1c0b928158d04405c66321e4ed6cfeec1468ee23
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
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 msg = "unable to get buffer time";
118 /* alsa wants microseconds */
119 pad->buffer_time = conf->buffer_time_arg * 1000;
120 msg = "could not set buffer time";
121 ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
122 &pad->buffer_time, NULL);
123 if (ret < 0)
124 goto fail;
125 pad->buffer_time /= 1000; /* we prefer milliseconds */
126 period_time = pad->buffer_time * 250; /* buffer time / 4 */
127 msg = "could not set period time";
128 ret = snd_pcm_hw_params_set_period_time_near(pad->handle, hwparams,
129 &period_time, 0);
130 if (ret < 0)
131 goto fail;
132
133 msg = "unable to install hw params";
134 ret = snd_pcm_hw_params(pad->handle, hwparams);
135 if (ret < 0)
136 goto fail;
137 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
138 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
139 msg = "period size equals buffer size";
140 if (period_size == buffer_size)
141 goto fail;
142
143 /* software parameter setup */
144 snd_pcm_sw_params_alloca(&swparams);
145 snd_pcm_sw_params_current(pad->handle, swparams);
146 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
147 if (buffer_size < 1)
148 start_threshold = 1;
149 else
150 start_threshold = PARA_MIN(buffer_size,
151 (snd_pcm_uframes_t)pad->sample_rate);
152 msg = "could not set start threshold";
153 ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
154 start_threshold);
155 if (ret < 0)
156 goto fail;
157 stop_threshold = buffer_size;
158 msg = "could not set stop threshold";
159 ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
160 stop_threshold);
161 if (ret < 0)
162 goto fail;
163 msg = "unable to install sw params";
164 ret = snd_pcm_sw_params(pad->handle, swparams);
165 if (ret < 0)
166 goto fail;
167 msg = "unable to determine bytes per frame";
168 ret = snd_pcm_format_physical_width(pad->sample_format);
169 if (ret <= 0)
170 goto fail;
171 pad->bytes_per_frame = ret * pad->channels / 8;
172 msg = "failed to set alsa handle to nonblock mode";
173 ret = snd_pcm_nonblock(pad->handle, 1);
174 if (ret < 0)
175 goto fail;
176 ret = snd_output_buffer_open(&output_log);
177 if (ret == 0) {
178 char *buf, *p;
179 size_t sz;
180 PARA_DEBUG_LOG("dumping alsa configuration\n");
181 snd_pcm_dump(pad->handle, output_log);
182 snd_pcm_hw_params_dump(hwparams, output_log);
183 sz = snd_output_buffer_string(output_log, &buf);
184 for (p = buf; p < buf + sz;) {
185 char *q = memchr(p, '\n', buf + sz - p);
186 if (!q)
187 break;
188 *q = '\0';
189 PARA_DEBUG_LOG("%s\n", p);
190 p = q + 1;
191 }
192 snd_output_close(output_log);
193 }
194 return 1;
195 fail:
196 if (ret < 0)
197 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
198 else
199 PARA_ERROR_LOG("%s\n", msg);
200 return -E_ALSA;
201 }
202
203 static void alsa_write_pre_select(struct sched *s, struct task *t)
204 {
205 struct pollfd pfd;
206 struct writer_node *wn = container_of(t, struct writer_node, task);
207 struct private_alsa_write_data *pad = wn->private_data;
208 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
209
210 if (pad)
211 pad->poll_fd = -1;
212 if (ret == 0)
213 return;
214 if (!pad) {
215 sched_min_delay(s);
216 return;
217 }
218 if (ret < 0) {
219 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
220 return;
221 }
222 /* wait at most 50% of the buffer time */
223 sched_request_timeout_ms(pad->buffer_time / 2, s);
224 ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
225 if (ret < 0) {
226 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
227 snd_strerror(-ret));
228 return;
229 }
230 pad->poll_fd = pfd.fd;
231 para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
232 }
233
234 static void alsa_close(struct writer_node *wn)
235 {
236 struct private_alsa_write_data *pad = wn->private_data;
237 PARA_INFO_LOG("closing writer node %p\n", wn);
238
239 if (!pad)
240 return;
241 /*
242 * It's OK to have a blocking operation here because we already made
243 * sure that the PCM output buffer is (nearly) empty.
