alsa_write.c

   1 /*
   2  * Copyright (C) 2005-2008 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 "write.h"
  25 #include "alsa_write.cmdline.h"
  26 #include "error.h"
  27
  28 /** always use 16 bit little endian */
  29 #define FORMAT SND_PCM_FORMAT_S16_LE
  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_open() */
  36         size_t bytes_per_frame;
  37         /** don't write anything until this time */
  38         struct timeval next_chunk;
  39         /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
  40         unsigned buffer_time;
  41         /**
  42          * the samplerate given by command line option or the decoder
  43          * of the writer node group
  44          */
  45         unsigned samplerate;
  46         /**
  47          * the number of channels, also given by command line option or the
  48          * decoder of the writer node group
  49          */
  50         unsigned channels;
  51 };
  52
  53 /*
  54  * open and prepare the PCM handle for writing
  55  *
  56  * Install PCM software and hardware configuration. Exit on errors.
  57  */
  58 static int alsa_open(struct writer_node *w)
  59 {
  60         snd_pcm_hw_params_t *hwparams;
  61         snd_pcm_sw_params_t *swparams;
  62         snd_pcm_uframes_t buffer_size, start_threshold, stop_threshold;
  63         int err;
  64         snd_pcm_info_t *info;
  65         snd_pcm_uframes_t period_size;
  66         struct private_alsa_write_data *pad = para_calloc(sizeof(struct
  67                 private_alsa_write_data));
  68         struct alsa_write_args_info *conf = w->conf;
  69         struct writer_node_group *wng = w->wng;
  70
  71         if (!conf->samplerate_given && wng->samplerate)
  72                 pad->samplerate = *wng->samplerate;
  73         else
  74                 pad->samplerate = conf->samplerate_arg;
  75         if (!conf->channels_given && wng->channels)
  76                 pad->channels = *wng->channels;
  77         else
  78                 pad->channels = conf->channels_arg;
  79         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
  80         w->private_data = pad;
  81         snd_pcm_info_alloca(&info);
  82         err = snd_pcm_open(&pad->handle, conf->device_arg,
  83                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  84         if (err < 0)
  85                 return -E_PCM_OPEN;
  86         if ((err = snd_pcm_info(pad->handle, info)) < 0)
  87                 return -E_SND_PCM_INFO;
  88
  89         snd_pcm_hw_params_alloca(&hwparams);
  90         snd_pcm_sw_params_alloca(&swparams);
  91         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  92                 return -E_BROKEN_CONF;
  93         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  94                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  95                 return -E_ACCESS_TYPE;
  96         if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
  97                 return -E_SAMPLE_FORMAT;
  98         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
  99                         pad->channels) < 0)
 100                 return -E_CHANNEL_COUNT;
 101         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
 102                         &pad->samplerate, 0) < 0)
 103                 return -E_SET_RATE;
 104         err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
 105         if (err < 0 || !pad->buffer_time)
 106                 return -E_GET_BUFFER_TIME;
 107         PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
 108         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
 109                         &pad->buffer_time, 0) < 0)
 110                 return -E_SET_BUFFER_TIME;
 111         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
 112                 return -E_HW_PARAMS;
 113         snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
 114         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
 115         PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
 116                 period_size);
 117         if (period_size == buffer_size)
 118                 return -E_BAD_PERIOD;
 119         snd_pcm_sw_params_current(pad->handle, swparams);
 120         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 121         if (buffer_size < 1)
 122                 start_threshold = 1;
 123         else
 124                 start_threshold = buffer_size;
 125         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 126                         start_threshold) < 0)
 127                 return -E_START_THRESHOLD;
 128         stop_threshold = buffer_size;
 129         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 130                         stop_threshold) < 0)
 131                 return -E_STOP_THRESHOLD;
 132         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 133                 return -E_SW_PARAMS;
 134         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 135                 * pad->channels / 8;
 136         if (snd_pcm_nonblock(pad->handle, 1))
 137                 PARA_ERROR_LOG("%s\n", "failed to set nonblock mode");
 138         return period_size * pad->bytes_per_frame;
 139 }
 140
 141 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 142 {
 143         struct private_alsa_write_data *pad = wn->private_data;
 144         struct writer_node_group *wng = wn->wng;
 145         struct timeval diff;
 146
 147         if (*wng->loaded < pad->bytes_per_frame)
 148                 return 1;
 149         if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
 150                 if (tv_diff(&s->timeout, &diff, NULL) > 0)
 151                         s->timeout = diff;
 152         } else {
 153                 s->timeout.tv_sec = 0;
 154                 s->timeout.tv_usec = 1;
 155         }
 156         return 1;
 157 //      PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
 158 }
 159
 160 static int alsa_write_post_select(__a_unused struct sched *s,
 161                 struct writer_node *wn)
 162 {
 163         struct private_alsa_write_data *pad = wn->private_data;
 164         struct writer_node_group *wng = wn->wng;
 165         size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame;
 166         snd_pcm_sframes_t ret;
 167         unsigned char *data = (unsigned char*)wng->buf + wn->written;
 168         struct timeval tv;
 169
 170 //      PARA_INFO_LOG("%zd frames\n", frames);
 171         if (!frames) {
 172                 if (*wng->input_error)
 173                         wn->written = *wng->loaded;
 174                 return 1;
 175         }
 176         if (tv_diff(now, &pad->next_chunk, NULL) < 0)
 177                 return 1;
 178         ret = snd_pcm_writei(pad->handle, data, frames);
 179         if (ret == -EPIPE) {
 180                 PARA_WARNING_LOG("EPIPE\n");
 181                 snd_pcm_prepare(pad->handle);
 182                 return 1;
 183         }
 184         if (ret < 0 && ret != -EAGAIN) {
 185                 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
 186                         frames, (int)ret);
 187                 return -E_ALSA_WRITE;
 188         }
 189         if (ret == -EAGAIN) { /* try again in 5ms */
 190                 PARA_WARNING_LOG("EAGAIN\n");
 191                 ms2tv(5, &tv);
 192         } else {
 193                 wn->written += ret * pad->bytes_per_frame;
 194                 ms2tv(pad->buffer_time / 4000, &tv);
 195         }
 196         tv_add(now, &tv, &pad->next_chunk);
 197         return 1;
 198 }
 199
 200 static void alsa_close(struct writer_node *wn)
 201 {
 202         struct private_alsa_write_data *pad = wn->private_data;
 203         PARA_INFO_LOG("closing writer node %p\n", wn);
 204         snd_pcm_drain(pad->handle);
 205         snd_pcm_close(pad->handle);
 206         snd_config_update_free_global();
 207         free(pad);
 208 }
 209
 210 __malloc static void *alsa_parse_config(const char *options)
 211 {
 212         struct alsa_write_args_info *conf
 213                 = para_calloc(sizeof(struct alsa_write_args_info));
 214         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 215         int ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 216         if (ret)
 217                 goto err_out;
 218         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 219         return conf;
 220 err_out:
 221         free(conf);
 222         return NULL;
 223 }
 224
 225 /**
 226  * the init function of the alsa writer
 227  *
 228  * \param w pointer to the writer to initialize
 229  *
 230  * \sa struct writer
 231  */
 232 void alsa_write_init(struct writer *w)
 233 {
 234         w->open = alsa_open;
 235         w->close = alsa_close;
 236         w->pre_select = alsa_write_pre_select;
 237         w->post_select = alsa_write_post_select;
 238         w->parse_config = alsa_parse_config;
 239         w->shutdown = NULL; /* nothing to do */
 240 }