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 <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 "write.h"
  29 #include "alsa_write.cmdline.h"
  30 #include "error.h"
  31 #include "buffer_tree.h"
  32
  33 /** always use 16 bit little endian */
  34 #define FORMAT SND_PCM_FORMAT_S16_LE
  35
  36 /** Data specific to the alsa writer. */
  37 struct private_alsa_write_data {
  38         /** The alsa handle */
  39         snd_pcm_t *handle;
  40         /** Determined and set by alsa_open(). */
  41         int bytes_per_frame;
  42         /** The approximate maximum buffer duration in us. */
  43         unsigned buffer_time;
  44         /* Number of frames that fit into the buffer. */
  45         unsigned buffer_frames;
  46         /**
  47          * The samplerate given by command line option or the decoder
  48          * of the writer node group.
  49          */
  50         unsigned samplerate;
  51         /**
  52          * The number of channels, given by command line option or the
  53          * decoder of the writer node group.
  54          */
  55         unsigned channels;
  56 };
  57
  58 /* Install PCM software and hardware configuration. */
  59 static int alsa_init(struct private_alsa_write_data *pad,
  60                 struct alsa_write_args_info *conf)
  61 {
  62         snd_pcm_hw_params_t *hwparams;
  63         snd_pcm_sw_params_t *swparams;
  64         snd_pcm_uframes_t buffer_size, start_threshold, stop_threshold;
  65         snd_pcm_uframes_t period_size;
  66         int err;
  67
  68         err = snd_pcm_open(&pad->handle, conf->device_arg,
  69                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  70         if (err < 0)
  71                 return -E_PCM_OPEN;
  72
  73         snd_pcm_hw_params_alloca(&hwparams);
  74         snd_pcm_sw_params_alloca(&swparams);
  75         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  76                 return -E_BROKEN_CONF;
  77         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  78                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  79                 return -E_ACCESS_TYPE;
  80         if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
  81                 return -E_SAMPLE_FORMAT;
  82         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
  83                         pad->channels) < 0)
  84                 return -E_CHANNEL_COUNT;
  85         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
  86                         &pad->samplerate, NULL) < 0)
  87                 return -E_SET_RATE;
  88         err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
  89                 &pad->buffer_time, NULL);
  90         if (err < 0 || !pad->buffer_time)
  91                 return -E_GET_BUFFER_TIME;
  92         PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
  93         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
  94                         &pad->buffer_time, NULL) < 0)
  95                 return -E_SET_BUFFER_TIME;
  96         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
  97                 return -E_HW_PARAMS;
  98         snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
  99         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
 100         PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
 101                 period_size);
 102         if (period_size == buffer_size)
 103                 return -E_BAD_PERIOD;
 104         snd_pcm_sw_params_current(pad->handle, swparams);
 105         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 106         if (buffer_size < 1)
 107                 start_threshold = 1;
 108         else
 109                 start_threshold = PARA_MIN(buffer_size,
 110                         (snd_pcm_uframes_t)pad->samplerate);
 111         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 112                         start_threshold) < 0)
 113                 return -E_START_THRESHOLD;
 114         stop_threshold = buffer_size;
 115         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 116                         stop_threshold) < 0)
 117                 return -E_STOP_THRESHOLD;
 118         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 119                 PARA_WARNING_LOG("unable to install sw params\n");
 120         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 121                 * pad->channels / 8;
 122         if (pad->bytes_per_frame <= 0)
 123                 return -E_PHYSICAL_WIDTH;
 124         PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
 125         if (snd_pcm_nonblock(pad->handle, 1))
 126                 PARA_ERROR_LOG("failed to set nonblock mode\n");
 127         pad->buffer_frames = 1000 * pad->buffer_time / pad->samplerate;
 128         PARA_INFO_LOG("max buffered frames: %d\n", pad->buffer_frames);
 129         return 1;
 130 }
 131
 132 /* Open an instance of the alsa writer. */
 133 static int alsa_open_nobtr(struct writer_node *wn)
 134 {
 135         struct alsa_write_args_info *conf = wn->conf;
 136         struct writer_node_group *wng = wn->wng;
 137         struct private_alsa_write_data *pad = para_calloc(sizeof(*pad));
 138
 139         wn->private_data = pad;
 140         if (!conf->samplerate_given && wng->samplerate)
 141                 pad->samplerate = *wng->samplerate;
 142         else
 143                 pad->samplerate = conf->samplerate_arg;
 144         if (!conf->channels_given && wng->channels)
 145                 pad->channels = *wng->channels;
