alsa_write.c

   1 /*
   2  * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file alsa_write.c paraslash's alsa output plugin */
  20
  21 /*
  22  * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
  23  * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
  24  * based on the vplay program by Michael Beck.
  25  */
  26
  27 #include "para.h"
  28 #include "fd.h"
  29 #include "string.h"
  30 #include "list.h"
  31 #include "sched.h"
  32 #include "write.h"
  33
  34 #include <alsa/asoundlib.h>
  35
  36 #include "alsa_write.cmdline.h"
  37 #include "error.h"
  38
  39 /** always use 16 bit little endian */
  40 #define FORMAT SND_PCM_FORMAT_S16_LE
  41
  42 /** data specific to the alsa writer */
  43 struct private_alsa_write_data {
  44         /** the alsa handle */
  45         snd_pcm_t *handle;
  46         /** determined and set by alsa_open() */
  47         size_t bytes_per_frame;
  48         /** don't write anything until this time */
  49         struct timeval next_chunk;
  50         /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
  51         unsigned buffer_time;
  52         /**
  53          * the samplerate given by command line option or the decoder
  54          * of the writer node group
  55          */
  56         unsigned samplerate;
  57         /**
  58          * the number of channels, also given by command line option or the
  59          * decoder of the writer node group
  60          */
  61         unsigned channels;
  62 };
  63
  64 /*
  65  * open and prepare the PCM handle for writing
  66  *
  67  * Install PCM software and hardware configuration. Exit on errors.
  68  */
  69 static int alsa_open(struct writer_node *w)
  70 {
  71         snd_pcm_hw_params_t *hwparams;
  72         snd_pcm_sw_params_t *swparams;
  73         snd_pcm_uframes_t buffer_size, xfer_align, start_threshold,
  74                 stop_threshold;
  75         int err;
  76         snd_pcm_info_t *info;
  77         snd_pcm_uframes_t period_size;
  78         struct private_alsa_write_data *pad = para_calloc(sizeof(struct
  79                 private_alsa_write_data));
  80         struct alsa_write_args_info *conf = w->conf;
  81         struct writer_node_group *wng = w->wng;
  82
  83         if (!conf->samplerate_given && wng->samplerate)
  84                 pad->samplerate = *wng->samplerate;
  85         else
  86                 pad->samplerate = conf->samplerate_arg;
  87         if (!conf->channels_given && wng->channels)
  88                 pad->channels = *wng->channels;
  89         else
  90                 pad->channels = conf->channels_arg;
  91         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
  92         w->private_data = pad;
  93         snd_pcm_info_alloca(&info);
  94         err = snd_pcm_open(&pad->handle, conf->device_arg,
  95                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  96         if (err < 0)
  97                 return -E_PCM_OPEN;
  98         if ((err = snd_pcm_info(pad->handle, info)) < 0)
  99                 return -E_SND_PCM_INFO;
 100
 101         snd_pcm_hw_params_alloca(&hwparams);
 102         snd_pcm_sw_params_alloca(&swparams);
 103         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
 104                 return -E_BROKEN_CONF;
 105         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
 106                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
 107                 return -E_ACCESS_TYPE;
 108         if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
 109                 return -E_SAMPLE_FORMAT;
 110         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
 111                         pad->channels) < 0)
 112                 return -E_CHANNEL_COUNT;
 113         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
 114                         &pad->samplerate, 0) < 0)
 115                 return -E_SET_RATE;
 116         err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
 117         if (err < 0 || !pad->buffer_time)
 118                 return -E_GET_BUFFER_TIME;
 119         PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
 120         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
 121                         &pad->buffer_time, 0) < 0)
 122                 return -E_SET_BUFFER_TIME;
 123         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
 124                 return -E_HW_PARAMS;
 125         snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
 126         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
 127         PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
 128                 period_size);
 129         if (period_size == buffer_size)
 130                 return -E_BAD_PERIOD;
 131         snd_pcm_sw_params_current(pad->handle, swparams);
