/* GStreamer

 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>

 *                    2004,2005 Wim Taymans <wim@fluendo.com>

 *

 * gstpipeline.c: Overall pipeline management element

 *

 * 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:gstpipeline

 * @title: GstPipeline

 * @short_description: Top-level bin with clocking and bus management

                       functionality.

 * @see_also: #GstElement, #GstBin, #GstClock, #GstBus

 *

 * A #GstPipeline is a special #GstBin used as the toplevel container for

 * the filter graph. The #GstPipeline will manage the selection and

 * distribution of a global #GstClock as well as provide a #GstBus to the

 * application.

 *

 * gst_pipeline_new() is used to create a pipeline. when you are done with

 * the pipeline, use gst_object_unref() to free its resources including all

 * added #GstElement objects (if not otherwise referenced).

 *

 * Elements are added and removed from the pipeline using the #GstBin

 * methods like gst_bin_add() and gst_bin_remove() (see #GstBin).

 *

 * Before changing the state of the #GstPipeline (see #GstElement) a #GstBus

 * can be retrieved with gst_pipeline_get_bus(). This bus can then be

 * used to receive #GstMessage from the elements in the pipeline.

 *

 * By default, a #GstPipeline will automatically flush the pending #GstBus

 * messages when going to the NULL state to ensure that no circular

 * references exist when no messages are read from the #GstBus. This

 * behaviour can be changed with gst_pipeline_set_auto_flush_bus().

 *

 * When the #GstPipeline performs the PAUSED to PLAYING state change it will

 * select a clock for the elements. The clock selection algorithm will by

 * default select a clock provided by an element that is most upstream

 * (closest to the source). For live pipelines (ones that return

 * #GST_STATE_CHANGE_NO_PREROLL from the gst_element_set_state() call) this

 * will select the clock provided by the live source. For normal pipelines

 * this will select a clock provided by the sinks (most likely the audio

 * sink). If no element provides a clock, a default #GstSystemClock is used.

 *

 * The clock selection can be controlled with the gst_pipeline_use_clock()

 * method, which will enforce a given clock on the pipeline. With

 * gst_pipeline_auto_clock() the default clock selection algorithm can be

 * restored.

 *

 * A #GstPipeline maintains a running time for the elements. The running

 * time is defined as the difference between the current clock time and

 * the base time. When the pipeline goes to READY or a flushing seek is

 * performed on it, the running time is reset to 0. When the pipeline is

 * set from PLAYING to PAUSED, the current clock time is sampled and used to

 * configure the base time for the elements when the pipeline is set

 * to PLAYING again. The effect is that the running time (as the difference

 * between the clock time and the base time) will count how much time was spent

 * in the PLAYING state. This default behaviour can be changed with the

 * gst_element_set_start_time() method.

 */

#include "gst_private.h"

#include "gsterror.h"

#include "gst-i18n-lib.h"

#include "gstpipeline.h"

#include "gstinfo.h"

#include "gstsystemclock.h"

#include "gstutils.h"

GST_DEBUG_CATEGORY_STATIC (pipeline_debug);

#define GST_CAT_DEFAULT pipeline_debug

/* Pipeline signals and args */

enum

{

  /* FILL ME */

  LAST_SIGNAL

};

#define DEFAULT_DELAY           0

#define DEFAULT_AUTO_FLUSH_BUS  TRUE

#define DEFAULT_LATENCY         GST_CLOCK_TIME_NONE

enum

{

  PROP_0,

  PROP_DELAY,

  PROP_AUTO_FLUSH_BUS,

  PROP_LATENCY

};

#define GST_PIPELINE_GET_PRIVATE(obj)  \

   (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_PIPELINE, GstPipelinePrivate))

struct _GstPipelinePrivate

{

  /* with LOCK */

  gboolean auto_flush_bus;

  /* when we need to update stream_time or clock when going back to

   * PLAYING*/

  GstClockTime last_start_time;

  gboolean update_clock;

