1 /*****************************************************************************
2  * oss.c: Open Sound System audio output plugin for VLC
3  *****************************************************************************
4  * Copyright (C) 2000-2002 VLC authors and VideoLAN
5  * Copyright (C) 2007-2012 Rémi Denis-Courmont
6  *
7  * Authors: Michel Kaempf <maxx@via.ecp.fr>
8  *          Sam Hocevar <sam@zoy.org>
9  *          Christophe Massiot <massiot@via.ecp.fr>
10  *
11  * This program is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU Lesser General Public License as published by
13  * the Free Software Foundation; either version 2.1 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public License
22  * along with this program; if not, write to the Free Software Foundation,
23  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
24  *****************************************************************************/
25 
26 #ifdef HAVE_CONFIG_H
27 # include "config.h"
28 #endif
29 
30 #include <stdlib.h>
31 #include <math.h>
32 #include <errno.h>
33 #include <sys/types.h>
34 #include <fcntl.h>
35 #include <sys/ioctl.h>
36 #ifdef HAVE_SOUNDCARD_H
37 # include <soundcard.h>
38 #else
39 # include <sys/soundcard.h>
40 #endif
41 
42 #ifndef SNDCTL_DSP_HALT
43 # define SNDCTL_DSP_HALT SNDCTL_DSP_RESET
44 #endif
45 
46 #include <vlc_common.h>
47 #include <vlc_plugin.h>
48 #include <vlc_fs.h>
49 #include <vlc_cpu.h>
50 #include <vlc_aout.h>
51 
52 #define A52_FRAME_NB 1536
53 
54 struct aout_sys_t
55 {
56     int fd;
57     audio_sample_format_t format;
58     bool starting;
59     bool soft_mute;
60     float soft_gain;
61     char *device;
62 };
63 
64 #include "volume.h"
65 
66 static int Open (vlc_object_t *);
67 static void Close (vlc_object_t *);
68 
69 #define AUDIO_DEV_TEXT N_("Audio output device")
70 #define AUDIO_DEV_LONGTEXT N_("OSS device node path.")
71 
72 vlc_module_begin ()
73     set_shortname( "OSS" )
74     set_description (N_("Open Sound System audio output"))
75     set_category( CAT_AUDIO )
76     set_subcategory( SUBCAT_AUDIO_AOUT )
77     add_string ("oss-audio-device", "",
78                 AUDIO_DEV_TEXT, AUDIO_DEV_LONGTEXT, false)
79     add_sw_gain ()
80     set_capability( "audio output", 100 )
81     set_callbacks (Open, Close)
82 vlc_module_end ()
83 
84 static int TimeGet (audio_output_t *, mtime_t *);
85 static void Play (audio_output_t *, block_t *);
86 static void Pause (audio_output_t *, bool, mtime_t);
87 static void Flush (audio_output_t *, bool);
88 
Start(audio_output_t * aout,audio_sample_format_t * restrict fmt)89 static int Start (audio_output_t *aout, audio_sample_format_t *restrict fmt)
90 {
91     aout_sys_t* sys = aout->sys;
92 
93     if (aout_FormatNbChannels(fmt) == 0)
94         return VLC_EGENERIC;
95 
96     /* Open the device */
97     const char *device = sys->device;
98     if (device == NULL)
99         device = getenv ("OSS_AUDIODEV");
100     if (device == NULL)
101         device = "/dev/dsp";
102 
103     int fd = vlc_open (device, O_WRONLY);
104     if (fd == -1)
105     {
106         msg_Err (aout, "cannot open OSS device %s: %s", device,
107                  vlc_strerror_c(errno));
108         return VLC_EGENERIC;
109     }
110     msg_Dbg (aout, "using OSS device: %s", device);
111 
112     /* Select audio format */
113     int format;
114     bool spdif = false;
115 
116     switch (fmt->i_format)
117     {
118 #ifdef AFMT_FLOAT
119         case VLC_CODEC_FL64:
120         case VLC_CODEC_FL32:
121             format = AFMT_FLOAT;
122             break;
123 #endif
124         case VLC_CODEC_S32N:
125             format = AFMT_S32_NE;
126             break;
127         case VLC_CODEC_S16N:
128             format = AFMT_S16_NE;
129             break;
130         case VLC_CODEC_U8:
131             format = AFMT_U8;
132             break;
133         default:
134             if (AOUT_FMT_SPDIF(fmt))
135                 spdif = var_InheritBool (aout, "spdif");
136             if (spdif)
137                 format = AFMT_AC3;
