gstreamer/ext/alsa/gstalsasink.c

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/*
* Copyright (C) 2001 CodeFactory AB
* Copyright (C) 2001 Thomas Nyberg <thomas@codefactory.se>
* Copyright (C) 2001-2002 Andy Wingo <apwingo@eos.ncsu.edu>
* Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstalsasink.h"
#include "gstalsaclock.h"
/* elementfactory information */
static GstElementDetails gst_alsa_sink_details = GST_ELEMENT_DETAILS (
"Alsa Sink",
"Sink/Audio",
"Output to a sound card via ALSA",
"Thomas Nyberg <thomas@codefactory.se>, "
"Andy Wingo <apwingo@eos.ncsu.edu>, "
"Benjamin Otte <in7y118@public.uni-hamburg.de>"
);
static GstPadTemplate * gst_alsa_sink_pad_factory (void);
static GstPadTemplate * gst_alsa_sink_request_pad_factory(void);
static void gst_alsa_sink_base_init (gpointer g_class);
static void gst_alsa_sink_class_init (gpointer g_klass,
gpointer class_data);
static void gst_alsa_sink_init (GstAlsaSink * this);
static inline void gst_alsa_sink_flush_one_pad (GstAlsaSink * sink,
gint i);
static void gst_alsa_sink_flush_pads (GstAlsaSink * sink);
static int gst_alsa_sink_mmap (GstAlsa * this,
snd_pcm_sframes_t * avail);
static int gst_alsa_sink_write (GstAlsa * this,
snd_pcm_sframes_t * avail);
static void gst_alsa_sink_loop (GstElement * element);
static gboolean gst_alsa_sink_check_event (GstAlsaSink * sink,
gint pad_nr);
static GstElementStateReturn gst_alsa_sink_change_state (GstElement * element);
static GstClockTime gst_alsa_sink_get_time (GstAlsa * this);
static GstAlsa *sink_parent_class = NULL;
static GstPadTemplate *
gst_alsa_sink_pad_factory (void)
{
static GstPadTemplate *template = NULL;
if (!template)
template = gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
gst_alsa_caps (SND_PCM_FORMAT_UNKNOWN, -1, -1));
return template;
}
static GstPadTemplate *
gst_alsa_sink_request_pad_factory (void)
{
static GstPadTemplate *template = NULL;
if (!template)
template =
gst_pad_template_new ("sink%d", GST_PAD_SINK, GST_PAD_REQUEST,
gst_alsa_caps (SND_PCM_FORMAT_UNKNOWN, -1, 1));
return template;
}
GType
gst_alsa_sink_get_type (void)
{
static GType alsa_sink_type = 0;
if (!alsa_sink_type) {
static const GTypeInfo alsa_sink_info = {
sizeof (GstAlsaSinkClass),
gst_alsa_sink_base_init,
NULL,
gst_alsa_sink_class_init,
NULL,
NULL,
sizeof (GstAlsaSink),
0,
(GInstanceInitFunc) gst_alsa_sink_init,
};
alsa_sink_type = g_type_register_static (GST_TYPE_ALSA, "GstAlsaSink", &alsa_sink_info, 0);
}
return alsa_sink_type;
}
static void
gst_alsa_sink_base_init (gpointer g_class)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
gst_element_class_add_pad_template (element_class, gst_alsa_sink_pad_factory ());
gst_element_class_add_pad_template (element_class, gst_alsa_sink_request_pad_factory ());
gst_element_class_set_details (element_class, &gst_alsa_sink_details);
}
static void
gst_alsa_sink_class_init (gpointer g_class, gpointer class_data)
{
GObjectClass *object_class;
GstElementClass *element_class;
GstAlsaClass *alsa_class;
GstAlsaSinkClass *klass;
klass = (GstAlsaSinkClass *) g_class;
object_class = (GObjectClass *) klass;
element_class = (GstElementClass *) klass;
alsa_class = (GstAlsaClass *) klass;
if (sink_parent_class == NULL)
sink_parent_class = g_type_class_ref (GST_TYPE_ALSA);
alsa_class->stream = SND_PCM_STREAM_PLAYBACK;
alsa_class->transmit_mmap = gst_alsa_sink_mmap;
alsa_class->transmit_rw = gst_alsa_sink_write;
element_class->change_state = gst_alsa_sink_change_state;