  GstClockTime latency;

};

static void gst_pipeline_dispose (GObject * object);

static void gst_pipeline_set_property (GObject * object, guint prop_id,

    const GValue * value, GParamSpec * pspec);

static void gst_pipeline_get_property (GObject * object, guint prop_id,

    GValue * value, GParamSpec * pspec);

static GstClock *gst_pipeline_provide_clock_func (GstElement * element);

static GstStateChangeReturn gst_pipeline_change_state (GstElement * element,

    GstStateChange transition);

static void gst_pipeline_handle_message (GstBin * bin, GstMessage * message);

static gboolean gst_pipeline_do_latency (GstBin * bin);

/* static guint gst_pipeline_signals[LAST_SIGNAL] = { 0 }; */

#define _do_init \

{ \

  GST_DEBUG_CATEGORY_INIT (pipeline_debug, "pipeline", GST_DEBUG_BOLD, \

      "debugging info for the 'pipeline' container element"); \

}

#define gst_pipeline_parent_class parent_class

G_DEFINE_TYPE_WITH_CODE (GstPipeline, gst_pipeline, GST_TYPE_BIN, _do_init);

static void

gst_pipeline_class_init (GstPipelineClass * klass)

{

  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);

  GstBinClass *gstbin_class = GST_BIN_CLASS (klass);

  g_type_class_add_private (klass, sizeof (GstPipelinePrivate));

  gobject_class->set_property = gst_pipeline_set_property;

  gobject_class->get_property = gst_pipeline_get_property;

  /**

   * GstPipeline:delay:

   *

   * The expected delay needed for elements to spin up to the

   * PLAYING state expressed in nanoseconds.

   * see gst_pipeline_set_delay() for more information on this option.

   **/

  g_object_class_install_property (gobject_class, PROP_DELAY,

      g_param_spec_uint64 ("delay", "Delay",

          "Expected delay needed for elements "

          "to spin up to PLAYING in nanoseconds", 0, G_MAXUINT64, DEFAULT_DELAY,

          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**

   * GstPipeline:auto-flush-bus:

   *

   * Whether or not to automatically flush all messages on the

   * pipeline's bus when going from READY to NULL state. Please see

   * gst_pipeline_set_auto_flush_bus() for more information on this option.

   **/

  g_object_class_install_property (gobject_class, PROP_AUTO_FLUSH_BUS,

      g_param_spec_boolean ("auto-flush-bus", "Auto Flush Bus",

          "Whether to automatically flush the pipeline's bus when going "

          "from READY into NULL state", DEFAULT_AUTO_FLUSH_BUS,

          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  /**

   * GstPipeline:latency:

   *

   * Latency to configure on the pipeline. See gst_pipeline_set_latency().

   *

   * Since: 1.6

   **/

  g_object_class_install_property (gobject_class, PROP_LATENCY,

      g_param_spec_uint64 ("latency", "Latency",

          "Latency to configure on the pipeline", 0, G_MAXUINT64,

          DEFAULT_LATENCY, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  gobject_class->dispose = gst_pipeline_dispose;

  gst_element_class_set_static_metadata (gstelement_class, "Pipeline object",

      "Generic/Bin",

      "Complete pipeline object",

      "Erik Walthinsen <omega@cse.ogi.edu>, Wim Taymans <wim@fluendo.com>");

  gstelement_class->change_state =

      GST_DEBUG_FUNCPTR (gst_pipeline_change_state);

  gstelement_class->provide_clock =

      GST_DEBUG_FUNCPTR (gst_pipeline_provide_clock_func);

  gstbin_class->handle_message =

      GST_DEBUG_FUNCPTR (gst_pipeline_handle_message);

  gstbin_class->do_latency = GST_DEBUG_FUNCPTR (gst_pipeline_do_latency);

}

static void

gst_pipeline_init (GstPipeline * pipeline)

{

  GstBus *bus;

  pipeline->priv = GST_PIPELINE_GET_PRIVATE (pipeline);

