X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=cf0f335bebc7426c9b24aad7537601be3dbb0dd7;hp=c856ef4a2d23d256015028a89131fb19824f9a26;hb=afb43ec103ea5c0e194451c1289c514faee3b2e5;hpb=19d9318abf42debb15d833d4e56ab636893285c3

diff --git a/alsa_write.c b/alsa_write.c
index c856ef4a..cf0f335b 100644
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -21,6 +21,7 @@
 #include "string.h"
 #include "list.h"
 #include "sched.h"
+#include "ggo.h"
 #include "write.h"
 #include "alsa_write.cmdline.h"
 #include "error.h"
@@ -28,64 +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, 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);
@@ -118,14 +97,12 @@ static int alsa_open(struct writer_node *w)
 	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;
@@ -133,16 +110,37 @@ 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");
+	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)
@@ -151,7 +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)
@@ -161,7 +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,
@@ -169,57 +166,72 @@ 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) { /* try again in 5ms */
-		PARA_WARNING_LOG("EAGAIN\n");
-		ms2tv(5, &tv);
-	} else {
-		wn->written += ret * pad->bytes_per_frame;
-		ms2tv(pad->buffer_time / 4000, &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);
 }
 
 __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, %zd\n", options, strcspn(options, " \t"));
-	int ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
+	ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 	if (ret)
 		goto err_out;
 	PARA_INFO_LOG("help given: %d\n", conf->help_given);
@@ -238,10 +250,17 @@ err_out:
  */
 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
+	};
 }