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gstreamer/libs/gst/net/gstnetclientclock.c
Sebastian Dröge f7a7a569cd netclientclock: Filter RTTs based on the median of the last RTTs before considering them at all 
This improves accuracy on wifi or similar networks, where the RTT can go very
high up for a single observation every now and then. Without filtering them
away completely, they would still still modify the average RTT, and thus all
clock estimations.
2015-06-06 14:31:16 +02:00

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28 KiB
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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2005 Wim Taymans <wim@fluendo.com>
* 2005 Andy Wingo <wingo@pobox.com>
* Copyright (C) 2012 Collabora Ltd. <tim.muller@collabora.co.uk>
*
* gstnetclientclock.h: clock that synchronizes itself to a time provider over
* the network
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstnetclientclock
* @short_description: Special clock that synchronizes to a remote time
* provider.
* @see_also: #GstClock, #GstNetTimeProvider, #GstPipeline
*
* This object implements a custom #GstClock that synchronizes its time
* to a remote time provider such as #GstNetTimeProvider.
*
* A new clock is created with gst_net_client_clock_new() which takes the
* address and port of the remote time provider along with a name and
* an initial time.
*
* This clock will poll the time provider and will update its calibration
* parameters based on the local and remote observations.
*
* The "round-trip" property limits the maximum round trip packets can take.
*
* Various parameters of the clock can be configured with the parent #GstClock
* "timeout", "window-size" and "window-threshold" object properties.
*
* A #GstNetClientClock is typically set on a #GstPipeline with
* gst_pipeline_use_clock().
*
* If you set a #GstBus on the clock via the "bus" object property, it will
* send @GST_MESSAGE_ELEMENT messages with an attached #GstStructure containing
* statistics about clock accuracy and network traffic.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstnettimepacket.h"
#include "gstnetclientclock.h"
#include <gio/gio.h>
#include <string.h>
GST_DEBUG_CATEGORY_STATIC (ncc_debug);
#define GST_CAT_DEFAULT (ncc_debug)
#define DEFAULT_ADDRESS "127.0.0.1"
#define DEFAULT_PORT 5637
#define DEFAULT_TIMEOUT GST_SECOND
#define DEFAULT_ROUNDTRIP_LIMIT GST_SECOND
/* Minimum timeout will be immediately (ie, as fast as one RTT), but no
* more often than 1/20th second (arbitrarily, to spread observations a little) */
#define DEFAULT_MINIMUM_UPDATE_INTERVAL (GST_SECOND / 20)
/* Maximum number of clock updates we can skip before updating */
#define MAX_SKIPPED_UPDATES 5
#define MEDIAN_PRE_FILTERING_WINDOW 9
enum
{
PROP_0,
PROP_ADDRESS,
PROP_PORT,
PROP_ROUNDTRIP_LIMIT,
PROP_MINIMUM_UPDATE_INTERVAL,
PROP_BUS
};
#define GST_NET_CLIENT_CLOCK_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_NET_CLIENT_CLOCK, GstNetClientClockPrivate))
struct _GstNetClientClockPrivate
{
GThread *thread;
GSocket *socket;
GSocketAddress *servaddr;
GCancellable *cancel;
gboolean made_cancel_fd;
GstClockTime timeout_expiration;
GstClockTime roundtrip_limit;
GstClockTime rtt_avg;
GstClockTime minimum_update_interval;
guint skipped_updates;
GstClockTime last_rtts[MEDIAN_PRE_FILTERING_WINDOW];
gint last_rtts_missing;
gchar *address;
gint port;
GstBus *bus;
};
#define _do_init \
GST_DEBUG_CATEGORY_INIT (ncc_debug, "netclock", 0, "Network client clock");
#define gst_net_client_clock_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstNetClientClock, gst_net_client_clock,
GST_TYPE_SYSTEM_CLOCK, _do_init);
static void gst_net_client_clock_finalize (GObject * object);
static void gst_net_client_clock_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_net_client_clock_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void gst_net_client_clock_stop (GstNetClientClock * self);
static void
gst_net_client_clock_class_init (GstNetClientClockClass * klass)
{
GObjectClass *gobject_class;
gobject_class = G_OBJECT_CLASS (klass);
g_type_class_add_private (klass, sizeof (GstNetClientClockPrivate));
gobject_class->finalize = gst_net_client_clock_finalize;
gobject_class->get_property = gst_net_client_clock_get_property;
gobject_class->set_property = gst_net_client_clock_set_property;
g_object_class_install_property (gobject_class, PROP_ADDRESS,
g_param_spec_string ("address", "address",
"The IP address of the machine providing a time server",
DEFAULT_ADDRESS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_PORT,
g_param_spec_int ("port", "port",
"The port on which the remote server is listening", 0, G_MAXUINT16,
DEFAULT_PORT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_BUS,
g_param_spec_object ("bus", "bus",
"A GstBus on which to send clock status information", GST_TYPE_BUS,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
/**
* GstNetClientClock::round-trip-limit:
*
* Maximum allowed round-trip for packets. If this property is set to a nonzero
* value, all packets with a round-trip interval larger than this limit will be
* ignored. This is useful for networks with severe and fluctuating transport
* delays. Filtering out these packets increases stability of the synchronization.
