From 015055963d095abd0e153832f5b3f0fda3ac8306 Mon Sep 17 00:00:00 2001 From: Andre Noll Date: Mon, 4 Jan 2010 23:11:32 +0100 Subject: [PATCH 1/1] Alsa improvement and fixes. Wait until pending frames are played. The old code was buggy because snd_pcm_drain() always fails on a non-blocking fd. We therefore called snd_pcm_close() while frames for playback are still availabe, causing the last few frames being skipped. --- alsa_write.c | 76 +++++++++++++++++++++++++++++----------------------- error.h | 2 +- 2 files changed, 44 insertions(+), 34 deletions(-) diff --git a/alsa_write.c b/alsa_write.c index e2ca45b6..8b56f31a 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -27,6 +27,7 @@ #include "ggo.h" #include "buffer_tree.h" #include "write.h" +#include "write_common.h" #include "alsa_write.cmdline.h" #include "error.h" @@ -38,11 +39,11 @@ struct private_alsa_write_data { /** The alsa handle */ snd_pcm_t *handle; /** Determined and set by alsa_open(). */ - int bytes_per_frame; + int bytes_per_frame; /* TODO: Kill this after btr switch */ /** The approximate maximum buffer duration in us. */ unsigned buffer_time; /* Number of frames that fit into the buffer. */ - unsigned buffer_frames; + snd_pcm_uframes_t buffer_frames; /** * The samplerate given by command line option or the decoder * of the writer node group. @@ -61,7 +62,7 @@ static int alsa_init(struct private_alsa_write_data *pad, { snd_pcm_hw_params_t *hwparams; snd_pcm_sw_params_t *swparams; - snd_pcm_uframes_t buffer_size, start_threshold, stop_threshold; + snd_pcm_uframes_t start_threshold, stop_threshold; snd_pcm_uframes_t period_size; int err; @@ -96,22 +97,22 @@ static int alsa_init(struct private_alsa_write_data *pad, if (snd_pcm_hw_params(pad->handle, hwparams) < 0) return -E_HW_PARAMS; 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, + 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 = PARA_MIN(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; @@ -124,8 +125,6 @@ static int alsa_init(struct private_alsa_write_data *pad, 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"); - pad->buffer_frames = 1000 * pad->buffer_time / pad->samplerate; - PARA_INFO_LOG("max buffered frames: %d\n", pad->buffer_frames); return 1; } @@ -175,8 +174,12 @@ static int alsa_write_pre_select(struct sched *s, struct writer_node *wn) return 1; if (wn->btrn) { size_t sz = btr_get_input_queue_size(wn->btrn); - if (sz < pad->bytes_per_frame) - return 1; + if (sz < pad->bytes_per_frame) { + if (!btr_no_parent(wn->btrn)) + return 1; + underrun = 10; + goto timeout; + } } else { if (*wng->loaded - wn->written < pad->bytes_per_frame) return 1; @@ -199,6 +202,7 @@ static int alsa_write_pre_select(struct sched *s, struct writer_node *wn) if (underrun < 50) underrun = 50; underrun -= 50; +timeout: ms2tv(underrun, &tv); if (tv_diff(&s->timeout, &tv, NULL) > 0) s->timeout = tv; @@ -278,6 +282,11 @@ static void alsa_close(struct writer_node *wn) PARA_INFO_LOG("closing writer node %p\n", wn); 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(); @@ -290,18 +299,29 @@ static void alsa_write_post_select_btr(__a_unused struct sched *s, { 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, avail; int ret; again: - bytes = btr_next_buffer(wn->btrn, &data); - //PARA_CRIT_LOG("have: %zu\n", bytes); t->error = 0; - ret = -E_ALSA_ORPHAN; - if (btr_no_parent(wn->btrn) && (!pad->handle || bytes < pad->bytes_per_frame)) - goto err; + ret = prepare_writer_node(wn); + if (ret == 0) + return; + bytes = btr_next_buffer(btrn, &data); + if (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 */ + avail = snd_pcm_avail_update(pad->handle); + if (avail + 1000 > pad->buffer_frames) + goto err; + return; + } if (!pad->handle) { char *buf; struct alsa_write_args_info *conf = wn->conf; @@ -314,7 +334,7 @@ again: if (!conf->samplerate_given) { /* config option trumps btr_exec */ /* ask parent btr nodes */ buf = NULL; - ret = btr_exec_up(wn->btrn, "samplerate", &buf); + ret = btr_exec_up(btrn, "samplerate", &buf); PARA_CRIT_LOG("ret: %d\n", ret); if (ret >= 0) { int32_t rate; @@ -328,7 +348,7 @@ again: } if (!conf->channels_given) { buf = NULL; - ret = btr_exec_up(wn->btrn, "channels", &buf); + ret = btr_exec_up(btrn, "channels", &buf); if (ret >= 0) { int32_t ch; @@ -344,16 +364,7 @@ again: ret = alsa_init(pad, wn->conf); if (ret < 0) goto err; - } - for (;;) { - if (bytes == 0) - return; - if (bytes >= pad->bytes_per_frame) - break; - /* should not be possible to reach this */ - PARA_CRIT_LOG("dropping %zu byte buffer\n", bytes); - btr_consume(wn->btrn, bytes); - bytes = btr_next_buffer(wn->btrn, &data); + wn->min_iqs = pad->bytes_per_frame; } frames = bytes / pad->bytes_per_frame; avail = snd_pcm_avail_update(pad->handle); @@ -363,7 +374,7 @@ again: //PARA_CRIT_LOG("writing %ld frames\n", frames); frames = snd_pcm_writei(pad->handle, data, frames); if (frames >= 0) { - btr_consume(wn->btrn, frames * pad->bytes_per_frame); + btr_consume(btrn, frames * pad->bytes_per_frame); goto again; } if (frames == -EPIPE) { @@ -377,9 +388,8 @@ again: ret = -E_ALSA_WRITE; err: assert(ret < 0); + btr_del_node(btrn); alsa_close(wn); - btr_del_node(wn->btrn); - wn->btrn = NULL; t->error = ret; } diff --git a/error.h b/error.h index 08d6bd6e..bf633f54 100644 --- a/error.h +++ b/error.h @@ -412,7 +412,7 @@ extern const char **para_errlist[]; PARA_ERROR(SET_RATE, "snd_pcm_hw_params_set_rate_near failed"), \ PARA_ERROR(START_THRESHOLD, "snd_pcm_sw_params_set_start_threshold() failed"), \ PARA_ERROR(STOP_THRESHOLD, "snd_pcm_sw_params_set_stop_threshold() failed"), \ - PARA_ERROR(ALSA_ORPHAN, "alsa btr node has no parent"), \ + PARA_ERROR(ALSA_EOF, "alsa: end of file"), \ #define FILE_WRITE_ERRORS \ -- 2.30.2