X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=7a4b868d251f0ee780647f72457b1c3162549bf0;hp=3a1e76e62c3e60c4c488f86c9b378a5d431be17e;hb=a4f75cecaaee538edb7aae3f0ff19168a1dab59d;hpb=3b38d93529573b89089a67f494e17205d723021f diff --git a/alsa_write.c b/alsa_write.c index 3a1e76e6..7a4b868d 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2005-2008 Andre Noll + * Copyright (C) 2005-2010 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -12,9 +12,12 @@ * based on the vplay program by Michael Beck. */ +#include #include #include #include +#include +#include #include "para.h" #include "fd.h" @@ -22,70 +25,53 @@ #include "list.h" #include "sched.h" #include "ggo.h" +#include "buffer_tree.h" #include "write.h" +#include "write_common.h" #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. */ + snd_pcm_uframes_t buffer_frames; /** - * the samplerate given by command line option or the decoder - * of the writer node group + * 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 + * The number of channels, given by command line option or the + * decoder of the writer node group. */ unsigned channels; + struct timeval drain_barrier; }; -/* - * 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, start_threshold, stop_threshold; - int err; - snd_pcm_info_t *info; + snd_pcm_uframes_t 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); + PARA_INFO_LOG("opening %s\n", conf->device_arg); 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); @@ -100,33 +86,35 @@ 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_buffer_size(hwparams, &buffer_size); - PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size, + snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL); + snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames); + PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames, period_size); - if (period_size == buffer_size) + if (period_size == pad->buffer_frames) return -E_BAD_PERIOD; snd_pcm_sw_params_current(pad->handle, swparams); snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size); - if (buffer_size < 1) + if (pad->buffer_frames < 1) start_threshold = 1; else - start_threshold = buffer_size; + start_threshold = PARA_MIN(pad->buffer_frames, + (snd_pcm_uframes_t)pad->samplerate); if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams, start_threshold) < 0) return -E_START_THRESHOLD; - stop_threshold = buffer_size; + stop_threshold = pad->buffer_frames; if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams, stop_threshold) < 0) return -E_STOP_THRESHOLD; @@ -134,84 +122,155 @@ static int alsa_open(struct writer_node *w) PARA_WARNING_LOG("unable to install sw params\n"); pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT) * pad->channels / 8; - PARA_INFO_LOG("bytes per frame: %zu\n", pad->bytes_per_frame); + 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("failed to set nonblock mode\n"); - tv_add(now, &(struct timeval ){0, 100 * 1000}, &pad->next_chunk); - return period_size * pad->bytes_per_frame; + return 1; } -static int alsa_write_pre_select(struct sched *s, struct writer_node *wn) +/* Open an instance of the alsa writer. */ +static int alsa_open(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; - } + wn->private_data = para_calloc(sizeof(struct private_alsa_write_data)); 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) +static void alsa_write_pre_select(struct sched *s, struct task *t) { + struct writer_node *wn = container_of(t, struct writer_node, task); 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; + snd_pcm_sframes_t avail, underrun; + int ret; -// PARA_INFO_LOG("%zd frames\n", frames); - if (!frames) { - if (*wng->input_error) - 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("EPIPE\n"); - snd_pcm_prepare(pad->handle); - return 1; - } - if (ret < 0 && ret != -EAGAIN) { - PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n", - frames, (int)ret); - return -E_ALSA_WRITE; - } - if (ret == -EAGAIN) - PARA_DEBUG_LOG("EAGAIN\n"); - else - wn->written += ret * pad->bytes_per_frame; - if (ret == frames) /* we wrote everything, try again immediately */ - pad->next_chunk = *now; - else { - ms2tv(pad->buffer_time / pad->bytes_per_frame / 1000, &tv); - tv_add(now, &tv, &pad->next_chunk); - } - return 1; + if (!pad->handle) + return; + ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF); + if (ret < 0) + sched_request_timeout_ms(20, s); + if (ret <= 0) + return; + /* + * 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; } 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) { + /* + * It's OK to have a blocking operation here because we already + * made sure that the PCM output buffer is (nearly) empty. + */ + snd_pcm_nonblock(pad->handle, 0); + snd_pcm_drain(pad->handle); + snd_pcm_close(pad->handle); + snd_config_update_free_global(); + } free(pad); } +static void alsa_write_post_select(__a_unused struct sched *s, + struct task *t) +{ + struct writer_node *wn = container_of(t, struct writer_node, task); + struct private_alsa_write_data *pad = wn->private_data; + struct btr_node *btrn = wn->btrn; + char *data; + size_t bytes; + snd_pcm_sframes_t frames; + int ret; + +again: + t->error = 0; + ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF); + if (ret == 0) + return; + btr_merge(btrn, wn->min_iqs); + bytes = btr_next_buffer(btrn, &data); + if (ret < 0 || bytes < pad->bytes_per_frame) { /* eof */ + assert(btr_no_parent(btrn)); + ret = -E_ALSA_EOF; + if (!pad->handle) + goto err; + /* wait until pending frames are played */ + if (pad->drain_barrier.tv_sec == 0) { + PARA_DEBUG_LOG("waiting for device to drain\n"); + tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000), + &pad->drain_barrier); + return; + } + if (tv_diff(now, &pad->drain_barrier, NULL) > 0) + goto err; + return; + } + if (!pad->handle) { + struct alsa_write_args_info *conf = wn->conf; + if (bytes == 0) /* no data available */ + return; + /* defaults */ + pad->samplerate = conf->samplerate_arg; + pad->channels = conf->channels_arg; + if (!conf->samplerate_given) { /* config option trumps btr_exec */ + int32_t rate; + if (get_btr_samplerate(btrn, &rate) >= 0) + pad->samplerate = rate; + } + if (!conf->channels_given) { + int32_t ch; + if (get_btr_channels(btrn, &ch) >= 0) + pad->channels = ch; + } + PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate); + ret = alsa_init(pad, wn->conf); + if (ret < 0) + goto err; + wn->min_iqs = pad->bytes_per_frame; + } + frames = bytes / pad->bytes_per_frame; + frames = snd_pcm_writei(pad->handle, data, frames); + if (frames >= 0) { + btr_consume(btrn, frames * pad->bytes_per_frame); + goto again; + } + if (frames == -EPIPE) { + PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes); + snd_pcm_prepare(pad->handle); + return; + } + if (frames == -EAGAIN) + return; + PARA_WARNING_LOG("%s\n", snd_strerror(-frames)); + ret = -E_ALSA_WRITE; +err: + assert(ret < 0); + btr_remove_node(btrn); + t->error = ret; +} + __malloc static void *alsa_parse_config(const char *options) { int ret; @@ -229,12 +288,17 @@ err_out: return NULL; } +static void alsa_free_config(void *conf) +{ + alsa_cmdline_parser_free(conf); +} + /** - * the init function of the alsa writer + * The init function of the alsa writer. * - * \param w pointer to the writer to initialize + * \param w Pointer to the writer to initialize. * - * \sa struct writer + * \sa struct \ref writer. */ void alsa_write_init(struct writer *w) { @@ -247,8 +311,10 @@ void alsa_write_init(struct writer *w) w->post_select = alsa_write_post_select; w->parse_config = alsa_parse_config; w->shutdown = NULL; /* nothing to do */ + w->free_config = alsa_free_config; 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); }