/* GStreamer
 * Copyright (C) 2008 Wim Taymans <wim.taymans at gmail.com>
 *
 * 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., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "rtsp-media-factory.h"

#define DEFAULT_LAUNCH          NULL
#define DEFAULT_SHARED          FALSE
#define DEFAULT_EOS_SHUTDOWN    FALSE
#define DEFAULT_PROTOCOLS       GST_RTSP_LOWER_TRANS_UDP | GST_RTSP_LOWER_TRANS_TCP
#define DEFAULT_BUFFER_SIZE     0x80000
#define DEFAULT_MULTICAST_GROUP "224.2.0.1"

enum
{
  PROP_0,
  PROP_LAUNCH,
  PROP_SHARED,
  PROP_EOS_SHUTDOWN,
  PROP_PROTOCOLS,
  PROP_BUFFER_SIZE,
  PROP_MULTICAST_GROUP,
  PROP_LAST
};

enum
{
  SIGNAL_MEDIA_CONSTRUCTED,
  SIGNAL_MEDIA_CONFIGURE,
  SIGNAL_LAST
};

GST_DEBUG_CATEGORY_STATIC (rtsp_media_debug);
#define GST_CAT_DEFAULT rtsp_media_debug

static guint gst_rtsp_media_factory_signals[SIGNAL_LAST] = { 0 };

static void gst_rtsp_media_factory_get_property (GObject * object, guint propid,
    GValue * value, GParamSpec * pspec);
static void gst_rtsp_media_factory_set_property (GObject * object, guint propid,
    const GValue * value, GParamSpec * pspec);
static void gst_rtsp_media_factory_finalize (GObject * obj);

static gchar *default_gen_key (GstRTSPMediaFactory * factory,
    const GstRTSPUrl * url);
static GstElement *default_get_element (GstRTSPMediaFactory * factory,
    const GstRTSPUrl * url);
static GstRTSPMedia *default_construct (GstRTSPMediaFactory * factory,
    const GstRTSPUrl * url);
static void default_configure (GstRTSPMediaFactory * factory,
    GstRTSPMedia * media);
static GstElement *default_create_pipeline (GstRTSPMediaFactory * factory,
    GstRTSPMedia * media);

G_DEFINE_TYPE (GstRTSPMediaFactory, gst_rtsp_media_factory, G_TYPE_OBJECT);

static void
gst_rtsp_media_factory_class_init (GstRTSPMediaFactoryClass * klass)
{
  GObjectClass *gobject_class;

  gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->get_property = gst_rtsp_media_factory_get_property;
  gobject_class->set_property = gst_rtsp_media_factory_set_property;
  gobject_class->finalize = gst_rtsp_media_factory_finalize;

  /**
   * GstRTSPMediaFactory::launch
   *
   * The gst_parse_launch() line to use for constructing the pipeline in the
   * default prepare vmethod.
   *
   * The pipeline description should return a GstBin as the toplevel element
   * which can be accomplished by enclosing the dscription with brackets '('
   * ')'.
   *
   * The description should return a pipeline with payloaders named pay0, pay1,
   * etc.. Each of the payloaders will result in a stream.
   *
   * Support for dynamic payloaders can be accomplished by adding payloaders
   * named dynpay0, dynpay1, etc..
   */
  g_object_class_install_property (gobject_class, PROP_LAUNCH,
      g_param_spec_string ("launch", "Launch",
          "A launch description of the pipeline", DEFAULT_LAUNCH,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class, PROP_SHARED,
      g_param_spec_boolean ("shared", "Shared",
          "If media from this factory is shared", DEFAULT_SHARED,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class, PROP_EOS_SHUTDOWN,
      g_param_spec_boolean ("eos-shutdown", "EOS Shutdown",
          "Send EOS down the pipeline before shutting down",
          DEFAULT_EOS_SHUTDOWN, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class, PROP_PROTOCOLS,
      g_param_spec_flags ("protocols", "Protocols",
          "Allowed lower transport protocols", GST_TYPE_RTSP_LOWER_TRANS,
          DEFAULT_PROTOCOLS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class, PROP_BUFFER_SIZE,
      g_param_spec_uint ("buffer-size", "Buffer Size",
          "The kernel UDP buffer size to use", 0, G_MAXUINT,
          DEFAULT_BUFFER_SIZE, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class, PROP_MULTICAST_GROUP,
      g_param_spec_string ("multicast-group", "Multicast Group",
          "The Multicast group to send media to",
          DEFAULT_MULTICAST_GROUP, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  gst_rtsp_media_factory_signals[SIGNAL_MEDIA_CONSTRUCTED] =
      g_signal_new ("media-constructed", G_TYPE_FROM_CLASS (klass),
      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstRTSPMediaFactoryClass,
          media_constructed), NULL, NULL, g_cclosure_marshal_VOID__OBJECT,
      G_TYPE_NONE, 1, GST_TYPE_RTSP_MEDIA);

