/* * Copyright (C) 2005-2007 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ /** \file alsa_write.c paraslash's alsa output plugin */ /* * Based in parts on aplay.c from the alsa-utils-1.0.8 package, * Copyright (c) by Jaroslav Kysela , which is * based on the vplay program by Michael Beck. */ #include "para.h" #include "fd.h" #include "string.h" #include "list.h" #include "sched.h" #include "write.h" #include #include "alsa_write.cmdline.h" #include "error.h" /** always use 16 bit little endian */ #define FORMAT SND_PCM_FORMAT_S16_LE /** data specific to the alsa writer */ struct private_alsa_write_data { /** the alsa handle */ snd_pcm_t *handle; /** determined and set by alsa_open() */ size_t bytes_per_frame; /** don't write anything until this time */ struct timeval next_chunk; /** the return value of snd_pcm_hw_params_get_buffer_time_max() */ unsigned buffer_time; /** * the samplerate given by command line option or the decoder * of the writer node group */ unsigned samplerate; /** * the number of channels, also given by command line option or the * decoder of the writer node group */ unsigned channels; }; /* * open and prepare the PCM handle for writing * * Install PCM software and hardware configuration. Exit on errors. */ static int alsa_open(struct writer_node *w) { snd_pcm_hw_params_t *hwparams; snd_pcm_sw_params_t *swparams; snd_pcm_uframes_t buffer_size, xfer_align, start_threshold, stop_threshold; int err; snd_pcm_info_t *info; snd_pcm_uframes_t period_size; struct private_alsa_write_data *pad = para_calloc(sizeof(struct private_alsa_write_data)); struct alsa_write_args_info *conf = w->conf; struct writer_node_group *wng = w->wng; if (!conf->samplerate_given && wng->samplerate) pad->samplerate = *wng->samplerate; else pad->samplerate = conf->samplerate_arg; if (!conf->channels_given && wng->channels) pad->channels = *wng->channels; else pad->channels = conf->channels_arg; PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate); w->private_data = pad; snd_pcm_info_alloca(&info); err = snd_pcm_open(&pad->handle, conf->device_arg, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK); if (err < 0) return -E_PCM_OPEN; if ((err = snd_pcm_info(pad->handle, info)) < 0) return -E_SND_PCM_INFO; snd_pcm_hw_params_alloca(&hwparams); snd_pcm_sw_params_alloca(&swparams); if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0) return -E_BROKEN_CONF; if (snd_pcm_hw_params_set_access(pad->handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED) < 0) return -E_ACCESS_TYPE; if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0) return -E_SAMPLE_FORMAT; if (snd_pcm_hw_params_set_channels(pad->handle, hwparams, pad->channels) < 0) return -E_CHANNEL_COUNT; if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams, &pad->samplerate, 0) < 0) return -E_SET_RATE; err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0); if (err < 0 || !pad->buffer_time) return -E_GET_BUFFER_TIME; PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time); if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams, &pad->buffer_time, 0) < 0) return -E_SET_BUFFER_TIME; if (snd_pcm_hw_params(pad->handle, hwparams) < 0) return -E_HW_PARAMS; snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0); snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size); PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size, period_size); if (period_size == buffer_size) return -E_BAD_PERIOD; snd_pcm_sw_params_current(pad->handle, swparams); err = snd_pcm_sw_params_get_xfer_align(swparams, &xfer_align); if (err < 0 || !xfer_align) return -E_GET_XFER; snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size); /* round to closest transfer boundary */ start_threshold = (buffer_size / xfer_align) * xfer_align; if (start_threshold < 1) start_threshold = 1; if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams, start_threshold) < 0) return -E_START_THRESHOLD; stop_threshold = buffer_size; if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams, stop_threshold) < 0) return -E_STOP_THRESHOLD; if (snd_pcm_sw_params_set_xfer_align(pad->handle, swparams, xfer_align) < 0) return -E_SET_XFER; if (snd_pcm_sw_params(pad->handle, swparams) < 0) return -E_SW_PARAMS; pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT) * pad->channels / 8; if (snd_pcm_nonblock(pad->handle, 1)) PARA_ERROR_LOG("%s\n", "failed to set nonblock mode"); return period_size * pad->bytes_per_frame; } static int alsa_write_pre_select(struct sched *s, struct writer_node *wn) { struct private_alsa_write_data *pad = wn->private_data; struct writer_node_group *wng = wn->wng; struct timeval diff; if (*wng->loaded < pad->bytes_per_frame) return 1; if (tv_diff(now, &pad->next_chunk, &diff) < 0) { if (tv_diff(&s->timeout, &diff, NULL) > 0) s->timeout = diff; } else { s->timeout.tv_sec = 0; s->timeout.tv_usec = 1; } return 1; // PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout)); } static int alsa_write_post_select(__a_unused struct sched *s, struct writer_node *wn) { struct private_alsa_write_data *pad = wn->private_data; struct writer_node_group *wng = wn->wng; size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame; snd_pcm_sframes_t ret; unsigned char *data = (unsigned char*)wng->buf + wn->written; struct timeval tv; // PARA_INFO_LOG("%zd frames\n", frames); if (!frames) { if (*wng->input_eof) wn->written = *wng->loaded; return 1; } if (tv_diff(now, &pad->next_chunk, NULL) < 0) return 1; ret = snd_pcm_writei(pad->handle, data, frames); if (ret == -EPIPE) { PARA_WARNING_LOG("%s", "EPIPE\n"); snd_pcm_prepare(pad->handle); return 1; } if (ret < 0) { PARA_WARNING_LOG("%s", "ALSA ERROR\n"); return -E_ALSA_WRITE; } ms2tv(pad->buffer_time / 4000, &tv); // ms2tv(1, &tv); tv_add(now, &tv, &pad->next_chunk); wn->written += ret * pad->bytes_per_frame; return 1; } static void alsa_close(struct writer_node *wn) { struct private_alsa_write_data *pad = wn->private_data; PARA_INFO_LOG("closing writer node %p\n", wn); snd_pcm_drain(pad->handle); snd_pcm_close(pad->handle); snd_config_update_free_global(); free(pad); } __malloc static void *alsa_parse_config(const char *options) { struct alsa_write_args_info *conf = para_calloc(sizeof(struct alsa_write_args_info)); PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t")); int ret = alsa_cmdline_parser_string(options, conf, "alsa_write"); if (ret) goto err_out; PARA_INFO_LOG("help given: %d\n", conf->help_given); return conf; err_out: free(conf); return NULL; } /** * the init function of the alsa writer * * \param w pointer to the writer to initialize * * \sa struct writer */ void alsa_write_init(struct writer *w) { w->open = alsa_open; w->close = alsa_close; w->pre_select = alsa_write_pre_select; w->post_select = alsa_write_post_select; w->parse_config = alsa_parse_config; w->shutdown = NULL; /* nothing to do */ }