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 <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         int bytes_per_frame;
  38         /** Don't write anything until this time. */
  39         struct timeval next_chunk;
  40         /** The approximate maximum buffer duration in us. */
  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, given by command line option or the
  49          * decoder of the writer node group.
  50          */
  51         unsigned channels;
  52 };
  53
  54 /* Install PCM software and hardware configuration. */
  55 static int alsa_init(struct private_alsa_write_data *pad,
  56                 struct alsa_write_args_info *conf)
  57 {
  58         snd_pcm_hw_params_t *hwparams;
  59         snd_pcm_sw_params_t *swparams;
  60         snd_pcm_uframes_t buffer_size, start_threshold, stop_threshold;
  61         snd_pcm_uframes_t period_size;
  62         int err;
  63
  64         err = snd_pcm_open(&pad->handle, conf->device_arg,
  65                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  66         if (err < 0)
  67                 return -E_PCM_OPEN;
  68
  69         snd_pcm_hw_params_alloca(&hwparams);
  70         snd_pcm_sw_params_alloca(&swparams);
  71         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  72                 return -E_BROKEN_CONF;
  73         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  74                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  75                 return -E_ACCESS_TYPE;
  76         if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
  77                 return -E_SAMPLE_FORMAT;
  78         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
  79                         pad->channels) < 0)
  80                 return -E_CHANNEL_COUNT;
  81         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
  82                         &pad->samplerate, 0) < 0)
  83                 return -E_SET_RATE;
  84         err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
  85         if (err < 0 || !pad->buffer_time)
  86                 return -E_GET_BUFFER_TIME;
  87         PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
  88         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
  89                         &pad->buffer_time, 0) < 0)
  90                 return -E_SET_BUFFER_TIME;
  91         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
  92                 return -E_HW_PARAMS;
  93         snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
  94         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
  95         PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
  96                 period_size);
  97         if (period_size == buffer_size)
  98                 return -E_BAD_PERIOD;
  99         snd_pcm_sw_params_current(pad->handle, swparams);
 100         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 101         if (buffer_size < 1)
 102                 start_threshold = 1;
 103         else
 104                 start_threshold = PARA_MIN(buffer_size,
 105                         (snd_pcm_uframes_t)pad->samplerate);
 106         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 107                         start_threshold) < 0)
 108                 return -E_START_THRESHOLD;
 109         stop_threshold = buffer_size;
 110         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 111                         stop_threshold) < 0)
 112                 return -E_STOP_THRESHOLD;
 113         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 114                 PARA_WARNING_LOG("unable to install sw params\n");
 115         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 116                 * pad->channels / 8;
 117         if (pad->bytes_per_frame <= 0)
 118                 return -E_PHYSICAL_WIDTH;
 119         PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
 120         if (snd_pcm_nonblock(pad->handle, 1))
 121                 PARA_ERROR_LOG("failed to set nonblock mode\n");
 122         return 1;
 123 }
 124
 125 /* Open an instance of the alsa writer. */
 126 static int alsa_open(struct writer_node *wn)
 127 {
 128         struct alsa_write_args_info *conf = wn->conf;
 129         struct writer_node_group *wng = wn->wng;
 130         struct private_alsa_write_data *pad = para_calloc(sizeof(*pad));
 131
 132         wn->private_data = pad;
 133         if (!conf->samplerate_given && wng->samplerate)
 134                 pad->samplerate = *wng->samplerate;
 135         else
 136                 pad->samplerate = conf->samplerate_arg;
 137         if (!conf->channels_given && wng->channels)
 138                 pad->channels = *wng->channels;
 139         else
 140                 pad->channels = conf->channels_arg;
