X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=9d99c8e91af6c4c78e402f9efde4ce00e40cb785;hp=4510b975c6fe8d8a832995e84095bc45aaea8794;hb=f32d8b2bdb3760fcb441d87d77565807b6848c47;hpb=6f05bb12b7d9d2cfbd419e2709bafde27da1b21b diff --git a/alsa_write.c b/alsa_write.c index 4510b975..9d99c8e9 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -1,19 +1,7 @@ /* - * Copyright (C) 2005-2006 Andre Noll + * Copyright (C) 2005-2009 Andre Noll * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. + * Licensed under the GPL v2. For licencing details see COPYING. */ /** \file alsa_write.c paraslash's alsa output plugin */ @@ -24,71 +12,61 @@ * based on the vplay program by Michael Beck. */ +#include +#include +#include +#include +#include + #include "para.h" #include "fd.h" #include "string.h" #include "list.h" #include "sched.h" +#include "ggo.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 */ +/** Data specific to the alsa writer. */ struct private_alsa_write_data { - /** the alsa handle */ + /** 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() */ + /** Determined and set by alsa_open(). */ + int bytes_per_frame; + /** The approximate maximum buffer duration in us. */ unsigned buffer_time; + /* Number of frames that fit into the buffer. */ + unsigned buffer_frames; + /** + * The samplerate given by command line option or the decoder + * of the writer node group. + */ unsigned samplerate; + /** + * The number of channels, 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) +/* Install PCM software and hardware configuration. */ +static int alsa_init(struct private_alsa_write_data *pad, + struct alsa_write_args_info *conf) { 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 buffer_size, start_threshold, stop_threshold; 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; + int err; - 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); @@ -103,32 +81,31 @@ static int alsa_open(struct writer_node *w) pad->channels) < 0) return -E_CHANNEL_COUNT; if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams, - &pad->samplerate, 0) < 0) + &pad->samplerate, NULL) < 0) return -E_SET_RATE; - err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0); + err = snd_pcm_hw_params_get_buffer_time_max(hwparams, + &pad->buffer_time, NULL); 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) + &pad->buffer_time, NULL) < 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_period_size(hwparams, &period_size, NULL); 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) + if (buffer_size < 1) start_threshold = 1; + else + start_threshold = PARA_MIN(buffer_size, + (snd_pcm_uframes_t)pad->samplerate); if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams, start_threshold) < 0) return -E_START_THRESHOLD; @@ -136,35 +113,90 @@ static int alsa_open(struct writer_node *w) 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; + PARA_WARNING_LOG("unable to install sw params\n"); pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT) * pad->channels / 8; + if (pad->bytes_per_frame <= 0) + return -E_PHYSICAL_WIDTH; + PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame); if (snd_pcm_nonblock(pad->handle, 1)) - PARA_ERROR_LOG("%s\n", "failed to set nonblock mode"); - return period_size * pad->bytes_per_frame; + PARA_ERROR_LOG("failed to set nonblock mode\n"); + pad->buffer_frames = 1000 * pad->buffer_time / pad->samplerate; + PARA_INFO_LOG("max buffered frames: %d\n", pad->buffer_frames); + return 1; +} + +/* Open an instance of the alsa writer. */ +static int alsa_open(struct writer_node *wn) +{ + struct alsa_write_args_info *conf = wn->conf; + struct writer_node_group *wng = wn->wng; + struct private_alsa_write_data *pad = para_calloc(sizeof(*pad)); + + wn->private_data = pad; + 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); + return 1; } 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; + struct timeval tv; + snd_pcm_sframes_t avail, underrun; - if (*wng->loaded < pad->bytes_per_frame) + if (!pad->handle) 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; - } + if (*wng->loaded - wn->written < pad->bytes_per_frame) + return 