138 #ifdef AFMT_FLOAT
139             else if (HAVE_FPU)
140                 format = AFMT_FLOAT;
141 #endif
142             else
143                 format = AFMT_S16_NE;
144     }
145 
146     if (ioctl (fd, SNDCTL_DSP_SETFMT, &format) < 0)
147     {
148         msg_Err (aout, "cannot set audio format 0x%X: %s", format,
149                  vlc_strerror_c(errno));
150         goto error;
151     }
152 
153     switch (format)
154     {
155         case AFMT_U8:     fmt->i_format = VLC_CODEC_U8;   break;
156         case AFMT_S16_NE: fmt->i_format = VLC_CODEC_S16N; break;
157         case AFMT_S32_NE: fmt->i_format = VLC_CODEC_S32N; break;
158 #ifdef AFMT_FLOAT
159         case AFMT_FLOAT:  fmt->i_format = VLC_CODEC_FL32; break;
160 #endif
161         case AFMT_AC3:
162             if (spdif)
163             {
164                 fmt->i_format = VLC_CODEC_SPDIFL;
165                 break;
166             }
167         default:
168             msg_Err (aout, "unsupported audio format 0x%X", format);
169             goto error;
170     }
171 
172     /* Select channels count */
173     int channels = spdif ? 2 : aout_FormatNbChannels (fmt);
174     if (ioctl (fd, SNDCTL_DSP_CHANNELS, &channels) < 0)
175     {
176         msg_Err (aout, "cannot set %d channels: %s", channels,
177                  vlc_strerror_c(errno));
178         goto error;
179     }
180 
181     switch (channels)
182     {
183         case 1: channels = AOUT_CHAN_CENTER;  break;
184         case 2: channels = AOUT_CHANS_STEREO; break;
185         case 4: channels = AOUT_CHANS_4_0;    break;
186         case 6: channels = AOUT_CHANS_5_1;    break;
187         case 8: channels = AOUT_CHANS_7_1;    break;
188         default:
189             msg_Err (aout, "unsupported channels count %d", channels);
190             goto error;
191     }
192 
193     /* Select sample rate */
194     int rate = spdif ? 48000 : fmt->i_rate;
195     if (ioctl (fd, SNDCTL_DSP_SPEED, &rate) < 0)
196     {
197         msg_Err (aout, "cannot set %d Hz sample rate: %s", rate,
198                  vlc_strerror_c(errno));
199         goto error;
200     }
201 
202     /* Setup audio_output_t */
203     aout->time_get = TimeGet;
204     aout->play = Play;
205     aout->pause = Pause;
206     aout->flush = Flush;
207 
208     if (spdif)
209     {
210         fmt->i_bytes_per_frame = AOUT_SPDIF_SIZE;
211         fmt->i_frame_length = A52_FRAME_NB;
212     }
213     else
214     {
215         fmt->i_rate = rate;
216         fmt->i_physical_channels = channels;
217     }
218     fmt->channel_type = AUDIO_CHANNEL_TYPE_BITMAP;
219     aout_FormatPrepare (fmt);
220 
221     /* Select timing */
222     unsigned bytes;
223     if (spdif)
224         bytes = AOUT_SPDIF_SIZE;
225     else
226         bytes = fmt->i_rate / (CLOCK_FREQ / AOUT_MIN_PREPARE_TIME)
227                 * fmt->i_bytes_per_frame;
228     if (unlikely(bytes < 16))
229         bytes = 16;
230 
231     int frag = (AOUT_MAX_ADVANCE_TIME / AOUT_MIN_PREPARE_TIME) << 16
232              | (32 - clz32(bytes - 1));
233     if (ioctl (fd, SNDCTL_DSP_SETFRAGMENT, &frag) < 0)
234         msg_Err (aout, "cannot set 0x%08x fragment: %s", frag,
235                  vlc_strerror_c(errno));
236 
237     sys->fd = fd;
238     aout_SoftVolumeStart (aout);
239     sys->starting = true;
240     sys->format = *fmt;
241     return VLC_SUCCESS;
242 error:
243     vlc_close (fd);
244     return VLC_EGENERIC;
245 }
246 
TimeGet(audio_output_t * aout,mtime_t * restrict pts)247 static int TimeGet (audio_output_t *aout, mtime_t *restrict pts)
248 {
249     aout_sys_t *sys = aout->sys;
250     int delay;
251 
252     if (ioctl (sys->fd, SNDCTL_DSP_GETODELAY, &delay) < 0)
253     {
254         msg_Warn (aout, "cannot get delay: %s", vlc_strerror_c(errno));
255         return -1;
256     }
257 
258     *pts = (delay * CLOCK_FREQ * sys->format.i_frame_length)
259                         / (sys->format.i_rate * sys->format.i_bytes_per_frame);
260     return 0;
261 }
262 
263 /**
264  * Queues one audio buffer to the hardware.
