Merge branch 'maint'
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2014 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file alsa_write.c paraslash's alsa output plugin */
8
9 /*
10 * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
11 * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
12 * based on the vplay program by Michael Beck.
13 */
14
15 #include <regex.h>
16 #include <sys/types.h>
17 #include <alsa/asoundlib.h>
18
19 #include "para.h"
20 #include "fd.h"
21 #include "string.h"
22 #include "list.h"
23 #include "sched.h"
24 #include "ggo.h"
25 #include "buffer_tree.h"
26 #include "write.h"
27 #include "write_common.h"
28 #include "alsa_write.cmdline.h"
29 #include "error.h"
30
31 /** Data specific to the alsa writer. */
32 struct private_alsa_write_data {
33 /** The alsa handle */
34 snd_pcm_t *handle;
35 /** Determined and set by alsa_init(). */
36 int bytes_per_frame;
37 /*
38 * If the sample rate is not given at the command line and no wav
39 * header was detected, the btr exec mechanism is employed to query the
40 * ancestor buffer tree nodes for this information. In a typical setup
41 * the decoder passes the sample rate back to the alsa writer.
42 *
43 * \sa \ref btr_exec_up().
44 */
45 unsigned sample_rate;
46 /*
47 * The sample format (8/16 bit, signed/unsigned, little/big endian) is
48 * determined in the same way as the \a sample_rate.
49 */
50 snd_pcm_format_t sample_format;
51 /* The number of channels, again determined like \a sample_rate. */
52 unsigned channels;
53 /* time until buffer underrun occurs, in milliseconds */
54 unsigned buffer_time;
55 struct timeval drain_barrier;
56 /* File descriptor for select(). */
57 int poll_fd;
58 };
59
60 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
61 {
62 switch (sf) {
63 case SF_S8: return SND_PCM_FORMAT_S8;
64 case SF_U8: return SND_PCM_FORMAT_U8;
65 case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
66 case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
67 case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
68 case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
69 default: return SND_PCM_FORMAT_S16_LE;
70 }
71 }
72
73 /* Install PCM software and hardware configuration. */
74 static int alsa_init(struct private_alsa_write_data *pad,
75 struct alsa_write_args_info *conf)
76 {
77 snd_pcm_hw_params_t *hwparams;
78 snd_pcm_sw_params_t *swparams;
79 snd_pcm_uframes_t start_threshold, stop_threshold;
80 snd_pcm_uframes_t buffer_size, period_size;
81 snd_output_t *output_log;
82 int ret;
83 const char *msg;
84 unsigned period_time;
85
86 PARA_INFO_LOG("opening %s\n", conf->device_arg);
87 msg = "unable to open pcm";
88 ret = snd_pcm_open(&pad->handle, conf->device_arg,
89 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
90 if (ret < 0)
91 goto fail;
92 snd_pcm_hw_params_alloca(&hwparams);
93 msg = "Broken alsa configuration";
94 ret = snd_pcm_hw_params_any(pad->handle, hwparams);
95 if (ret < 0)
96 goto fail;
97 msg = "access type not available";
98 ret = snd_pcm_hw_params_set_access(pad->handle, hwparams,
99 SND_PCM_ACCESS_RW_INTERLEAVED);
100 if (ret < 0)
101 goto fail;
102 msg = "sample format not available";
103 ret = snd_pcm_hw_params_set_format(pad->handle, hwparams,
104 pad->sample_format);
105 if (ret < 0)
106 goto fail;
107 msg = "channels count not available";
108 ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams,
109 pad->channels);
110 if (ret < 0)
111 goto fail;
112 msg = "could not set sample rate";
113 ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
114 &pad->sample_rate, NULL);
115 if (ret < 0)
116 goto fail;
117 /* alsa wants microseconds */
118 pad->buffer_time = conf->buffer_time_arg * 1000;
119 msg = "could not set buffer time";