* On the other hand, the lower the limit, the higher the amount of filtered
* packets. Empirical tests are typically necessary to estimate a good value
* for the limit.
* If the property is set to zero, the limit is disabled.
*
* Since: 1.4
*/
g_object_class_install_property (gobject_class, PROP_ROUNDTRIP_LIMIT,
g_param_spec_uint64 ("round-trip-limit", "round-trip limit",
"Maximum tolerable round-trip interval for packets, in nanoseconds "
"(0 = no limit)", 0, G_MAXUINT64, DEFAULT_ROUNDTRIP_LIMIT,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_MINIMUM_UPDATE_INTERVAL,
g_param_spec_uint64 ("minimum-update-interval", "minimum update interval",
"Minimum polling interval for packets, in nanoseconds"
"(0 = no limit)", 0, G_MAXUINT64, DEFAULT_MINIMUM_UPDATE_INTERVAL,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
}
static void
gst_net_client_clock_init (GstNetClientClock * self)
{
GstClock *clock = GST_CLOCK_CAST (self);
GstNetClientClockPrivate *priv;
self->priv = priv = GST_NET_CLIENT_CLOCK_GET_PRIVATE (self);
priv->port = DEFAULT_PORT;
priv->address = g_strdup (DEFAULT_ADDRESS);
gst_clock_set_timeout (clock, DEFAULT_TIMEOUT);
priv->thread = NULL;
priv->servaddr = NULL;
priv->rtt_avg = GST_CLOCK_TIME_NONE;
priv->roundtrip_limit = DEFAULT_ROUNDTRIP_LIMIT;
priv->minimum_update_interval = DEFAULT_MINIMUM_UPDATE_INTERVAL;
priv->skipped_updates = 0;
priv->last_rtts_missing = MEDIAN_PRE_FILTERING_WINDOW;
}
static void
gst_net_client_clock_finalize (GObject * object)
{
GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
if (self->priv->thread) {
gst_net_client_clock_stop (self);
}
g_free (self->priv->address);
self->priv->address = NULL;
if (self->priv->servaddr != NULL) {
g_object_unref (self->priv->servaddr);
self->priv->servaddr = NULL;
}
if (self->priv->socket != NULL) {
g_socket_close (self->priv->socket, NULL);
g_object_unref (self->priv->socket);
self->priv->socket = NULL;
}
if (self->priv->bus != NULL) {
gst_object_unref (self->priv->bus);
self->priv->bus = NULL;
}
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_net_client_clock_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
switch (prop_id) {
case PROP_ADDRESS:
GST_OBJECT_LOCK (self);
g_free (self->priv->address);
self->priv->address = g_value_dup_string (value);
if (self->priv->address == NULL)
self->priv->address = g_strdup (DEFAULT_ADDRESS);
GST_OBJECT_UNLOCK (self);
break;
case PROP_PORT:
GST_OBJECT_LOCK (self);
self->priv->port = g_value_get_int (value);
GST_OBJECT_UNLOCK (self);
break;
case PROP_ROUNDTRIP_LIMIT:
GST_OBJECT_LOCK (self);
self->priv->roundtrip_limit = g_value_get_uint64 (value);
GST_OBJECT_UNLOCK (self);
break;
case PROP_MINIMUM_UPDATE_INTERVAL:
GST_OBJECT_LOCK (self);
self->priv->minimum_update_interval = g_value_get_uint64 (value);
GST_OBJECT_UNLOCK (self);
break;
case PROP_BUS:
GST_OBJECT_LOCK (self);
if (self->priv->bus)
gst_object_unref (self->priv->bus);
self->priv->bus = g_value_dup_object (value);
