gstreamer/libs/gst/net/gstnetclientclock.c
Tim-Philipp Müller 6eb6d9ec38 docs: remove outdated and pointless 'Last reviewed' lines from docs
They are very confusing for people, and more often than not
also just not very accurate. Seeing 'last reviewed: 2005' in
your docs is not very confidence-inspiring. Let's just remove
those comments.
2014-04-26 21:21:51 +01:00

603 lines
18 KiB
C

/* 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().
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "gstnettimepacket.h"
#include "gstnetclientclock.h"
#include <gio/gio.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
enum
{
PROP_0,
PROP_ADDRESS,
PROP_PORT,
PROP_ROUNDTRIP_LIMIT
};
#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;
GstClockTime timeout_expiration;
GstClockTime roundtrip_limit;
GstClockTime rtt_avg;
gchar *address;
gint port;
};
#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));
/**
* 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));
}
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;
}
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;
}
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:
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);
break;
case PROP_PORT:
self->priv->port = g_value_get_int (value);
break;
case PROP_ROUNDTRIP_LIMIT:
self->priv->roundtrip_limit = g_value_get_uint64 (value);
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:
g_value_set_string (value, self->priv->address);
break;
case PROP_PORT:
g_value_set_int (value, self->priv->port);
break;
case PROP_ROUNDTRIP_LIMIT:
g_value_set_uint64 (value, self->priv->roundtrip_limit);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
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;
GstClockTime local_avg;
gdouble r_squared;
GstClock *clock;
GstClockTime rtt;
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 ((self->priv->roundtrip_limit > 0) && (rtt > self->priv->roundtrip_limit)) {
GST_LOG_OBJECT (self,
"Dropping observation: RTT %" GST_TIME_FORMAT " > limit %"
GST_TIME_FORMAT, GST_TIME_ARGS (rtt),
GST_TIME_ARGS (self->priv->roundtrip_limit));
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 = (7 * priv->rtt_avg + rtt) / 8;
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);
if (gst_clock_add_observation (GST_CLOCK (self), local_avg, remote,
&r_squared)) {
/* 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));
} else {
current_timeout = 0;
}
GST_INFO ("next timeout: %" GST_TIME_FORMAT, GST_TIME_ARGS (current_timeout));
self->priv->timeout_expiration = gst_util_get_timestamp () + current_timeout;
return;
bogus_observation:
/* 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;
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->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;
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;
}
}