replay_server.c

/* GStreamer
 * Copyright (C) 2019 Mathieu Duponchelle <mathieu@centricular.com>
 * Copyright (C) 2020 Seungha Yang <seungha@centricular.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., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */


#include <gst/gst.h>

#include <gst/rtsp-server/rtsp-server.h>

G_BEGIN_DECLS

#define GST_TYPE_REPLAY_BIN (gst_replay_bin_get_type ())
G_DECLARE_FINAL_TYPE (GstReplayBin, gst_replay_bin, GST, REPLAY_BIN, GstBin);

#define GST_TYPE_RTSP_MEDIA_FACTORY_REPLAY (gst_rtsp_media_factory_replay_get_type ())
G_DECLARE_FINAL_TYPE (GstRTSPMediaFactoryReplay,
    gst_rtsp_media_factory_replay, GST, RTSP_MEDIA_FACTORY_REPLAY,
    GstRTSPMediaFactory);

G_END_DECLS

GST_DEBUG_CATEGORY_STATIC (replay_server_debug);
#define GST_CAT_DEFAULT (replay_server_debug)

static GstStaticCaps raw_video_caps = GST_STATIC_CAPS ("video/x-raw");
static GstStaticCaps raw_audio_caps = GST_STATIC_CAPS ("audio/x-raw");

static GList
    * gst_rtsp_media_factory_replay_get_demuxers (GstRTSPMediaFactoryReplay *
    factory);
static GList
    * gst_rtsp_media_factory_replay_get_payloaders (GstRTSPMediaFactoryReplay *
    factory);
static GList
    * gst_rtsp_media_factory_replay_get_decoders (GstRTSPMediaFactoryReplay *
    factory);

typedef struct
{
  GstPad *srcpad;
  gulong block_id;
} GstReplayBinPad;

static void
gst_replay_bin_pad_unblock_and_free (GstReplayBinPad * pad)
{
  if (pad->srcpad && pad->block_id) {
    GST_DEBUG_OBJECT (pad->srcpad, "Unblock");
    gst_pad_remove_probe (pad->srcpad, pad->block_id);
    pad->block_id = 0;
  }

  gst_clear_object (&pad->srcpad);
  g_free (pad);
}

/* NOTE: this bin implementation is almost completely taken from rtsp-media-factory-uri
 * but this example doesn't use the GstRTSPMediaFactoryURI object so that
 * we can handle events and messages ourselves.
 * Specifically,
 * - Handle segment-done message for looping given source
 * - Drop all incoming seek event because client seek is not implemented
 *   and do initial segment seeking on no-more-pads signal
 */
struct _GstReplayBin
{
  GstBin parent;

  gint64 num_loops;

  GstCaps *raw_vcaps;
  GstCaps *raw_acaps;

  guint pt;

  /* without ref */
  GstElement *uridecodebin;
  GstElement *inner_bin;

  /* holds ref */
  GstRTSPMediaFactoryReplay *factory;

  GMutex lock;

  GList *srcpads;
};

static void gst_replay_bin_dispose (GObject * object);
static void gst_replay_bin_finalize (GObject * object);
static void gst_replay_bin_handle_message (GstBin * bin, GstMessage * message);

static gboolean autoplug_continue_cb (GstElement * dbin, GstPad * pad,
    GstCaps * caps, GstReplayBin * self);
static void pad_added_cb (GstElement * dbin, GstPad * pad, GstReplayBin * self);
static void no_more_pads_cb (GstElement * uribin, GstReplayBin * self);

#define gst_replay_bin_parent_class bin_parent_class
G_DEFINE_TYPE (GstReplayBin, gst_replay_bin, GST_TYPE_BIN);

static void
gst_replay_bin_class_init (GstReplayBinClass * klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  GstBinClass *bin_class = GST_BIN_CLASS (klass);

  gobject_class->dispose = gst_replay_bin_dispose;
  gobject_class->finalize = gst_replay_bin_finalize;

  bin_class->handle_message = GST_DEBUG_FUNCPTR (gst_replay_bin_handle_message);
}

static void
gst_replay_bin_init (GstReplayBin * self)
{
  self->raw_vcaps = gst_static_caps_get (&raw_video_caps);
  self->raw_acaps = gst_static_caps_get (&raw_audio_caps);

  self->uridecodebin = gst_element_factory_make ("uridecodebin", NULL);
  if (!self->uridecodebin) {
    GST_ERROR_OBJECT (self, "uridecodebin is unavailable");
    return;
  }