  /* set default property values */

  pipeline->priv->auto_flush_bus = DEFAULT_AUTO_FLUSH_BUS;

  pipeline->delay = DEFAULT_DELAY;

  pipeline->priv->latency = DEFAULT_LATENCY;

  /* create and set a default bus */

  bus = gst_bus_new ();

#if 0

  /* FIXME, disabled for 0.10.5 release as it caused to many regressions */

  /* Start our bus in flushing if appropriate */

  if (pipeline->priv->auto_flush_bus)

    gst_bus_set_flushing (bus, TRUE);

#endif

  gst_element_set_bus (GST_ELEMENT_CAST (pipeline), bus);

  GST_DEBUG_OBJECT (pipeline, "set bus %" GST_PTR_FORMAT " on pipeline", bus);

  gst_object_unref (bus);

}

static void

gst_pipeline_dispose (GObject * object)

{

  GstPipeline *pipeline = GST_PIPELINE (object);

  GstClock **clock_p = &pipeline->fixed_clock;

  GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, pipeline, "%p dispose", pipeline);

  /* clear and unref any fixed clock */

  gst_object_replace ((GstObject **) clock_p, NULL);

  G_OBJECT_CLASS (parent_class)->dispose (object);

}

static void

gst_pipeline_set_property (GObject * object, guint prop_id,

    const GValue * value, GParamSpec * pspec)

{

  GstPipeline *pipeline = GST_PIPELINE (object);

  switch (prop_id) {

    case PROP_DELAY:

      gst_pipeline_set_delay (pipeline, g_value_get_uint64 (value));

      break;

    case PROP_AUTO_FLUSH_BUS:

      gst_pipeline_set_auto_flush_bus (pipeline, g_value_get_boolean (value));

      break;

    case PROP_LATENCY:

      gst_pipeline_set_latency (pipeline, g_value_get_uint64 (value));

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

  }

}

static void

gst_pipeline_get_property (GObject * object, guint prop_id,

    GValue * value, GParamSpec * pspec)

{

  GstPipeline *pipeline = GST_PIPELINE (object);

  switch (prop_id) {

    case PROP_DELAY:

      g_value_set_uint64 (value, gst_pipeline_get_delay (pipeline));

      break;

    case PROP_AUTO_FLUSH_BUS:

      g_value_set_boolean (value, gst_pipeline_get_auto_flush_bus (pipeline));

      break;

    case PROP_LATENCY:

      g_value_set_uint64 (value, gst_pipeline_get_latency (pipeline));

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

  }

}

/* set the start_time to 0, this will cause us to select a new base_time and

 * make the running_time start from 0 again. */

static void

reset_start_time (GstPipeline * pipeline, GstClockTime start_time)

{

  GST_OBJECT_LOCK (pipeline);

  if (GST_ELEMENT_START_TIME (pipeline) != GST_CLOCK_TIME_NONE) {

    GST_DEBUG_OBJECT (pipeline, "reset start_time to 0");

    GST_ELEMENT_START_TIME (pipeline) = start_time;

    pipeline->priv->last_start_time = -1;

  } else {

    GST_DEBUG_OBJECT (pipeline, "application asked to not reset stream_time");

  }

  GST_OBJECT_UNLOCK (pipeline);

}

/**

 * gst_pipeline_new:

 * @name: (allow-none): name of new pipeline

 *

 * Create a new pipeline with the given name.

 *

 * Returns: (transfer floating): newly created GstPipeline

 *

 * MT safe.

