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 "buffer_tree.h"
  29 #include "write.h"
  30 #include "write_common.h"
  31 #include "alsa_write.cmdline.h"
  32 #include "error.h"
  33
  34 /** always use 16 bit little endian */
  35 #define FORMAT SND_PCM_FORMAT_S16_LE
  36
  37 /** Data specific to the alsa writer. */
  38 struct private_alsa_write_data {
  39         /** The alsa handle */
  40         snd_pcm_t *handle;
  41         /** Determined and set by alsa_open(). */
  42         int bytes_per_frame; /* TODO: Kill this after btr switch */
  43         /** The approximate maximum buffer duration in us. */
  44         unsigned buffer_time;
  45         /* Number of frames that fit into the buffer. */
  46         snd_pcm_uframes_t buffer_frames;
  47         /**
  48          * The samplerate given by command line option or the decoder
  49          * of the writer node group.
  50          */
  51         unsigned samplerate;
  52         /**
  53          * The number of channels, given by command line option or the
  54          * decoder of the writer node group.
  55          */
  56         unsigned channels;
  57 };
  58
  59 /* Install PCM software and hardware configuration. */
  60 static int alsa_init(struct private_alsa_write_data *pad,
  61                 struct alsa_write_args_info *conf)
  62 {
  63         snd_pcm_hw_params_t *hwparams;
  64         snd_pcm_sw_params_t *swparams;
  65         snd_pcm_uframes_t start_threshold, stop_threshold;
  66         snd_pcm_uframes_t period_size;
  67         int err;
  68
  69         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  70         err = snd_pcm_open(&pad->handle, conf->device_arg,
  71                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  72         if (err < 0)
  73                 return -E_PCM_OPEN;
  74
  75         snd_pcm_hw_params_alloca(&hwparams);
  76         snd_pcm_sw_params_alloca(&swparams);
  77         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  78                 return -E_BROKEN_CONF;
  79         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  80                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  81                 return -E_ACCESS_TYPE;
  82         if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
  83                 return -E_SAMPLE_FORMAT;
  84         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
  85                         pad->channels) < 0)
  86                 return -E_CHANNEL_COUNT;
  87         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
  88                         &pad->samplerate, NULL) < 0)
  89                 return -E_SET_RATE;
  90         err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
  91                 &pad->buffer_time, NULL);
  92         if (err < 0 || !pad->buffer_time)
  93                 return -E_GET_BUFFER_TIME;
  94         PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
  95         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
  96                         &pad->buffer_time, NULL) < 0)
  97                 return -E_SET_BUFFER_TIME;
  98         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
  99                 return -E_HW_PARAMS;
 100         snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
 101         snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames);
 102         PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames,
 103                 period_size);
 104         if (period_size == pad->buffer_frames)
 105                 return -E_BAD_PERIOD;
 106         snd_pcm_sw_params_current(pad->handle, swparams);
 107         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 108         if (pad->buffer_frames < 1)
 109                 start_threshold = 1;
 110         else
 111                 start_threshold = PARA_MIN(pad->buffer_frames,
 112                         (snd_pcm_uframes_t)pad->samplerate);
 113         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 114                         start_threshold) < 0)
 115                 return -E_START_THRESHOLD;
 116         stop_threshold = pad->buffer_frames;
 117         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 118                         stop_threshold) < 0)
 119                 return -E_STOP_THRESHOLD;
 120         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 121                 PARA_WARNING_LOG("unable to install sw params\n");
 122         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 123                 * pad->channels / 8;
 124         if (pad->bytes_per_frame <= 0)
 125                 return -E_PHYSICAL_WIDTH;
 126         PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
 127         if (snd_pcm_nonblock(pad->handle, 1))
 128                 PARA_ERROR_LOG("failed to set nonblock mode\n");
 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 private_alsa_write_data *pad = para_calloc(sizeof(*pad));
 155
 156         wn->private_data = pad;
 157         return 1;
 158 }
 159 static int alsa_open(struct writer_node *wn)
 160 {
 161         if (wn->btrn)
 162                 return alsa_open_btr(wn);
 163         return alsa_open_nobtr(wn);
 164 }
 165
 166 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 167 {
 168         struct private_alsa_write_data *pad = wn->private_data;
 169         struct writer_node_group *wng = wn->wng;
 170         struct timeval tv;
 171         snd_pcm_sframes_t avail, underrun;
 172
 173         if (!pad->handle)
 174                 return 1;
 175         if (wn->btrn) {
 176                 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 177                 if (ret == 0)
 178                         return 1;
 179                 if (ret < 0) {
 180                         underrun = 10;
 181                         goto timeout;
 182                 }
 183         } else {
 184                 if (*wng->loaded - wn->written < pad->bytes_per_frame)
 185                         return 1;
 186         }
 187         /*
 188          * Data is available to be written to the alsa handle.  Compute number
 189          * of milliseconds until next buffer underrun would occur.