  /* our bin will dynamically expose payloaded pads */
  self->inner_bin = gst_bin_new ("dynpay0");
  gst_bin_add (GST_BIN_CAST (self), self->inner_bin);
  gst_bin_add (GST_BIN_CAST (self->inner_bin), self->uridecodebin);

  g_signal_connect (self->uridecodebin, "autoplug-continue",
      G_CALLBACK (autoplug_continue_cb), self);
  g_signal_connect (self->uridecodebin, "pad-added",
      G_CALLBACK (pad_added_cb), self);
  g_signal_connect (self->uridecodebin, "no-more-pads",
      G_CALLBACK (no_more_pads_cb), self);

  self->pt = 96;

  g_mutex_init (&self->lock);
}

static void
gst_replay_bin_dispose (GObject * object)
{
  GstReplayBin *self = GST_REPLAY_BIN (object);

  GST_DEBUG_OBJECT (self, "dispose");

  gst_clear_caps (&self->raw_vcaps);
  gst_clear_caps (&self->raw_acaps);
  gst_clear_object (&self->factory);

  if (self->srcpads) {
    g_list_free_full (self->srcpads,
        (GDestroyNotify) gst_replay_bin_pad_unblock_and_free);
    self->srcpads = NULL;
  }

  G_OBJECT_CLASS (bin_parent_class)->dispose (object);
}

static void
gst_replay_bin_finalize (GObject * object)
{
  GstReplayBin *self = GST_REPLAY_BIN (object);

  g_mutex_clear (&self->lock);

  G_OBJECT_CLASS (bin_parent_class)->finalize (object);
}

static gboolean
send_eos_foreach_srcpad (GstElement * element, GstPad * pad, gpointer user_data)
{
  GST_DEBUG_OBJECT (pad, "Sending EOS to downstream");
  gst_pad_push_event (pad, gst_event_new_eos ());

  return TRUE;
}

static void
gst_replay_bin_do_segment_seek (GstElement * element, GstReplayBin * self)
{
  gboolean ret;

  ret = gst_element_seek (element, 1.0, GST_FORMAT_TIME,
      GST_SEEK_FLAG_ACCURATE | GST_SEEK_FLAG_SEGMENT,
      GST_SEEK_TYPE_SET, 0, GST_SEEK_TYPE_NONE, -1);

  if (!ret) {
    GST_WARNING_OBJECT (self, "segment seeking failed");
    gst_element_foreach_src_pad (element,
        (GstElementForeachPadFunc) send_eos_foreach_srcpad, NULL);
  }
}

static void
gst_replay_bin_handle_message (GstBin * bin, GstMessage * message)
{
  GstReplayBin *self = GST_REPLAY_BIN (bin);

  if (GST_MESSAGE_TYPE (message) == GST_MESSAGE_SEGMENT_DONE) {
    gboolean next_loop = TRUE;

    GST_DEBUG_OBJECT (self, "Have segment done message");

    g_mutex_lock (&self->lock);
    if (self->num_loops != -1) {
      self->num_loops--;

      if (self->num_loops < 1)
        next_loop = FALSE;
    }

    if (next_loop) {
      /* Send seek event from non-streaming thread */
      gst_element_call_async (GST_ELEMENT_CAST (self->uridecodebin),
          (GstElementCallAsyncFunc) gst_replay_bin_do_segment_seek, self, NULL);
    } else {
      gst_element_foreach_src_pad (GST_ELEMENT_CAST (self->uridecodebin),
          (GstElementForeachPadFunc) send_eos_foreach_srcpad, NULL);
    }

    g_mutex_unlock (&self->lock);
  }

  GST_BIN_CLASS (bin_parent_class)->handle_message (bin, message);
}

static GstElementFactory *
find_payloader (GstReplayBin * self, GstCaps * caps)
{
  GList *list;
  GstElementFactory *factory = NULL;
  gboolean autoplug_more = FALSE;
  GList *demuxers = NULL;
  GList *payloaders = NULL;

  demuxers = gst_rtsp_media_factory_replay_get_demuxers (self->factory);