 146         else
 147                 pad->channels = conf->channels_arg;
 148         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
 149         return 1;
 150 }
 151
 152 static int alsa_open_btr(struct writer_node *wn)
 153 {
 154         struct alsa_write_args_info *conf = wn->conf;
 155         struct private_alsa_write_data *pad = para_calloc(sizeof(*pad));
 156         int ret;
 157         char *buf = NULL;
 158
 159         sprintf(wn->task.status, "alsa writer");
 160         wn->private_data = pad;
 161
 162         /* defaults */
 163         pad->samplerate = conf->samplerate_arg;
 164         pad->channels = conf->channels_arg;
 165
 166         if (!conf->samplerate_given) { /* config option trumps btr_exec */
 167                 /* ask parent btr nodes */
 168                 ret = btr_exec_up(wn->btrn, "samplerate", &buf);
 169                 if (ret >= 0) {
 170                         int32_t rate;
 171                         ret = para_atoi32(buf, &rate);
 172                         if (ret < 0) /* should not happen */
 173                                 goto out;
 174                         pad->samplerate = rate;
 175                 }
 176                 freep(&buf);
 177         }
 178
 179         if (!conf->channels_given) {
 180                 ret = btr_exec_up(wn->btrn, "channels", &buf);
 181                 if (ret >= 0) {
 182                         int32_t ch;
 183                         ret = para_atoi32(buf, &ch);
 184                         if (ret < 0)
 185                                 goto out;
 186                         pad->channels = ch;
 187                 }
 188                 freep(&buf);
 189         }
 190         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
 191         ret = 1;
 192 out:
 193         freep(&buf);
 194         if (ret < 0)
 195                 free(pad);
 196         return ret;
 197 }
 198 static int alsa_open(struct writer_node *wn)
 199 {
 200         struct alsa_write_args_info *conf = wn->conf;
 201
 202         if (conf->buffer_tree_given)
 203                 return alsa_open_btr(wn);
 204         else
 205                 return alsa_open_nobtr(wn);
 206
 207 }
 208
 209 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 210 {
 211         struct alsa_write_args_info *conf = wn->conf;
 212         struct private_alsa_write_data *pad = wn->private_data;
 213         struct writer_node_group *wng = wn->wng;
 214         struct timeval tv;
 215         snd_pcm_sframes_t avail, underrun;
 216
 217         if (!pad->handle)
 218                 return 1;
 219         if (conf->buffer_tree_given) {
 220                 size_t sz = btr_get_input_queue_size(wn->btrn);
 221                 if (sz < pad->bytes_per_frame)
 222                         return 1;
 223         } else {
 224                 if (*wng->loaded - wn->written < pad->bytes_per_frame)
 225                         return 1;
 226         }
 227         /*
 228          * Data is available to be written to the alsa handle.  Compute number
 229          * of milliseconds until next buffer underrun would occur.
 230          *
 231          * snd_pcm_avail_update() updates the current available count of
 232          * samples for writing.  It is a light method to obtain current stream
 233          * position, because it does not require the user <-> kernel context
 234          * switch, but the value is less accurate, because ring buffer pointers
 235          * are updated in kernel drivers only when an interrupt occurs.
 236          */
 237         avail = snd_pcm_avail_update(pad->handle);
 238         if (avail < 0)
 239                 avail = 0;
 240         underrun = (pad->buffer_frames - avail) * pad->buffer_time
 241                 / pad->buffer_frames / 1000;
 242         if (underrun < 50)
 243                 underrun = 50;
 244         underrun -= 50;
 245         ms2tv(underrun, &tv);
 246         if (tv_diff(&s->timeout, &tv, NULL) > 0)
 247                 s->timeout = tv;
 248         //PARA_CRIT_LOG("timout: %lu\n", tv2ms(&s->timeout));
 249         return 1;
 250 }
 251
 252 static void alsa_write_pre_select_btr(struct sched *s, struct task *t)
 253 {
 254         struct writer_node *wn = container_of(t, struct writer_node, task);
 255         t->error = alsa_write_pre_select(s, wn);
 256 }
 257
 258 static void xrun(snd_pcm_t *handle)
 259 {
 260         snd_pcm_status_t *status;
 261         int ret;
 262         struct timeval tv, diff;
 263
 264         snd_pcm_status_alloca(&status);
 265         ret = snd_pcm_status(handle, status);
 266         if (ret < 0)
 267                 return;
 268         if (snd_pcm_status_get_state(status) != SND_PCM_STATE_XRUN)
 269                 return;
 270         snd_pcm_status_get_trigger_tstamp(status, &tv);
 271         tv_diff(now, &tv, &diff);
 272         PARA_WARNING_LOG("underrun: %lums\n", tv2ms(&diff));
 273 }
 274
 275 static int alsa_write_post_select(__a_unused struct sched *s,
 276                 struct writer_node *wn)
 277 {
 278         struct private_alsa_write_data *pad = wn->private_data;
 279         struct writer_node_group *wng = wn->wng;
 280         size_t bytes = *wng->loaded - wn->written;
 281         unsigned char *data = (unsigned char*)*wng->bufp + wn->written;
 282         snd_pcm_sframes_t ret, frames, avail;
 283
 284         if (*wng->input_error < 0 && (!pad->handle || bytes < pad->bytes_per_frame)) {
 285                 wn->written = *wng->loaded;
 286                 return *wng->input_error;