  gst_rtsp_media_factory_signals[SIGNAL_MEDIA_CONFIGURE] =
      g_signal_new ("media-configure", G_TYPE_FROM_CLASS (klass),
      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstRTSPMediaFactoryClass,
          media_configure), NULL, NULL, g_cclosure_marshal_VOID__OBJECT,
      G_TYPE_NONE, 1, GST_TYPE_RTSP_MEDIA);

  klass->gen_key = default_gen_key;
  klass->get_element = default_get_element;
  klass->construct = default_construct;
  klass->configure = default_configure;
  klass->create_pipeline = default_create_pipeline;

  GST_DEBUG_CATEGORY_INIT (rtsp_media_debug, "rtspmediafactory", 0,
      "GstRTSPMediaFactory");
}

static void
gst_rtsp_media_factory_init (GstRTSPMediaFactory * factory)
{
  factory->launch = g_strdup (DEFAULT_LAUNCH);
  factory->shared = DEFAULT_SHARED;
  factory->eos_shutdown = DEFAULT_EOS_SHUTDOWN;
  factory->protocols = DEFAULT_PROTOCOLS;
  factory->buffer_size = DEFAULT_BUFFER_SIZE;
  factory->multicast_group = g_strdup (DEFAULT_MULTICAST_GROUP);

  factory->lock = g_mutex_new ();
  factory->medias_lock = g_mutex_new ();
  factory->medias = g_hash_table_new_full (g_str_hash, g_str_equal,
      g_free, g_object_unref);
}

static void
gst_rtsp_media_factory_finalize (GObject * obj)
{
  GstRTSPMediaFactory *factory = GST_RTSP_MEDIA_FACTORY (obj);

  g_hash_table_unref (factory->medias);
  g_mutex_free (factory->medias_lock);
  g_free (factory->launch);
  g_free (factory->multicast_group);
  g_mutex_free (factory->lock);
  if (factory->auth)
    g_object_unref (factory->auth);

  G_OBJECT_CLASS (gst_rtsp_media_factory_parent_class)->finalize (obj);
}

static void
gst_rtsp_media_factory_get_property (GObject * object, guint propid,
    GValue * value, GParamSpec * pspec)
{
  GstRTSPMediaFactory *factory = GST_RTSP_MEDIA_FACTORY (object);

  switch (propid) {
    case PROP_LAUNCH:
      g_value_take_string (value, gst_rtsp_media_factory_get_launch (factory));
      break;
    case PROP_SHARED:
      g_value_set_boolean (value, gst_rtsp_media_factory_is_shared (factory));
      break;
    case PROP_EOS_SHUTDOWN:
      g_value_set_boolean (value,
          gst_rtsp_media_factory_is_eos_shutdown (factory));
      break;
    case PROP_PROTOCOLS:
      g_value_set_flags (value, gst_rtsp_media_factory_get_protocols (factory));
      break;
    case PROP_BUFFER_SIZE:
      g_value_set_uint (value,
          gst_rtsp_media_factory_get_buffer_size (factory));
      break;
    case PROP_MULTICAST_GROUP:
      g_value_take_string (value,
          gst_rtsp_media_factory_get_multicast_group (factory));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, propid, pspec);
  }
}

static void
gst_rtsp_media_factory_set_property (GObject * object, guint propid,
    const GValue * value, GParamSpec * pspec)
{
  GstRTSPMediaFactory *factory = GST_RTSP_MEDIA_FACTORY (object);