265  */
Play(audio_output_t * aout,block_t * block)266 static void Play (audio_output_t *aout, block_t *block)
267 {
268     aout_sys_t *sys = aout->sys;
269     int fd = sys->fd;
270 
271     while (block->i_buffer > 0)
272     {
273         ssize_t bytes = write (fd, block->p_buffer, block->i_buffer);
274         if (bytes >= 0)
275         {
276             block->p_buffer += bytes;
277             block->i_buffer -= bytes;
278         }
279         else
280             msg_Err (aout, "cannot write samples: %s", vlc_strerror_c(errno));
281     }
282     block_Release (block);
283 }
284 
285 /**
286  * Pauses/resumes the audio playback.
287  */
Pause(audio_output_t * aout,bool pause,mtime_t date)288 static void Pause (audio_output_t *aout, bool pause, mtime_t date)
289 {
290     aout_sys_t *sys = aout->sys;
291     int fd = sys->fd;
292 
293     (void) date;
294     ioctl (fd, pause ? SNDCTL_DSP_SILENCE : SNDCTL_DSP_SKIP, NULL);
295 }
296 
297 /**
298  * Flushes/drains the audio playback buffer.
299  */
Flush(audio_output_t * aout,bool wait)300 static void Flush (audio_output_t *aout, bool wait)
301 {
302     aout_sys_t *sys = aout->sys;
303     int fd = sys->fd;
304 
305     if (wait)
306         return; /* drain is implicit with OSS */
307     ioctl (fd, SNDCTL_DSP_HALT, NULL);
308 }
309 
310 /**
311  * Releases the audio output device.
312  */
Stop(audio_output_t * aout)313 static void Stop (audio_output_t *aout)
314 {
315     aout_sys_t *sys = aout->sys;
316     int fd = sys->fd;
317 
318     ioctl (fd, SNDCTL_DSP_HALT, NULL);
319     vlc_close (fd);
320     sys->fd = -1;
321 }
322 
DevicesEnum(audio_output_t * aout)323 static int DevicesEnum (audio_output_t *aout)
324 {
325     int fd = vlc_open ("/dev/dsp", O_WRONLY);
326     if (fd == -1)
327         return -1;
328 
329     oss_sysinfo si;
330     int n = -1;
331 
332     if (ioctl (fd, SNDCTL_SYSINFO, &si) < 0)
333     {
334         msg_Err (aout, "cannot get system infos: %s", vlc_strerror(errno));
335         goto out;
336     }
337 
338     msg_Dbg (aout, "using %s version %s (0x%06X) under %s", si.product,
339              si.version, si.versionnum, si.license);
340 
341     for (int i = 0; i < si.numaudios; i++)
342     {
343         oss_audioinfo ai = { .dev = i };
344 
345         if (ioctl (fd, SNDCTL_AUDIOINFO, &ai) < 0)
346         {
347             msg_Warn (aout, "cannot get device %d infos: %s", i,
348                       vlc_strerror_c(errno));
349             continue;
350         }
351         if (ai.caps & (PCM_CAP_HIDDEN|PCM_CAP_MODEM))
352             continue;
353         if (!(ai.caps & PCM_CAP_OUTPUT))
354             continue;
355         if (!ai.enabled)
356             continue;
357 
358         aout_HotplugReport (aout, ai.devnode, ai.name);
359         n++;
360     }
361 out:
362     vlc_close (fd);
363     return n;
364 }
365 
DeviceSelect(audio_output_t * aout,const char * id)366 static int DeviceSelect (audio_output_t *aout, const char *id)
367 {
368     aout_sys_t *sys = aout->sys;
369     char *path = NULL;
370 
371     if (id != NULL)
372     {
373         path = strdup (id);
374         if (unlikely(path == NULL))
375             return -1;
376     }
377 
378     free (sys->device);
379     sys->device = path;
380     aout_DeviceReport (aout, path);
381     aout_RestartRequest (aout, AOUT_RESTART_OUTPUT);
382     return 0;
383 }
384 
Open(vlc_object_t * obj)385 static int Open (vlc_object_t *obj)
386 {
387     audio_output_t *aout = (audio_output_t *)obj;
388 
389     aout_sys_t *sys = malloc (sizeof (*sys));
390     if(unlikely( sys == NULL ))
391         return VLC_ENOMEM;
392 
393     sys->fd = -1;
394     sys->device = var_InheritString (aout, "oss-audio-device");
395 
396     aout->sys = sys;
397     aout->start = Start;
398     aout->stop = Stop;
399     aout->device_select = DeviceSelect;
400     aout_DeviceReport (aout, sys->device);
401     aout_SoftVolumeInit (aout);
402 
403     DevicesEnum (aout);
404     return VLC_SUCCESS;
405 }
406 
Close(vlc_object_t * obj)407 static void Close (vlc_object_t *obj)
408 {
409     audio_output_t *aout = (audio_output_t *)obj;
410     aout_sys_t *sys = aout->sys;
411 
412     free (sys->device);
413     free (sys);
414 }
415