}
static void
gst_alsa_sink_init (GstAlsaSink *sink)
{
GstAlsa *this = GST_ALSA (sink);
this->pad[0] = gst_pad_new_from_template (gst_alsa_sink_pad_factory (), "sink");
gst_pad_set_link_function (this->pad[0], gst_alsa_link);
gst_pad_set_getcaps_function (this->pad[0], gst_alsa_get_caps);
gst_element_add_pad (GST_ELEMENT (this), this->pad[0]);
this->clock = gst_alsa_clock_new ("alsasinkclock", gst_alsa_sink_get_time, this);
/* we hold a ref to our clock until we're disposed */
gst_object_ref (GST_OBJECT (this->clock));
gst_object_sink (GST_OBJECT (this->clock));
gst_element_set_loop_function (GST_ELEMENT (this), gst_alsa_sink_loop);
}
static inline void
gst_alsa_sink_flush_one_pad (GstAlsaSink *sink, gint i)
{
switch (sink->behaviour[i]) {
case 0:
if (sink->buf[i])
gst_data_unref (GST_DATA (sink->buf[i]));
sink->buf[i] = NULL;
sink->data[i] = NULL;
sink->behaviour[i] = 0;
sink->size[i] = 0;
break;
case 1:
g_free (sink->data[i]);
sink->data[i] = NULL;
sink->behaviour[i] = 0;
sink->size[i] = 0;
break;
default:
g_assert_not_reached ();
}
}
static void
gst_alsa_sink_flush_pads (GstAlsaSink *sink)
{
gint i;
for (i = 0; i < GST_ELEMENT (sink)->numpads; i++) {
/* flush twice to unref buffer when behaviour == 1 */
gst_alsa_sink_flush_one_pad (sink, i);
gst_alsa_sink_flush_one_pad (sink, i);
}
}
/* TRUE, if everything should continue */
static gboolean
gst_alsa_sink_check_event (GstAlsaSink *sink, gint pad_nr)
{
gboolean cont = TRUE;
GstEvent *event = GST_EVENT (sink->buf[pad_nr]);
GstAlsa *this = GST_ALSA (sink);
if (event) {
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_EOS:
gst_alsa_set_eos (this);
cont = FALSE;
break;
case GST_EVENT_INTERRUPT:
cont = FALSE;
break;
case GST_EVENT_DISCONTINUOUS:
{
GstClockTime value;
/* only the first pad my seek */
if (pad_nr != 0) {
break;
}
if (gst_event_discont_get_value (event, GST_FORMAT_TIME, &value)) {
gst_element_set_time (GST_ELEMENT (this), value);
} else if (gst_event_discont_get_value (event, GST_FORMAT_DEFAULT, &value)) {
value = gst_alsa_samples_to_timestamp (this, value);
gst_element_set_time (GST_ELEMENT (this), value);
} else if (gst_event_discont_get_value (event, GST_FORMAT_BYTES, &value)) {
value = gst_alsa_bytes_to_timestamp (this, value);
gst_element_set_time (GST_ELEMENT (this), value);
} else {
GST_ERROR_OBJECT (this, "couldn't extract time from discont event. Bad things might happen!");
}
break;
}
default:
GST_INFO_OBJECT (this, "got an unknown event (Type: %d)", GST_EVENT_TYPE (event));
break;
}
gst_event_unref (event);
sink->buf[pad_nr] = NULL;
} else {
/* the element at the top of the chain did not emit an event. */
g_assert_not_reached ();
}
return cont;
}
static int
gst_alsa_sink_mmap (GstAlsa *this, snd_pcm_sframes_t *avail)
{
snd_pcm_uframes_t offset;
const snd_pcm_channel_area_t *dst;
snd_pcm_channel_area_t *src;
GstAlsaSink *sink = GST_ALSA_SINK (this);
int i, err, width = snd_pcm_format_physical_width (this->format->format);
/* areas points to the memory areas that belong to gstreamer. */
src = g_malloc0 (this->format->channels * sizeof(snd_pcm_channel_area_t));
if (((GstElement *) this)->numpads == 1) {
/* interleaved */
for (i = 0; i < this->format->channels; i++) {
src[i].addr = sink->data[0];
src[i].first = i * width;
src[i].step = this->format->channels * width;
}
} else {
/* noninterleaved */
for (i = 0; i < this->format->channels; i++) {
src[i].addr = sink->data[i];
src[i].first = 0;
src[i].step = width;
}
}
