Merge branch 't/net_cleanups'
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2011 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 #include <sys/time.h>
19 #include <stdbool.h>
20
21 #include "para.h"
22 #include "fd.h"
23 #include "string.h"
24 #include "list.h"
25 #include "sched.h"
26 #include "ggo.h"
27 #include "buffer_tree.h"
28 #include "write.h"
29 #include "write_common.h"
30 #include "alsa_write.cmdline.h"
31 #include "error.h"
32
33 /** Data specific to the alsa writer. */
34 struct private_alsa_write_data {
35 /** The alsa handle */
36 snd_pcm_t *handle;
37 /** Determined and set by alsa_init(). */
38 int bytes_per_frame;
39 /** The approximate maximum buffer duration in us. */
40 unsigned buffer_time;
41 /* Number of frames that fit into the buffer. */
42 snd_pcm_uframes_t buffer_frames;
43 /**
44 * The sample rate given by command line option or the decoder
45 * of the writer node group.
46 */
47 unsigned sample_rate;
48 snd_pcm_format_t sample_format;
49 /**
50 * The number of channels, given by command line option or the
51 * decoder of the writer node group.
52 */
53 unsigned channels;
54 struct timeval drain_barrier;
55 };
56
57 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
58 {
59 switch (sf) {
60 case SF_S8: return SND_PCM_FORMAT_S8;
61 case SF_U8: return SND_PCM_FORMAT_U8;
62 case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
63 case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
64 case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
65 case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
66 default: return SND_PCM_FORMAT_S16_LE;
67 }
68 }
69
70 /* Install PCM software and hardware configuration. */
71 static int alsa_init(struct private_alsa_write_data *pad,
72 struct alsa_write_args_info *conf)
73 {
74 snd_pcm_hw_params_t *hwparams;
75 snd_pcm_sw_params_t *swparams;
76 snd_pcm_uframes_t start_threshold, stop_threshold;
77 snd_pcm_uframes_t period_size;
78 int err;
79
80 PARA_INFO_LOG("opening %s\n", conf->device_arg);
81 err = snd_pcm_open(&pad->handle, conf->device_arg,
82 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
83 if (err < 0)
84 return -E_PCM_OPEN;
85
86 snd_pcm_hw_params_alloca(&hwparams);
87 snd_pcm_sw_params_alloca(&swparams);
88 if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
89 return -E_BROKEN_CONF;
90 if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
91 SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
92 return -E_ACCESS_TYPE;
93 if (snd_pcm_hw_params_set_format(pad->handle, hwparams,
94 pad->sample_format) < 0)
95 return -E_SAMPLE_FORMAT;
96 if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
97 pad->channels) < 0)
98 return -E_CHANNEL_COUNT;
99 if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
100 &pad->sample_rate, NULL) < 0)
101 return -E_SET_RATE;
102 err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
103 &pad->buffer_time, NULL);
104 if (err < 0 || !pad->buffer_time)
105 return -E_GET_BUFFER_TIME;
106 PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
107 if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
108 &pad->buffer_time, NULL) < 0)
109 return -E_SET_BUFFER_TIME;
110 if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
111 return -E_HW_PARAMS;
112 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
113 snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames);
114 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames,
115 period_size);
116 if (period_size == pad->buffer_frames)
117 return -E_BAD_PERIOD;
118 snd_pcm_sw_params_current(pad->handle, swparams);
119 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
120 if (pad->buffer_frames < 1)
121 start_threshold = 1;
122 else
123 start_threshold = PARA_MIN(pad->buffer_frames,
124 (snd_pcm_uframes_t)pad->sample_rate);
125 if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
126 start_threshold) < 0)
127 return -E_START_THRESHOLD;
128 stop_threshold = pad->buffer_frames;
129 if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
130 stop_threshold) < 0)
131 return -E_STOP_THRESHOLD;
132 if (snd_pcm_sw_params(pad->handle, swparams) < 0)
133 PARA_WARNING_LOG("unable to install sw params\n");
134 pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format)
135 * pad->channels / 8;
136 if (pad->bytes_per_frame <= 0)
137 return -E_PHYSICAL_WIDTH;
138 PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
139 if (snd_pcm_nonblock(pad->handle, 1))
140 PARA_ERROR_LOG("failed to set nonblock mode\n");
141 return 1;
142 }
143
144 static void alsa_write_pre_select(struct sched *s, struct task *t)
145 {
146 struct writer_node *wn = container_of(t, struct writer_node, task);
147 struct private_alsa_write_data *pad = wn->private_data;
148 snd_pcm_sframes_t avail, underrun;
149 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
150
151 if (ret == 0)
152 return;
153 if (ret < 0 || !pad)
154 return sched_min_delay(s);
155 /*
156 * Data is available to be written to the alsa handle. Compute number
157 * of milliseconds until next buffer underrun would occur.
