alsa: Fix a typo in comment.
[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 <sys/types.h>
16 #include <dirent.h>
17 #include <alsa/asoundlib.h>
18
19 #include "para.h"
20 #include "fd.h"
21 #include "string.h"
22 #include "list.h"
23 #include "sched.h"
24 #include "ggo.h"
25 #include "write.h"
26 #include "alsa_write.cmdline.h"
27 #include "error.h"
28
29 /** always use 16 bit little endian */
30 #define FORMAT SND_PCM_FORMAT_S16_LE
31
32 /** data specific to the alsa writer */
33 struct private_alsa_write_data {
34 /** the alsa handle */
35 snd_pcm_t *handle;
36 /** determined and set by alsa_open() */
37 size_t bytes_per_frame;
38 /** don't write anything until this time */
39 struct timeval next_chunk;
40 /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
41 unsigned buffer_time;
42 /**
43 * the samplerate given by command line option or the decoder
44 * of the writer node group
45 */
46 unsigned samplerate;
47 /**
48 * The number of channels, given by command line option or the
49 * decoder of the writer node group.
50 */
51 unsigned channels;
52 };
53
54 /* Install PCM software and hardware configuration. */
55 static int alsa_init(struct private_alsa_write_data *pad,
56 struct alsa_write_args_info *conf)
57 {
58 snd_pcm_hw_params_t *hwparams;
59 snd_pcm_sw_params_t *swparams;
60 snd_pcm_uframes_t buffer_size, start_threshold, stop_threshold;
61 snd_pcm_uframes_t period_size;
62 int err;
63
64 err = snd_pcm_open(&pad->handle, conf->device_arg,
65 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
66 if (err < 0)
67 return -E_PCM_OPEN;
68
69 snd_pcm_hw_params_alloca(&hwparams);
70 snd_pcm_sw_params_alloca(&swparams);
71 if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
72 return -E_BROKEN_CONF;
73 if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
74 SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
75 return -E_ACCESS_TYPE;
76 if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
77 return -E_SAMPLE_FORMAT;
78 if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
79 pad->channels) < 0)
80 return -E_CHANNEL_COUNT;
81 if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
82 &pad->samplerate, 0) < 0)
83 return -E_SET_RATE;
84 err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
85 if (err < 0 || !pad->buffer_time)
86 return -E_GET_BUFFER_TIME;
87 PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
88 if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
89 &pad->buffer_time, 0) < 0)
90 return -E_SET_BUFFER_TIME;
91 if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
92 return -E_HW_PARAMS;
93 snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
94 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
95 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
96 period_size);
97 if (period_size == buffer_size)
98 return -E_BAD_PERIOD;
99 snd_pcm_sw_params_current(pad->handle, swparams);
100 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
101 if (buffer_size < 1)
102 start_threshold = 1;
103 else
104 start_threshold = buffer_size;
105 if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
106 start_threshold) < 0)
107 return -E_START_THRESHOLD;
108 stop_threshold = buffer_size;
109 if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
110 stop_threshold) < 0)
111 return -E_STOP_THRESHOLD;
112 if (snd_pcm_sw_params(pad->handle, swparams) < 0)
113 PARA_WARNING_LOG("unable to install sw params\n");
114 pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
115 * pad->channels / 8;
116 PARA_INFO_LOG("bytes per frame: %zu\n", pad->bytes_per_frame);
117 if (snd_pcm_nonblock(pad->handle, 1))
118 PARA_ERROR_LOG("failed to set nonblock mode\n");
119 return 1;
120 }
121
122 /* Open an instance of the alsa writer. */
123 static int alsa_open(struct writer_node *wn)
124 {
125 struct alsa_write_args_info *conf = wn->conf;