 190          *
 191          * snd_pcm_avail_update() updates the current available count of
 192          * samples for writing.  It is a light method to obtain current stream
 193          * position, because it does not require the user <-> kernel context
 194          * switch, but the value is less accurate, because ring buffer pointers
 195          * are updated in kernel drivers only when an interrupt occurs.
 196          */
 197         avail = snd_pcm_avail_update(pad->handle);
 198         if (avail < 0)
 199                 avail = 0;
 200         underrun = (pad->buffer_frames - avail) * pad->buffer_time
 201                 / pad->buffer_frames / 1000;
 202         if (underrun < 50)
 203                 underrun = 50;
 204         underrun -= 50;
 205 timeout:
 206         ms2tv(underrun, &tv);
 207         if (tv_diff(&s->timeout, &tv, NULL) > 0)
 208                 s->timeout = tv;
 209         //PARA_CRIT_LOG("timout: %lu\n", tv2ms(&s->timeout));
 210         return 1;
 211 }
 212
 213 static void alsa_write_pre_select_btr(struct sched *s, struct task *t)
 214 {
 215         struct writer_node *wn = container_of(t, struct writer_node, task);
 216         alsa_write_pre_select(s, wn);
 217 }
 218
 219 static void xrun(snd_pcm_t *handle)
 220 {
 221         snd_pcm_status_t *status;
 222         int ret;
 223         struct timeval tv, diff;
 224
 225         snd_pcm_status_alloca(&status);
 226         ret = snd_pcm_status(handle, status);
 227         if (ret < 0)
 228                 return;
 229         if (snd_pcm_status_get_state(status) != SND_PCM_STATE_XRUN)
 230                 return;
 231         snd_pcm_status_get_trigger_tstamp(status, &tv);
 232         tv_diff(now, &tv, &diff);
 233         PARA_WARNING_LOG("underrun: %lums\n", tv2ms(&diff));
 234 }
 235
 236 static int alsa_write_post_select(__a_unused struct sched *s,
 237                 struct writer_node *wn)
 238 {
 239         struct private_alsa_write_data *pad = wn->private_data;
 240         struct writer_node_group *wng = wn->wng;
 241         size_t bytes = *wng->loaded - wn->written;
 242         unsigned char *data = (unsigned char*)*wng->bufp + wn->written;
 243         snd_pcm_sframes_t ret, frames, avail;
 244
 245         if (*wng->input_error < 0 && (!pad->handle || bytes < pad->bytes_per_frame)) {
 246                 wn->written = *wng->loaded;
 247                 return *wng->input_error;
 248         }
 249         if (!bytes) /* no data available */
 250                 return 0;
 251         if (!pad->handle) {
 252                 int err = alsa_init(pad, wn->conf);
 253                 if (err < 0)
 254                         return err;
 255         }
 256         frames = bytes / pad->bytes_per_frame;
 257         if (!frames) /* less than a single frame available */
 258                 return 0;
 259         avail = snd_pcm_avail_update(pad->handle);
 260         if (avail <= 0)
 261                 return 0;
 262         frames = PARA_MIN(frames, avail);
 263         ret = snd_pcm_writei(pad->handle, data, frames);
 264         if (ret >= 0) {
 265                 wn->written += ret * pad->bytes_per_frame;
 266                 return 1;
 267         }
 268         if (ret == -EPIPE) {
 269                 xrun(pad->handle);
 270                 snd_pcm_prepare(pad->handle);
 271                 return 0;
 272         }
 273         PARA_WARNING_LOG("%s\n", snd_strerror(-ret));
 274         if (ret == -EAGAIN)
 275                 return 0;
 276         return -E_ALSA_WRITE;
 277 }
 278
 279 static void alsa_close(struct writer_node *wn)
 280 {
 281         struct private_alsa_write_data *pad = wn->private_data;
 282         PARA_INFO_LOG("closing writer node %p\n", wn);
 283
 284         if (pad->handle) {
 285                 /*
 286                  * It's OK to have a blocking operation here because we already
 287                  * made sure that the PCM output buffer is (nearly) empty.