  /* first find a demuxer that can link */
  list = gst_element_factory_list_filter (demuxers, caps, GST_PAD_SINK, FALSE);

  if (list) {
    GstStructure *structure = gst_caps_get_structure (caps, 0);
    gboolean parsed = FALSE;
    gint mpegversion = 0;

    if (!gst_structure_get_boolean (structure, "parsed", &parsed) &&
        gst_structure_has_name (structure, "audio/mpeg") &&
        gst_structure_get_int (structure, "mpegversion", &mpegversion) &&
        (mpegversion == 2 || mpegversion == 4)) {
      /* for AAC it's framed=true instead of parsed=true */
      gst_structure_get_boolean (structure, "framed", &parsed);
    }

    /* Avoid plugging parsers in a loop. This is not 100% correct, as some
     * parsers don't set parsed=true in caps. We should do something like
     * decodebin does and track decode chains and elements plugged in those
     * chains...
     */
    if (parsed) {
      GList *walk;
      const gchar *klass;

      for (walk = list; walk; walk = walk->next) {
        factory = GST_ELEMENT_FACTORY (walk->data);
        klass = gst_element_factory_get_metadata (factory,
            GST_ELEMENT_METADATA_KLASS);
        if (strstr (klass, "Parser"))
          /* caps have parsed=true, so skip this parser to avoid loops */
          continue;

        autoplug_more = TRUE;
        break;
      }
    } else {
      /* caps don't have parsed=true set and we have a demuxer/parser */
      autoplug_more = TRUE;
    }

    gst_plugin_feature_list_free (list);
  }

  if (autoplug_more)
    /* we have a demuxer, try that one first */
    return NULL;

  payloaders = gst_rtsp_media_factory_replay_get_payloaders (self->factory);

  /* no demuxer try a depayloader */
  list = gst_element_factory_list_filter (payloaders,
      caps, GST_PAD_SINK, FALSE);

  if (list == NULL) {
    GList *decoders =
        gst_rtsp_media_factory_replay_get_decoders (self->factory);
    /* no depayloader, try a decoder, we'll get to a payloader for a decoded
     * video or audio format, worst case. */
    list = gst_element_factory_list_filter (decoders,
        caps, GST_PAD_SINK, FALSE);

    if (list != NULL) {
      /* we have a decoder, try that one first */
      gst_plugin_feature_list_free (list);
      return NULL;
    }
  }

  if (list != NULL) {
    factory = GST_ELEMENT_FACTORY_CAST (list->data);
    g_object_ref (factory);
    gst_plugin_feature_list_free (list);
  }

  return factory;
}

static gboolean
autoplug_continue_cb (GstElement * dbin, GstPad * pad, GstCaps * caps,
    GstReplayBin * self)
{
  GstElementFactory *factory;

  GST_DEBUG_OBJECT (self, "found pad %s:%s of caps %" GST_PTR_FORMAT,
      GST_DEBUG_PAD_NAME (pad), caps);

  if (!(factory = find_payloader (self, caps)))
    goto no_factory;

  /* we found a payloader, stop autoplugging so we can plug the
   * payloader. */
  GST_DEBUG_OBJECT (self, "found factory %s",
      gst_plugin_feature_get_name (GST_PLUGIN_FEATURE (factory)));
  gst_object_unref (factory);

  return FALSE;

no_factory:
  {
    /* no payloader, continue autoplugging */
    GST_DEBUG_OBJECT (self, "no payloader found for caps %" GST_PTR_FORMAT,
        caps);
    return TRUE;
  }
}

static GstPadProbeReturn
replay_bin_sink_probe (GstPad * pad, GstPadProbeInfo * info,
    GstReplayBin * self)
{
  GstPadProbeReturn ret = GST_PAD_PROBE_OK;

  if (GST_IS_EVENT (GST_PAD_PROBE_INFO_DATA (info))) {
    GstEvent *event = GST_PAD_PROBE_INFO_EVENT (info);

    switch (GST_EVENT_TYPE (event)) {
      case GST_EVENT_SEEK:
        /* Ideally this shouldn't happen because we are responding
         * seeking query with non-seekable */
        GST_DEBUG_OBJECT (pad, "Drop seek event");
        ret = GST_PAD_PROBE_DROP;
        break;
      default:
        break;
    }
  } else if (GST_IS_QUERY (GST_PAD_PROBE_INFO_DATA (info))) {
    GstQuery *query = GST_PAD_PROBE_INFO_QUERY (info);

