alsa_write.c

   1 /*
   2  * Copyright (C) 2005-2007 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, xfer_align, start_threshold,
  63                 stop_threshold;
  64         int err;
  65         snd_pcm_info_t *info;
  66         snd_pcm_uframes_t period_size;
  67         struct private_alsa_write_data *pad = para_calloc(sizeof(struct
  68                 private_alsa_write_data));
  69         struct alsa_write_args_info *conf = w->conf;
  70         struct writer_node_group *wng = w->wng;
  71
  72         if (!conf->samplerate_given && wng->samplerate)
  73                 pad->samplerate = *wng->samplerate;
  74         else
  75                 pad->samplerate = conf->samplerate_arg;
  76         if (!conf->channels_given && wng->channels)
  77                 pad->channels = *wng->channels;
  78         else
  79                 pad->channels = conf->channels_arg;
  80         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
  81         w->private_data = pad;
  82         snd_pcm_info_alloca(&info);
  83         err = snd_pcm_open(&pad->handle, conf->device_arg,
  84                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  85         if (err < 0)
  86                 return -E_PCM_OPEN;
  87         if ((err = snd_pcm_info(pad->handle, info)) < 0)
  88                 return -E_SND_PCM_INFO;
  89
  90         snd_pcm_hw_params_alloca(&hwparams);
  91         snd_pcm_sw_params_alloca(&swparams);
  92         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  93                 return -E_BROKEN_CONF;
  94         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  95                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  96                 return -E_ACCESS_TYPE;
  97         if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
  98                 return -E_SAMPLE_FORMAT;
  99         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
 100                         pad->channels) < 0)
 101                 return -E_CHANNEL_COUNT;
 102         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
 103                         &pad->samplerate, 0) < 0)
 104                 return -E_SET_RATE;
 105         err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
 106         if (err < 0 || !pad->buffer_time)
 107                 return -E_GET_BUFFER_TIME;
 108         PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
 109         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
 110                         &pad->buffer_time, 0) < 0)
 111                 return -E_SET_BUFFER_TIME;
 112         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
 113                 return -E_HW_PARAMS;
 114         snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
 115         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
 116         PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
 117                 period_size);
 118         if (period_size == buffer_size)
 119                 return -E_BAD_PERIOD;
 120         snd_pcm_sw_params_current(pad->handle, swparams);
 121         err = snd_pcm_sw_params_get_xfer_align(swparams, &xfer_align);
 122         if (err < 0 || !xfer_align)
 123                 return -E_GET_XFER;
 124         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 125         /* round to closest transfer boundary */
 126         start_threshold = (buffer_size / xfer_align) * xfer_align;
 127         if (start_threshold < 1)
 128                 start_threshold = 1;
 129         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 130                         start_threshold) < 0)
 131                 return -E_START_THRESHOLD;
 132         stop_threshold = buffer_size;
 133         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 134                         stop_threshold) < 0)
 135                 return -E_STOP_THRESHOLD;
 136         if (snd_pcm_sw_params_set_xfer_align(pad->handle, swparams,
 137                         xfer_align) < 0)
 138                 return -E_SET_XFER;
 139         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 140                 return -E_SW_PARAMS;
 141         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 142                 * pad->channels / 8;
 143         if (snd_pcm_nonblock(pad->handle, 1))
 144                 PARA_ERROR_LOG("%s\n", "failed to set nonblock mode");
 145         return period_size * pad->bytes_per_frame;
 146 }
 147
 148 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 149 {
 150         struct private_alsa_write_data *pad = wn->private_data;
 151         struct writer_node_group *wng = wn->wng;
 152         struct timeval diff;
 153
 154         if (*wng->loaded < pad->bytes_per_frame)
 155                 return 1;
 156         if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
 157                 if (tv_diff(&s->timeout, &diff, NULL) > 0)
 158                         s->timeout = diff;
 159         } else {
 160                 s->timeout.tv_sec = 0;
 161                 s->timeout.tv_usec = 1;
 162         }
 163         return 1;
 164 //      PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
 165 }
 166
 167 static int alsa_write_post_select(__a_unused struct sched *s,
 168                 struct writer_node *wn)
 169 {
 170         struct private_alsa_write_data *pad = wn->private_data;
 171         struct writer_node_group *wng = wn->wng;
 172         size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame;
 173         snd_pcm_sframes_t ret;
 174         unsigned char *data = (unsigned char*)wng->buf + wn->written;
 175         struct timeval tv;
 176
 177 //      PARA_INFO_LOG("%zd frames\n", frames);
 178         if (!frames) {
 179                 if (*wng->input_error)
 180                         wn->written = *wng->loaded;
 181                 return 1;
 182         }
 183         if (tv_diff(now, &pad->next_chunk, NULL) < 0)
 184                 return 1;
 185         ret = snd_pcm_writei(pad->handle, data, frames);
 186         if (ret == -EPIPE) {
 187                 PARA_WARNING_LOG("EPIPE\n");
 188                 snd_pcm_prepare(pad->handle);
 189                 return 1;
 190         }
 191         if (ret < 0 && ret != -EAGAIN) {
 192                 PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
 193                         frames, (int)ret);
 194                 return -E_ALSA_WRITE;
 195         }
 196         if (ret == -EAGAIN) { /* try again in 5ms */
 197                 PARA_WARNING_LOG("EAGAIN\n");
 198                 ms2tv(5, &tv);
 199         } else {
 200                 wn->written += ret * pad->bytes_per_frame;
 201                 ms2tv(pad->buffer_time / 4000, &tv);
 202         }
 203         tv_add(now, &tv, &pad->next_chunk);
 204         return 1;
 205 }
 206
 207 static void alsa_close(struct writer_node *wn)
 208 {
 209         struct private_alsa_write_data *pad = wn->private_data;
 210         PARA_INFO_LOG("closing writer node %p\n", wn);
 211         snd_pcm_drain(pad->handle);
 212         snd_pcm_close(pad->handle);
 213         snd_config_update_free_global();
 214         free(pad);
 215 }
 216
 217 __malloc static void *alsa_parse_config(const char *options)
 218 {
 219         struct alsa_write_args_info *conf
 220                 = para_calloc(sizeof(struct alsa_write_args_info));
 221         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 222         int ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 223         if (ret)
 224                 goto err_out;
 225         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 226         return conf;
 227 err_out:
 228         free(conf);
 229         return NULL;
 230 }
 231
 232 /**
 233  * the init function of the alsa writer
 234  *
 235  * \param w pointer to the writer to initialize
 236  *
 237  * \sa struct writer
 238  */
 239 void alsa_write_init(struct writer *w)
 240 {
 241         w->open = alsa_open;
 242         w->close = alsa_close;
 243         w->pre_select = alsa_write_pre_select;
 244         w->post_select = alsa_write_post_select;
 245         w->parse_config = alsa_parse_config;
 246         w->shutdown = NULL; /* nothing to do */
 247 }