Skip btr suffix from {pre,post}_select_btr().
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2009 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 <dirent.h>
18 #include <alsa/asoundlib.h>
19 #include <sys/time.h>
20 #include <stdbool.h>
21
22 #include "para.h"
23 #include "fd.h"
24 #include "string.h"
25 #include "list.h"
26 #include "sched.h"
27 #include "ggo.h"
28 #include "buffer_tree.h"
29 #include "write.h"
30 #include "write_common.h"
31 #include "alsa_write.cmdline.h"
32 #include "error.h"
33
34 /** always use 16 bit little endian */
35 #define FORMAT SND_PCM_FORMAT_S16_LE
36
37 /** Data specific to the alsa writer. */
38 struct private_alsa_write_data {
39 /** The alsa handle */
40 snd_pcm_t *handle;
41 /** Determined and set by alsa_open(). */
42 int bytes_per_frame;
43 /** The approximate maximum buffer duration in us. */
44 unsigned buffer_time;
45 /* Number of frames that fit into the buffer. */
46 snd_pcm_uframes_t buffer_frames;
47 /**
48 * The samplerate given by command line option or the decoder
49 * of the writer node group.
50 */
51 unsigned samplerate;
52 /**
53 * The number of channels, given by command line option or the
54 * decoder of the writer node group.
55 */
56 unsigned channels;
57 };
58
59 /* Install PCM software and hardware configuration. */
60 static int alsa_init(struct private_alsa_write_data *pad,
61 struct alsa_write_args_info *conf)
62 {
63 snd_pcm_hw_params_t *hwparams;
64 snd_pcm_sw_params_t *swparams;
65 snd_pcm_uframes_t start_threshold, stop_threshold;
66 snd_pcm_uframes_t period_size;
67 int err;
68
69 PARA_INFO_LOG("opening %s\n", conf->device_arg);
70 err = snd_pcm_open(&pad->handle, conf->device_arg,
71 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
72 if (err < 0)
73 return -E_PCM_OPEN;
74
75 snd_pcm_hw_params_alloca(&hwparams);
76 snd_pcm_sw_params_alloca(&swparams);
77 if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
78 return -E_BROKEN_CONF;
79 if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
80 SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
81 return -E_ACCESS_TYPE;
82 if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
83 return -E_SAMPLE_FORMAT;
84 if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
85 pad->channels) < 0)
86 return -E_CHANNEL_COUNT;
87 if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
88 &pad->samplerate, NULL) < 0)
89 return -E_SET_RATE;
90 err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
91 &pad->buffer_time, NULL);
92 if (err < 0 || !pad->buffer_time)
93 return -E_GET_BUFFER_TIME;
94 PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
95 if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
96 &pad->buffer_time, NULL) < 0)
97 return -E_SET_BUFFER_TIME;
98 if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
99 return -E_HW_PARAMS;
100 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
101 snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames);
102 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames,
103 period_size);
104 if (period_size == pad->buffer_frames)
105 return -E_BAD_PERIOD;
106 snd_pcm_sw_params_current(pad->handle, swparams);
107 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
108 if (pad->buffer_frames < 1)
109 start_threshold = 1;
110 else
111 start_threshold = PARA_MIN(pad->buffer_frames,
112 (snd_pcm_uframes_t)pad->samplerate);
113 if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
114 start_threshold) < 0)
115 return -E_START_THRESHOLD;
116 stop_threshold = pad->buffer_frames;
117 if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
118 stop_threshold) < 0)
119 return -E_STOP_THRESHOLD;
120 if (snd_pcm_sw_params(pad->handle, swparams) < 0)
121 PARA_WARNING_LOG("unable to install sw params\n");
122 pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
123 * pad->channels / 8;
124 if (pad->bytes_per_frame <= 0)
125 return -E_PHYSICAL_WIDTH;
126 PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
127 if (snd_pcm_nonblock(pad->handle, 1))
128 PARA_ERROR_LOG("failed to set nonblock mode\n");
129 return 1;
130 }
131
132 /* Open an instance of the alsa writer. */
133 static int alsa_open(struct writer_node *wn)
134 {
135 wn->private_data = para_calloc(sizeof(struct private_alsa_write_data));
136 return 1;
137 }
138
139 static void alsa_write_pre_select(struct sched *s, struct task *t)
140 {
141 struct writer_node *wn = container_of(t, struct writer_node, task);
142 struct private_alsa_write_data *pad = wn->private_data;
143 struct timeval tv;
144 snd_pcm_sframes_t avail, underrun;
145 int ret;
146
147 if (!pad->handle)
148 return;
149 ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
150 if (ret < 0)
151 sched_request_timeout_ms(20, s);
152 if (ret <= 0)
153 return;
154 /*
155 * Data is available to be written to the alsa handle. Compute number
156 * of milliseconds until next buffer underrun would occur.
157 *
158 * snd_pcm_avail_update() updates the current available count of
159 * samples for writing. It is a light method to obtain current stream
160 * position, because it does not require the user <-> kernel context
161 * switch, but the value is less accurate, because ring buffer pointers
162 * are updated in kernel drivers only when an interrupt occurs.