244 */
245 snd_pcm_nonblock(pad->handle, 0);
246 snd_pcm_drain(pad->handle);
247 snd_pcm_close(pad->handle);
248 snd_config_update_free_global();
249 free(pad);
250 }
251
252 static int alsa_write_post_select(__a_unused struct sched *s,
253 struct task *t)
254 {
255 struct writer_node *wn = container_of(t, struct writer_node, task);
256 struct private_alsa_write_data *pad = wn->private_data;
257 struct btr_node *btrn = wn->btrn;
258 char *data;
259 size_t bytes;
260 snd_pcm_sframes_t frames;
261 int ret;
262
263 ret = task_get_notification(t);
264 if (ret < 0)
265 goto err;
266 again:
267 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
268 if (ret == 0)
269 return 0;
270 btr_merge(btrn, wn->min_iqs);
271 bytes = btr_next_buffer(btrn, &data);
272 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
273 assert(btr_no_parent(btrn));
274 ret = -E_WRITE_COMMON_EOF;
275 if (!pad)
276 goto err;
277 /* wait until pending frames are played */
278 if (pad->drain_barrier.tv_sec == 0) {
279 PARA_DEBUG_LOG("waiting for device to drain\n");
280 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
281 &pad->drain_barrier);
282 return 0;
283 }
284 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
285 goto err;
286 return 0;
287 }
288 if (!pad) {
289 int32_t val;
290
291 if (bytes == 0) /* no data available */
292 return 0;
293 pad = para_calloc(sizeof(*pad));
294 get_btr_sample_rate(btrn, &val);
295 pad->sample_rate = val;
296 get_btr_channels(btrn, &val);
297 pad->channels = val;
298 get_btr_sample_format(btrn, &val);
299 pad->sample_format = get_alsa_pcm_format(val);
300
301 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
302 pad->sample_rate);
303 ret = alsa_init(pad, wn->conf);
304 if (ret < 0) {
305 free(pad);
306 goto err;
307 }
308 wn->private_data = pad;
309 wn->min_iqs = pad->bytes_per_frame;
310 goto again;
311 }
312 frames = bytes / pad->bytes_per_frame;
313 frames = snd_pcm_writei(pad->handle, data, frames);
314 if (frames == 0 || frames == -EAGAIN) {
315 char buf[100];
316 if (pad->poll_fd >= 0 && FD_ISSET(pad->poll_fd, &s->rfds))
317 if (read(pad->poll_fd, buf, 100))
318 do_nothing;
319 return 0;
320 }
321 if (frames > 0) {
322 btr_consume(btrn, frames * pad->bytes_per_frame);
323 goto again;
324 }
325 if (frames == -EPIPE) {
326 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
327 snd_pcm_prepare(pad->handle);
328 return 0;
329 }
330 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
331 ret = -E_ALSA;
332 err:
333 assert(ret < 0);
334 btr_remove_node(&wn->btrn);
335 return ret;
336 }
337
338 __malloc static void *alsa_parse_config_or_die(int argc, char **argv)
339 {
340 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
341
342 /* exits on errors */
343 alsa_write_cmdline_parser(argc, argv, conf);
344 return conf;
345 }
346
347 static void alsa_free_config(void *conf)
348 {
349 alsa_write_cmdline_parser_free(conf);
350 }
351
352 /**
353 * The init function of the alsa writer.
354 *
355 * \param w Pointer to the writer to initialize.
356 *
357 * \sa struct \ref writer.
358 */
359 void alsa_write_init(struct writer *w)
360 {
361 struct alsa_write_args_info dummy;
362
363 alsa_write_cmdline_parser_init(&dummy);
364 w->close = alsa_close;
365 w->pre_select = alsa_write_pre_select;
366 w->post_select = alsa_write_post_select;
367 w->parse_config_or_die = alsa_parse_config_or_die;
368 w->free_config = alsa_free_config;
369 w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
370 alsa_write_cmdline_parser_free(&dummy);
371 }