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