alsa_write.c

   1 /*
   2  * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
   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 <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 "buffer_tree.h"
  26 #include "write.h"
  27 #include "write_common.h"
  28 #include "alsa_write.cmdline.h"
  29 #include "error.h"
  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_init(). */
  36         int bytes_per_frame;
  37         /*
  38          * If the sample rate is not given at the command line and no wav
  39          * header was detected, the btr exec mechanism is employed to query the
  40          * ancestor buffer tree nodes for this information. In a typical setup
  41          * the decoder passes the sample rate back to the alsa writer.
  42          *
  43          *  \sa \ref btr_exec_up().
  44          */
  45         unsigned sample_rate;
  46         /*
  47          * The sample format (8/16 bit, signed/unsigned, little/big endian) is
  48          * determined in the same way as the \a sample_rate.
  49          */
  50         snd_pcm_format_t sample_format;
  51         /* The number of channels, again determined like \a sample_rate. */
  52         unsigned channels;
  53         /* time until buffer underrun occurs, in milliseconds */
  54         unsigned buffer_time;
  55         struct timeval drain_barrier;
  56         /* File descriptor for select(). */
  57         int poll_fd;
  58 };
  59
  60 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
  61 {
  62         switch (sf) {
  63         case SF_S8: return SND_PCM_FORMAT_S8;
  64         case SF_U8: return SND_PCM_FORMAT_U8;
  65         case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
  66         case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
  67         case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
  68         case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
  69         default: return SND_PCM_FORMAT_S16_LE;
  70         }
  71 }
  72
  73 /* Install PCM software and hardware configuration. */
  74 static int alsa_init(struct private_alsa_write_data *pad,
  75                 struct alsa_write_args_info *conf)
  76 {
  77         snd_pcm_hw_params_t *hwparams = NULL;
  78         snd_pcm_sw_params_t *swparams = NULL;
  79         snd_pcm_uframes_t start_threshold, stop_threshold;
  80         snd_pcm_uframes_t buffer_size, period_size;
  81         snd_output_t *output_log;
  82         int ret;
  83         const char *msg;
  84         unsigned period_time;
  85
  86         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  87         msg = "unable to open pcm";
  88         ret = snd_pcm_open(&pad->handle, conf->device_arg,
  89                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  90         if (ret < 0)
  91                 goto fail;
  92         ret = snd_pcm_hw_params_malloc(&hwparams);
  93         assert(ret >= 0);
  94         msg = "Broken alsa configuration";
  95         ret = snd_pcm_hw_params_any(pad->handle, hwparams);
  96         if (ret < 0)
  97                 goto fail;
  98         msg = "access type not available";
  99         ret = snd_pcm_hw_params_set_access(pad->handle, hwparams,
 100                 SND_PCM_ACCESS_RW_INTERLEAVED);
 101         if (ret < 0)
 102                 goto fail;
 103         msg = "sample format not available";
 104         ret = snd_pcm_hw_params_set_format(pad->handle, hwparams,
 105                 pad->sample_format);
 106         if (ret < 0)
 107                 goto fail;
 108         msg = "channels count not available";
 109         ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams,
 110                 pad->channels);
 111         if (ret < 0)
 112                 goto fail;
 113         msg = "could not set sample rate";
 114         ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
 115                 &pad->sample_rate, NULL);
 116         if (ret < 0)
 117                 goto fail;
 118         /* alsa wants microseconds */
 119         pad->buffer_time = conf->buffer_time_arg * 1000;
 120         msg = "could not set buffer time";
 121         ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
 122                 &pad->buffer_time, NULL);
 123         if (ret < 0)
 124                 goto fail;
 125         pad->buffer_time /= 1000; /* we prefer milliseconds */
 126         period_time = pad->buffer_time * 250; /* buffer time / 4 */
 127         msg = "could not set period time";
 128         ret = snd_pcm_hw_params_set_period_time_near(pad->handle, hwparams,
 129                 &period_time, NULL);
 130         if (ret < 0)
 131                 goto fail;
 132
 133         msg = "unable to install hw params";