 141         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
 142         tv_add(now, &(struct timeval){0, 100 * 1000}, &pad->next_chunk);
 143         return 1;
 144 }
 145
 146 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 147 {
 148         struct private_alsa_write_data *pad = wn->private_data;
 149         struct writer_node_group *wng = wn->wng;
 150         struct timeval diff;
 151
 152         if (!*wng->loaded)
 153                 return 1;
 154         if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
 155                 if (tv_diff(&s->timeout, &diff, NULL) > 0)
 156                         s->timeout = diff;
 157         } else {
 158                 s->timeout.tv_sec = 0;
 159                 s->timeout.tv_usec = 1;
 160         }
 161         return 1;
 162 }
 163
 164 static int alsa_write_post_select(__a_unused struct sched *s,
 165                 struct writer_node *wn)
 166 {
 167         struct private_alsa_write_data *pad = wn->private_data;
 168         struct writer_node_group *wng = wn->wng;
 169         size_t frames, bytes = *wng->loaded - wn->written;
 170         unsigned char *data = (unsigned char*)wng->buf + wn->written;
 171         struct timeval tv;
 172         snd_pcm_sframes_t ret;
 173
 174         if (*wng->input_error < 0 && (!pad->handle || bytes < pad->bytes_per_frame)) {
 175                 wn->written = *wng->loaded;
 176                 return *wng->input_error;
 177         }
 178         if (!bytes) /* no data available */
 179                 goto out;
 180         if (tv_diff(now, &pad->next_chunk, NULL) < 0)
 181                 goto out;
 182         if (!pad->handle) {
 183                 int err = alsa_init(pad, wn->conf);
 184                 if (err < 0)
 185                         return err;
 186         }
 187         frames = bytes / pad->bytes_per_frame;
 188         if (!frames) /* less than a single frame available */
 189                 goto out;
 190         ret = snd_pcm_writei(pad->handle, data, frames);
 191         if (ret == -EPIPE) {
 192                 PARA_WARNING_LOG("EPIPE\n");
 193                 snd_pcm_prepare(pad->handle);
 194                 return 1;
 195         }
 196         if (ret < 0 && ret != -EAGAIN) {
 197                 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
 198                         frames, (int)ret);
 199                 return -E_ALSA_WRITE;
 200         }
 201         if (ret == -EAGAIN)
 202                 PARA_DEBUG_LOG("EAGAIN\n");
 203         else
 204                 wn->written += ret * pad->bytes_per_frame;
 205         if (ret == frames) /* we wrote everything, try again immediately */
 206                 pad->next_chunk = *now;
 207         else { /* wait until 50% buffer space is available */
 208                 ms2tv(pad->buffer_time / 2000, &tv);
 209                 tv_add(now, &tv, &pad->next_chunk);
 210         }
 211 out:
 212         return 1;
 213 }
 214
 215 static void alsa_close(struct writer_node *wn)
 216 {
 217         struct private_alsa_write_data *pad = wn->private_data;
 218         PARA_INFO_LOG("closing writer node %p\n", wn);
 219
 220         if (pad->handle) {
 221                 snd_pcm_drain(pad->handle);
 222                 snd_pcm_close(pad->handle);
 223                 snd_config_update_free_global();
 224         }
 225         free(pad);
 226 }
 227
 228 __malloc static void *alsa_parse_config(const char *options)
 229 {
 230         int ret;
 231         struct alsa_write_args_info *conf
 232                 = para_calloc(sizeof(struct alsa_write_args_info));
 233
 234         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 235         ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 236         if (ret)
 237                 goto err_out;
 238         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 239         return conf;
 240 err_out:
 241         free(conf);
 242         return NULL;
 243 }
 244
 245 /**
 246  * the init function of the alsa writer
 247  *
 248  * \param w pointer to the writer to initialize
 249  *
 250  * \sa struct writer
 251  */
 252 void alsa_write_init(struct writer *w)
 253 {
 254         struct alsa_write_args_info dummy;
 255
 256         alsa_cmdline_parser_init(&dummy);
 257         w->open = alsa_open;
 258         w->close = alsa_close;
 259         w->pre_select = alsa_write_pre_select;
 260         w->post_select = alsa_write_post_select;
 261         w->parse_config = alsa_parse_config;
 262         w->shutdown = NULL; /* nothing to do */
 263         w->help = (struct ggo_help) {
 264                 .short_help = alsa_write_args_info_help,
 265                 .detailed_help = alsa_write_args_info_detailed_help
 266         };
 267 }