 287         }
 288         if (!bytes) /* no data available */
 289                 return 0;
 290         if (!pad->handle) {
 291                 int err = alsa_init(pad, wn->conf);
 292                 if (err < 0)
 293                         return err;
 294         }
 295         frames = bytes / pad->bytes_per_frame;
 296         if (!frames) /* less than a single frame available */
 297                 return 0;
 298         avail = snd_pcm_avail_update(pad->handle);
 299         if (avail <= 0)
 300                 return 0;
 301         frames = PARA_MIN(frames, avail);
 302         ret = snd_pcm_writei(pad->handle, data, frames);
 303         if (ret >= 0) {
 304                 wn->written += ret * pad->bytes_per_frame;
 305                 return 1;
 306         }
 307         if (ret == -EPIPE) {
 308                 xrun(pad->handle);
 309                 snd_pcm_prepare(pad->handle);
 310                 return 0;
 311         }
 312         PARA_WARNING_LOG("%s\n", snd_strerror(-ret));
 313         if (ret == -EAGAIN)
 314                 return 0;
 315         return -E_ALSA_WRITE;
 316 }
 317
 318 static void alsa_close(struct writer_node *wn)
 319 {
 320         struct private_alsa_write_data *pad = wn->private_data;
 321         PARA_INFO_LOG("closing writer node %p\n", wn);
 322
 323         if (pad->handle) {
 324                 snd_pcm_drain(pad->handle);
 325                 snd_pcm_close(pad->handle);
 326                 snd_config_update_free_global();
 327         }
 328         free(pad);
 329 }
 330
 331 static void alsa_write_post_select_btr(__a_unused struct sched *s,
 332                 struct task *t)
 333 {
 334         struct writer_node *wn = container_of(t, struct writer_node, task);
 335         struct private_alsa_write_data *pad = wn->private_data;
 336         char *data;
 337         size_t bytes;
 338         snd_pcm_sframes_t frames, avail;
 339         int ret;
 340
 341 again:
 342         bytes = btr_next_buffer(wn->btrn, &data);
 343         //PARA_CRIT_LOG("have: %zu\n", bytes);
 344         t->error = 0;
 345         ret = -E_ALSA_ORPHAN;
 346         if (btr_no_parent(wn->btrn) && (!pad->handle || bytes < pad->bytes_per_frame))
 347                 goto err;
 348         if (!pad->handle) {
 349                 if (bytes == 0) /* no data available */
 350                         return;
 351                 PARA_CRIT_LOG("alsa init\n");
 352                 ret = alsa_init(pad, wn->conf);
 353                 if (ret < 0)
 354                         goto err;
 355         }
 356         for (;;) {
 357                 if (bytes == 0)
 358                         return;
 359                 if (bytes >= pad->bytes_per_frame)
 360                         break;
 361                 /* should not be possible to reach this */
 362                 PARA_CRIT_LOG("dropping %zu byte buffer\n", bytes);
 363                 btr_consume(wn->btrn, bytes);
 364                 bytes = btr_next_buffer(wn->btrn, &data);
 365         }
 366         frames = bytes / pad->bytes_per_frame;
 367         avail = snd_pcm_avail_update(pad->handle);
 368         if (avail <= 0)
 369                 return;
 370         frames = PARA_MIN(frames, avail);
 371         //PARA_CRIT_LOG("writing %ld frames\n", frames);
 372         frames = snd_pcm_writei(pad->handle, data, frames);
 373         if (frames >= 0) {
 374                 btr_consume(wn->btrn, frames * pad->bytes_per_frame);
 375                 goto again;
 376         }
 377         if (frames == -EPIPE) {
 378                 xrun(pad->handle);
 379                 snd_pcm_prepare(pad->handle);
 380                 return;
 381         }
 382         PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
 383         if (frames == -EAGAIN)
 384                 return;
 385         ret = -E_ALSA_WRITE;
 386 err:
 387         assert(ret < 0);
 388         alsa_close(wn);
 389         btr_del_node(wn->btrn);
 390         wn->btrn = NULL;
 391         t->error = ret;
 392 }
 393
 394 __malloc static void *alsa_parse_config(const char *options)
 395 {
 396         int ret;
 397         struct alsa_write_args_info *conf
 398                 = para_calloc(sizeof(struct alsa_write_args_info));
 399
 400         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 401         ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 402         if (ret)
 403                 goto err_out;
 404         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 405         return conf;
 406 err_out:
 407         free(conf);
 408         return NULL;
 409 }
 410
 411 /**
 412  * the init function of the alsa writer
 413  *
 414  * \param w pointer to the writer to initialize
 415  *
 416  * \sa struct writer
 417  */
 418 void alsa_write_init(struct writer *w)
 419 {
 420         struct alsa_write_args_info dummy;
 421
 422         alsa_cmdline_parser_init(&dummy);
 423         w->open = alsa_open;
 424         w->close = alsa_close;
 425         w->pre_select = alsa_write_pre_select;
 426         w->pre_select_btr = alsa_write_pre_select_btr;
 427         w->post_select = alsa_write_post_select;
 428         w->post_select_btr = alsa_write_post_select_btr;
 429         w->parse_config = alsa_parse_config;
 430         w->shutdown = NULL; /* nothing to do */
 431         w->help = (struct ggo_help) {
 432                 .short_help = alsa_write_args_info_help,
 433                 .detailed_help = alsa_write_args_info_detailed_help
 434         };
 435         alsa_cmdline_parser_free(&dummy);
 436 }