 134         ret = snd_pcm_hw_params(pad->handle, hwparams);
 135         if (ret < 0)
 136                 goto fail;
 137         snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
 138         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
 139         msg = "period size equals buffer size";
 140         if (period_size == buffer_size)
 141                 goto fail;
 142
 143         /* software parameter setup */
 144         ret = snd_pcm_sw_params_malloc(&swparams);
 145         assert(ret >= 0);
 146         snd_pcm_sw_params_current(pad->handle, swparams);
 147         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 148         if (buffer_size < 1)
 149                 start_threshold = 1;
 150         else
 151                 start_threshold = PARA_MIN(buffer_size,
 152                         (snd_pcm_uframes_t)pad->sample_rate);
 153         msg = "could not set start threshold";
 154         ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 155                 start_threshold);
 156         if (ret < 0)
 157                 goto fail;
 158         stop_threshold = buffer_size;
 159         msg = "could not set stop threshold";
 160         ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 161                 stop_threshold);
 162         if (ret < 0)
 163                 goto fail;
 164         msg = "unable to install sw params";
 165         ret = snd_pcm_sw_params(pad->handle, swparams);
 166         if (ret < 0)
 167                 goto fail;
 168         msg = "unable to determine bytes per frame";
 169         ret = snd_pcm_format_physical_width(pad->sample_format);
 170         if (ret <= 0)
 171                 goto fail;
 172         pad->bytes_per_frame = ret * pad->channels / 8;
 173         msg = "failed to set alsa handle to nonblock mode";
 174         ret = snd_pcm_nonblock(pad->handle, 1);
 175         if (ret < 0)
 176                 goto fail;
 177         ret = snd_output_buffer_open(&output_log);
 178         if (ret == 0) {
 179                 char *buf, *p;
 180                 size_t sz;
 181                 PARA_DEBUG_LOG("dumping alsa configuration\n");
 182                 snd_pcm_dump(pad->handle, output_log);
 183                 snd_pcm_hw_params_dump(hwparams, output_log);
 184                 sz = snd_output_buffer_string(output_log, &buf);
 185                 for (p = buf; p < buf + sz;) {
 186                         char *q = memchr(p, '\n', buf + sz - p);
 187                         if (!q)
 188                                 break;
 189                         *q = '\0';
 190                         PARA_DEBUG_LOG("%s\n", p);
 191                         p = q + 1;
 192                 }
 193                 snd_output_close(output_log);
 194         }
 195         ret = 1;
 196         goto out;
 197 fail:
 198         if (ret < 0)
 199                 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
 200         else
 201                 PARA_ERROR_LOG("%s\n", msg);
 202         ret = -E_ALSA;
 203 out:
 204         snd_pcm_hw_params_free(hwparams);
 205         snd_pcm_sw_params_free(swparams);
 206         return ret;
 207 }
 208
 209 static void alsa_write_pre_select(struct sched *s, void *context)
 210 {
 211         struct pollfd pfd;
 212         struct writer_node *wn = context;
 213         struct private_alsa_write_data *pad = wn->private_data;
 214         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 215
 216         if (pad)
 217                 pad->poll_fd = -1;
 218         if (ret == 0)
 219                 return;
 220         if (!pad) {
 221                 sched_min_delay(s);
 222                 return;
 223         }
 224         if (ret < 0) {
 225                 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
 226                 return;
 227         }
 228         /* wait at most 50% of the buffer time */
 229         sched_request_timeout_ms(pad->buffer_time / 2, s);
 230         ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
 231         if (ret < 0) {
 232                 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
 233                         snd_strerror(-ret));
 234                 return;
 235         }
 236         pad->poll_fd = pfd.fd;
 237         para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
 238 }
 239
 240 static void alsa_close(struct writer_node *wn)
 241 {
 242         struct private_alsa_write_data *pad = wn->private_data;
 243         PARA_INFO_LOG("closing writer node %p\n", wn);
 244
 245         if (!pad)
 246                 return;
 247         /*
 248          * It's OK to have a blocking operation here because we already made
 249          * sure that the PCM output buffer is (nearly) empty.