GST_OBJECT_UNLOCK (self);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_net_client_clock_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstNetClientClock *self = GST_NET_CLIENT_CLOCK (object);
switch (prop_id) {
case PROP_ADDRESS:
GST_OBJECT_LOCK (self);
g_value_set_string (value, self->priv->address);
GST_OBJECT_UNLOCK (self);
break;
case PROP_PORT:
g_value_set_int (value, self->priv->port);
break;
case PROP_ROUNDTRIP_LIMIT:
GST_OBJECT_LOCK (self);
g_value_set_uint64 (value, self->priv->roundtrip_limit);
GST_OBJECT_UNLOCK (self);
break;
case PROP_MINIMUM_UPDATE_INTERVAL:
GST_OBJECT_LOCK (self);
g_value_set_uint64 (value, self->priv->minimum_update_interval);
GST_OBJECT_UNLOCK (self);
break;
case PROP_BUS:
GST_OBJECT_LOCK (self);
g_value_set_object (value, self->priv->bus);
GST_OBJECT_UNLOCK (self);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gint
compare_clock_time (const GstClockTime * a, const GstClockTime * b)
{
if (*a < *b)
return -1;
else if (*a > *b)
return 1;
return 0;
}
static void
gst_net_client_clock_observe_times (GstNetClientClock * self,
GstClockTime local_1, GstClockTime remote, GstClockTime local_2)
{
GstNetClientClockPrivate *priv = self->priv;
GstClockTime current_timeout = 0;
GstClockTime local_avg;
gdouble r_squared;
GstClock *clock;
GstClockTime rtt, rtt_limit, min_update_interval;
GstBus *bus = NULL;
/* Use for discont tracking */
GstClockTime time_before = 0;
GstClockTime min_guess = 0;
GstClockTimeDiff time_discont = 0;
gboolean synched, now_synched;
GstClockTime internal_time, external_time, rate_num, rate_den;
GstClockTime orig_internal_time, orig_external_time, orig_rate_num,
orig_rate_den;
GstClockTime max_discont;
GstClockTime last_rtts[MEDIAN_PRE_FILTERING_WINDOW];
GstClockTime median;
gint i;
GST_OBJECT_LOCK (self);
rtt_limit = self->priv->roundtrip_limit;
min_update_interval = self->priv->minimum_update_interval;
if (self->priv->bus)
bus = gst_object_ref (self->priv->bus);
GST_OBJECT_UNLOCK (self);
if (local_2 < local_1) {
GST_LOG_OBJECT (self, "Dropping observation: receive time %" GST_TIME_FORMAT
" < send time %" GST_TIME_FORMAT, GST_TIME_ARGS (local_1),
GST_TIME_ARGS (local_2));
goto bogus_observation;
}
rtt = GST_CLOCK_DIFF (local_1, local_2);
if ((rtt_limit > 0) && (rtt > rtt_limit)) {
GST_LOG_OBJECT (self,
"Dropping observation: RTT %" GST_TIME_FORMAT " > limit %"
GST_TIME_FORMAT, GST_TIME_ARGS (rtt), GST_TIME_ARGS (rtt_limit));
goto bogus_observation;
}
for (i = 1; i < MEDIAN_PRE_FILTERING_WINDOW; i++)
self->priv->last_rtts[i - 1] = self->priv->last_rtts[i];
self->priv->last_rtts[i - 1] = rtt;
if (self->priv->last_rtts_missing) {
self->priv->last_rtts_missing--;
} else {
memcpy (&last_rtts, &self->priv->last_rtts, sizeof (last_rtts));
g_qsort_with_data (&last_rtts,
MEDIAN_PRE_FILTERING_WINDOW, sizeof (GstClockTime),
(GCompareDataFunc) compare_clock_time, NULL);
median = last_rtts[MEDIAN_PRE_FILTERING_WINDOW / 2];
/* FIXME: We might want to use something else here, like only allowing
* things in the interquartile range, or also filtering away delays that
* are too small compared to the median. This here worked well enough
* in tests so far.