 288                  */
 289                 snd_pcm_nonblock(pad->handle, 0);
 290                 snd_pcm_drain(pad->handle);
 291                 snd_pcm_close(pad->handle);
 292                 snd_config_update_free_global();
 293         }
 294         free(pad);
 295 }
 296
 297 static void alsa_write_post_select_btr(__a_unused struct sched *s,
 298                 struct task *t)
 299 {
 300         struct writer_node *wn = container_of(t, struct writer_node, task);
 301         struct private_alsa_write_data *pad = wn->private_data;
 302         struct btr_node *btrn = wn->btrn;
 303         char *data;
 304         size_t bytes;
 305         snd_pcm_sframes_t frames, avail;
 306         int ret;
 307
 308 again:
 309         t->error = 0;
 310         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 311         if (ret == 0)
 312                 return;
 313         btr_merge(btrn, wn->min_iqs);
 314         bytes = btr_next_buffer(btrn, &data);
 315         if (ret < 0 || bytes < pad->bytes_per_frame) { /* eof */
 316                 assert(btr_no_parent(btrn));
 317                 ret = -E_ALSA_EOF;
 318                 if (!pad->handle)
 319                         goto err;
 320                 /* wait until pending frames are played */
 321                 avail = snd_pcm_avail_update(pad->handle);
 322                 if (avail + 1000 > pad->buffer_frames)
 323                         goto err;
 324                 PARA_DEBUG_LOG("waiting for device to drain\n");
 325                 return;
 326         }
 327         if (!pad->handle) {
 328                 struct alsa_write_args_info *conf = wn->conf;
 329                 if (bytes == 0) /* no data available */
 330                         return;
 331                 /* defaults */
 332                 pad->samplerate = conf->samplerate_arg;
 333                 pad->channels = conf->channels_arg;
 334                 if (!conf->samplerate_given) { /* config option trumps btr_exec */
 335                         int32_t rate;
 336                         ret = get_btr_samplerate(btrn, &rate);
 337                         if (ret < 0)
 338                                 goto err;
 339                         pad->samplerate = rate;
 340                 }
 341                 if (!conf->channels_given) {
 342                         int32_t ch;
 343                         ret = get_btr_channels(btrn, &ch);
 344                         if (ret < 0)
 345                                 goto err;
 346                         pad->channels = ch;
 347                 }
 348                 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
 349                 ret = 1;
 350                 ret = alsa_init(pad, wn->conf);
 351                 if (ret < 0)
 352                         goto err;
 353                 wn->min_iqs = pad->bytes_per_frame;
 354         }
 355         frames = bytes / pad->bytes_per_frame;
 356         avail = snd_pcm_avail_update(pad->handle);
 357         if (avail <= 0)
 358                 return;
 359         frames = PARA_MIN(frames, avail);
 360         //PARA_CRIT_LOG("writing %ld frames\n", frames);
 361         frames = snd_pcm_writei(pad->handle, data, frames);
 362         if (frames >= 0) {
 363                 btr_consume(btrn, frames * pad->bytes_per_frame);
 364                 goto again;
 365         }
 366         if (frames == -EPIPE) {
 367                 xrun(pad->handle);
 368                 snd_pcm_prepare(pad->handle);
 369                 return;
 370         }
 371         PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
 372         if (frames == -EAGAIN)
 373                 return;
 374         ret = -E_ALSA_WRITE;
 375 err:
 376         assert(ret < 0);
 377         t->error = ret;
 378 }
 379
 380 __malloc static void *alsa_parse_config(const char *options)
 381 {
 382         int ret;
 383         struct alsa_write_args_info *conf
 384                 = para_calloc(sizeof(struct alsa_write_args_info));
 385
 386         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 387         ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 388         if (ret)
 389                 goto err_out;
 390         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 391         return conf;
 392 err_out:
 393         free(conf);
 394         return NULL;
 395 }
 396
 397 static void alsa_free_config(void *conf)
 398 {
 399         alsa_cmdline_parser_free(conf);
 400 }
 401
 402 /**
 403  * The init function of the alsa writer.
 404  *
 405  * \param w Pointer to the writer to initialize.
 406  *
 407  * \sa \ref struct writer.
 408  */
 409 void alsa_write_init(struct writer *w)
 410 {
 411         struct alsa_write_args_info dummy;
 412
 413         alsa_cmdline_parser_init(&dummy);
 414         w->open = alsa_open;
 415         w->close = alsa_close;
 416         w->pre_select = alsa_write_pre_select;
 417         w->pre_select_btr = alsa_write_pre_select_btr;
 418         w->post_select = alsa_write_post_select;
 419         w->post_select_btr = alsa_write_post_select_btr;
 420         w->parse_config = alsa_parse_config;
 421         w->shutdown = NULL; /* nothing to do */
 422         w->free_config = alsa_free_config;
 423         w->help = (struct ggo_help) {
 424                 .short_help = alsa_write_args_info_help,
 425                 .detailed_help = alsa_write_args_info_detailed_help
 426         };
 427         alsa_cmdline_parser_free(&dummy);
 428 }