 250          */
 251         snd_pcm_nonblock(pad->handle, 0);
 252         snd_pcm_drain(pad->handle);
 253         snd_pcm_close(pad->handle);
 254         snd_config_update_free_global();
 255         free(pad);
 256 }
 257
 258 static int alsa_write_post_select(__a_unused struct sched *s, void *context)
 259 {
 260         struct writer_node *wn = context;
 261         struct private_alsa_write_data *pad = wn->private_data;
 262         struct btr_node *btrn = wn->btrn;
 263         char *data;
 264         size_t bytes;
 265         snd_pcm_sframes_t frames;
 266         int ret;
 267
 268         ret = task_get_notification(wn->task);
 269         if (ret < 0)
 270                 goto err;
 271 again:
 272         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 273         if (ret == 0)
 274                 return 0;
 275         btr_merge(btrn, wn->min_iqs);
 276         bytes = btr_next_buffer(btrn, &data);
 277         if (ret < 0 || bytes < wn->min_iqs) { /* eof */
 278                 assert(btr_no_parent(btrn));
 279                 ret = -E_WRITE_COMMON_EOF;
 280                 if (!pad)
 281                         goto err;
 282                 /* wait until pending frames are played */
 283                 if (pad->drain_barrier.tv_sec == 0) {
 284                         PARA_DEBUG_LOG("waiting for device to drain\n");
 285                         tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
 286                                 &pad->drain_barrier);
 287                         return 0;
 288                 }
 289                 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
 290                         goto err;
 291                 return 0;
 292         }
 293         if (!pad) {
 294                 int32_t val;
 295
 296                 if (bytes == 0) /* no data available */
 297                         return 0;
 298                 pad = para_calloc(sizeof(*pad));
 299                 get_btr_sample_rate(btrn, &val);
 300                 pad->sample_rate = val;
 301                 get_btr_channels(btrn, &val);
 302                 pad->channels = val;
 303                 get_btr_sample_format(btrn, &val);
 304                 pad->sample_format = get_alsa_pcm_format(val);
 305
 306                 PARA_INFO_LOG("%u channel(s), %uHz\n", pad->channels,
 307                         pad->sample_rate);
 308                 ret = alsa_init(pad, wn->conf);
 309                 if (ret < 0) {
 310                         free(pad);
 311                         goto err;
 312                 }
 313                 wn->private_data = pad;
 314                 wn->min_iqs = pad->bytes_per_frame;
 315                 goto again;
 316         }
 317         frames = bytes / pad->bytes_per_frame;
 318         frames = snd_pcm_writei(pad->handle, data, frames);
 319         if (frames == 0 || frames == -EAGAIN) {
 320                 char buf[100];
 321                 if (pad->poll_fd >= 0 && FD_ISSET(pad->poll_fd, &s->rfds))
 322                         if (read(pad->poll_fd, buf, 100))
 323                                 do_nothing;
 324                 return 0;
 325         }
 326         if (frames > 0) {
 327                 btr_consume(btrn, frames * pad->bytes_per_frame);
 328                 goto again;
 329         }
 330         if (frames == -EPIPE) {
 331                 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
 332                 snd_pcm_prepare(pad->handle);
 333                 return 0;
 334         }
 335         PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
 336         ret = -E_ALSA;
 337 err:
 338         assert(ret < 0);
 339         btr_remove_node(&wn->btrn);
 340         return ret;
 341 }
 342
 343 __malloc static void *alsa_parse_config_or_die(int argc, char **argv)
 344 {
 345         struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
 346
 347         /* exits on errors */
 348         alsa_write_cmdline_parser(argc, argv, conf);
 349         return conf;
 350 }
 351
 352 static void alsa_free_config(void *conf)
 353 {
 354         alsa_write_cmdline_parser_free(conf);
 355 }
 356
 357 /**
 358  * The init function of the alsa writer.
 359  *
 360  * \param w Pointer to the writer to initialize.
 361  *
 362  * \sa struct \ref writer.
 363  */
 364 void alsa_write_init(struct writer *w)
 365 {
 366         struct alsa_write_args_info dummy;
 367
 368         alsa_write_cmdline_parser_init(&dummy);
 369         w->close = alsa_close;
 370         w->pre_select = alsa_write_pre_select;
 371         w->post_select = alsa_write_post_select;
 372         w->parse_config_or_die = alsa_parse_config_or_die;
 373         w->free_config = alsa_free_config;
 374         w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
 375         alsa_write_cmdline_parser_free(&dummy);
 376 }