*/
if (rtt > 2 * median) {
GST_LOG_OBJECT (self,
"Dropping observation, long RTT %" GST_TIME_FORMAT " > 2 * median %"
GST_TIME_FORMAT, GST_TIME_ARGS (rtt), GST_TIME_ARGS (median));
goto bogus_observation;
}
}
/* Track an average round trip time, for a bit of smoothing */
/* Always update before discarding a sample, so genuine changes in
* the network get picked up, eventually */
if (priv->rtt_avg == GST_CLOCK_TIME_NONE)
priv->rtt_avg = rtt;
else if (rtt < priv->rtt_avg) /* Shorter RTTs carry more weight than longer */
priv->rtt_avg = (3 * priv->rtt_avg + rtt) / 4;
else
priv->rtt_avg = (15 * priv->rtt_avg + rtt) / 16;
if (rtt > 2 * priv->rtt_avg) {
GST_LOG_OBJECT (self,
"Dropping observation, long RTT %" GST_TIME_FORMAT " > 2 * avg %"
GST_TIME_FORMAT, GST_TIME_ARGS (rtt), GST_TIME_ARGS (priv->rtt_avg));
goto bogus_observation;
}
local_avg = (local_2 + local_1) / 2;
GST_LOG_OBJECT (self, "local1 %" G_GUINT64_FORMAT " remote %" G_GUINT64_FORMAT
" localavg %" G_GUINT64_FORMAT " local2 %" G_GUINT64_FORMAT,
local_1, remote, local_avg, local_2);
clock = GST_CLOCK_CAST (self);
/* Store what the clock produced as 'now' before this update */
gst_clock_get_calibration (GST_CLOCK (self), &orig_internal_time,
&orig_external_time, &orig_rate_num, &orig_rate_den);
internal_time = orig_internal_time;
external_time = orig_external_time;
rate_num = orig_rate_num;
rate_den = orig_rate_den;
min_guess =
gst_clock_adjust_with_calibration (GST_CLOCK (self), local_1,
internal_time, external_time, rate_num, rate_den);
time_before =
gst_clock_adjust_with_calibration (GST_CLOCK (self), local_2,
internal_time, external_time, rate_num, rate_den);
/* Maximum discontinuity, when we're synched with the master. Could make this a property,
* but this value seems to work fine */
max_discont = priv->rtt_avg / 4;
/* If the remote observation was within a max_discont window around our min/max estimates, we're synched */
synched =
(GST_CLOCK_DIFF (remote, min_guess) < (GstClockTimeDiff) (max_discont)
&& GST_CLOCK_DIFF (time_before,
remote) < (GstClockTimeDiff) (max_discont));
if (gst_clock_add_observation_unapplied (GST_CLOCK (self), local_avg, remote,
&r_squared, &internal_time, &external_time, &rate_num, &rate_den)) {
/* Now compare the difference (discont) in the clock
* after this observation */
time_discont = GST_CLOCK_DIFF (time_before,
gst_clock_adjust_with_calibration (GST_CLOCK (self), local_2,
internal_time, external_time, rate_num, rate_den));
/* If we were in sync with the remote clock, clamp the allowed
* discontinuity to within quarter of one RTT. In sync means our send/receive estimates
* of remote time correctly windowed the actual remote time observation */
if (synched && ABS (time_discont) > max_discont) {
GstClockTimeDiff offset;
GST_DEBUG_OBJECT (clock,
"Too large a discont, clamping to 1/4 average RTT = %"
GST_TIME_FORMAT, GST_TIME_ARGS (max_discont));
if (time_discont > 0) { /* Too large a forward step - add a -ve offset */
offset = max_discont - time_discont;
if (-offset > external_time)
external_time = 0;
else
external_time += offset;
} else { /* Too large a backward step - add a +ve offset */
offset = -(max_discont + time_discont);
external_time += offset;
}
time_discont += offset;
}
/* Check if the new clock params would have made our observation within range */
now_synched =
(GST_CLOCK_DIFF (remote,
gst_clock_adjust_with_calibration (GST_CLOCK (self), local_1,
internal_time, external_time, rate_num,
rate_den)) < (GstClockTimeDiff) (max_discont))