  switch (propid) {
    case PROP_LAUNCH:
      gst_rtsp_media_factory_set_launch (factory, g_value_get_string (value));
      break;
    case PROP_SHARED:
      gst_rtsp_media_factory_set_shared (factory, g_value_get_boolean (value));
      break;
    case PROP_EOS_SHUTDOWN:
      gst_rtsp_media_factory_set_eos_shutdown (factory,
          g_value_get_boolean (value));
      break;
    case PROP_PROTOCOLS:
      gst_rtsp_media_factory_set_protocols (factory, g_value_get_flags (value));
      break;
    case PROP_BUFFER_SIZE:
      gst_rtsp_media_factory_set_buffer_size (factory,
          g_value_get_uint (value));
      break;
    case PROP_MULTICAST_GROUP:
      gst_rtsp_media_factory_set_multicast_group (factory,
          g_value_get_string (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, propid, pspec);
  }
}

/**
 * gst_rtsp_media_factory_new:
 *
 * Create a new #GstRTSPMediaFactory instance.
 *
 * Returns: a new #GstRTSPMediaFactory object.
 */
GstRTSPMediaFactory *
gst_rtsp_media_factory_new (void)
{
  GstRTSPMediaFactory *result;

  result = g_object_new (GST_TYPE_RTSP_MEDIA_FACTORY, NULL);

  return result;
}

/**
 * gst_rtsp_media_factory_set_launch:
 * @factory: a #GstRTSPMediaFactory
 * @launch: the launch description
 *
 *
 * The gst_parse_launch() line to use for constructing the pipeline in the
 * default prepare vmethod.
 *
 * The pipeline description should return a GstBin as the toplevel element
 * which can be accomplished by enclosing the dscription with brackets '('
 * ')'.
 *
 * The description should return a pipeline with payloaders named pay0, pay1,
 * etc.. Each of the payloaders will result in a stream.
 */
void
gst_rtsp_media_factory_set_launch (GstRTSPMediaFactory * factory,
    const gchar * launch)
{
  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));
  g_return_if_fail (launch != NULL);

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  g_free (factory->launch);
  factory->launch = g_strdup (launch);
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);
}

/**
 * gst_rtsp_media_factory_get_launch:
 * @factory: a #GstRTSPMediaFactory
 *
 * Get the gst_parse_launch() pipeline description that will be used in the
 * default prepare vmethod.
 *
 * Returns: the configured launch description. g_free() after usage.
 */
gchar *
gst_rtsp_media_factory_get_launch (GstRTSPMediaFactory * factory)
{
  gchar *result;

  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory), NULL);

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  result = g_strdup (factory->launch);
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);

  return result;
}

/**
 * gst_rtsp_media_factory_set_shared:
 * @factory: a #GstRTSPMediaFactory
 * @shared: the new value
 *
 * Configure if media created from this factory can be shared between clients.
 */
void
gst_rtsp_media_factory_set_shared (GstRTSPMediaFactory * factory,
    gboolean shared)
{
  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  factory->shared = shared;
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);
}

/**
 * gst_rtsp_media_factory_is_shared:
 * @factory: a #GstRTSPMediaFactory
 *
 * Get if media created from this factory can be shared between clients.
 *
 * Returns: %TRUE if the media will be shared between clients.
 */
gboolean
gst_rtsp_media_factory_is_shared (GstRTSPMediaFactory * factory)
{
  gboolean result;

  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory), FALSE);

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  result = factory->shared;
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);

  return result;
}

/**
 * gst_rtsp_media_factory_set_eos_shutdown:
 * @factory: a #GstRTSPMediaFactory
 * @eos_shutdown: the new value
 *
 * Configure if media created from this factory will have an EOS sent to the
 * pipeline before shutdown.
 */
void
gst_rtsp_media_factory_set_eos_shutdown (GstRTSPMediaFactory * factory,
    gboolean eos_shutdown)
{
  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  factory->eos_shutdown = eos_shutdown;
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);
}

/**
 * gst_rtsp_media_factory_is_eos_shutdown:
 * @factory: a #GstRTSPMediaFactory
 *
 * Get if media created from this factory will have an EOS event sent to the
 * pipeline before shutdown.
 *
 * Returns: %TRUE if the media will receive EOS before shutdown.
 */
gboolean
gst_rtsp_media_factory_is_eos_shutdown (GstRTSPMediaFactory * factory)
{
  gboolean result;

  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory), FALSE);

