374<para>int fd</para>
375</entry><entry
376 align="char">
377<para>File descriptor returned by a previous call to open().</para>
378</entry>
379 </row><row><entry
380 align="char">
381<para>int request</para>
382</entry><entry
383 align="char">
384<para>Equals AUDIO_STOP for this command.</para>
385</entry>
386 </row></tbody></tgroup></informaltable>
387&return-value-dvb;
388
389</section><section id="AUDIO_PLAY"
390role="subsection"><title>AUDIO_PLAY</title>
391<para>DESCRIPTION
392</para>
393<informaltable><tgroup cols="1"><tbody><row><entry
394 align="char">
395<para>This ioctl call asks the Audio Device to start playing an audio stream from the
396 selected source.</para>
397</entry>
398 </row></tbody></tgroup></informaltable>
399<para>SYNOPSIS
400</para>
401<informaltable><tgroup cols="1"><tbody><row><entry
402 align="char">
403<para>int ioctl(int fd, int request = AUDIO_PLAY);</para>
404</entry>
405 </row></tbody></tgroup></informaltable>
406<para>PARAMETERS
407</para>
408<informaltable><tgroup cols="2"><tbody><row><entry
409 align="char">
410<para>int fd</para>
411</entry><entry
412 align="char">
413<para>File descriptor returned by a previous call to open().</para>
414</entry>
415 </row><row><entry
416 align="char">
417<para>int request</para>
418</entry><entry
419 align="char">
420<para>Equals AUDIO_PLAY for this command.</para>
421</entry>
422 </row></tbody></tgroup></informaltable>
423&return-value-dvb;
424
425</section><section id="AUDIO_PAUSE"
426role="subsection"><title>AUDIO_PAUSE</title>
427<para>DESCRIPTION
428</para>
429<informaltable><tgroup cols="1"><tbody><row><entry
430 align="char">
431<para>This ioctl call suspends the audio stream being played. Decoding and playing
432 are paused. It is then possible to restart again decoding and playing process of
433 the audio stream using AUDIO_CONTINUE command.</para>
434</entry>
435 </row><row><entry
436 align="char">
437<para>If AUDIO_SOURCE_MEMORY is selected in the ioctl call
438 AUDIO_SELECT_SOURCE, the DVB-subsystem will not decode (consume)
439 any more data until the ioctl call AUDIO_CONTINUE or AUDIO_PLAY is
440 performed.</para>
441</entry>
442 </row></tbody></tgroup></informaltable>
443<para>SYNOPSIS
444</para>
445<informaltable><tgroup cols="1"><tbody><row><entry
446 align="char">
447<para>int ioctl(int fd, int request = AUDIO_PAUSE);</para>
448</entry>
449 </row></tbody></tgroup></informaltable>
450<para>PARAMETERS
451</para>
452<informaltable><tgroup cols="2"><tbody><row><entry
453 align="char">
454<para>int fd</para>
455</entry><entry
456 align="char">
457<para>File descriptor returned by a previous call to open().</para>
458</entry>
459 </row><row><entry
460 align="char">
461<para>int request</para>
462</entry><entry
463 align="char">
464<para>Equals AUDIO_PAUSE for this command.</para>
465</entry>
466 </row></tbody></tgroup></informaltable>
467&return-value-dvb;
468
469</section><section id="AUDIO_CONTINUE"
470role="subsection"><title>AUDIO_CONTINUE</title>
471<para>DESCRIPTION
472</para>
473<informaltable><tgroup cols="1"><tbody><row><entry
474 align="char">
475<para>This ioctl restarts the decoding and playing process previously paused
476with AUDIO_PAUSE command.</para>
477</entry>
478 </row><row><entry
479 align="char">
480<para>It only works if the stream were previously stopped with AUDIO_PAUSE</para>
481</entry>
482 </row></tbody></tgroup></informaltable>
483<para>SYNOPSIS
484</para>
485<informaltable><tgroup cols="1"><tbody><row><entry
486 align="char">
487<para>int ioctl(int fd, int request = AUDIO_CONTINUE);</para>
