dfd2421d3f6ddc51eefd6aa5db98098f11389f01
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2008 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, also given by command line option or the
49 * decoder of the writer node group
50 */
51 unsigned channels;
52 };
53
54 /*
55 * open and prepare the PCM handle for writing
56 *
57 * Install PCM software and hardware configuration. Exit on errors.
58 */
59 static int alsa_open(struct writer_node *w)
60 {
61 snd_pcm_hw_params_t *hwparams;
62 snd_pcm_sw_params_t *swparams;
63 snd_pcm_uframes_t buffer_size, start_threshold, stop_threshold;
64 int err;
65 snd_pcm_uframes_t period_size;
66 struct private_alsa_write_data *pad = para_calloc(sizeof(struct
67 private_alsa_write_data));
68 struct alsa_write_args_info *conf = w->conf;
69 struct writer_node_group *wng = w->wng;
70
71 if (!conf->samplerate_given && wng->samplerate)
72 pad->samplerate = *wng->samplerate;
73 else
74 pad->samplerate = conf->samplerate_arg;
75 if (!conf->channels_given && wng->channels)
76 pad->channels = *wng->channels;
77 else
78 pad->channels = conf->channels_arg;
79 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
80 w->private_data = pad;
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, FORMAT) < 0)
94 return -E_SAMPLE_FORMAT;
95 if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
96 pad->channels) < 0)
97 return -E_CHANNEL_COUNT;
98 if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
99 &pad->samplerate, 0) < 0)
100 return -E_SET_RATE;
101 err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
102 if (err < 0 || !pad->buffer_time)
103 return -E_GET_BUFFER_TIME;
104 PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
105 if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
106 &pad->buffer_time, 0) < 0)
107 return -E_SET_BUFFER_TIME;
108 if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
109 return -E_HW_PARAMS;
110 snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
111 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
112 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
113 period_size);
114 if (period_size == buffer_size)
115 return -E_BAD_PERIOD;
116 snd_pcm_sw_params_current(pad->handle, swparams);
117 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
118 if (buffer_size < 1)
119 start_threshold = 1;
120 else
121 start_threshold = buffer_size;
122 if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
123 start_threshold) < 0)
124 return -E_START_THRESHOLD;
125 stop_threshold = buffer_size;
126 if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
127 stop_threshold) < 0)
128 return -E_STOP_THRESHOLD;
129 if (snd_pcm_sw_params(pad->handle, swparams) < 0)
130 PARA_WARNING_LOG("unable to install sw params\n");
131 pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
132 * pad->channels / 8;
133 PARA_INFO_LOG("bytes per frame: %zu\n", pad->bytes_per_frame);
134 if (snd_pcm_nonblock(pad->handle, 1))
135 PARA_ERROR_LOG("failed to set nonblock mode\n");
136 tv_add(now, &(struct timeval ){0, 100 * 1000}, &pad->next_chunk);
137 return 1;
138 }
139
140 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
141 {
142 struct private_alsa_write_data *pad = wn->private_data;
143 struct writer_node_group *wng = wn->wng;
144 struct timeval diff;
145
146 if (*wng->loaded < pad->bytes_per_frame)
147 return 1;
148 if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
149 if (tv_diff(&s->timeout, &diff, NULL) > 0)
150 s->timeout = diff;
151 } else {
152 s->timeout.tv_sec = 0;
153 s->timeout.tv_usec = 1;
154 }
155 return 1;
156 // PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
157 }
158
159 static int alsa_write_post_select(__a_unused struct sched *s,
160 struct writer_node *wn)
161 {
162 struct private_alsa_write_data *pad = wn->private_data;
163 struct writer_node_group *wng = wn->wng;
164 size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame;
165 snd_pcm_sframes_t ret;
166 unsigned char *data = (unsigned char*)wng->buf + wn->written;
167 struct timeval tv;
168
169 // PARA_INFO_LOG("%zd frames\n", frames);
170 if (!frames) {
171 if (*wng->input_error)
172 wn->written = *wng->loaded;
173 return 1;
174 }
175 if (tv_diff(now, &pad->next_chunk, NULL) < 0)
176 return 1;
177 ret = snd_pcm_writei(pad->handle, data, frames);
178 if (ret == -EPIPE) {
179 PARA_WARNING_LOG("EPIPE\n");
180 snd_pcm_prepare(pad->handle);
181 return 1;
182 }
183 if (ret < 0 && ret != -EAGAIN) {
184 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
185 frames, (int)ret);
186 return -E_ALSA_WRITE;
187 }
188 if (ret == -EAGAIN)
189 PARA_DEBUG_LOG("EAGAIN\n");
190 else
191 wn->written += ret * pad->bytes_per_frame;
192 if (ret == frames) /* we wrote everything, try again immediately */
193 pad->next_chunk = *now;
194 else {
195 ms2tv(pad->buffer_time / pad->bytes_per_frame / 1000, &tv);
196 tv_add(now, &tv, &pad->next_chunk);
197 }
198 return 1;
199 }
200
201 static void alsa_close(struct writer_node *wn)
202 {
203 struct private_alsa_write_data *pad = wn->private_data;
204 PARA_INFO_LOG("closing writer node %p\n", wn);
205 snd_pcm_drain(pad->handle);
206 snd_pcm_close(pad->handle);
207 snd_config_update_free_global();
208 free(pad);
209 }
210
211 __malloc static void *alsa_parse_config(const char *options)
212 {
213 int ret;
214 struct alsa_write_args_info *conf
215 = para_calloc(sizeof(struct alsa_write_args_info));
216
217 PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
218 ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
219 if (ret)
220 goto err_out;
221 PARA_INFO_LOG("help given: %d\n", conf->help_given);
222 return conf;
223 err_out:
224 free(conf);
225 return NULL;
226 }
227
228 /**
229 * the init function of the alsa writer
230 *
231 * \param w pointer to the writer to initialize
232 *
233 * \sa struct writer
234 */
235 void alsa_write_init(struct writer *w)
236 {
237 struct alsa_write_args_info dummy;
238
239 alsa_cmdline_parser_init(&dummy);
240 w->open = alsa_open;
241 w->close = alsa_close;
242 w->pre_select = alsa_write_pre_select;
243 w->post_select = alsa_write_post_select;
244 w->parse_config = alsa_parse_config;
245 w->shutdown = NULL; /* nothing to do */
246 w->help = (struct ggo_help) {
247 .short_help = alsa_write_args_info_help,
248 .detailed_help = alsa_write_args_info_detailed_help
249 };
250 }