163 */
164 avail = snd_pcm_avail_update(pad->handle);
165 if (avail < 0)
166 avail = 0;
167 underrun = (pad->buffer_frames - avail) * pad->buffer_time
168 / pad->buffer_frames / 1000;
169 if (underrun < 50)
170 underrun = 50;
171 underrun -= 50;
172 ms2tv(underrun, &tv);
173 if (tv_diff(&s->timeout, &tv, NULL) > 0)
174 s->timeout = tv;
175 }
176
177 static void xrun(snd_pcm_t *handle)
178 {
179 snd_pcm_status_t *status;
180 int ret;
181 struct timeval tv, diff;
182
183 snd_pcm_status_alloca(&status);
184 ret = snd_pcm_status(handle, status);
185 if (ret < 0)
186 return;
187 if (snd_pcm_status_get_state(status) != SND_PCM_STATE_XRUN)
188 return;
189 snd_pcm_status_get_trigger_tstamp(status, &tv);
190 tv_diff(now, &tv, &diff);
191 PARA_WARNING_LOG("underrun: %lums\n", tv2ms(&diff));
192 }
193
194 static void alsa_close(struct writer_node *wn)
195 {
196 struct private_alsa_write_data *pad = wn->private_data;
197 PARA_INFO_LOG("closing writer node %p\n", wn);
198
199 if (pad->handle) {
200 /*
201 * It's OK to have a blocking operation here because we already
202 * made sure that the PCM output buffer is (nearly) empty.
203 */
204 snd_pcm_nonblock(pad->handle, 0);
205 snd_pcm_drain(pad->handle);
206 snd_pcm_close(pad->handle);
207 snd_config_update_free_global();
208 }
209 free(pad);
210 }
211
212 static void alsa_write_post_select(__a_unused struct sched *s,
213 struct task *t)
214 {
215 struct writer_node *wn = container_of(t, struct writer_node, task);
216 struct private_alsa_write_data *pad = wn->private_data;
217 struct btr_node *btrn = wn->btrn;
218 char *data;
219 size_t bytes;
220 snd_pcm_sframes_t frames, avail;
221 int ret;
222
223 again:
224 t->error = 0;
225 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
226 if (ret == 0)
227 return;
228 btr_merge(btrn, wn->min_iqs);
229 bytes = btr_next_buffer(btrn, &data);
230 if (ret < 0 || bytes < pad->bytes_per_frame) { /* eof */
231 assert(btr_no_parent(btrn));
232 ret = -E_ALSA_EOF;
233 if (!pad->handle)
234 goto err;
235 /* wait until pending frames are played */
236 avail = snd_pcm_avail_update(pad->handle);
237 if (avail + 1000 > pad->buffer_frames)
238 goto err;
239 PARA_DEBUG_LOG("waiting for device to drain\n");
240 return;
241 }
242 if (!pad->handle) {
243 struct alsa_write_args_info *conf = wn->conf;
244 if (bytes == 0) /* no data available */
245 return;
246 /* defaults */
247 pad->samplerate = conf->samplerate_arg;
248 pad->channels = conf->channels_arg;
249 if (!conf->samplerate_given) { /* config option trumps btr_exec */
250 int32_t rate;
251 if (get_btr_samplerate(btrn, &rate) >= 0)
252 pad->samplerate = rate;
253 }
254 if (!conf->channels_given) {
255 int32_t ch;
256 if (get_btr_channels(btrn, &ch) >= 0)
257 pad->channels = ch;
258 }
259 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
260 ret = alsa_init(pad, wn->conf);
261 if (ret < 0)
262 goto err;
263 wn->min_iqs = pad->bytes_per_frame;
264 }
265 frames = bytes / pad->bytes_per_frame;
266 frames = snd_pcm_writei(pad->handle, data, frames);
267 if (frames >= 0) {
268 btr_consume(btrn, frames * pad->bytes_per_frame);
269 goto again;
270 }
271 if (frames == -EPIPE) {
272 xrun(pad->handle);
273 snd_pcm_prepare(pad->handle);
274 return;
275 }
276 if (frames == -EAGAIN)
277 return;
278 PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
279 ret = -E_ALSA_WRITE;
280 err:
281 assert(ret < 0);
282 btr_remove_node(btrn);
283 t->error = ret;
284 }
285
286 __malloc static void *alsa_parse_config(const char *options)
287 {
288 int ret;
289 struct alsa_write_args_info *conf
290 = para_calloc(sizeof(struct alsa_write_args_info));
291
292 PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
293 ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
294 if (ret)
295 goto err_out;
296 PARA_INFO_LOG("help given: %d\n", conf->help_given);
297 return conf;
298 err_out:
299 free(conf);
300 return NULL;
301 }
302
303 static void alsa_free_config(void *conf)
304 {
305 alsa_cmdline_parser_free(conf);
306 }
307
308 /**
309 * The init function of the alsa writer.
310 *
311 * \param w Pointer to the writer to initialize.
312 *
313 * \sa \ref struct writer.
314 */
315 void alsa_write_init(struct writer *w)
316 {
317 struct alsa_write_args_info dummy;
318
319 alsa_cmdline_parser_init(&dummy);
320 w->open = alsa_open;
321 w->close = alsa_close;
322 w->pre_select = alsa_write_pre_select;
323 w->post_select = alsa_write_post_select;
324 w->parse_config = alsa_parse_config;
325 w->shutdown = NULL; /* nothing to do */
326 w->free_config = alsa_free_config;
327 w->help = (struct ggo_help) {
328 .short_help = alsa_write_args_info_help,
329 .detailed_help = alsa_write_args_info_detailed_help
330 };
331 alsa_cmdline_parser_free(&dummy);
332 }