    switch (GST_QUERY_TYPE (query)) {
      case GST_QUERY_SEEKING:
      {
        /* FIXME: client seek is not implemented */
        gst_query_set_seeking (query, GST_FORMAT_TIME, FALSE, 0,
            GST_CLOCK_TIME_NONE);
        ret = GST_PAD_PROBE_HANDLED;
        break;
      }
      case GST_QUERY_SEGMENT:
        /* client seeking is not considered in here */
        gst_query_set_segment (query,
            1.0, GST_FORMAT_TIME, 0, GST_CLOCK_TIME_NONE);
        ret = GST_PAD_PROBE_HANDLED;
        break;
      default:
        break;
    }
  }

  return ret;
}

static GstPadProbeReturn
replay_bin_src_block (GstPad * pad, GstPadProbeInfo * info, GstReplayBin * self)
{
  GST_DEBUG_OBJECT (pad, "Block pad");

  return GST_PAD_PROBE_OK;
}

static void
pad_added_cb (GstElement * dbin, GstPad * pad, GstReplayBin * self)
{
  GstElementFactory *factory;
  GstElement *payloader;
  GstCaps *caps;
  GstPad *sinkpad, *srcpad, *ghostpad;
  GstPad *dpad = pad;
  GstElement *convert;
  gchar *padname, *payloader_name;
  GstElement *inner_bin = self->inner_bin;
  GstReplayBinPad *bin_pad;

  GST_DEBUG_OBJECT (self, "added pad %s:%s", GST_DEBUG_PAD_NAME (pad));

  /* ref to make refcounting easier later */
  gst_object_ref (pad);
  padname = gst_pad_get_name (pad);

  /* get pad caps first, then call get_caps, then fail */
  if ((caps = gst_pad_get_current_caps (pad)) == NULL)
    if ((caps = gst_pad_query_caps (pad, NULL)) == NULL)
      goto no_caps;

  /* check for raw caps */
  if (gst_caps_can_intersect (caps, self->raw_vcaps)) {
    /* we have raw video caps, insert converter */
    convert = gst_element_factory_make ("videoconvert", NULL);
  } else if (gst_caps_can_intersect (caps, self->raw_acaps)) {
    /* we have raw audio caps, insert converter */
    convert = gst_element_factory_make ("audioconvert", NULL);
  } else {
    convert = NULL;
  }

  if (convert) {
    gst_bin_add (GST_BIN_CAST (inner_bin), convert);
    gst_element_sync_state_with_parent (convert);

    sinkpad = gst_element_get_static_pad (convert, "sink");
    gst_pad_link (pad, sinkpad);
    gst_object_unref (sinkpad);

    /* unref old pad, we reffed before */
    gst_object_unref (pad);

    /* continue with new pad and caps */
    pad = gst_element_get_static_pad (convert, "src");
    if ((caps = gst_pad_get_current_caps (pad)) == NULL)
      if ((caps = gst_pad_query_caps (pad, NULL)) == NULL)
        goto no_caps;
  }

  if (!(factory = find_payloader (self, caps)))
    goto no_factory;

  gst_caps_unref (caps);

  /* we have a payloader now */
  GST_DEBUG_OBJECT (self, "found payloader factory %s",
      gst_plugin_feature_get_name (GST_PLUGIN_FEATURE (factory)));

  payloader_name = g_strdup_printf ("pay_%s", padname);
  payloader = gst_element_factory_create (factory, payloader_name);
  g_free (payloader_name);
  if (payloader == NULL)
    goto no_payloader;

  g_object_set (payloader, "pt", self->pt, NULL);
  self->pt++;

  if (g_object_class_find_property (G_OBJECT_GET_CLASS (payloader),
          "buffer-list"))
    g_object_set (payloader, "buffer-list", TRUE, NULL);

  /* add the payloader to the pipeline */
  gst_bin_add (GST_BIN_CAST (inner_bin), payloader);
  gst_element_sync_state_with_parent (payloader);

  /* link the pad to the sinkpad of the payloader */
  sinkpad = gst_element_get_static_pad (payloader, "sink");
  gst_pad_link (pad, sinkpad);
  gst_object_unref (pad);

  /* Add pad probe to handle events */
  gst_pad_add_probe (sinkpad,
      GST_PAD_PROBE_TYPE_EVENT_UPSTREAM | GST_PAD_PROBE_TYPE_QUERY_UPSTREAM,
      (GstPadProbeCallback) replay_bin_sink_probe, self, NULL);
  gst_object_unref (sinkpad);

  /* block data for initial segment seeking */
  bin_pad = g_new0 (GstReplayBinPad, 1);