&& (GST_CLOCK_DIFF (gst_clock_adjust_with_calibration (GST_CLOCK (self),
local_2, internal_time, external_time, rate_num, rate_den),
remote) < (GstClockTimeDiff) (max_discont));
/* Only update the clock if we had synch or just gained it */
if (synched || now_synched || priv->skipped_updates > MAX_SKIPPED_UPDATES) {
gst_clock_set_calibration (GST_CLOCK (self), internal_time, external_time,
rate_num, rate_den);
/* ghetto formula - shorter timeout for bad correlations */
current_timeout = (1e-3 / (1 - MIN (r_squared, 0.99999))) * GST_SECOND;
current_timeout = MIN (current_timeout, gst_clock_get_timeout (clock));
priv->skipped_updates = 0;
} else {
/* Restore original calibration vars for the report, we're not changing the clock */
internal_time = orig_internal_time;
external_time = orig_external_time;
rate_num = orig_rate_num;
rate_den = orig_rate_den;
time_discont = 0;
priv->skipped_updates++;
}
}
/* Limit the polling to at most one per minimum_update_interval */
if (rtt < min_update_interval)
current_timeout = MAX (min_update_interval - rtt, current_timeout);
if (bus) {
GstStructure *s;
GstMessage *msg;
/* Output a stats message, whether we updated the clock or not */
s = gst_structure_new ("gst-netclock-statistics",
"synchronised", G_TYPE_BOOLEAN, synched,
"rtt", G_TYPE_UINT64, rtt,
"rtt-average", G_TYPE_UINT64, priv->rtt_avg,
"local", G_TYPE_UINT64, local_avg,
"remote", G_TYPE_UINT64, remote,
"discontinuity", G_TYPE_INT64, time_discont,
"remote-min-estimate", G_TYPE_UINT64, min_guess,
"remote-max-estimate", G_TYPE_UINT64, time_before,
"remote-min-error", G_TYPE_INT64, GST_CLOCK_DIFF (remote, min_guess),
"remote-max-error", G_TYPE_INT64, GST_CLOCK_DIFF (remote, time_before),
"request-send", G_TYPE_UINT64, local_1,
"request-receive", G_TYPE_UINT64, local_2,
"r-squared", G_TYPE_DOUBLE, r_squared,
"timeout", G_TYPE_UINT64, current_timeout,
"internal-time", G_TYPE_UINT64, internal_time,
"external-time", G_TYPE_UINT64, external_time,
"rate-num", G_TYPE_UINT64, rate_num,
"rate-den", G_TYPE_UINT64, rate_den,
"rate", G_TYPE_DOUBLE, (gdouble) (rate_num) / rate_den,
"local-clock-offset", G_TYPE_INT64, GST_CLOCK_DIFF (internal_time,
external_time), NULL);
msg = gst_message_new_element (GST_OBJECT (self), s);
gst_bus_post (bus, msg);
}
GST_INFO ("next timeout: %" GST_TIME_FORMAT, GST_TIME_ARGS (current_timeout));
self->priv->timeout_expiration = gst_util_get_timestamp () + current_timeout;
if (bus)
gst_object_unref (bus);
return;
bogus_observation:
if (bus)
gst_object_unref (bus);
/* Schedule a new packet again soon */
self->priv->timeout_expiration = gst_util_get_timestamp () + (GST_SECOND / 4);
return;
}
static gpointer
gst_net_client_clock_thread (gpointer data)
{
GstNetClientClock *self = data;
GstNetTimePacket *packet;
GSocket *socket = self->priv->socket;
GError *err = NULL;
GstClock *clock = data;
GST_INFO_OBJECT (self, "net client clock thread running, socket=%p", socket);
g_socket_set_blocking (socket, TRUE);
g_socket_set_timeout (socket, 0);
while (!g_cancellable_is_cancelled (self->priv->cancel)) {
GstClockTime expiration_time = self->priv->timeout_expiration;
GstClockTime now = gst_util_get_timestamp ();
gint64 socket_timeout;
if (now >= expiration_time || (expiration_time - now) <= GST_MSECOND) {
socket_timeout = 0;
} else {
socket_timeout = (expiration_time - now) / GST_USECOND;
}
GST_TRACE_OBJECT (self, "timeout: %" G_GINT64_FORMAT "us", socket_timeout);
if (!g_socket_condition_timed_wait (socket, G_IO_IN, socket_timeout,