 */

GstElement *

gst_pipeline_new (const gchar * name)

{

  return gst_element_factory_make ("pipeline", name);

}

/* takes a snapshot of the running_time of the pipeline and store this as the

 * element start_time. This is the time we will set as the running_time of the

 * pipeline when we go to PLAYING next. */

static void

pipeline_update_start_time (GstElement * element)

{

  GstPipeline *pipeline = GST_PIPELINE_CAST (element);

  GstClock *clock;

  GST_OBJECT_LOCK (element);

  if ((clock = element->clock)) {

    GstClockTime now;

    gst_object_ref (clock);

    GST_OBJECT_UNLOCK (element);

    /* calculate the time when we stopped */

    now = gst_clock_get_time (clock);

    gst_object_unref (clock);

    GST_OBJECT_LOCK (element);

    /* store the current running time */

    if (GST_ELEMENT_START_TIME (pipeline) != GST_CLOCK_TIME_NONE) {

      if (now != GST_CLOCK_TIME_NONE)

        GST_ELEMENT_START_TIME (pipeline) = now - element->base_time;

      else

        GST_WARNING_OBJECT (element,

            "Clock %s returned invalid time, can't calculate "

            "running_time when going to the PAUSED state",

            GST_OBJECT_NAME (clock));

      /* we went to PAUSED, when going to PLAYING select clock and new

       * base_time */

      pipeline->priv->update_clock = TRUE;

    }

    GST_DEBUG_OBJECT (element,

        "start_time=%" GST_TIME_FORMAT ", now=%" GST_TIME_FORMAT

        ", base_time %" GST_TIME_FORMAT,

        GST_TIME_ARGS (GST_ELEMENT_START_TIME (pipeline)),

        GST_TIME_ARGS (now), GST_TIME_ARGS (element->base_time));

  }

  GST_OBJECT_UNLOCK (element);

}

/* MT safe */

static GstStateChangeReturn

gst_pipeline_change_state (GstElement * element, GstStateChange transition)

{

  GstStateChangeReturn result = GST_STATE_CHANGE_SUCCESS;

  GstPipeline *pipeline = GST_PIPELINE_CAST (element);

  GstClock *clock;

  switch (transition) {

    case GST_STATE_CHANGE_NULL_TO_NULL:

      break;

    case GST_STATE_CHANGE_READY_TO_READY:

      break;

    case GST_STATE_CHANGE_PAUSED_TO_PAUSED:

      break;

    case GST_STATE_CHANGE_PLAYING_TO_PLAYING:

      break;

    case GST_STATE_CHANGE_NULL_TO_READY:

      GST_OBJECT_LOCK (element);

      if (element->bus)

        gst_bus_set_flushing (element->bus, FALSE);

      GST_OBJECT_UNLOCK (element);

      break;

    case GST_STATE_CHANGE_READY_TO_PAUSED:

      GST_OBJECT_LOCK (element);

      pipeline->priv->update_clock = TRUE;

      GST_OBJECT_UNLOCK (element);

      /* READY to PAUSED starts running_time from 0 */

      reset_start_time (pipeline, 0);

      break;

    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:

    {

      GstClockTime now, start_time, last_start_time, delay;

      gboolean update_clock;

      GstClock *cur_clock;

      GST_DEBUG_OBJECT (element, "selecting clock and base_time");

      GST_OBJECT_LOCK (element);

      cur_clock = element->clock;

      if (cur_clock)

        gst_object_ref (cur_clock);

      /* get the desired running_time of the first buffer aka the start_time */

      start_time = GST_ELEMENT_START_TIME (pipeline);

      last_start_time = pipeline->priv->last_start_time;

      pipeline->priv->last_start_time = start_time;

      /* see if we need to update the clock */

      update_clock = pipeline->priv->update_clock;

      pipeline->priv->update_clock = FALSE;

      delay = pipeline->delay;

      GST_OBJECT_UNLOCK (element);

      /* running time changed, either with a PAUSED or a flush, we need to check

       * if there is a new clock & update the base time */

      /* only do this for top-level, however */

      if (GST_OBJECT_PARENT (element) == NULL &&

          (update_clock || last_start_time != start_time)) {

        GST_DEBUG_OBJECT (pipeline, "Need to update start_time");

