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         size_t bytes_per_frame;
  38         /** don't write anything until this time */
  39         struct timeval next_chunk;
  40         /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
  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, also 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 = buffer_size;
 105         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 106                         start_threshold) < 0)
 107                 return -E_START_THRESHOLD;
 108         stop_threshold = buffer_size;
 109         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 110                         stop_threshold) < 0)
 111                 return -E_STOP_THRESHOLD;
 112         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 113                 PARA_WARNING_LOG("unable to install sw params\n");
 114         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 115                 * pad->channels / 8;
 116         PARA_INFO_LOG("bytes per frame: %zu\n", pad->bytes_per_frame);
 117         if (snd_pcm_nonblock(pad->handle, 1))
 118                 PARA_ERROR_LOG("failed to set nonblock mode\n");
 119         return 1;
 120 }
 121
 122 /* Open an instance of the alsa writer. */
 123 static int alsa_open(struct writer_node *wn)
 124 {
 125         struct alsa_write_args_info *conf = wn->conf;
 126         struct writer_node_group *wng = wn->wng;
 127         struct private_alsa_write_data *pad = para_calloc(sizeof(*pad));
 128
 129         wn->private_data = pad;
 130         if (!conf->samplerate_given && wng->samplerate)
 131                 pad->samplerate = *wng->samplerate;
 132         else
 133                 pad->samplerate = conf->samplerate_arg;
 134         if (!conf->channels_given && wng->channels)
 135                 pad->channels = *wng->channels;
 136         else
 137                 pad->channels = conf->channels_arg;
 138         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
 139         tv_add(now, &(struct timeval){0, 100 * 1000}, &pad->next_chunk);
 140         return 1;
 141 }
 142
 143 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 144 {
 145         struct private_alsa_write_data *pad = wn->private_data;
 146         struct writer_node_group *wng = wn->wng;
 147         struct timeval diff;
 148
 149         if (!*wng->loaded)
 150                 return 1;
 151         if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
 152                 if (tv_diff(&s->timeout, &diff, NULL) > 0)
 153                         s->timeout = diff;
 154         } else {
 155                 s->timeout.tv_sec = 0;
 156                 s->timeout.tv_usec = 1;
 157         }
 158         return 1;
 159 }
 160
 161 static int alsa_write_post_select(__a_unused struct sched *s,
 162                 struct writer_node *wn)
 163 {
 164         struct private_alsa_write_data *pad = wn->private_data;
 165         struct writer_node_group *wng = wn->wng;
 166         size_t frames, bytes = *wng->loaded - wn->written;
 167         unsigned char *data = (unsigned char*)wng->buf + wn->written;
 168         struct timeval tv;
 169         snd_pcm_sframes_t ret;
 170
 171         if (!bytes) /* no data available */
 172                 goto out;
 173         if (tv_diff(now, &pad->next_chunk, NULL) < 0)
 174                 goto out;
 175         if (!pad->handle) {
 176                 int err = alsa_init(pad, wn->conf);
 177                 if (err < 0)
 178                         return err;
 179         }
 180         frames = bytes / pad->bytes_per_frame;
 181         ret = snd_pcm_writei(pad->handle, data, frames);
 182         if (ret == -EPIPE) {
 183                 PARA_WARNING_LOG("EPIPE\n");
 184                 snd_pcm_prepare(pad->handle);
 185                 return 1;
 186         }
 187         if (ret < 0 && ret != -EAGAIN) {
 188                 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
 189                         frames, (int)ret);
 190                 return -E_ALSA_WRITE;
 191         }
 192         if (ret == -EAGAIN)
 193                 PARA_DEBUG_LOG("EAGAIN\n");
 194         else
 195                 wn->written += ret * pad->bytes_per_frame;
 196         if (ret == frames) /* we wrote everything, try again immediately */
 197                 pad->next_chunk = *now;
 198         else {
 199                 ms2tv(pad->buffer_time / pad->bytes_per_frame / 1000, &tv);
 200                 tv_add(now, &tv, &pad->next_chunk);
 201         }
 202 out:
 203         if (*wng->input_error < 0) {
 204                 wn->written = *wng->loaded;
 205                 return *wng->input_error;
 206         }
 207         return 1;
 208 }
 209
 210 static void alsa_close(struct writer_node *wn)
 211 {
 212         struct private_alsa_write_data *pad = wn->private_data;
 213         PARA_INFO_LOG("closing writer node %p\n", wn);
 214         snd_pcm_drain(pad->handle);
 215         snd_pcm_close(pad->handle);
 216         snd_config_update_free_global();
 217         free(pad);
 218 }
 219
 220 __malloc static void *alsa_parse_config(const char *options)
 221 {
 222         int ret;
 223         struct alsa_write_args_info *conf
 224                 = para_calloc(sizeof(struct alsa_write_args_info));
 225
 226         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 227         ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 228         if (ret)
 229                 goto err_out;
 230         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 231         return conf;
 232 err_out:
 233         free(conf);
 234         return NULL;
 235 }
 236
 237 /**
 238  * the init function of the alsa writer
 239  *
 240  * \param w pointer to the writer to initialize
 241  *
 242  * \sa struct writer
 243  */
 244 void alsa_write_init(struct writer *w)
 245 {
 246         struct alsa_write_args_info dummy;
 247
 248         alsa_cmdline_parser_init(&dummy);
 249         w->open = alsa_open;
 250         w->close = alsa_close;
 251         w->pre_select = alsa_write_pre_select;
 252         w->post_select = alsa_write_post_select;
 253         w->parse_config = alsa_parse_config;
 254         w->shutdown = NULL; /* nothing to do */
 255         w->help = (struct ggo_help) {
 256                 .short_help = alsa_write_args_info_help,
 257                 .detailed_help = alsa_write_args_info_detailed_help
 258         };
 259 }