self->priv->cancel, &err)) {
/* cancelled, timeout or error */
if (err->code == G_IO_ERROR_CANCELLED) {
GST_INFO_OBJECT (self, "cancelled");
g_clear_error (&err);
break;
} else if (err->code == G_IO_ERROR_TIMED_OUT) {
/* timed out, let's send another packet */
GST_DEBUG_OBJECT (self, "timed out");
packet = gst_net_time_packet_new (NULL);
packet->local_time = gst_clock_get_internal_time (GST_CLOCK (self));
GST_DEBUG_OBJECT (self,
"sending packet, local time = %" GST_TIME_FORMAT,
GST_TIME_ARGS (packet->local_time));
gst_net_time_packet_send (packet, self->priv->socket,
self->priv->servaddr, NULL);
g_free (packet);
/* reset timeout (but are expecting a response sooner anyway) */
self->priv->timeout_expiration =
gst_util_get_timestamp () + gst_clock_get_timeout (clock);
} else {
GST_DEBUG_OBJECT (self, "socket error: %s", err->message);
g_usleep (G_USEC_PER_SEC / 10); /* throttle */
}
g_clear_error (&err);
} else {
GstClockTime new_local;
/* got packet */
new_local = gst_clock_get_internal_time (GST_CLOCK (self));
packet = gst_net_time_packet_receive (socket, NULL, &err);
if (packet != NULL) {
GST_LOG_OBJECT (self, "got packet back");
GST_LOG_OBJECT (self, "local_1 = %" GST_TIME_FORMAT,
GST_TIME_ARGS (packet->local_time));
GST_LOG_OBJECT (self, "remote = %" GST_TIME_FORMAT,
GST_TIME_ARGS (packet->remote_time));
GST_LOG_OBJECT (self, "local_2 = %" GST_TIME_FORMAT,
GST_TIME_ARGS (new_local));
/* observe_times will reset the timeout */
gst_net_client_clock_observe_times (self, packet->local_time,
packet->remote_time, new_local);
g_free (packet);
} else if (err != NULL) {
GST_WARNING_OBJECT (self, "receive error: %s", err->message);
g_clear_error (&err);
}
}
}
GST_INFO_OBJECT (self, "shutting down net client clock thread");
return NULL;
}
static gboolean
gst_net_client_clock_start (GstNetClientClock * self)
{
GSocketAddress *servaddr;
GSocketAddress *myaddr;
GSocketAddress *anyaddr;
GInetAddress *inetaddr;
GSocket *socket;
GError *error = NULL;
GSocketFamily family;
GPollFD dummy_pollfd;
g_return_val_if_fail (self->priv->address != NULL, FALSE);
g_return_val_if_fail (self->priv->servaddr == NULL, FALSE);
/* create target address */
inetaddr = g_inet_address_new_from_string (self->priv->address);
if (inetaddr == NULL)
goto bad_address;
family = g_inet_address_get_family (inetaddr);
servaddr = g_inet_socket_address_new (inetaddr, self->priv->port);
g_object_unref (inetaddr);
g_assert (servaddr != NULL);
GST_DEBUG_OBJECT (self, "will communicate with %s:%d", self->priv->address,
self->priv->port);
socket = g_socket_new (family, G_SOCKET_TYPE_DATAGRAM,
G_SOCKET_PROTOCOL_UDP, &error);
if (socket == NULL)
goto no_socket;
GST_DEBUG_OBJECT (self, "binding socket");
inetaddr = g_inet_address_new_any (family);
anyaddr = g_inet_socket_address_new (inetaddr, 0);
g_socket_bind (socket, anyaddr, TRUE, &error);
g_object_unref (anyaddr);
g_object_unref (inetaddr);
if (error != NULL)
goto bind_error;
/* check address we're bound to, mostly for debugging purposes */
myaddr = g_socket_get_local_address (socket, &error);
if (myaddr == NULL)
goto getsockname_error;
GST_DEBUG_OBJECT (self, "socket opened on UDP port %hd",
g_inet_socket_address_get_port (G_INET_SOCKET_ADDRESS (myaddr)));
g_object_unref (myaddr);
self->priv->cancel = g_cancellable_new ();
self->priv->made_cancel_fd =
g_cancellable_make_pollfd (self->priv->cancel, &dummy_pollfd);
self->priv->socket = socket;
self->priv->servaddr = G_SOCKET_ADDRESS (servaddr);