        /* when going to PLAYING, select a clock when needed. If we just got

         * flushed, we don't reselect the clock. */

        if (update_clock) {

          GST_DEBUG_OBJECT (pipeline, "Need to update clock.");

          clock = gst_element_provide_clock (element);

        } else {

          GST_DEBUG_OBJECT (pipeline,

              "Don't need to update clock, using old clock.");

          /* only try to ref if cur_clock is not NULL */

          if (cur_clock)

            gst_object_ref (cur_clock);

          clock = cur_clock;

        }

        if (clock) {

          now = gst_clock_get_time (clock);

        } else {

          GST_DEBUG_OBJECT (pipeline, "no clock, using base time of NONE");

          now = GST_CLOCK_TIME_NONE;

        }

        if (clock != cur_clock) {

          /* now distribute the clock (which could be NULL). If some

           * element refuses the clock, this will return FALSE and

           * we effectively fail the state change. */

          if (!gst_element_set_clock (element, clock))

            goto invalid_clock;

          /* if we selected and distributed a new clock, let the app

           * know about it */

          gst_element_post_message (element,

              gst_message_new_new_clock (GST_OBJECT_CAST (element), clock));

        }

        if (clock)

          gst_object_unref (clock);

        if (start_time != GST_CLOCK_TIME_NONE && now != GST_CLOCK_TIME_NONE) {

          GstClockTime new_base_time = now - start_time + delay;

          GST_DEBUG_OBJECT (element,

              "start_time=%" GST_TIME_FORMAT ", now=%" GST_TIME_FORMAT

              ", base_time %" GST_TIME_FORMAT,

              GST_TIME_ARGS (start_time), GST_TIME_ARGS (now),

              GST_TIME_ARGS (new_base_time));

          gst_element_set_base_time (element, new_base_time);

        } else {

          GST_DEBUG_OBJECT (pipeline,

              "NOT adjusting base_time because start_time is NONE");

        }

      } else {

        GST_DEBUG_OBJECT (pipeline,

            "NOT adjusting base_time because we selected one before");

      }

      if (cur_clock)

        gst_object_unref (cur_clock);

      break;

    }

    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:

    {

      /* we take a start_time snapshot before calling the children state changes

       * so that they know about when the pipeline PAUSED. */

      pipeline_update_start_time (element);

      break;

    }

    case GST_STATE_CHANGE_PAUSED_TO_READY:

      reset_start_time (pipeline, 0);

      break;

    case GST_STATE_CHANGE_READY_TO_NULL:

      break;

  }

  result = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);

  switch (transition) {

    case GST_STATE_CHANGE_NULL_TO_NULL:

      break;

    case GST_STATE_CHANGE_READY_TO_READY:

      break;

    case GST_STATE_CHANGE_PAUSED_TO_PAUSED:

      break;

    case GST_STATE_CHANGE_PLAYING_TO_PLAYING:

      break;

    case GST_STATE_CHANGE_NULL_TO_READY:

      break;

    case GST_STATE_CHANGE_READY_TO_PAUSED:

      break;

    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:

      break;

    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:

    {

      /* Take a new snapshot of the start_time after calling the state change on

       * all children. This will be the running_time of the pipeline when we go

       * back to PLAYING */

      pipeline_update_start_time (element);

      break;

    }

    case GST_STATE_CHANGE_PAUSED_TO_READY:

      break;

    case GST_STATE_CHANGE_READY_TO_NULL:

    {

      GstBus *bus;

      gboolean auto_flush;

      /* grab some stuff before we release the lock to flush out the bus */

      GST_OBJECT_LOCK (element);

      if ((bus = element->bus))

        gst_object_ref (bus);

      auto_flush = pipeline->priv->auto_flush_bus;

      GST_OBJECT_UNLOCK (element);

      if (bus) {

        if (auto_flush) {

          gst_bus_set_flushing (bus, TRUE);

        } else {

          GST_INFO_OBJECT (element, "not flushing bus, auto-flushing disabled");

        }

        gst_object_unref (bus);

      }

      break;

    }

  }

  return result;