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  result = factory->eos_shutdown;
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);

  return result;
}

/**
 * gst_rtsp_media_factory_set_buffer_size:
 * @factory: a #GstRTSPMedia
 * @size: the new value
 *
 * Set the kernel UDP buffer size.
 */
void
gst_rtsp_media_factory_set_buffer_size (GstRTSPMediaFactory * factory,
    guint size)
{
  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  factory->buffer_size = size;
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);
}

/**
 * gst_rtsp_media_factory_get_buffer_size:
 * @factory: a #GstRTSPMedia
 *
 * Get the kernel UDP buffer size.
 *
 * Returns: the kernel UDP buffer size.
 */
guint
gst_rtsp_media_factory_get_buffer_size (GstRTSPMediaFactory * factory)
{
  guint result;

  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory), 0);

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  result = factory->buffer_size;
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);

  return result;
}

/**
 * gst_rtsp_media_factory_set_multicast_group:
 * @factory: a #GstRTSPMedia
 * @mc: the new multicast group
 *
 * Set the multicast group that media from @factory will be streamed to.
 */
void
gst_rtsp_media_factory_set_multicast_group (GstRTSPMediaFactory * factory,
    const gchar * mc)
{
  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  g_free (factory->multicast_group);
  factory->multicast_group = g_strdup (mc);
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);
}

/**
 * gst_rtsp_media_factory_get_multicast_group:
 * @factory: a #GstRTSPMedia
 *
 * Get the multicast group that media from @factory will be streamed to.
 *
 * Returns: the multicast group
 */
gchar *
gst_rtsp_media_factory_get_multicast_group (GstRTSPMediaFactory * factory)
{
  gchar *result;

  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory), NULL);

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  result = g_strdup (factory->multicast_group);
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);

  return result;
}

/**
 * gst_rtsp_media_factory_set_auth:
 * @factory: a #GstRTSPMediaFactory
 * @auth: a #GstRTSPAuth
 *
 * configure @auth to be used as the authentication manager of @factory.
 */
void
gst_rtsp_media_factory_set_auth (GstRTSPMediaFactory * factory,
    GstRTSPAuth * auth)
{
  GstRTSPAuth *old;

  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));

  old = factory->auth;

  if (old != auth) {
    if (auth)
      g_object_ref (auth);
    factory->auth = auth;
    if (old)
      g_object_unref (old);
  }
}

/**
 * gst_rtsp_media_factory_get_auth:
 * @factory: a #GstRTSPMediaFactory
 *
 * Get the #GstRTSPAuth used as the authentication manager of @factory.
 *
 * Returns: the #GstRTSPAuth of @factory. g_object_unref() after
 * usage.
 */
GstRTSPAuth *
gst_rtsp_media_factory_get_auth (GstRTSPMediaFactory * factory)
{
  GstRTSPAuth *result;

  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory), NULL);

  if ((result = factory->auth))
    g_object_ref (result);

  return result;
}

/**
 * gst_rtsp_media_factory_set_protocols:
 * @factory: a #GstRTSPMediaFactory
 * @protocols: the new flags
 *
 * Configure the allowed lower transport for @factory.
 */
void
gst_rtsp_media_factory_set_protocols (GstRTSPMediaFactory * factory,
    GstRTSPLowerTrans protocols)
{
  g_return_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory));

  factory->protocols = protocols;
}

/**
 * gst_rtsp_media_factory_get_protocols:
 * @factory: a #GstRTSPMediaFactory
 *
 * Get the allowed protocols of @factory.
 *
 * Returns: a #GstRTSPLowerTrans
 */
GstRTSPLowerTrans
gst_rtsp_media_factory_get_protocols (GstRTSPMediaFactory * factory)
{
  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory),
      GST_RTSP_LOWER_TRANS_UNKNOWN);

  return factory->protocols;
}

static gboolean
compare_media (gpointer key, GstRTSPMedia * media1, GstRTSPMedia * media2)
{
  return (media1 == media2);
}

static void
media_unprepared (GstRTSPMedia * media, GstRTSPMediaFactory * factory)
{
  g_mutex_lock (factory->medias_lock);
  g_hash_table_foreach_remove (factory->medias, (GHRFunc) compare_media, media);
  g_mutex_unlock (factory->medias_lock);
}