self->priv->thread = g_thread_try_new ("GstNetClientClock",
gst_net_client_clock_thread, self, &error);
if (error != NULL)
goto no_thread;
return TRUE;
/* ERRORS */
no_socket:
{
GST_ERROR_OBJECT (self, "socket_new() failed: %s", error->message);
g_error_free (error);
return FALSE;
}
bind_error:
{
GST_ERROR_OBJECT (self, "bind failed: %s", error->message);
g_error_free (error);
g_object_unref (socket);
return FALSE;
}
getsockname_error:
{
GST_ERROR_OBJECT (self, "get_local_address() failed: %s", error->message);
g_error_free (error);
g_object_unref (socket);
return FALSE;
}
bad_address:
{
GST_ERROR_OBJECT (self, "inet_address_new_from_string('%s') failed",
self->priv->address);
return FALSE;
}
no_thread:
{
GST_ERROR_OBJECT (self, "could not create thread: %s", error->message);
g_object_unref (self->priv->servaddr);
self->priv->servaddr = NULL;
g_object_unref (self->priv->socket);
self->priv->socket = NULL;
g_error_free (error);
return FALSE;
}
}
static void
gst_net_client_clock_stop (GstNetClientClock * self)
{
if (self->priv->thread == NULL)
return;
GST_INFO_OBJECT (self, "stopping...");
g_cancellable_cancel (self->priv->cancel);
g_thread_join (self->priv->thread);
self->priv->thread = NULL;
if (self->priv->made_cancel_fd)
g_cancellable_release_fd (self->priv->cancel);
g_object_unref (self->priv->cancel);
self->priv->cancel = NULL;
g_object_unref (self->priv->servaddr);
self->priv->servaddr = NULL;
g_object_unref (self->priv->socket);
self->priv->socket = NULL;
GST_INFO_OBJECT (self, "stopped");
}
/**
* gst_net_client_clock_new:
* @name: a name for the clock
* @remote_address: the address of the remote clock provider
* @remote_port: the port of the remote clock provider
* @base_time: initial time of the clock
*
* Create a new #GstNetClientClock that will report the time
* provided by the #GstNetTimeProvider on @remote_address and
* @remote_port.
*
* Returns: a new #GstClock that receives a time from the remote
* clock.
*/
GstClock *
gst_net_client_clock_new (const gchar * name, const gchar * remote_address,
gint remote_port, GstClockTime base_time)
{
/* FIXME: gst_net_client_clock_new() should be a thin wrapper for g_object_new() */
GstNetClientClock *ret;
GstClockTime internal;
g_return_val_if_fail (remote_address != NULL, NULL);
g_return_val_if_fail (remote_port > 0, NULL);
g_return_val_if_fail (remote_port <= G_MAXUINT16, NULL);
g_return_val_if_fail (base_time != GST_CLOCK_TIME_NONE, NULL);
ret = g_object_new (GST_TYPE_NET_CLIENT_CLOCK, "address", remote_address,
"port", remote_port, NULL);
/* gst_clock_get_time() values are guaranteed to be increasing. because no one
* has called get_time on this clock yet we are free to adjust to any value
* without worrying about worrying about MAX() issues with the clock's
* internal time.
*/
/* update our internal time so get_time() give something around base_time.
assume that the rate is 1 in the beginning. */
internal = gst_clock_get_internal_time (GST_CLOCK (ret));
gst_clock_set_calibration (GST_CLOCK (ret), internal, base_time, 1, 1);
{
GstClockTime now = gst_clock_get_time (GST_CLOCK (ret));
if (GST_CLOCK_DIFF (now, base_time) > 0 ||
GST_CLOCK_DIFF (now, base_time + GST_SECOND) < 0) {
g_warning ("unable to set the base time, expect sync problems!");
}
}
if (!gst_net_client_clock_start (ret))
goto failed_start;
/* all systems go, cap'n */
return (GstClock *) ret;
failed_start:
{
/* already printed a nice error */
gst_object_unref (ret);
return NULL;
}
}
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