  /* ERRORS */

invalid_clock:

  {

    /* we generate this error when the selected clock was not

     * accepted by some element */

    GST_ELEMENT_ERROR (pipeline, CORE, CLOCK,

        (_("Selected clock cannot be used in pipeline.")),

        ("Pipeline cannot operate with selected clock"));

    GST_DEBUG_OBJECT (pipeline,

        "Pipeline cannot operate with selected clock %p", clock);

    if (clock)

      gst_object_unref (clock);

    return GST_STATE_CHANGE_FAILURE;

  }

}

/* intercept the bus messages from our children. We watch for the ASYNC_START

 * message with is posted by the elements (sinks) that require a reset of the

 * running_time after a flush. ASYNC_START also brings the pipeline back into

 * the PAUSED, pending PAUSED state. When the ASYNC_DONE message is received the

 * pipeline will redistribute the new base_time and will bring the elements back

 * to the desired state of the pipeline. */

static void

gst_pipeline_handle_message (GstBin * bin, GstMessage * message)

{

  GstPipeline *pipeline = GST_PIPELINE_CAST (bin);

  switch (GST_MESSAGE_TYPE (message)) {

    case GST_MESSAGE_RESET_TIME:

    {

      GstClockTime running_time;

      gst_message_parse_reset_time (message, &running_time);

      /* reset our running time if we need to distribute a new base_time to the

       * children. */

      reset_start_time (pipeline, running_time);

      break;

    }

    case GST_MESSAGE_CLOCK_LOST:

    {

      GstClock *clock;

      gst_message_parse_clock_lost (message, &clock);

      GST_OBJECT_LOCK (bin);

      if (clock == GST_ELEMENT_CAST (bin)->clock) {

        GST_DEBUG_OBJECT (bin, "Used clock '%s' got lost",

            GST_OBJECT_NAME (clock));

        pipeline->priv->update_clock = TRUE;

      }

      GST_OBJECT_UNLOCK (bin);

    }

    default:

      break;

  }

  GST_BIN_CLASS (parent_class)->handle_message (bin, message);

}

static gboolean

gst_pipeline_do_latency (GstBin * bin)

{

  GstPipeline *pipeline = GST_PIPELINE (bin);

  GstQuery *query;

  GstClockTime latency;

  GstClockTime min_latency, max_latency;

  gboolean res;

  GST_OBJECT_LOCK (pipeline);

  latency = pipeline->priv->latency;

  GST_OBJECT_UNLOCK (pipeline);

  if (latency == GST_CLOCK_TIME_NONE)

    return GST_BIN_CLASS (parent_class)->do_latency (bin);

  GST_DEBUG_OBJECT (pipeline, "querying latency");

  query = gst_query_new_latency ();

  if ((res = gst_element_query (GST_ELEMENT_CAST (pipeline), query))) {

    gboolean live;

    gst_query_parse_latency (query, &live, &min_latency, &max_latency);

    GST_DEBUG_OBJECT (pipeline,

        "got min latency %" GST_TIME_FORMAT ", max latency %"

        GST_TIME_FORMAT ", live %d", GST_TIME_ARGS (min_latency),

        GST_TIME_ARGS (max_latency), live);

    if (max_latency < min_latency) {

      /* this is an impossible situation, some parts of the pipeline might not

       * work correctly. We post a warning for now. */

      GST_ELEMENT_WARNING (pipeline, CORE, CLOCK, (NULL),

          ("Impossible to configure latency: max %" GST_TIME_FORMAT " < min %"

              GST_TIME_FORMAT ". Add queues or other buffering elements.",

              GST_TIME_ARGS (max_latency), GST_TIME_ARGS (min_latency)));

    }

    if (latency < min_latency) {

      /* This is a problematic situation as we will most likely drop lots of

       * data if we configure a too low latency */

      GST_ELEMENT_WARNING (pipeline, CORE, CLOCK, (NULL),

          ("Configured latency is lower than detected minimum latency: configured %"