/**
 * gst_rtsp_media_factory_construct:
 * @factory: a #GstRTSPMediaFactory
 * @url: the url used
 *
 * Prepare the media object and create its streams. Implementations
 * should create the needed gstreamer elements and add them to the result
 * object. No state changes should be performed on them yet.
 *
 * One or more GstRTSPMediaStream objects should be added to the result with
 * the srcpad member set to a source pad that produces buffer of type 
 * application/x-rtp.
 *
 * Returns: a new #GstRTSPMedia if the media could be prepared.
 */
GstRTSPMedia *
gst_rtsp_media_factory_construct (GstRTSPMediaFactory * factory,
    const GstRTSPUrl * url)
{
  gchar *key;
  GstRTSPMedia *media;
  GstRTSPMediaFactoryClass *klass;

  klass = GST_RTSP_MEDIA_FACTORY_GET_CLASS (factory);

  /* convert the url to a key for the hashtable. NULL return or a NULL function
   * will not cache anything for this factory. */
  if (klass->gen_key)
    key = klass->gen_key (factory, url);
  else
    key = NULL;

  g_mutex_lock (factory->medias_lock);
  if (key) {
    /* we have a key, see if we find a cached media */
    media = g_hash_table_lookup (factory->medias, key);
    if (media)
      g_object_ref (media);
  } else
    media = NULL;

  if (media == NULL) {
    /* nothing cached found, try to create one */
    if (klass->construct) {
      media = klass->construct (factory, url);
      if (media)
        g_signal_emit (factory,
            gst_rtsp_media_factory_signals[SIGNAL_MEDIA_CONSTRUCTED], 0, media,
            NULL);
    } else
      media = NULL;

    if (media) {
      /* configure the media */
      if (klass->configure)
        klass->configure (factory, media);

      g_signal_emit (factory,
          gst_rtsp_media_factory_signals[SIGNAL_MEDIA_CONFIGURE], 0, media,
          NULL);

      /* check if we can cache this media */
      if (gst_rtsp_media_is_shared (media)) {
        /* insert in the hashtable, takes ownership of the key */
        g_object_ref (media);
        g_hash_table_insert (factory->medias, key, media);
        key = NULL;
      }
      if (!gst_rtsp_media_is_reusable (media)) {
        /* when not reusable, connect to the unprepare signal to remove the item
         * from our cache when it gets unprepared */
        g_signal_connect (media, "unprepared", (GCallback) media_unprepared,
            factory);
      }
    }
  }
  g_mutex_unlock (factory->medias_lock);

  if (key)
    g_free (key);

  GST_INFO ("constructed media %p for url %s", media, url->abspath);

  return media;
}

static gchar *
default_gen_key (GstRTSPMediaFactory * factory, const GstRTSPUrl * url)
{
  gchar *result;
  const gchar *pre_query;
  const gchar *query;

  pre_query = url->query ? "?" : "";
  query = url->query ? url->query : "";

  result =
      g_strdup_printf ("%u%s%s%s", url->port, url->abspath, pre_query, query);

  return result;
}

static GstElement *
default_get_element (GstRTSPMediaFactory * factory, const GstRTSPUrl * url)
{
  GstElement *element;
  GError *error = NULL;

  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  /* we need a parse syntax */
  if (factory->launch == NULL)
    goto no_launch;

  /* parse the user provided launch line */
  element = gst_parse_launch (factory->launch, &error);
  if (element == NULL)
    goto parse_error;

  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);

  if (error != NULL) {
    /* a recoverable error was encountered */
    GST_WARNING ("recoverable parsing error: %s", error->message);
    g_error_free (error);
  }
  return element;

  /* ERRORS */
no_launch:
  {
    GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);
    g_critical ("no launch line specified");
    return NULL;
  }
parse_error:
  {
    GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);
    g_critical ("could not parse launch syntax (%s): %s", factory->launch,
        (error ? error->message : "unknown reason"));
    if (error)
      g_error_free (error);
    return NULL;
  }
}