if ((err = snd_pcm_mmap_begin (this->handle, &dst, &offset, avail)) < 0) {
GST_ERROR_OBJECT (this, "mmap failed: %s", snd_strerror (err));
return -1;
}
if ((err = snd_pcm_areas_copy (dst, offset, src, 0, this->format->channels, *avail, this->format->format)) < 0) {
snd_pcm_mmap_commit (this->handle, offset, 0);
GST_ERROR_OBJECT (this, "data copy failed: %s", snd_strerror (err));
return -1;
}
if ((err = snd_pcm_mmap_commit (this->handle, offset, *avail)) < 0) {
GST_ERROR_OBJECT (this, "mmap commit failed: %s", snd_strerror (err));
return -1;
}
return err;
}
static int
gst_alsa_sink_write (GstAlsa *this, snd_pcm_sframes_t *avail)
{
GstAlsaSink *sink = GST_ALSA_SINK (this);
void *channels[this->format->channels];
int err, i;
if (((GstElement *) this)->numpads == 1) {
/* interleaved */
err = snd_pcm_writei (this->handle, sink->data[0], *avail);
} else {
/* noninterleaved */
for (i = 0; i < this->format->channels; i++) {
channels[i] = sink->data[i];
}
err = snd_pcm_writen (this->handle, channels, *avail);
}
/* error handling */
if (err < 0) {
if (err == -EPIPE) {
gst_alsa_xrun_recovery (this);
return 0;
}
GST_ERROR_OBJECT (this, "error on data access: %s", snd_strerror (err));
}
return err;
}
static void
gst_alsa_sink_loop (GstElement *element)
{
snd_pcm_sframes_t avail, avail2, copied, sample_diff, max_discont;
snd_pcm_uframes_t samplestamp, time_sample;
gint i;
guint bytes; /* per channel */
GstAlsa *this = GST_ALSA (element);
GstAlsaSink *sink = GST_ALSA_SINK (element);
g_return_if_fail (sink != NULL);
sink_restart:
avail = gst_alsa_update_avail (this);
if (avail == -EPIPE) goto sink_restart;
if (avail < 0) return;
if (avail > 0) {
/* Not enough space. We grab data nonetheless and sleep afterwards */
if (avail < this->period_size) {
avail = this->period_size;
}
/* check how many bytes we still have in all our bytestreams */
/* initialize this value to a somewhat sane state, we might alloc this much data below (which would be a bug, but who knows)... */
bytes = this->period_size * this->period_count * element->numpads * 8; /* must be > max sample size in bytes */
for (i = 0; i < element->numpads; i++) {
g_assert (this->pad[i] != NULL);
while (sink->size[i] == 0) {
if (!sink->buf[i])
sink->buf[i] = GST_BUFFER (gst_pad_pull (this->pad[i]));
if (GST_IS_EVENT (sink->buf[i])) {
if (gst_alsa_sink_check_event (sink, i))
continue;
return;
}
/* caps nego failed somewhere */
if (this->format == NULL) {
GST_ELEMENT_ERROR (this, CORE, NEGOTIATION, (NULL),
("ALSA format not negotiated"));
}
samplestamp = gst_alsa_timestamp_to_samples (this, GST_BUFFER_TIMESTAMP (sink->buf[i]));
max_discont = gst_alsa_timestamp_to_samples (this, this->max_discont);
time_sample = gst_alsa_timestamp_to_samples (this, gst_element_get_time (GST_ELEMENT (this)));
snd_pcm_delay (this->handle, &sample_diff);
/* actual diff = buffer samplestamp - played - to_play */
sample_diff = samplestamp - time_sample - sample_diff;
if ((!GST_BUFFER_TIMESTAMP_IS_VALID (sink->buf[i])) ||
(-max_discont <= sample_diff && sample_diff <= max_discont)) {
/* difference between expected and current is < GST_ALSA_DEVIATION */
no_difference:
sink->size[i] = sink->buf[i]->size;
sink->data[i] = sink->buf[i]->data;
sink->behaviour[i] = 0;
} else if (sample_diff > 0) {
/* there are empty samples in front of us, fill them with silence */
int samples = MIN (bytes, sample_diff) *
(element->numpads == 1 ? this->format->channels : 1);
int size = samples * snd_pcm_format_physical_width (this->format->format) / 8;