              GST_TIME_FORMAT " < min %" GST_TIME_FORMAT,

              GST_TIME_ARGS (latency), GST_TIME_ARGS (min_latency)));

    }

  } else {

    /* this is not a real problem, we just don't configure any latency. */

    GST_WARNING_OBJECT (pipeline, "failed to query latency");

  }

  gst_query_unref (query);

  /* configure latency on elements */

  res =

      gst_element_send_event (GST_ELEMENT_CAST (pipeline),

      gst_event_new_latency (latency));

  if (res) {

    GST_INFO_OBJECT (pipeline, "configured latency of %" GST_TIME_FORMAT,

        GST_TIME_ARGS (latency));

  } else {

    GST_WARNING_OBJECT (pipeline,

        "did not really configure latency of %" GST_TIME_FORMAT,

        GST_TIME_ARGS (latency));

  }

  return res;

}

/**

 * gst_pipeline_get_bus:

 * @pipeline: a #GstPipeline

 *

 * Gets the #GstBus of @pipeline. The bus allows applications to receive

 * #GstMessage packets.

 *

 * Returns: (transfer full): a #GstBus, unref after usage.

 *

 * MT safe.

 */

GstBus *

gst_pipeline_get_bus (GstPipeline * pipeline)

{

  return gst_element_get_bus (GST_ELEMENT_CAST (pipeline));

}

static GstClock *

gst_pipeline_provide_clock_func (GstElement * element)

{

  GstClock *clock = NULL;

  GstPipeline *pipeline = GST_PIPELINE (element);

  /* if we have a fixed clock, use that one */

  GST_OBJECT_LOCK (pipeline);

  if (GST_OBJECT_FLAG_IS_SET (pipeline, GST_PIPELINE_FLAG_FIXED_CLOCK)) {

    clock = pipeline->fixed_clock;

    if (clock)

      gst_object_ref (clock);

    GST_OBJECT_UNLOCK (pipeline);

    GST_CAT_DEBUG (GST_CAT_CLOCK, "pipeline using fixed clock %p (%s)",

        clock, clock ? GST_STR_NULL (GST_OBJECT_NAME (clock)) : "-");

  } else {

    GST_OBJECT_UNLOCK (pipeline);

    /* let the parent bin select a clock */

    clock =

        GST_ELEMENT_CLASS (parent_class)->provide_clock (GST_ELEMENT

        (pipeline));

    /* no clock, use a system clock */

    if (!clock) {

      clock = gst_system_clock_obtain ();

      GST_CAT_DEBUG (GST_CAT_CLOCK, "pipeline obtained system clock: %p (%s)",

          clock, clock ? GST_STR_NULL (GST_OBJECT_NAME (clock)) : "-");

    } else {

      GST_CAT_DEBUG (GST_CAT_CLOCK, "pipeline obtained clock: %p (%s)",

          clock, clock ? GST_STR_NULL (GST_OBJECT_NAME (clock)) : "-");

    }

  }

  return clock;

}

/**

 * gst_pipeline_get_clock: (skip)

 * @pipeline: a #GstPipeline

 *

 * Gets the current clock used by @pipeline. Users of object

 * oriented languages should use gst_pipeline_get_pipeline_clock()

 * to avoid confusion with gst_element_get_clock() which has a different behavior.

 *

 * Unlike gst_element_get_clock(), this function will always return a

 * clock, even if the pipeline is not in the PLAYING state.

 *

 * Returns: (transfer full): a #GstClock, unref after usage.

 */

GstClock *

gst_pipeline_get_clock (GstPipeline * pipeline)

{

  return gst_pipeline_get_pipeline_clock (pipeline);

}

/**

 * gst_pipeline_get_pipeline_clock:

 * @pipeline: a #GstPipeline

 *

 * Gets the current clock used by @pipeline.

 *

 * Unlike gst_element_get_clock(), this function will always return a

 * clock, even if the pipeline is not in the PLAYING state.