120 ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
121 &pad->buffer_time, NULL);
122 if (ret < 0)
123 goto fail;
124 pad->buffer_time /= 1000; /* we prefer milliseconds */
125 period_time = pad->buffer_time * 250; /* buffer time / 4 */
126 msg = "could not set period time";
127 ret = snd_pcm_hw_params_set_period_time_near(pad->handle, hwparams,
128 &period_time, 0);
129 if (ret < 0)
130 goto fail;
131
132 msg = "unable to install hw params";
133 ret = snd_pcm_hw_params(pad->handle, hwparams);
134 if (ret < 0)
135 goto fail;
136 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
137 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
138 msg = "period size equals buffer size";
139 if (period_size == buffer_size)
140 goto fail;
141
142 /* software parameter setup */
143 snd_pcm_sw_params_alloca(&swparams);
144 snd_pcm_sw_params_current(pad->handle, swparams);
145 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
146 if (buffer_size < 1)
147 start_threshold = 1;
148 else
149 start_threshold = PARA_MIN(buffer_size,
150 (snd_pcm_uframes_t)pad->sample_rate);
151 msg = "could not set start threshold";
152 ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
153 start_threshold);
154 if (ret < 0)
155 goto fail;
156 stop_threshold = buffer_size;
157 msg = "could not set stop threshold";
158 ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
159 stop_threshold);
160 if (ret < 0)
161 goto fail;
162 msg = "unable to install sw params";
163 ret = snd_pcm_sw_params(pad->handle, swparams);
164 if (ret < 0)
165 goto fail;
166 msg = "unable to determine bytes per frame";
167 ret = snd_pcm_format_physical_width(pad->sample_format);
168 if (ret <= 0)
169 goto fail;
170 pad->bytes_per_frame = ret * pad->channels / 8;
171 msg = "failed to set alsa handle to nonblock mode";
172 ret = snd_pcm_nonblock(pad->handle, 1);
173 if (ret < 0)
174 goto fail;
175 ret = snd_output_buffer_open(&output_log);
176 if (ret == 0) {
177 char *buf, *p;
178 size_t sz;
179 PARA_DEBUG_LOG("dumping alsa configuration\n");
180 snd_pcm_dump(pad->handle, output_log);
181 snd_pcm_hw_params_dump(hwparams, output_log);
182 sz = snd_output_buffer_string(output_log, &buf);
183 for (p = buf; p < buf + sz;) {
184 char *q = memchr(p, '\n', buf + sz - p);
185 if (!q)
186 break;
187 *q = '\0';
188 PARA_DEBUG_LOG("%s\n", p);
189 p = q + 1;
190 }
191 snd_output_close(output_log);
192 }
193 return 1;
194 fail:
195 if (ret < 0)
196 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
197 else
198 PARA_ERROR_LOG("%s\n", msg);
199 return -E_ALSA;
200 }
201
202 static void alsa_write_pre_select(struct sched *s, void *context)
203 {
204 struct pollfd pfd;
205 struct writer_node *wn = context;
206 struct private_alsa_write_data *pad = wn->private_data;
207 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
208
209 if (pad)
210 pad->poll_fd = -1;
211 if (ret == 0)
212 return;
213 if (!pad) {
214 sched_min_delay(s);
215 return;
216 }
217 if (ret < 0) {
218 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
219 return;
220 }
221 /* wait at most 50% of the buffer time */
222 sched_request_timeout_ms(pad->buffer_time / 2, s);
223 ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
224 if (ret < 0) {
225 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
226 snd_strerror(-ret));
227 return;
228 }
229 pad->poll_fd = pfd.fd;
230 para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
231 }
232
233 static void alsa_close(struct writer_node *wn)
234 {
235 struct private_alsa_write_data *pad = wn->private_data;
236 PARA_INFO_LOG("closing writer node %p\n", wn);
237
238 if (!pad)
239 return;
240 /*
241 * It's OK to have a blocking operation here because we already made
242 * sure that the PCM output buffer is (nearly) empty.
