Introduce the vss task.
[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 "write.h"
25 #include "alsa_write.cmdline.h"
26 #include "error.h"
27
28 /** always use 16 bit little endian */
29 #define FORMAT SND_PCM_FORMAT_S16_LE
30
31 /** data specific to the alsa writer */
32 struct private_alsa_write_data {
33 /** the alsa handle */
34 snd_pcm_t *handle;
35 /** determined and set by alsa_open() */
36 size_t bytes_per_frame;
37 /** don't write anything until this time */
38 struct timeval next_chunk;
39 /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
40 unsigned buffer_time;
41 /**
42 * the samplerate given by command line option or the decoder
43 * of the writer node group
44 */
45 unsigned samplerate;
46 /**
47 * the number of channels, also given by command line option or the
48 * decoder of the writer node group
49 */
50 unsigned channels;
51 };
52
53 /*
54 * open and prepare the PCM handle for writing
55 *
56 * Install PCM software and hardware configuration. Exit on errors.
57 */
58 static int alsa_open(struct writer_node *w)
59 {
60 snd_pcm_hw_params_t *hwparams;
61 snd_pcm_sw_params_t *swparams;
62 snd_pcm_uframes_t buffer_size, start_threshold, stop_threshold;
63 int err;
64 snd_pcm_info_t *info;
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 snd_pcm_info_alloca(&info);
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 if ((err = snd_pcm_info(pad->handle, info)) < 0)
87 return -E_SND_PCM_INFO;
88
89 snd_pcm_hw_params_alloca(&hwparams);
90 snd_pcm_sw_params_alloca(&swparams);
91 if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
92 return -E_BROKEN_CONF;
93 if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
94 SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
95 return -E_ACCESS_TYPE;
96 if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
97 return -E_SAMPLE_FORMAT;
98 if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
99 pad->channels) < 0)
100 return -E_CHANNEL_COUNT;
101 if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
102 &pad->samplerate, 0) < 0)
103 return -E_SET_RATE;
104 err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
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, 0) < 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, 0);
114 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
115 PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
116 period_size);
117 if (period_size == buffer_size)
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 (buffer_size < 1)
122 start_threshold = 1;
123 else
124 start_threshold = buffer_size;
125 if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
126 start_threshold) < 0)
127 return -E_START_THRESHOLD;
128 stop_threshold = buffer_size;
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 return -E_SW_PARAMS;
134 pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
135 * pad->channels / 8;
136 if (snd_pcm_nonblock(pad->handle, 1))
137 PARA_ERROR_LOG("%s\n", "failed to set nonblock mode");
138 return period_size * pad->bytes_per_frame;
139 }
140
141 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
142 {
143 struct private_alsa_write_data *pad = wn->private_data;
144 struct writer_node_group *wng = wn->wng;
145 struct timeval diff;
146
147 if (*wng->loaded < pad->bytes_per_frame)
148 return 1;
149 if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
150 if (tv_diff(&s->timeout, &diff, NULL) > 0)
151 s->timeout = diff;
152 } else {
153 s->timeout.tv_sec = 0;
154 s->timeout.tv_usec = 1;
155 }
156 return 1;
157 // PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
158 }
159
160 static int alsa_write_post_select(__a_unused struct sched *s,
161 struct writer_node *wn)
162 {
163 struct private_alsa_write_data *pad = wn->private_data;
164 struct writer_node_group *wng = wn->wng;
165 size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame;
166 snd_pcm_sframes_t ret;
167 unsigned char *data = (unsigned char*)wng->buf + wn->written;
168 struct timeval tv;
169
170 // PARA_INFO_LOG("%zd frames\n", frames);
171 if (!frames) {
172 if (*wng->input_error)
173 wn->written = *wng->loaded;
174 return 1;
175 }
176 if (tv_diff(now, &pad->next_chunk, NULL) < 0)
177 return 1;
178 ret = snd_pcm_writei(pad->handle, data, frames);
179 if (ret == -EPIPE) {
180 PARA_WARNING_LOG("EPIPE\n");
181 snd_pcm_prepare(pad->handle);
182 return 1;
183 }
184 if (ret < 0 && ret != -EAGAIN) {
185 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
186 frames, (int)ret);
187 return -E_ALSA_WRITE;
188 }
189 if (ret == -EAGAIN) { /* try again in 5ms */
190 PARA_WARNING_LOG("EAGAIN\n");
191 ms2tv(5, &tv);
192 } else {
193 wn->written += ret * pad->bytes_per_frame;
194 ms2tv(pad->buffer_time / 4000, &tv);
195 }
196 tv_add(now, &tv, &pad->next_chunk);
197 return 1;
198 }
199
200 static void alsa_close(struct writer_node *wn)
201 {
202 struct private_alsa_write_data *pad = wn->private_data;
203 PARA_INFO_LOG("closing writer node %p\n", wn);
204 snd_pcm_drain(pad->handle);
205 snd_pcm_close(pad->handle);
206 snd_config_update_free_global();
207 free(pad);
208 }
209
210 __malloc static void *alsa_parse_config(const char *options)
211 {
212 struct alsa_write_args_info *conf
213 = para_calloc(sizeof(struct alsa_write_args_info));
214 PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
215 int ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
216 if (ret)
217 goto err_out;
218 PARA_INFO_LOG("help given: %d\n", conf->help_given);
219 return conf;
220 err_out:
221 free(conf);
222 return NULL;
223 }
224
225 /**
226 * the init function of the alsa writer
227 *
228 * \param w pointer to the writer to initialize
229 *
230 * \sa struct writer
231 */
232 void alsa_write_init(struct writer *w)
233 {
234 w->open = alsa_open;
235 w->close = alsa_close;
236 w->pre_select = alsa_write_pre_select;
237 w->post_select = alsa_write_post_select;
238 w->parse_config = alsa_parse_config;
239 w->shutdown = NULL; /* nothing to do */
240 }