488</entry>
489 </row></tbody></tgroup></informaltable>
490<para>PARAMETERS
491</para>
492<informaltable><tgroup cols="2"><tbody><row><entry
493 align="char">
494<para>int fd</para>
495</entry><entry
496 align="char">
497<para>File descriptor returned by a previous call to open().</para>
498</entry>
499 </row><row><entry
500 align="char">
501<para>int request</para>
502</entry><entry
503 align="char">
504<para>Equals AUDIO_CONTINUE for this command.</para>
505</entry>
506 </row></tbody></tgroup></informaltable>
507&return-value-dvb;
508
509</section><section id="AUDIO_SELECT_SOURCE"
510role="subsection"><title>AUDIO_SELECT_SOURCE</title>
511<para>DESCRIPTION
512</para>
513<informaltable><tgroup cols="1"><tbody><row><entry
514 align="char">
515<para>This ioctl call informs the audio device which source shall be used
516 for the input data. The possible sources are demux or memory. If
517 AUDIO_SOURCE_MEMORY is selected, the data is fed to the Audio Device
518 through the write command.</para>
519</entry>
520 </row></tbody></tgroup></informaltable>
521<para>SYNOPSIS
522</para>
523<informaltable><tgroup cols="1"><tbody><row><entry
524 align="char">
525<para>int ioctl(int fd, int request = AUDIO_SELECT_SOURCE,
526 audio_stream_source_t source);</para>
527</entry>
528 </row></tbody></tgroup></informaltable>
529<para>PARAMETERS
530</para>
531<informaltable><tgroup cols="2"><tbody><row><entry
532 align="char">
533<para>int fd</para>
534</entry><entry
535 align="char">
536<para>File descriptor returned by a previous call to open().</para>
537</entry>
538 </row><row><entry
539 align="char">
540<para>int request</para>
541</entry><entry
542 align="char">
543<para>Equals AUDIO_SELECT_SOURCE for this command.</para>
544</entry>
545 </row><row><entry
546 align="char">
547<para>audio_stream_source_t
548 source</para>
549</entry><entry
550 align="char">
551<para>Indicates the source that shall be used for the Audio
552 stream.</para>
553</entry>
554 </row></tbody></tgroup></informaltable>
555&return-value-dvb;
556
557</section><section id="AUDIO_SET_MUTE"
558role="subsection"><title>AUDIO_SET_MUTE</title>
559<para>DESCRIPTION
560</para>
561<informaltable><tgroup cols="1"><tbody><row><entry
562 align="char">
563<para>This ioctl call asks the audio device to mute the stream that is currently being
564 played.</para>
565</entry>
566 </row></tbody></tgroup></informaltable>
567<para>SYNOPSIS
568</para>
569<informaltable><tgroup cols="1"><tbody><row><entry
570 align="char">
571<para>int ioctl(int fd, int request = AUDIO_SET_MUTE,
572 boolean state);</para>
573</entry>
574 </row></tbody></tgroup></informaltable>
575<para>PARAMETERS
576</para>
577<informaltable><tgroup cols="2"><tbody><row><entry
578 align="char">
579<para>int fd</para>
580</entry><entry
581 align="char">
582<para>File descriptor returned by a previous call to open().</para>
583</entry>
584 </row><row><entry
585 align="char">
586<para>int request</para>
587</entry><entry
588 align="char">
589<para>Equals AUDIO_SET_MUTE for this command.</para>
590</entry>
591 </row><row><entry
592 align="char">
593<para>boolean state</para>
594</entry><entry
595 align="char">
596<para>Indicates if audio device shall mute or not.</para>
597</entry>
598 </row><row><entry
599 align="char">
600</entry><entry
601 align="char">
602<para>TRUE Audio Mute</para>
603</entry>
604 </row><row><entry
605 align="char">
606</entry><entry
607 align="char">
608<para>FALSE Audio Un-mute</para>
609</entry>
610 </row></tbody></tgroup></informaltable>