 *

 * Returns: (transfer full): a #GstClock, unref after usage.

 *

 * Since: 1.6

 */

GstClock *

gst_pipeline_get_pipeline_clock (GstPipeline * pipeline)

{

  g_return_val_if_fail (GST_IS_PIPELINE (pipeline), NULL);

  return gst_pipeline_provide_clock_func (GST_ELEMENT_CAST (pipeline));

}

/**

 * gst_pipeline_use_clock:

 * @pipeline: a #GstPipeline

 * @clock: (transfer none) (allow-none): the clock to use

 *

 * Force @pipeline to use the given @clock. The pipeline will

 * always use the given clock even if new clock providers are added

 * to this pipeline.

 *

 * If @clock is %NULL all clocking will be disabled which will make

 * the pipeline run as fast as possible.

 *

 * MT safe.

 */

void

gst_pipeline_use_clock (GstPipeline * pipeline, GstClock * clock)

{

  GstClock **clock_p;

  g_return_if_fail (GST_IS_PIPELINE (pipeline));

  GST_OBJECT_LOCK (pipeline);

  GST_OBJECT_FLAG_SET (pipeline, GST_PIPELINE_FLAG_FIXED_CLOCK);

  clock_p = &pipeline->fixed_clock;

  gst_object_replace ((GstObject **) clock_p, (GstObject *) clock);

  GST_OBJECT_UNLOCK (pipeline);

  GST_CAT_DEBUG (GST_CAT_CLOCK, "pipeline using fixed clock %p (%s)", clock,

      (clock ? GST_OBJECT_NAME (clock) : "nil"));

}

/**

 * gst_pipeline_set_clock: (skip)

 * @pipeline: a #GstPipeline

 * @clock: (transfer none): the clock to set

 *

 * Set the clock for @pipeline. The clock will be distributed

 * to all the elements managed by the pipeline.

 *

 * Returns: %TRUE if the clock could be set on the pipeline. %FALSE if

 *   some element did not accept the clock.

 *

 * MT safe.

 */

gboolean

gst_pipeline_set_clock (GstPipeline * pipeline, GstClock * clock)

{

  g_return_val_if_fail (pipeline != NULL, FALSE);

  g_return_val_if_fail (GST_IS_PIPELINE (pipeline), FALSE);

  return

      GST_ELEMENT_CLASS (parent_class)->set_clock (GST_ELEMENT_CAST (pipeline),

      clock);

}

/**

 * gst_pipeline_auto_clock:

 * @pipeline: a #GstPipeline

 *

 * Let @pipeline select a clock automatically. This is the default

 * behaviour.

 *

 * Use this function if you previous forced a fixed clock with

 * gst_pipeline_use_clock() and want to restore the default

 * pipeline clock selection algorithm.

 *

 * MT safe.

 */

void

gst_pipeline_auto_clock (GstPipeline * pipeline)

{

  GstClock **clock_p;

  g_return_if_fail (pipeline != NULL);

  g_return_if_fail (GST_IS_PIPELINE (pipeline));

  GST_OBJECT_LOCK (pipeline);

  GST_OBJECT_FLAG_UNSET (pipeline, GST_PIPELINE_FLAG_FIXED_CLOCK);

  clock_p = &pipeline->fixed_clock;

  gst_object_replace ((GstObject **) clock_p, NULL);

  GST_OBJECT_UNLOCK (pipeline);

  GST_CAT_DEBUG (GST_CAT_CLOCK, "pipeline using automatic clock");

}

/**

 * gst_pipeline_set_delay:

 * @pipeline: a #GstPipeline

 * @delay: the delay

 *

 * Set the expected delay needed for all elements to perform the

 * PAUSED to PLAYING state change. @delay will be added to the

 * base time of the elements so that they wait an additional @delay

 * amount of time before starting to process buffers and cannot be

 * #GST_CLOCK_TIME_NONE.

 *

 * This option is used for tuning purposes and should normally not be