7f8aae01c22a6b9fcc2a48712c490b6bde73b40e
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2010 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 /** Data specific to the alsa writer. */
35 struct private_alsa_write_data {
36 /** The alsa handle */
37 snd_pcm_t *handle;
38 /** Determined and set by alsa_open(). */
39 int bytes_per_frame;
40 /** The approximate maximum buffer duration in us. */
41 unsigned buffer_time;
42 /* Number of frames that fit into the buffer. */
43 snd_pcm_uframes_t buffer_frames;
44 /**
45 * The sample rate given by command line option or the decoder
46 * of the writer node group.
47 */
48 unsigned sample_rate;
49
50 snd_pcm_format_t sample_format;
51 /**
52 * The number of channels, given by command line option or the
53 * decoder of the writer node group.
54 */
55 unsigned channels;
56 struct timeval drain_barrier;
57 };
58
59 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
60 {
61 switch (sf) {
62 case SF_S8: return SND_PCM_FORMAT_S8;
63 case SF_U8: return SND_PCM_FORMAT_U8;
64 case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
65 case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
66 case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
67 case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
68 default: return SND_PCM_FORMAT_S16_LE;
69 }
70 }
71
72 /* Install PCM software and hardware configuration. */
73 static int alsa_init(struct private_alsa_write_data *pad,
74 struct alsa_write_args_info *conf)
75 {
76 snd_pcm_hw_params_t *hwparams;
77 snd_pcm_sw_params_t *swparams;
78 snd_pcm_uframes_t start_threshold, stop_threshold;
79 snd_pcm_uframes_t period_size;
80 int err;
81
82 PARA_INFO_LOG("opening %s\n", conf->device_arg);
83 err = snd_pcm_open(&pad->handle, conf->device_arg,
84 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
85 if (err < 0)
86 return -E_PCM_OPEN;
87
88 snd_pcm_hw_params_alloca(&hwparams);
89 snd_pcm_sw_params_alloca(&swparams);
90 if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
91 return -E_BROKEN_CONF;
92 if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
93 SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
94 return -E_ACCESS_TYPE;
95 if (snd_pcm_hw_params_set_format(pad->handle, hwparams,
96 pad->sample_format) < 0)
97 return -E_SAMPLE_FORMAT;
98 if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
99 pad->channels) < 0)
100 return -E_CHANNEL_COUNT;
101 if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
102 &pad->sample_rate, NULL) < 0)
103 return -E_SET_RATE;
104 err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
105 &pad->buffer_time, NULL);
106 if (err < 0 || !pad->buffer_time)
107 return -E_GET_BUFFER_TIME;
108 PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
109 if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
110 &pad->buffer_time, NULL) < 0)
111 return -E_SET_BUFFER_TIME;
112 if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
113 return -E_HW_PARAMS;
114 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
115 snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames);
116 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames,
117 period_size);
118 if (period_size == pad->buffer_frames)
119 return -E_BAD_PERIOD;
120 snd_pcm_sw_params_current(pad->handle, swparams);
121 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
122 if (pad->buffer_frames < 1)
123 start_threshold = 1;
124 else
125 start_threshold = PARA_MIN(pad->buffer_frames,
126 (snd_pcm_uframes_t)pad->sample_rate);
127 if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
128 start_threshold) < 0)
129 return -E_START_THRESHOLD;
130 stop_threshold = pad->buffer_frames;
131 if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
132 stop_threshold) < 0)
133 return -E_STOP_THRESHOLD;
134 if (snd_pcm_sw_params(pad->handle, swparams) < 0)
135 PARA_WARNING_LOG("unable to install sw params\n");
136 pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format)
137 * pad->channels / 8;
138 if (pad->bytes_per_frame <= 0)
139 return -E_PHYSICAL_WIDTH;
140 PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
141 if (snd_pcm_nonblock(pad->handle, 1))
142 PARA_ERROR_LOG("failed to set nonblock mode\n");
143 return 1;
144 }
145
146 /* Open an instance of the alsa writer. */
147 static int alsa_open(struct writer_node *wn)
148 {
149 wn->private_data = para_calloc(sizeof(struct private_alsa_write_data));
150 return 1;
151 }
152
153 static void alsa_write_pre_select(struct sched *s, struct task *t)
154 {
155 struct writer_node *wn = container_of(t, struct writer_node, task);
156 struct private_alsa_write_data *pad = wn->private_data;
157 struct timeval tv;
158 snd_pcm_sframes_t avail, underrun;
159 int ret;
160
161 if (!pad->handle)
162 return;
163 ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
164 if (ret < 0)
165 sched_request_timeout_ms(20, s);
166 if (ret <= 0)
167 return;
168 /*
169 * Data is available to be written to the alsa handle. Compute number
170 * of milliseconds until next buffer underrun would occur.
171 *
172 * snd_pcm_avail_update() updates the current available count of
173 * samples for writing. It is a light method to obtain current stream
174 * position, because it does not require the user <-> kernel context
175 * switch, but the value is less accurate, because ring buffer pointers
176 * are updated in kernel drivers only when an interrupt occurs.