611&return-value-dvb;
612
613</section><section id="AUDIO_SET_AV_SYNC"
614role="subsection"><title>AUDIO_SET_AV_SYNC</title>
615<para>DESCRIPTION
616</para>
617<informaltable><tgroup cols="1"><tbody><row><entry
618 align="char">
619<para>This ioctl call asks the Audio Device to turn ON or OFF A/V synchronization.</para>
620</entry>
621 </row></tbody></tgroup></informaltable>
622<para>SYNOPSIS
623</para>
624<informaltable><tgroup cols="1"><tbody><row><entry
625 align="char">
626<para>int ioctl(int fd, int request = AUDIO_SET_AV_SYNC,
627 boolean state);</para>
628</entry>
629 </row></tbody></tgroup></informaltable>
630<para>PARAMETERS
631</para>
632<informaltable><tgroup cols="2"><tbody><row><entry
633 align="char">
634<para>int fd</para>
635</entry><entry
636 align="char">
637<para>File descriptor returned by a previous call to open().</para>
638</entry>
639 </row><row><entry
640 align="char">
641<para>int request</para>
642</entry><entry
643 align="char">
644<para>Equals AUDIO_AV_SYNC for this command.</para>
645</entry>
646 </row><row><entry
647 align="char">
648<para>boolean state</para>
649</entry><entry
650 align="char">
651<para>Tells the DVB subsystem if A/V synchronization shall be
652 ON or OFF.</para>
653</entry>
654 </row><row><entry
655 align="char">
656</entry><entry
657 align="char">
658<para>TRUE AV-sync ON</para>
659</entry>
660 </row><row><entry
661 align="char">
662</entry><entry
663 align="char">
664<para>FALSE AV-sync OFF</para>
665</entry>
666 </row></tbody></tgroup></informaltable>
667&return-value-dvb;
668
669</section><section id="AUDIO_SET_BYPASS_MODE"
670role="subsection"><title>AUDIO_SET_BYPASS_MODE</title>
671<para>DESCRIPTION
672</para>
673<informaltable><tgroup cols="1"><tbody><row><entry
674 align="char">
675<para>This ioctl call asks the Audio Device to bypass the Audio decoder and forward
676 the stream without decoding. This mode shall be used if streams that can&#8217;t be
677 handled by the DVB system shall be decoded. Dolby DigitalTM streams are
678 automatically forwarded by the DVB subsystem if the hardware can handle it.</para>
679</entry>
680 </row></tbody></tgroup></informaltable>
681<para>SYNOPSIS
682</para>
683<informaltable><tgroup cols="1"><tbody><row><entry
684 align="char">
685<para>int ioctl(int fd, int request =
686 AUDIO_SET_BYPASS_MODE, boolean mode);</para>
687</entry>
688 </row></tbody></tgroup></informaltable>
689<para>PARAMETERS
690</para>
691<informaltable><tgroup cols="2"><tbody><row><entry
692 align="char">
693<para>int fd</para>
694</entry><entry
695 align="char">
696<para>File descriptor returned by a previous call to open().</para>
697</entry>
698 </row><row><entry
699 align="char">
700<para>int request</para>
701</entry><entry
702 align="char">
703<para>Equals AUDIO_SET_BYPASS_MODE for this
704 command.</para>
705</entry>
706 </row><row><entry
707 align="char">
708<para>boolean mode</para>
709</entry><entry
710 align="char">
711<para>Enables or disables the decoding of the current Audio
712 stream in the DVB subsystem.</para>
713</entry>
714 </row><row><entry
715 align="char">
716</entry><entry
717 align="char">
718<para>TRUE Bypass is disabled</para>
719</entry>
720 </row><row><entry
721 align="char">
722</entry><entry
723 align="char">
724<para>FALSE Bypass is enabled</para>
725</entry>
726 </row></tbody></tgroup></informaltable>
727&return-value-dvb;
728
729</section><section id="AUDIO_CHANNEL_SELECT"
730role="subsection"><title>AUDIO_CHANNEL_SELECT</title>
731<para>DESCRIPTION
732</para>
733<informaltable><tgroup cols="1"><tbody><row><entry
