b685e4f79b039010a439503095adaf00f9187c6b
[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;
158
159 if (!pad->handle)
160 return;
161 ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
162 if (ret < 0)
163 sched_request_timeout_ms(20, s);
164 if (ret <= 0)
165 return;
166 /*
167 * Data is available to be written to the alsa handle. Compute number
168 * of milliseconds until next buffer underrun would occur.
169 *
170 * snd_pcm_avail_update() updates the current available count of
171 * samples for writing. It is a light method to obtain current stream
172 * position, because it does not require the user <-> kernel context
173 * switch, but the value is less accurate, because ring buffer pointers
174 * are updated in kernel drivers only when an interrupt occurs.
175 */
176 avail = snd_pcm_avail_update(pad->handle);
177 if (avail < 0)
178 avail = 0;
179 underrun = (pad->buffer_frames - avail) * pad->buffer_time
180 / pad->buffer_frames / 1000;
181 if (underrun < 50)
182 underrun = 50;
183 underrun -= 50;
184 ms2tv(underrun, &tv);
185 sched_request_timeout(&tv, s);
186 }
187
188 static void alsa_close(struct writer_node *wn)
189 {
190 struct private_alsa_write_data *pad = wn->private_data;
191 PARA_INFO_LOG("closing writer node %p\n", wn);
192
193 if (pad->handle) {
194 /*
195 * It's OK to have a blocking operation here because we already
196 * made sure that the PCM output buffer is (nearly) empty.
197 */
198 snd_pcm_nonblock(pad->handle, 0);
199 snd_pcm_drain(pad->handle);
200 snd_pcm_close(pad->handle);
201 snd_config_update_free_global();
202 }
203 free(pad);
204 }
205
206 static void alsa_write_post_select(__a_unused struct sched *s,
207 struct task *t)
208 {
209 struct writer_node *wn = container_of(t, struct writer_node, task);
210 struct private_alsa_write_data *pad = wn->private_data;
211 struct btr_node *btrn = wn->btrn;
212 char *data;
213 size_t bytes;
214 snd_pcm_sframes_t frames;
215 int ret;
216
217 again:
218 t->error = 0;
219 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
220 if (ret == 0)
221 return;
222 btr_merge(btrn, wn->min_iqs);
223 bytes = btr_next_buffer(btrn, &data);
224 if (ret < 0 || bytes < pad->bytes_per_frame) { /* eof */
225 assert(btr_no_parent(btrn));
226 ret = -E_ALSA_EOF;
227 if (!pad->handle)
228 goto err;
229 /* wait until pending frames are played */
230 if (pad->drain_barrier.tv_sec == 0) {
231 PARA_DEBUG_LOG("waiting for device to drain\n");
232 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
233 &pad->drain_barrier);
234 return;
235 }
236 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
237 goto err;
238 return;
239 }
240 if (!pad->handle) {
241 int32_t val;
242
243 if (bytes == 0) /* no data available */
244 return;
245 get_btr_sample_rate(btrn, &val);
246 pad->sample_rate = val;
247 get_btr_channels(btrn, &val);
248 pad->channels = val;
249 get_btr_sample_format(btrn, &val);
250 pad->sample_format = get_alsa_pcm_format(val);
251
252 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
253 pad->sample_rate);
254 ret = alsa_init(pad, wn->conf);
255 if (ret < 0)
256 goto err;
257 wn->min_iqs = pad->bytes_per_frame;
258 goto again;
259 }
260 frames = bytes / pad->bytes_per_frame;
261 frames = snd_pcm_writei(pad->handle, data, frames);
262 if (frames >= 0) {
263 btr_consume(btrn, frames * pad->bytes_per_frame);
264 goto again;
265 }
266 if (frames == -EPIPE) {
267 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
268 snd_pcm_prepare(pad->handle);
269 return;
270 }
271 if (frames == -EAGAIN)
272 return;
273 PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
274 ret = -E_ALSA_WRITE;
275 err:
276 assert(ret < 0);
277 btr_remove_node(btrn);
278 t->error = ret;
279 }
280
281 __malloc static void *alsa_parse_config_or_die(const char *options)
282 {
283 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
284
285 PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
286 /* exits on errors */
287 alsa_cmdline_parser_string(options, conf, "alsa_write");
288 return conf;
289 }
290
291 static void alsa_free_config(void *conf)
292 {
293 alsa_cmdline_parser_free(conf);
294 }
295
296 /**
297 * The init function of the alsa writer.
298 *
299 * \param w Pointer to the writer to initialize.
300 *
301 * \sa struct \ref writer.
302 */
303 void alsa_write_init(struct writer *w)
304 {
305 struct alsa_write_args_info dummy;
306
307 alsa_cmdline_parser_init(&dummy);
308 w->open = alsa_open;
309 w->close = alsa_close;
310 w->pre_select = alsa_write_pre_select;
311 w->post_select = alsa_write_post_select;
312 w->parse_config_or_die = alsa_parse_config_or_die;
313 w->shutdown = NULL; /* nothing to do */
314 w->free_config = alsa_free_config;
315 w->help = (struct ggo_help) {
316 .short_help = alsa_write_args_info_help,
317 .detailed_help = alsa_write_args_info_detailed_help
318 };
319 alsa_cmdline_parser_free(&dummy);
320 }