1; + /* + * Data is available to be written to the alsa handle. Compute number + * of milliseconds until next buffer underrun would occur. + * + * snd_pcm_avail_update() updates the current available count of + * samples for writing. It is a light method to obtain current stream + * position, because it does not require the user <-> kernel context + * switch, but the value is less accurate, because ring buffer pointers + * are updated in kernel drivers only when an interrupt occurs. + */ + avail = snd_pcm_avail_update(pad->handle); + if (avail < 0) + avail = 0; + underrun = (pad->buffer_frames - avail) * pad->buffer_time + / pad->buffer_frames / 1000; + if (underrun < 50) + underrun = 50; + underrun -= 50; + ms2tv(underrun, &tv); + if (tv_diff(&s->timeout, &tv, NULL) > 0) + s->timeout = tv; return 1; -// PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout)); +} + +static void xrun(snd_pcm_t *handle) +{ + snd_pcm_status_t *status; + int ret; + struct timeval tv, diff; + + snd_pcm_status_alloca(&status); + ret = snd_pcm_status(handle, status); + if (ret < 0) + return; + if (snd_pcm_status_get_state(status) != SND_PCM_STATE_XRUN) + return; + snd_pcm_status_get_trigger_tstamp(status, &tv); + tv_diff(now, &tv, &diff); + PARA_WARNING_LOG("underrun: %lums\n", tv2ms(&diff)); } static int alsa_write_post_select(__a_unused struct sched *s, @@ -172,52 +204,65 @@ static int alsa_write_post_select(__a_unused struct sched *s, { 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; + size_t bytes = *wng->loaded - wn->written; + unsigned char *data = (unsigned char*)*wng->bufp + wn->written; + snd_pcm_sframes_t ret, frames, avail; -// PARA_INFO_LOG("%zd frames\n", frames); - if (!frames) { - if (*wng->input_eof) - wn->written = *wng->loaded; - return 1; + if (*wng->input_error < 0 && (!pad->handle || bytes < pad->bytes_per_frame)) { + wn->written = *wng->loaded; + return *wng->input_error; } - if (tv_diff(now, &pad->next_chunk, NULL) < 0) - return 1; + if (!bytes) /* no data available */ + return 0; + if (!pad->handle) { + int err = alsa_init(pad, wn->conf); + if (err < 0) + return err; + } + frames = bytes / pad->bytes_per_frame; + if (!frames) /* less than a single frame available */ + return 0; + avail = snd_pcm_avail_update(pad->handle); + if (avail <= 0) + return 0; + frames = PARA_MIN(frames, avail); ret = snd_pcm_writei(pad->handle, data, frames); - if (ret == -EPIPE) { - PARA_WARNING_LOG("%s", "EPIPE\n"); - snd_pcm_prepare(pad->handle); + if (ret >= 0) { + wn->written += ret * pad->bytes_per_frame; return 1; } - if (ret < 0) { - PARA_WARNING_LOG("%s", "ALSA ERROR\n"); - return -E_ALSA_WRITE; + if (ret == -EPIPE) { + xrun(pad->handle); + snd_pcm_prepare(pad->handle); + return 0; } - 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; + PARA_WARNING_LOG("%s\n", snd_strerror(-ret)); + if (ret == -EAGAIN) + return 0; + return -E_ALSA_WRITE; } 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(); + + if (pad->handle) { + snd_pcm_drain(pad->handle); + snd_pcm_close(pad->handle); + snd_config_update_free_global(); + } free(pad); } -__malloc void *alsa_parse_config(char *options) +__malloc static void *alsa_parse_config(const char *options) { + int ret; struct alsa_write_args_info *conf = para_calloc(sizeof(struct alsa_write_args_info)); - PARA_INFO_LOG("options: %s, %d\n", options, strcspn(options, " \t")); - int ret = alsa_cmdline_parser_string(options, conf, "alsa_write"); + + PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t")); + ret = alsa_cmdline_parser_string(options, conf, "alsa_write"); if (ret) goto err_out; PARA_INFO_LOG("help given: %d\n", conf->help_given); @@ -227,13 +272,27 @@ err_out: return NULL; } -/** the init function of the alsa writer */ +/** + * 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) { + struct alsa_write_args_info dummy; + + alsa_cmdline_parser_init(&dummy); 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 */ + w->help = (struct ggo_help) { + .short_help = alsa_write_args_info_help, + .detailed_help = alsa_write_args_info_detailed_help + }; + alsa_cmdline_parser_free(&dummy); }