734 align="char">
735<para>This ioctl call asks the Audio Device to select the requested channel if possible.</para>
736</entry>
737 </row></tbody></tgroup></informaltable>
738<para>SYNOPSIS
739</para>
740<informaltable><tgroup cols="1"><tbody><row><entry
741 align="char">
742<para>int ioctl(int fd, int request =
743 AUDIO_CHANNEL_SELECT, audio_channel_select_t);</para>
744</entry>
745 </row></tbody></tgroup></informaltable>
746<para>PARAMETERS
747</para>
748<informaltable><tgroup cols="2"><tbody><row><entry
749 align="char">
750<para>int fd</para>
751</entry><entry
752 align="char">
753<para>File descriptor returned by a previous call to open().</para>
754</entry>
755 </row><row><entry
756 align="char">
757<para>int request</para>
758</entry><entry
759 align="char">
760<para>Equals AUDIO_CHANNEL_SELECT for this
761 command.</para>
762</entry>
763 </row><row><entry
764 align="char">
765<para>audio_channel_select_t
766 ch</para>
767</entry><entry
768 align="char">
769<para>Select the output format of the audio (mono left/right,
770 stereo).</para>
771</entry>
772 </row></tbody></tgroup></informaltable>
773&return-value-dvb;
774
775</section><section id="AUDIO_GET_STATUS"
776role="subsection"><title>AUDIO_GET_STATUS</title>
777<para>DESCRIPTION
778</para>
779<informaltable><tgroup cols="1"><tbody><row><entry
780 align="char">
781<para>This ioctl call asks the Audio Device to return the current state of the Audio
782 Device.</para>
783</entry>
784 </row></tbody></tgroup></informaltable>
785<para>SYNOPSIS
786</para>
787<informaltable><tgroup cols="1"><tbody><row><entry
788 align="char">
789<para>int ioctl(int fd, int request = AUDIO_GET_STATUS,
790 struct audio_status &#x22C6;status);</para>
791</entry>
792 </row></tbody></tgroup></informaltable>
793<para>PARAMETERS
794</para>
795<informaltable><tgroup cols="2"><tbody><row><entry
796 align="char">
797<para>int fd</para>
798</entry><entry
799 align="char">
800<para>File descriptor returned by a previous call to open().</para>
801</entry>
802 </row><row><entry
803 align="char">
804<para>int request</para>
805</entry><entry
806 align="char">
807<para>Equals AUDIO_GET_STATUS for this command.</para>
808</entry>
809 </row><row><entry
810 align="char">
811<para>struct audio_status
812 *status</para>
813</entry><entry
814 align="char">
815<para>Returns the current state of Audio Device.</para>
816</entry>
817 </row></tbody></tgroup></informaltable>
818&return-value-dvb;
819
820</section><section id="AUDIO_GET_CAPABILITIES"
821role="subsection"><title>AUDIO_GET_CAPABILITIES</title>
822<para>DESCRIPTION
823</para>
824<informaltable><tgroup cols="1"><tbody><row><entry
825 align="char">
826<para>This ioctl call asks the Audio Device to tell us about the decoding capabilities
827 of the audio hardware.</para>
828</entry>
829 </row></tbody></tgroup></informaltable>
830<para>SYNOPSIS
831</para>
832<informaltable><tgroup cols="1"><tbody><row><entry
833 align="char">
834<para>int ioctl(int fd, int request =
835 AUDIO_GET_CAPABILITIES, unsigned int &#x22C6;cap);</para>
836</entry>
837 </row></tbody></tgroup></informaltable>
838<para>PARAMETERS
839</para>
840<informaltable><tgroup cols="2"><tbody><row><entry
841 align="char">
842<para>int fd</para>
843</entry><entry
844 align="char">
845<para>File descriptor returned by a previous call to open().</para>
846</entry>
847 </row><row><entry
848 align="char">
849<para>int request</para>
850</entry><entry
851 align="char">
852<para>Equals AUDIO_GET_CAPABILITIES for this
853 command.</para>