126 struct writer_node_group *wng = wn->wng;
127 struct private_alsa_write_data *pad = para_calloc(sizeof(*pad));
128
129 wn->private_data = pad;
130 if (!conf->samplerate_given && wng->samplerate)
131 pad->samplerate = *wng->samplerate;
132 else
133 pad->samplerate = conf->samplerate_arg;
134 if (!conf->channels_given && wng->channels)
135 pad->channels = *wng->channels;
136 else
137 pad->channels = conf->channels_arg;
138 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
139 tv_add(now, &(struct timeval){0, 100 * 1000}, &pad->next_chunk);
140 return 1;
141 }
142
143 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
144 {
145 struct private_alsa_write_data *pad = wn->private_data;
146 struct writer_node_group *wng = wn->wng;
147 struct timeval diff;
148
149 if (!*wng->loaded)
150 return 1;
151 if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
152 if (tv_diff(&s->timeout, &diff, NULL) > 0)
153 s->timeout = diff;
154 } else {
155 s->timeout.tv_sec = 0;
156 s->timeout.tv_usec = 1;
157 }
158 return 1;
159 }
160
161 static int alsa_write_post_select(__a_unused struct sched *s,
162 struct writer_node *wn)
163 {
164 struct private_alsa_write_data *pad = wn->private_data;
165 struct writer_node_group *wng = wn->wng;
166 size_t frames, bytes = *wng->loaded - wn->written;
167 unsigned char *data = (unsigned char*)wng->buf + wn->written;
168 struct timeval tv;
169 snd_pcm_sframes_t ret;
170
171 if (!bytes) /* no data available */
172 goto out;
173 if (tv_diff(now, &pad->next_chunk, NULL) < 0)
174 goto out;
175 if (!pad->handle) {
176 int err = alsa_init(pad, wn->conf);
177 if (err < 0)
178 return err;
179 }
180 frames = bytes / pad->bytes_per_frame;
181 ret = snd_pcm_writei(pad->handle, data, frames);
182 if (ret == -EPIPE) {
183 PARA_WARNING_LOG("EPIPE\n");
184 snd_pcm_prepare(pad->handle);
185 return 1;
186 }
187 if (ret < 0 && ret != -EAGAIN) {
188 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
189 frames, (int)ret);
190 return -E_ALSA_WRITE;
191 }
192 if (ret == -EAGAIN)
193 PARA_DEBUG_LOG("EAGAIN\n");
194 else
195 wn->written += ret * pad->bytes_per_frame;
196 if (ret == frames) /* we wrote everything, try again immediately */
197 pad->next_chunk = *now;
198 else {
199 ms2tv(pad->buffer_time / pad->bytes_per_frame / 1000, &tv);
200 tv_add(now, &tv, &pad->next_chunk);
201 }
202 out:
203 if (*wng->input_error < 0) {
204 wn->written = *wng->loaded;
205 return *wng->input_error;
206 }
207 return 1;
208 }
209
210 static void alsa_close(struct writer_node *wn)
211 {
212 struct private_alsa_write_data *pad = wn->private_data;
213 PARA_INFO_LOG("closing writer node %p\n", wn);
214 snd_pcm_drain(pad->handle);
215 snd_pcm_close(pad->handle);
216 snd_config_update_free_global();
217 free(pad);
218 }
219
220 __malloc static void *alsa_parse_config(const char *options)
221 {
222 int ret;
223 struct alsa_write_args_info *conf
224 = para_calloc(sizeof(struct alsa_write_args_info));
225
226 PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
227 ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
228 if (ret)
229 goto err_out;
230 PARA_INFO_LOG("help given: %d\n", conf->help_given);
231 return conf;
232 err_out:
233 free(conf);
234 return NULL;
235 }
236
237 /**
238 * the init function of the alsa writer
239 *
240 * \param w pointer to the writer to initialize
241 *
242 * \sa struct writer
243 */
244 void alsa_write_init(struct writer *w)
245 {
246 struct alsa_write_args_info dummy;
247
248 alsa_cmdline_parser_init(&dummy);
249 w->open = alsa_open;
250 w->close = alsa_close;
251 w->pre_select = alsa_write_pre_select;
252 w->post_select = alsa_write_post_select;
253 w->parse_config = alsa_parse_config;
254 w->shutdown = NULL; /* nothing to do */
255 w->help = (struct ggo_help) {
256 .short_help = alsa_write_args_info_help,
257 .detailed_help = alsa_write_args_info_detailed_help
258 };
259 }