243 */
244 snd_pcm_nonblock(pad->handle, 0);
245 snd_pcm_drain(pad->handle);
246 snd_pcm_close(pad->handle);
247 snd_config_update_free_global();
248 free(pad);
249 }
250
251 static int alsa_write_post_select(__a_unused struct sched *s, void *context)
252 {
253 struct writer_node *wn = context;
254 struct private_alsa_write_data *pad = wn->private_data;
255 struct btr_node *btrn = wn->btrn;
256 char *data;
257 size_t bytes;
258 snd_pcm_sframes_t frames;
259 int ret;
260
261 ret = task_get_notification(wn->task);
262 if (ret < 0)
263 goto err;
264 again:
265 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
266 if (ret == 0)
267 return 0;
268 btr_merge(btrn, wn->min_iqs);
269 bytes = btr_next_buffer(btrn, &data);
270 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
271 assert(btr_no_parent(btrn));
272 ret = -E_WRITE_COMMON_EOF;
273 if (!pad)
274 goto err;
275 /* wait until pending frames are played */
276 if (pad->drain_barrier.tv_sec == 0) {
277 PARA_DEBUG_LOG("waiting for device to drain\n");
278 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
279 &pad->drain_barrier);
280 return 0;
281 }
282 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
283 goto err;
284 return 0;
285 }
286 if (!pad) {
287 int32_t val;
288
289 if (bytes == 0) /* no data available */
290 return 0;
291 pad = para_calloc(sizeof(*pad));
292 get_btr_sample_rate(btrn, &val);
293 pad->sample_rate = val;
294 get_btr_channels(btrn, &val);
295 pad->channels = val;
296 get_btr_sample_format(btrn, &val);
297 pad->sample_format = get_alsa_pcm_format(val);
298
299 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
300 pad->sample_rate);
301 ret = alsa_init(pad, wn->conf);
302 if (ret < 0) {
303 free(pad);
304 goto err;
305 }
306 wn->private_data = pad;
307 wn->min_iqs = pad->bytes_per_frame;
308 goto again;
309 }
310 frames = bytes / pad->bytes_per_frame;
311 frames = snd_pcm_writei(pad->handle, data, frames);
312 if (frames == 0 || frames == -EAGAIN) {
313 char buf[100];
314 if (pad->poll_fd >= 0 && FD_ISSET(pad->poll_fd, &s->rfds))
315 if (read(pad->poll_fd, buf, 100))
316 do_nothing;
317 return 0;
318 }
319 if (frames > 0) {
320 btr_consume(btrn, frames * pad->bytes_per_frame);
321 goto again;
322 }
323 if (frames == -EPIPE) {
324 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
325 snd_pcm_prepare(pad->handle);
326 return 0;
327 }
328 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
329 ret = -E_ALSA;
330 err:
331 assert(ret < 0);
332 btr_remove_node(&wn->btrn);
333 return ret;
334 }
335
336 __malloc static void *alsa_parse_config_or_die(int argc, char **argv)
337 {
338 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
339
340 /* exits on errors */
341 alsa_write_cmdline_parser(argc, argv, conf);
342 return conf;
343 }
344
345 static void alsa_free_config(void *conf)
346 {
347 alsa_write_cmdline_parser_free(conf);
348 }
349
350 /**
351 * The init function of the alsa writer.
352 *
353 * \param w Pointer to the writer to initialize.
354 *
355 * \sa struct \ref writer.
356 */
357 void alsa_write_init(struct writer *w)
358 {
359 struct alsa_write_args_info dummy;
360
361 alsa_write_cmdline_parser_init(&dummy);
362 w->close = alsa_close;
363 w->pre_select = alsa_write_pre_select;
364 w->post_select = alsa_write_post_select;
365 w->parse_config_or_die = alsa_parse_config_or_die;
366 w->free_config = alsa_free_config;
367 w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
368 alsa_write_cmdline_parser_free(&dummy);
369 }