854</entry>
855 </row><row><entry
856 align="char">
857<para>unsigned int *cap</para>
858</entry><entry
859 align="char">
860<para>Returns a bit array of supported sound formats.</para>
861</entry>
862 </row></tbody></tgroup></informaltable>
863&return-value-dvb;
864
865</section><section id="AUDIO_CLEAR_BUFFER"
866role="subsection"><title>AUDIO_CLEAR_BUFFER</title>
867<para>DESCRIPTION
868</para>
869<informaltable><tgroup cols="1"><tbody><row><entry
870 align="char">
871<para>This ioctl call asks the Audio Device to clear all software and hardware buffers
872 of the audio decoder device.</para>
873</entry>
874 </row></tbody></tgroup></informaltable>
875<para>SYNOPSIS
876</para>
877<informaltable><tgroup cols="1"><tbody><row><entry
878 align="char">
879<para>int ioctl(int fd, int request = AUDIO_CLEAR_BUFFER);</para>
880</entry>
881 </row></tbody></tgroup></informaltable>
882<para>PARAMETERS
883</para>
884<informaltable><tgroup cols="2"><tbody><row><entry
885 align="char">
886<para>int fd</para>
887</entry><entry
888 align="char">
889<para>File descriptor returned by a previous call to open().</para>
890</entry>
891 </row><row><entry
892 align="char">
893<para>int request</para>
894</entry><entry
895 align="char">
896<para>Equals AUDIO_CLEAR_BUFFER for this command.</para>
897</entry>
898 </row></tbody></tgroup></informaltable>
899&return-value-dvb;
900
901</section><section id="AUDIO_SET_ID"
902role="subsection"><title>AUDIO_SET_ID</title>
903<para>DESCRIPTION
904</para>
905<informaltable><tgroup cols="1"><tbody><row><entry
906 align="char">
907<para>This ioctl selects which sub-stream is to be decoded if a program or system
908 stream is sent to the video device. If no audio stream type is set the id has to be
909 in [0xC0,0xDF] for MPEG sound, in [0x80,0x87] for AC3 and in [0xA0,0xA7]
910 for LPCM. More specifications may follow for other stream types. If the stream
911 type is set the id just specifies the substream id of the audio stream and only
912 the first 5 bits are recognized.</para>
913</entry>
914 </row></tbody></tgroup></informaltable>
915<para>SYNOPSIS
916</para>
917<informaltable><tgroup cols="1"><tbody><row><entry
918 align="char">
919<para>int ioctl(int fd, int request = AUDIO_SET_ID, int
920 id);</para>
921</entry>
922 </row></tbody></tgroup></informaltable>
923<para>PARAMETERS
924</para>
925<informaltable><tgroup cols="2"><tbody><row><entry
926 align="char">
927<para>int fd</para>
928</entry><entry
929 align="char">
930<para>File descriptor returned by a previous call to open().</para>
931</entry>
932 </row><row><entry
933 align="char">
934<para>int request</para>
935</entry><entry
936 align="char">
937<para>Equals AUDIO_SET_ID for this command.</para>
938</entry>
939 </row><row><entry
940 align="char">
941<para>int id</para>
942</entry><entry
943 align="char">
944<para>audio sub-stream id</para>
945</entry>
946 </row></tbody></tgroup></informaltable>
947&return-value-dvb;
948
949</section><section id="AUDIO_SET_MIXER"
950role="subsection"><title>AUDIO_SET_MIXER</title>
951<para>DESCRIPTION
952</para>
953<informaltable><tgroup cols="1"><tbody><row><entry
954 align="char">
955<para>This ioctl lets you adjust the mixer settings of the audio decoder.</para>
956</entry>
957 </row></tbody></tgroup></informaltable>
958<para>SYNOPSIS
959</para>
960<informaltable><tgroup cols="1"><tbody><row><entry
961 align="char">
962<para>int ioctl(int fd, int request = AUDIO_SET_MIXER,
963 audio_mixer_t &#x22C6;mix);</para>
964</entry>
965 </row></tbody></tgroup></informaltable>
966<para>PARAMETERS