158 *
159 * snd_pcm_avail_update() updates the current available count of
160 * samples for writing. It is a light method to obtain current stream
161 * position, because it does not require the user <-> kernel context
162 * switch, but the value is less accurate, because ring buffer pointers
163 * are updated in kernel drivers only when an interrupt occurs.
164 */
165 avail = snd_pcm_avail_update(pad->handle);
166 if (avail < 0)
167 avail = 0;
168 underrun = (pad->buffer_frames - avail) * pad->buffer_time
169 / pad->buffer_frames / 1000;
170 if (underrun < 50)
171 underrun = 50;
172 underrun -= 50;
173 sched_request_timeout_ms(underrun, s);
174 }
175
176 static void alsa_close(struct writer_node *wn)
177 {
178 struct private_alsa_write_data *pad = wn->private_data;
179 PARA_INFO_LOG("closing writer node %p\n", wn);
180
181 if (!pad)
182 return;
183 /*
184 * It's OK to have a blocking operation here because we already made
185 * sure that the PCM output buffer is (nearly) empty.
186 */
187 snd_pcm_nonblock(pad->handle, 0);
188 snd_pcm_drain(pad->handle);
189 snd_pcm_close(pad->handle);
190 snd_config_update_free_global();
191 free(pad);
192 }
193
194 static void alsa_write_post_select(__a_unused struct sched *s,
195 struct task *t)
196 {
197 struct writer_node *wn = container_of(t, struct writer_node, task);
198 struct private_alsa_write_data *pad = wn->private_data;
199 struct btr_node *btrn = wn->btrn;
200 char *data;
201 size_t bytes;
202 snd_pcm_sframes_t frames;
203 int ret;
204
205 again:
206 t->error = 0;
207 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
208 if (ret == 0)
209 return;
210 btr_merge(btrn, wn->min_iqs);
211 bytes = btr_next_buffer(btrn, &data);
212 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
213 assert(btr_no_parent(btrn));
214 ret = -E_WRITE_COMMON_EOF;
215 if (!pad)
216 goto err;
217 /* wait until pending frames are played */
218 if (pad->drain_barrier.tv_sec == 0) {
219 PARA_DEBUG_LOG("waiting for device to drain\n");
220 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
221 &pad->drain_barrier);
222 return;
223 }
224 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
225 goto err;
226 return;
227 }
228 if (!pad) {
229 int32_t val;
230
231 if (bytes == 0) /* no data available */
232 return;
233 pad = para_calloc(sizeof(*pad));
234 get_btr_sample_rate(btrn, &val);
235 pad->sample_rate = val;
236 get_btr_channels(btrn, &val);
237 pad->channels = val;
238 get_btr_sample_format(btrn, &val);
239 pad->sample_format = get_alsa_pcm_format(val);
240
241 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
242 pad->sample_rate);
243 ret = alsa_init(pad, wn->conf);
244 if (ret < 0) {
245 free(pad);
246 goto err;
247 }
248 wn->private_data = pad;
249 wn->min_iqs = pad->bytes_per_frame;
250 goto again;
251 }
252 frames = bytes / pad->bytes_per_frame;
253 frames = snd_pcm_writei(pad->handle, data, frames);
254 if (frames >= 0) {
255 btr_consume(btrn, frames * pad->bytes_per_frame);
256 goto again;
257 }
258 if (frames == -EPIPE) {
259 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
260 snd_pcm_prepare(pad->handle);
261 return;
262 }
263 if (frames == -EAGAIN)
264 return;
265 PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
266 ret = -E_ALSA_WRITE;
267 err:
268 assert(ret < 0);
269 btr_remove_node(btrn);
270 t->error = ret;
271 }
272
273 __malloc static void *alsa_parse_config_or_die(const char *options)
274 {
275 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
276
277 PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
278 /* exits on errors */
279 alsa_cmdline_parser_string(options, conf, "alsa_write");
280 return conf;
281 }
282
283 static void alsa_free_config(void *conf)
284 {
285 alsa_cmdline_parser_free(conf);
286 }
287
288 /**
289 * The init function of the alsa writer.
290 *
291 * \param w Pointer to the writer to initialize.
292 *
293 * \sa struct \ref writer.
294 */
295 void alsa_write_init(struct writer *w)
296 {
297 struct alsa_write_args_info dummy;
298
299 alsa_cmdline_parser_init(&dummy);
300 w->close = alsa_close;
301 w->pre_select = alsa_write_pre_select;
302 w->post_select = alsa_write_post_select;
303 w->parse_config_or_die = alsa_parse_config_or_die;
304 w->shutdown = NULL; /* nothing to do */
305 w->free_config = alsa_free_config;
306 w->help = (struct ggo_help) {
307 .short_help = alsa_write_args_info_help,
308 .detailed_help = alsa_write_args_info_detailed_help
309 };
310 alsa_cmdline_parser_free(&dummy);
311 }