 132         err = snd_pcm_sw_params_get_xfer_align(swparams, &xfer_align);
 133         if (err < 0 || !xfer_align)
 134                 return -E_GET_XFER;
 135         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 136         /* round to closest transfer boundary */
 137         start_threshold = (buffer_size / xfer_align) * xfer_align;
 138         if (start_threshold < 1)
 139                 start_threshold = 1;
 140         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 141                         start_threshold) < 0)
 142                 return -E_START_THRESHOLD;
 143         stop_threshold = buffer_size;
 144         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 145                         stop_threshold) < 0)
 146                 return -E_STOP_THRESHOLD;
 147         if (snd_pcm_sw_params_set_xfer_align(pad->handle, swparams,
 148                         xfer_align) < 0)
 149                 return -E_SET_XFER;
 150         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 151                 return -E_SW_PARAMS;
 152         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 153                 * pad->channels / 8;
 154         if (snd_pcm_nonblock(pad->handle, 1))
 155                 PARA_ERROR_LOG("%s\n", "failed to set nonblock mode");
 156         return period_size * pad->bytes_per_frame;
 157 }
 158
 159 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 160 {
 161         struct private_alsa_write_data *pad = wn->private_data;
 162         struct writer_node_group *wng = wn->wng;
 163         struct timeval diff;
 164
 165         if (*wng->loaded < pad->bytes_per_frame)
 166                 return 1;
 167         if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
 168                 if (tv_diff(&s->timeout, &diff, NULL) > 0)
 169                         s->timeout = diff;
 170         } else {
 171                 s->timeout.tv_sec = 0;
 172                 s->timeout.tv_usec = 1;
 173         }
 174         return 1;
 175 //      PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
 176 }
 177
 178 static int alsa_write_post_select(__a_unused struct sched *s,
 179                 struct writer_node *wn)
 180 {
 181         struct private_alsa_write_data *pad = wn->private_data;
 182         struct writer_node_group *wng = wn->wng;
 183         size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame;
 184         snd_pcm_sframes_t ret;
 185         unsigned char *data = (unsigned char*)wng->buf + wn->written;
 186         struct timeval tv;
 187
 188 //      PARA_INFO_LOG("%zd frames\n", frames);
 189         if (!frames) {
 190                 if (*wng->input_eof)
 191                         wn->written = *wng->loaded;
 192                 return 1;
 193         }
 194         if (tv_diff(now, &pad->next_chunk, NULL) < 0)
 195                 return 1;
 196         ret = snd_pcm_writei(pad->handle, data, frames);
 197         if (ret == -EPIPE) {
 198                 PARA_WARNING_LOG("%s", "EPIPE\n");
 199                 snd_pcm_prepare(pad->handle);
 200                 return 1;
 201         }
 202         if (ret < 0) {
 203                 PARA_WARNING_LOG("%s", "ALSA ERROR\n");
 204                 return -E_ALSA_WRITE;
 205         }
 206         ms2tv(pad->buffer_time / 4000, &tv);
 207 //      ms2tv(1, &tv);
 208         tv_add(now, &tv, &pad->next_chunk);
 209         wn->written += ret * pad->bytes_per_frame;
 210         return 1;
 211 }
 212
 213 static void alsa_close(struct writer_node *wn)
 214 {
 215         struct private_alsa_write_data *pad = wn->private_data;
 216         PARA_INFO_LOG("closing writer node %p\n", wn);
 217         snd_pcm_drain(pad->handle);
 218         snd_pcm_close(pad->handle);
 219         snd_config_update_free_global();
 220         free(pad);
 221 }
 222
 223 __malloc static void *alsa_parse_config(const char *options)
 224 {
 225         struct alsa_write_args_info *conf
 226                 = para_calloc(sizeof(struct alsa_write_args_info));
 227         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 228         int ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 229         if (ret)
 230                 goto err_out;
 231         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 232         return conf;
 233 err_out:
 234         free(conf);
 235         return NULL;
 236 }
 237
 238 /**
 239  * the init function of the alsa writer
 240  *
 241  * \param w pointer to the writer to initialize
 242  *
 243  * \sa struct writer
 244  */
 245 void alsa_write_init(struct writer *w)
 246 {
 247         w->open = alsa_open;
 248         w->close = alsa_close;
 249         w->pre_select = alsa_write_pre_select;
 250         w->post_select = alsa_write_post_select;
 251         w->parse_config = alsa_parse_config;
 252         w->shutdown = NULL; /* nothing to do */
 253 }