967</para>
968<informaltable><tgroup cols="2"><tbody><row><entry
969 align="char">
970<para>int fd</para>
971</entry><entry
972 align="char">
973<para>File descriptor returned by a previous call to open().</para>
974</entry>
975 </row><row><entry
976 align="char">
977<para>int request</para>
978</entry><entry
979 align="char">
980<para>Equals AUDIO_SET_ID for this command.</para>
981</entry>
982 </row><row><entry
983 align="char">
984<para>audio_mixer_t *mix</para>
985</entry><entry
986 align="char">
987<para>mixer settings.</para>
988</entry>
989 </row></tbody></tgroup></informaltable>
990&return-value-dvb;
991
992</section><section id="AUDIO_SET_STREAMTYPE"
993role="subsection"><title>AUDIO_SET_STREAMTYPE</title>
994<para>DESCRIPTION
995</para>
996<informaltable><tgroup cols="1"><tbody><row><entry
997 align="char">
998<para>This ioctl tells the driver which kind of audio stream to expect. This is useful
999 if the stream offers several audio sub-streams like LPCM and AC3.</para>
1000</entry>
1001 </row></tbody></tgroup></informaltable>
1002<para>SYNOPSIS
1003</para>
1004<informaltable><tgroup cols="1"><tbody><row><entry
1005 align="char">
1006<para>int ioctl(fd, int request = AUDIO_SET_STREAMTYPE,
1007 int type);</para>
1008</entry>
1009 </row></tbody></tgroup></informaltable>
1010<para>PARAMETERS
1011</para>
1012<informaltable><tgroup cols="2"><tbody><row><entry
1013 align="char">
1014<para>int fd</para>
1015</entry><entry
1016 align="char">
1017<para>File descriptor returned by a previous call to open().</para>
1018</entry>
1019 </row><row><entry
1020 align="char">
1021<para>int request</para>
1022</entry><entry
1023 align="char">
1024<para>Equals AUDIO_SET_STREAMTYPE for this
1025 command.</para>
1026</entry>
1027 </row><row><entry
1028 align="char">
1029<para>int type</para>
1030</entry><entry
1031 align="char">
1032<para>stream type</para>
1033</entry>
1034 </row></tbody></tgroup></informaltable>
1035&return-value-dvb;
1036<informaltable><tgroup cols="2"><tbody><row><entry
1037 align="char">
1038<para>EINVAL</para>
1039</entry><entry
1040 align="char">
1041<para>type is not a valid or supported stream type.</para>
1042</entry>
1043 </row></tbody></tgroup></informaltable>
1044
1045</section><section id="AUDIO_SET_EXT_ID"
1046role="subsection"><title>AUDIO_SET_EXT_ID</title>
1047<para>DESCRIPTION
1048</para>
1049<informaltable><tgroup cols="1"><tbody><row><entry
1050 align="char">
1051<para>This ioctl can be used to set the extension id for MPEG streams in DVD
1052 playback. Only the first 3 bits are recognized.</para>
1053</entry>
1054 </row></tbody></tgroup></informaltable>
1055<para>SYNOPSIS
1056</para>
1057<informaltable><tgroup cols="1"><tbody><row><entry
1058 align="char">
1059<para>int ioctl(fd, int request = AUDIO_SET_EXT_ID, int
1060 id);</para>
1061</entry>
1062 </row></tbody></tgroup></informaltable>
1063<para>PARAMETERS
1064</para>
1065<informaltable><tgroup cols="2"><tbody><row><entry
1066 align="char">
1067<para>int fd</para>
1068</entry><entry
1069 align="char">
1070<para>File descriptor returned by a previous call to open().</para>
1071</entry>
1072 </row><row><entry
1073 align="char">
1074<para>int request</para>
1075</entry><entry
1076 align="char">
1077<para>Equals AUDIO_SET_EXT_ID for this command.</para>
1078</entry>
1079 </row><row><entry
1080 align="char">
1081<para>int id</para>
1082</entry><entry
1083 align="char">
1084<para>audio sub_stream_id</para>
1085</entry>
1086 </row></tbody></tgroup></informaltable>
1087&return-value-dvb;
