X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=cf0f335bebc7426c9b24aad7537601be3dbb0dd7;hp=ae471679f076f17fbce5b3d8d27ed5458d1fb4cd;hb=afb43ec103ea5c0e194451c1289c514faee3b2e5;hpb=40de1dd2fdbb054444d585aa70e2d50166a66e07 diff --git a/alsa_write.c b/alsa_write.c index ae471679..cf0f335b 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2005-2008 Andre Noll + * Copyright (C) 2005-2009 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -29,63 +29,42 @@ /** 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 */ + /** Determined and set by alsa_open(). */ + int 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() */ + /** The approximate maximum buffer duration in us. */ unsigned buffer_time; /** - * 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; }; -/* - * 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 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); @@ -122,7 +101,8 @@ static int alsa_open(struct writer_node *w) if (buffer_size < 1) start_threshold = 1; else - start_threshold = buffer_size; + 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; @@ -131,13 +111,36 @@ static int alsa_open(struct writer_node *w) stop_threshold) < 0) return -E_STOP_THRESHOLD; 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; - 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"); - return period_size * pad->bytes_per_frame; + 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); + tv_add(now, &(struct timeval){0, 100 * 1000}, &pad->next_chunk); + return 1; } static int alsa_write_pre_select(struct sched *s, struct writer_node *wn) @@ -146,7 +149,7 @@ static int alsa_write_pre_select(struct sched *s, struct writer_node *wn) struct writer_node_group *wng = wn->wng; struct timeval diff; - if (*wng->loaded < pad->bytes_per_frame) + if (!*wng->loaded) return 1; if (tv_diff(now, &pad->next_chunk, &diff) < 0) { if (tv_diff(&s->timeout, &diff, NULL) > 0) @@ -156,7 +159,6 @@ static int alsa_write_pre_select(struct sched *s, struct writer_node *wn) 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, @@ -164,50 +166,61 @@ 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; + size_t bytes = *wng->loaded - wn->written; + unsigned char *data = (unsigned char*)*wng->bufp + wn->written; struct timeval tv; + snd_pcm_sframes_t ret, frames, avail; -// PARA_INFO_LOG("%zd frames\n", frames); - if (!frames) { - if (*wng->input_error) - 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 (!bytes) /* no data available */ + return 0; 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; + return 0; + if (!pad->handle) { + int err = alsa_init(pad, wn->conf); + if (err < 0) + return err; } - if (ret < 0 && ret != -EAGAIN) { - PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n", - frames, (int)ret); + 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) + goto delay; + frames = PARA_MIN(frames, avail); + ret = snd_pcm_writei(pad->handle, data, frames); + if (ret < 0) { + PARA_WARNING_LOG("%s\n", snd_strerror(-ret)); + if (ret == -EPIPE) { + snd_pcm_prepare(pad->handle); + return 0; + } + if (ret == -EAGAIN) + goto delay; 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); - } + wn->written += ret * pad->bytes_per_frame; return 1; +delay: + /* wait until 50% buffer space is available */ + ms2tv(pad->buffer_time / 2000, &tv); + tv_add(now, &tv, &pad->next_chunk); + return 0; } 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); }