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 "para.h"
  16 #include "fd.h"
  17 #include "string.h"
  18 #include "list.h"
  19 #include "sched.h"
  20 #include "write.h"
  21
  22 #include <alsa/asoundlib.h>
  23
  24 #include "alsa_write.cmdline.h"
  25 #include "error.h"
  26
  27 /** always use 16 bit little endian */
  28 #define FORMAT SND_PCM_FORMAT_S16_LE
  29
  30 /** data specific to the alsa writer */
  31 struct private_alsa_write_data {
  32         /** the alsa handle */
  33         snd_pcm_t *handle;
  34         /** determined and set by alsa_open() */
  35         size_t bytes_per_frame;
  36         /** don't write anything until this time */
  37         struct timeval next_chunk;
  38         /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
  39         unsigned buffer_time;
  40         /**
  41          * the samplerate given by command line option or the decoder
  42          * of the writer node group
  43          */
  44         unsigned samplerate;
  45         /**
  46          * the number of channels, also given by command line option or the
  47          * decoder of the writer node group
  48          */
  49         unsigned channels;
  50 };
  51
  52 /*
  53  * open and prepare the PCM handle for writing
  54  *
  55  * Install PCM software and hardware configuration. Exit on errors.
  56  */
  57 static int alsa_open(struct writer_node *w)
  58 {
  59         snd_pcm_hw_params_t *hwparams;
  60         snd_pcm_sw_params_t *swparams;
  61         snd_pcm_uframes_t buffer_size, xfer_align, start_threshold,
  62                 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         err = snd_pcm_sw_params_get_xfer_align(swparams, &xfer_align);
 121         if (err < 0 || !xfer_align)
 122                 return -E_GET_XFER;
 123         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 124         /* round to closest transfer boundary */
 125         start_threshold = (buffer_size / xfer_align) * xfer_align;
 126         if (start_threshold < 1)
 127                 start_threshold = 1;
 128         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 129                         start_threshold) < 0)
 130                 return -E_START_THRESHOLD;
 131         stop_threshold = buffer_size;
 132         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 133                         stop_threshold) < 0)
 134                 return -E_STOP_THRESHOLD;
 135         if (snd_pcm_sw_params_set_xfer_align(pad->handle, swparams,
 136                         xfer_align) < 0)
 137                 return -E_SET_XFER;
 138         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 139                 return -E_SW_PARAMS;
 140         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 141                 * pad->channels / 8;
 142         if (snd_pcm_nonblock(pad->handle, 1))
 143                 PARA_ERROR_LOG("%s\n", "failed to set nonblock mode");
 144         return period_size * pad->bytes_per_frame;
 145 }
 146
 147 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 148 {
 149         struct private_alsa_write_data *pad = wn->private_data;
 150         struct writer_node_group *wng = wn->wng;
 151         struct timeval diff;
 152
 153         if (*wng->loaded < pad->bytes_per_frame)
 154                 return 1;
 155         if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
 156                 if (tv_diff(&s->timeout, &diff, NULL) > 0)
 157                         s->timeout = diff;
 158         } else {
 159                 s->timeout.tv_sec = 0;
 160                 s->timeout.tv_usec = 1;
 161         }
 162         return 1;
 163 //      PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
 164 }
 165
 166 static int alsa_write_post_select(__a_unused struct sched *s,
 167                 struct writer_node *wn)
 168 {
 169         struct private_alsa_write_data *pad = wn->private_data;
 170         struct writer_node_group *wng = wn->wng;
 171         size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame;
 172         snd_pcm_sframes_t ret;
 173         unsigned char *data = (unsigned char*)wng->buf + wn->written;
 174         struct timeval tv;
 175
 176 //      PARA_INFO_LOG("%zd frames\n", frames);
 177         if (!frames) {
 178                 if (*wng->input_eof)
 179                         wn->written = *wng->loaded;
 180                 return 1;
 181         }
 182         if (tv_diff(now, &pad->next_chunk, NULL) < 0)
 183                 return 1;
 184         ret = snd_pcm_writei(pad->handle, data, frames);
 185         if (ret == -EPIPE) {
 186                 PARA_WARNING_LOG("%s", "EPIPE\n");
 187                 snd_pcm_prepare(pad->handle);
 188                 return 1;
 189         }
 190         if (ret < 0) {
 191                 PARA_WARNING_LOG("%s", "ALSA ERROR\n");
 192                 return -E_ALSA_WRITE;
 193         }
 194         ms2tv(pad->buffer_time / 4000, &tv);
 195 //      ms2tv(1, &tv);
 196         tv_add(now, &tv, &pad->next_chunk);
 197         wn->written += ret * pad->bytes_per_frame;
 198         return 1;
 199 }
 200
 201 static void alsa_close(struct writer_node *wn)
 202 {
 203         struct private_alsa_write_data *pad = wn->private_data;
 204         PARA_INFO_LOG("closing writer node %p\n", wn);
 205         snd_pcm_drain(pad->handle);
 206         snd_pcm_close(pad->handle);
 207         snd_config_update_free_global();
 208         free(pad);
 209 }
 210
 211 __malloc static void *alsa_parse_config(const char *options)
 212 {
 213         struct alsa_write_args_info *conf
 214                 = para_calloc(sizeof(struct alsa_write_args_info));
 215         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 216         int ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 217         if (ret)
 218                 goto err_out;
 219         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 220         return conf;
 221 err_out:
 222         free(conf);
 223         return NULL;
 224 }
 225
 226 /**
 227  * the init function of the alsa writer
 228  *
 229  * \param w pointer to the writer to initialize
 230  *
 231  * \sa struct writer
 232  */
 233 void alsa_write_init(struct writer *w)
 234 {
 235         w->open = alsa_open;
 236         w->close = alsa_close;
 237         w->pre_select = alsa_write_pre_select;
 238         w->post_select = alsa_write_post_select;
 239         w->parse_config = alsa_parse_config;
 240         w->shutdown = NULL; /* nothing to do */
 241 }