GST_INFO_OBJECT (this, "Allocating %d bytes (%ld samples) now to resync: sample %ld expected, but got %ld",
size, MIN (bytes, sample_diff), time_sample, samplestamp);
sink->data[i] = g_try_malloc (size);
if (!sink->data[i]) {
GST_WARNING_OBJECT (this, "error allocating %d bytes, buffers unsynced now.", size);
goto no_difference;
}
sink->size[i] = size;
if (0 != snd_pcm_format_set_silence (this->format->format, sink->data[i], samples)) {
GST_WARNING_OBJECT (this, "error silencing buffer, enjoy the noise.");
}
sink->behaviour[i] = 1;
} else if (gst_alsa_samples_to_bytes (this, -sample_diff) >= sink->buf[i]->size) {
GST_INFO_OBJECT (this, "Skipping %lu samples to resync (complete buffer): sample %ld expected, but got %ld",
gst_alsa_bytes_to_samples (this, sink->buf[i]->size), time_sample, samplestamp);
/* this buffer is way behind */
gst_buffer_unref (sink->buf[i]);
sink->buf[i] = NULL;
continue;
} else if (sample_diff < 0) {
gint difference = gst_alsa_samples_to_bytes (this, -samplestamp);
GST_INFO_OBJECT (this, "Skipping %lu samples to resync: sample %ld expected, but got %ld",
(gulong) -sample_diff, time_sample, samplestamp);
/* this buffer is only a bit behind */
sink->size[i] = sink->buf[i]->size - difference;
sink->data[i] = sink->buf[i]->data + difference;
sink->behaviour[i] = 0;
} else {
g_assert_not_reached ();
}
}
bytes = MIN (bytes, sink->size[i]);
}
avail = MIN (avail, gst_alsa_bytes_to_samples (this, bytes));
/* wait until the hw buffer has enough space */
while (gst_element_get_state (element) == GST_STATE_PLAYING && (avail2 = gst_alsa_update_avail (this)) < avail) {
if (avail2 <= -EPIPE) goto sink_restart;
if (avail2 < 0) return;
if (avail2 < avail && snd_pcm_state(this->handle) != SND_PCM_STATE_RUNNING)
if (!gst_alsa_start (this)) return;
if (gst_alsa_pcm_wait (this) == FALSE)
return;
}
/* FIXME: lotsa stuff can have happened while fetching data. Do we need to check something? */
/* put this data into alsa */
if ((copied = this->transmit (this, &avail)) < 0)
return;
/* update our clock */
this->transmitted += copied;
/* flush the data */
bytes = gst_alsa_samples_to_bytes (this, copied);
for (i = 0; i < element->numpads; i++) {
if ((sink->size[i] -= bytes) == 0) {
gst_alsa_sink_flush_one_pad (sink, i);
continue;
}
g_assert (sink->size[i] > 0);
if (sink->behaviour[i] != 1)
sink->data[i] += bytes;
}
}
if (snd_pcm_state(this->handle) != SND_PCM_STATE_RUNNING && snd_pcm_avail_update (this->handle) == 0) {
gst_alsa_start (this);
}
}
static GstElementStateReturn
gst_alsa_sink_change_state (GstElement *element)
{
GstAlsaSink *sink;
g_return_val_if_fail (element != NULL, FALSE);
sink = GST_ALSA_SINK (element);
switch (GST_STATE_TRANSITION (element)) {
case GST_STATE_NULL_TO_READY:
case GST_STATE_READY_TO_PAUSED:
case GST_STATE_PAUSED_TO_PLAYING:
case GST_STATE_PLAYING_TO_PAUSED:
break;
case GST_STATE_PAUSED_TO_READY:
gst_alsa_sink_flush_pads (sink);
break;
case GST_STATE_READY_TO_NULL:
break;
default:
g_assert_not_reached();
}
if (GST_ELEMENT_CLASS (sink_parent_class)->change_state)
return GST_ELEMENT_CLASS (sink_parent_class)->change_state (element);
return GST_STATE_SUCCESS;
}
static GstClockTime
gst_alsa_sink_get_time (GstAlsa *this)
{
snd_pcm_sframes_t delay;
if (snd_pcm_delay (this->handle, &delay) == 0 && this->format) {
return GST_SECOND * (GstClockTime) (this->transmitted > delay ? this->transmitted - delay : 0) / this->format->rate;
} else {
return 0;
}
}