/* try to find all the payloader elements, they should be named 'pay%d'. for
 * each of the payloaders we will create a stream and collect the source pad. */
void
gst_rtsp_media_factory_collect_streams (GstRTSPMediaFactory * factory,
    const GstRTSPUrl * url, GstRTSPMedia * media)
{
  GstElement *element, *elem;
  GstPad *pad;
  gint i;
  GstRTSPMediaStream *stream;
  gboolean have_elem;

  element = media->element;

  have_elem = TRUE;
  for (i = 0; have_elem; i++) {
    gchar *name;

    have_elem = FALSE;

    name = g_strdup_printf ("pay%d", i);
    if ((elem = gst_bin_get_by_name (GST_BIN (element), name))) {
      /* create the stream */
      stream = g_new0 (GstRTSPMediaStream, 1);
      stream->payloader = elem;

      GST_INFO ("found stream %d with payloader %p", i, elem);

      pad = gst_element_get_static_pad (elem, "src");

      /* ghost the pad of the payloader to the element */
      stream->srcpad = gst_ghost_pad_new (name, pad);
      gst_pad_set_active (stream->srcpad, TRUE);
      gst_element_add_pad (media->element, stream->srcpad);
      gst_object_unref (elem);

      /* add stream now */
      g_array_append_val (media->streams, stream);
      have_elem = TRUE;
    }
    g_free (name);

    name = g_strdup_printf ("dynpay%d", i);
    if ((elem = gst_bin_get_by_name (GST_BIN (element), name))) {
      /* a stream that will dynamically create pads to provide RTP packets */

      GST_INFO ("found dynamic element %d, %p", i, elem);

      media->dynamic = g_list_prepend (media->dynamic, elem);

      have_elem = TRUE;
    }
    g_free (name);
  }
}

static GstRTSPMedia *
default_construct (GstRTSPMediaFactory * factory, const GstRTSPUrl * url)
{
  GstRTSPMedia *media;
  GstElement *element;
  GstRTSPMediaFactoryClass *klass;

  klass = GST_RTSP_MEDIA_FACTORY_GET_CLASS (factory);

  if (!klass->create_pipeline)
    goto no_create;

  if (klass->get_element)
    element = klass->get_element (factory, url);
  else
    element = NULL;
  if (element == NULL)
    goto no_element;

  /* create a new empty media */
  media = gst_rtsp_media_new ();
  media->element = element;

  media->pipeline = klass->create_pipeline (factory, media);
  if (media->pipeline == NULL)
    goto no_pipeline;

  gst_rtsp_media_factory_collect_streams (factory, url, media);

  return media;

  /* ERRORS */
no_create:
  {
    g_critical ("no create_pipeline function");
    return NULL;
  }
no_element:
  {
    g_critical ("could not create element");
    return NULL;
  }
no_pipeline:
  {
    g_critical ("can't create pipeline");
    g_object_unref (media);
    return NULL;
  }
}

static GstElement *
default_create_pipeline (GstRTSPMediaFactory * factory, GstRTSPMedia * media)
{
  GstElement *pipeline;

  if (media->element == NULL)
    goto no_element;

  pipeline = gst_pipeline_new ("media-pipeline");
  gst_bin_add (GST_BIN_CAST (pipeline), media->element);

  return pipeline;

  /* ERRORS */
no_element:
  {
    g_critical ("no element");
    return NULL;
  }
}

static void
default_configure (GstRTSPMediaFactory * factory, GstRTSPMedia * media)
{
  gboolean shared, eos_shutdown;
  guint size;
  GstRTSPAuth *auth;
  GstRTSPLowerTrans protocols;
  gchar *mc;

  /* configure the sharedness */
  GST_RTSP_MEDIA_FACTORY_LOCK (factory);
  shared = factory->shared;
  eos_shutdown = factory->eos_shutdown;
  size = factory->buffer_size;
  protocols = factory->protocols;
  GST_RTSP_MEDIA_FACTORY_UNLOCK (factory);

  gst_rtsp_media_set_shared (media, shared);
  gst_rtsp_media_set_eos_shutdown (media, eos_shutdown);
  gst_rtsp_media_set_buffer_size (media, size);
  gst_rtsp_media_set_protocols (media, protocols);

  if ((auth = gst_rtsp_media_factory_get_auth (factory))) {
    gst_rtsp_media_set_auth (media, auth);
    g_object_unref (auth);
  }
  if ((mc = gst_rtsp_media_factory_get_multicast_group (factory))) {
    gst_rtsp_media_set_multicast_group (media, mc);
    g_free (mc);
  }
}