  /* Move ownership of pad to this struct */
  bin_pad->srcpad = gst_object_ref (dpad);
  bin_pad->block_id =
      gst_pad_add_probe (dpad, GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM,
      (GstPadProbeCallback) replay_bin_src_block, self, NULL);
  g_mutex_lock (&self->lock);
  self->srcpads = g_list_append (self->srcpads, bin_pad);
  g_mutex_unlock (&self->lock);

  /* now expose the srcpad of the payloader as a ghostpad with the same name
   * as the uridecodebin pad name. */
  srcpad = gst_element_get_static_pad (payloader, "src");
  ghostpad = gst_ghost_pad_new (padname, srcpad);
  gst_object_unref (srcpad);
  g_free (padname);

  gst_pad_set_active (ghostpad, TRUE);
  gst_element_add_pad (inner_bin, ghostpad);

  return;

  /* ERRORS */
no_caps:
  {
    GST_WARNING ("could not get caps from pad");
    g_free (padname);
    gst_object_unref (pad);
    return;
  }
no_factory:
  {
    GST_DEBUG ("no payloader found");
    g_free (padname);
    gst_caps_unref (caps);
    gst_object_unref (pad);
    return;
  }
no_payloader:
  {
    GST_ERROR ("could not create payloader from factory");
    g_free (padname);
    gst_caps_unref (caps);
    gst_object_unref (pad);
    return;
  }
}

static void
gst_replay_bin_do_initial_segment_seek (GstElement * element,
    GstReplayBin * self)
{
  gboolean ret;
  GstQuery *query;
  gboolean seekable;

  query = gst_query_new_seeking (GST_FORMAT_TIME);
  ret = gst_element_query (element, query);

  if (!ret) {
    GST_WARNING_OBJECT (self, "Cannot query seeking");
    gst_query_unref (query);
    goto done;
  }

  gst_query_parse_seeking (query, NULL, &seekable, NULL, NULL);
  gst_query_unref (query);

  if (!seekable) {
    GST_WARNING_OBJECT (self, "Source is not seekable");
    ret = FALSE;
    goto done;
  }

  ret = gst_element_seek (element, 1.0, GST_FORMAT_TIME,
      GST_SEEK_FLAG_ACCURATE | GST_SEEK_FLAG_SEGMENT | GST_SEEK_FLAG_FLUSH,
      GST_SEEK_TYPE_SET, 0, GST_SEEK_TYPE_NONE, -1);

  if (!ret)
    GST_WARNING_OBJECT (self, "segment seeking failed");

done:
  /* Unblock all pads then */
  g_mutex_lock (&self->lock);
  if (self->srcpads) {
    g_list_free_full (self->srcpads,
        (GDestroyNotify) gst_replay_bin_pad_unblock_and_free);
    self->srcpads = NULL;
  }
  g_mutex_unlock (&self->lock);

  if (!ret) {
    GST_WARNING_OBJECT (self, "Sending eos to all pads");
    gst_element_foreach_src_pad (element,
        (GstElementForeachPadFunc) send_eos_foreach_srcpad, NULL);
  }
}

static void
no_more_pads_cb (GstElement * uribin, GstReplayBin * self)
{
  GST_DEBUG_OBJECT (self, "no-more-pads");
  gst_element_no_more_pads (GST_ELEMENT_CAST (self->inner_bin));

  /* Flush seeking from streaming thread might not be good idea.
   * Do this from another (non-streaming) thread */
  gst_element_call_async (GST_ELEMENT_CAST (self->uridecodebin),
      (GstElementCallAsyncFunc) gst_replay_bin_do_initial_segment_seek,
      self, NULL);
}

static GstElement *
gst_replay_bin_new (const gchar * uri, gint64 num_loops,
    GstRTSPMediaFactoryReplay * factory, const gchar * name)
{
  GstReplayBin *self;

  g_return_val_if_fail (uri != NULL, NULL);
  g_return_val_if_fail (GST_IS_RTSP_MEDIA_FACTORY (factory), NULL);

  if (!name)
    name = "GstRelayBin";

  self = GST_REPLAY_BIN (g_object_new (GST_TYPE_REPLAY_BIN,
          "name", name, NULL));

  if (!self->uridecodebin) {
    gst_object_unref (self);
    return NULL;
  }

  g_object_set (self->uridecodebin, "uri", uri, NULL);
  self->factory = g_object_ref (factory);
  self->num_loops = num_loops;

  return GST_ELEMENT_CAST (self);
}

struct _GstRTSPMediaFactoryReplay
{
  GstRTSPMediaFactory parent;

  gchar *uri;