177 */
178 avail = snd_pcm_avail_update(pad->handle);
179 if (avail < 0)
180 avail = 0;
181 underrun = (pad->buffer_frames - avail) * pad->buffer_time
182 / pad->buffer_frames / 1000;
183 if (underrun < 50)
184 underrun = 50;
185 underrun -= 50;
186 ms2tv(underrun, &tv);
187 if (tv_diff(&s->timeout, &tv, NULL) > 0)
188 s->timeout = tv;
189 }
190
191 static void alsa_close(struct writer_node *wn)
192 {
193 struct private_alsa_write_data *pad = wn->private_data;
194 PARA_INFO_LOG("closing writer node %p\n", wn);
195
196 if (pad->handle) {
197 /*
198 * It's OK to have a blocking operation here because we already
199 * made sure that the PCM output buffer is (nearly) empty.
200 */
201 snd_pcm_nonblock(pad->handle, 0);
202 snd_pcm_drain(pad->handle);
203 snd_pcm_close(pad->handle);
204 snd_config_update_free_global();
205 }
206 free(pad);
207 }
208
209 static void alsa_write_post_select(__a_unused struct sched *s,
210 struct task *t)
211 {
212 struct writer_node *wn = container_of(t, struct writer_node, task);
213 struct private_alsa_write_data *pad = wn->private_data;
214 struct btr_node *btrn = wn->btrn;
215 char *data;
216 size_t bytes;
217 snd_pcm_sframes_t frames;
218 int ret;
219
220 again:
221 t->error = 0;
222 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
223 if (ret == 0)
224 return;
225 btr_merge(btrn, wn->min_iqs);
226 bytes = btr_next_buffer(btrn, &data);
227 if (ret < 0 || bytes < pad->bytes_per_frame) { /* eof */
228 assert(btr_no_parent(btrn));
229 ret = -E_ALSA_EOF;
230 if (!pad->handle)
231 goto err;
232 /* wait until pending frames are played */
233 if (pad->drain_barrier.tv_sec == 0) {
234 PARA_DEBUG_LOG("waiting for device to drain\n");
235 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
236 &pad->drain_barrier);
237 return;
238 }
239 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
240 goto err;
241 return;
242 }
243 if (!pad->handle) {
244 int32_t val;
245
246 if (bytes == 0) /* no data available */
247 return;
248 get_btr_sample_rate(btrn, &val);
249 pad->sample_rate = val;
250 get_btr_channels(btrn, &val);
251 pad->channels = val;
252 get_btr_sample_format(btrn, &val);
253 pad->sample_format = get_alsa_pcm_format(val);
254
255 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
256 pad->sample_rate);
257 ret = alsa_init(pad, wn->conf);
258 if (ret < 0)
259 goto err;
260 wn->min_iqs = pad->bytes_per_frame;
261 goto again;
262 }
263 frames = bytes / pad->bytes_per_frame;
264 frames = snd_pcm_writei(pad->handle, data, frames);
265 if (frames >= 0) {
266 btr_consume(btrn, frames * pad->bytes_per_frame);
267 goto again;
268 }
269 if (frames == -EPIPE) {
270 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
271 snd_pcm_prepare(pad->handle);
272 return;
273 }
274 if (frames == -EAGAIN)
275 return;
276 PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
277 ret = -E_ALSA_WRITE;
278 err:
279 assert(ret < 0);
280 btr_remove_node(btrn);
281 t->error = ret;
282 }
283
284 __malloc static void *alsa_parse_config(const char *options)
285 {
286 int ret;
287 struct alsa_write_args_info *conf
288 = para_calloc(sizeof(struct alsa_write_args_info));
289
290 PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
291 ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
292 if (ret)
293 goto err_out;
294 PARA_INFO_LOG("help given: %d\n", conf->help_given);
295 return conf;
296 err_out:
297 free(conf);
298 return NULL;
299 }
300
301 static void alsa_free_config(void *conf)
302 {
303 alsa_cmdline_parser_free(conf);
304 }
305
306 /**
307 * The init function of the alsa writer.
308 *
309 * \param w Pointer to the writer to initialize.
310 *
311 * \sa struct \ref writer.
312 */
313 void alsa_write_init(struct writer *w)
314 {
315 struct alsa_write_args_info dummy;
316
317 alsa_cmdline_parser_init(&dummy);
318 w->open = alsa_open;
319 w->close = alsa_close;
320 w->pre_select = alsa_write_pre_select;
321 w->post_select = alsa_write_post_select;
322 w->parse_config = alsa_parse_config;
323 w->shutdown = NULL; /* nothing to do */
324 w->free_config = alsa_free_config;
325 w->help = (struct ggo_help) {
326 .short_help = alsa_write_args_info_help,
327 .detailed_help = alsa_write_args_info_detailed_help
328 };
329 alsa_cmdline_parser_free(&dummy);
330 }