1088<informaltable><tgroup cols="2"><tbody><row><entry
1089 align="char">
1090<para>EINVAL</para>
1091</entry><entry
1092 align="char">
1093<para>id is not a valid id.</para>
1094</entry>
1095 </row></tbody></tgroup></informaltable>
1096
1097</section><section id="AUDIO_SET_ATTRIBUTES"
1098role="subsection"><title>AUDIO_SET_ATTRIBUTES</title>
1099<para>DESCRIPTION
1100</para>
1101<informaltable><tgroup cols="1"><tbody><row><entry
1102 align="char">
1103<para>This ioctl is intended for DVD playback and allows you to set certain
1104 information about the audio stream.</para>
1105</entry>
1106 </row></tbody></tgroup></informaltable>
1107<para>SYNOPSIS
1108</para>
1109<informaltable><tgroup cols="1"><tbody><row><entry
1110 align="char">
1111<para>int ioctl(fd, int request = AUDIO_SET_ATTRIBUTES,
1112 audio_attributes_t attr );</para>
1113</entry>
1114 </row></tbody></tgroup></informaltable>
1115<para>PARAMETERS
1116</para>
1117<informaltable><tgroup cols="2"><tbody><row><entry
1118 align="char">
1119<para>int fd</para>
1120</entry><entry
1121 align="char">
1122<para>File descriptor returned by a previous call to open().</para>
1123</entry>
1124 </row><row><entry
1125 align="char">
1126<para>int request</para>
1127</entry><entry
1128 align="char">
1129<para>Equals AUDIO_SET_ATTRIBUTES for this command.</para>
1130</entry>
1131 </row><row><entry
1132 align="char">
1133<para>audio_attributes_t
1134 attr</para>
1135</entry><entry
1136 align="char">
1137<para>audio attributes according to section ??</para>
1138</entry>
1139 </row></tbody></tgroup></informaltable>
1140&return-value-dvb;
1141<informaltable><tgroup cols="2"><tbody><row><entry
1142 align="char">
1143<para>EINVAL</para>
1144</entry><entry
1145 align="char">
1146<para>attr is not a valid or supported attribute setting.</para>
1147</entry>
1148 </row></tbody></tgroup></informaltable>
1149
1150</section><section id="AUDIO_SET_KARAOKE"
1151role="subsection"><title>AUDIO_SET_KARAOKE</title>
1152<para>DESCRIPTION
1153</para>
1154<informaltable><tgroup cols="1"><tbody><row><entry
1155 align="char">
1156<para>This ioctl allows one to set the mixer settings for a karaoke DVD.</para>
1157</entry>
1158 </row></tbody></tgroup></informaltable>
1159<para>SYNOPSIS
1160</para>
1161<informaltable><tgroup cols="1"><tbody><row><entry
1162 align="char">
1163<para>int ioctl(fd, int request = AUDIO_SET_KARAOKE,
1164 audio_karaoke_t &#x22C6;karaoke);</para>
1165</entry>
1166 </row></tbody></tgroup></informaltable>
1167<para>PARAMETERS
1168</para>
1169<informaltable><tgroup cols="2"><tbody><row><entry
1170 align="char">
1171<para>int fd</para>
1172</entry><entry
1173 align="char">
1174<para>File descriptor returned by a previous call to open().</para>
1175</entry>
1176 </row><row><entry
1177 align="char">
1178<para>int request</para>
1179</entry><entry
1180 align="char">
1181<para>Equals AUDIO_SET_KARAOKE for this
1182 command.</para>
1183</entry>
1184 </row><row><entry
1185 align="char">
1186<para>audio_karaoke_t
1187 *karaoke</para>
1188</entry><entry
1189 align="char">
1190<para>karaoke settings according to section ??.</para>
1191</entry>
1192 </row></tbody></tgroup></informaltable>
1193&return-value-dvb;
1194<informaltable><tgroup cols="2"><tbody><row><entry
1195 align="char">
1196<para>EINVAL</para>
1197</entry><entry
1198 align="char">
1199<para>karaoke is not a valid or supported karaoke setting.</para>
1200</entry>
1201 </row></tbody></tgroup></informaltable>
1202 </section>
1203</section>
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-04 17:23:19 -0500