  GList *demuxers;
  GList *payloaders;
  GList *decoders;

  gint64 num_loops;
};

enum
{
  PROP_0,
  PROP_URI,
  PROP_NUM_LOOPS,
};

#define DEFAULT_NUM_LOOPS (-1)

static void gst_rtsp_media_factory_replay_get_property (GObject * object,
    guint propid, GValue * value, GParamSpec * pspec);
static void gst_rtsp_media_factory_replay_set_property (GObject * object,
    guint propid, const GValue * value, GParamSpec * pspec);
static void gst_rtsp_media_factory_replay_finalize (GObject * object);

static GstElement
    * gst_rtsp_media_factory_replay_create_element (GstRTSPMediaFactory *
    factory, const GstRTSPUrl * url);

typedef struct
{
  GList *demux;
  GList *payload;
  GList *decode;
} FilterData;

static gboolean
payloader_filter (GstPluginFeature * feature, FilterData * self);

#define gst_rtsp_media_factory_replay_parent_class parent_class
G_DEFINE_TYPE (GstRTSPMediaFactoryReplay,
    gst_rtsp_media_factory_replay, GST_TYPE_RTSP_MEDIA_FACTORY);

static void
gst_rtsp_media_factory_replay_class_init (GstRTSPMediaFactoryReplayClass
    * klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  GstRTSPMediaFactoryClass *mf_class = GST_RTSP_MEDIA_FACTORY_CLASS (klass);

  gobject_class->get_property = gst_rtsp_media_factory_replay_get_property;
  gobject_class->set_property = gst_rtsp_media_factory_replay_set_property;
  gobject_class->finalize = gst_rtsp_media_factory_replay_finalize;

  g_object_class_install_property (gobject_class, PROP_URI,
      g_param_spec_string ("uri", "URI",
          "The URI of the resource to stream", NULL,
          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_property (gobject_class, PROP_NUM_LOOPS,
      g_param_spec_int64 ("num-loops", "Num Loops",
          "The number of loops (-1 = infinite)", -1, G_MAXINT64,
          DEFAULT_NUM_LOOPS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  mf_class->create_element =
      GST_DEBUG_FUNCPTR (gst_rtsp_media_factory_replay_create_element);
}

static void
gst_rtsp_media_factory_replay_init (GstRTSPMediaFactoryReplay * self)
{
  FilterData data = { NULL, };

  /* get the feature list using the filter */
  gst_registry_feature_filter (gst_registry_get (), (GstPluginFeatureFilter)
      payloader_filter, FALSE, &data);

  /* sort */
  self->demuxers =
      g_list_sort (data.demux, gst_plugin_feature_rank_compare_func);
  self->payloaders =
      g_list_sort (data.payload, gst_plugin_feature_rank_compare_func);
  self->decoders =
      g_list_sort (data.decode, gst_plugin_feature_rank_compare_func);

  self->num_loops = DEFAULT_NUM_LOOPS;
}

static void
gst_rtsp_media_factory_replay_get_property (GObject * object, guint propid,
    GValue * value, GParamSpec * pspec)
{
  GstRTSPMediaFactoryReplay *self = GST_RTSP_MEDIA_FACTORY_REPLAY (object);

  switch (propid) {
    case PROP_URI:
      g_value_take_string (value, self->uri);
      break;
    case PROP_NUM_LOOPS:
      g_value_set_int64 (value, self->num_loops);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, propid, pspec);
  }
}

static void
gst_rtsp_media_factory_replay_set_property (GObject * object, guint propid,
    const GValue * value, GParamSpec * pspec)
{
  GstRTSPMediaFactoryReplay *self = GST_RTSP_MEDIA_FACTORY_REPLAY (object);

  switch (propid) {
    case PROP_URI:
      g_free (self->uri);
      self->uri = g_value_dup_string (value);
      break;
    case PROP_NUM_LOOPS:
      self->num_loops = g_value_get_int64 (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, propid, pspec);
  }
}

static void
gst_rtsp_media_factory_replay_finalize (GObject * object)
{
  GstRTSPMediaFactoryReplay *self = GST_RTSP_MEDIA_FACTORY_REPLAY (object);

  g_free (self->uri);

  gst_plugin_feature_list_free (self->demuxers);
  gst_plugin_feature_list_free (self->payloaders);
  gst_plugin_feature_list_free (self->decoders);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static GstElement *
gst_rtsp_media_factory_replay_create_element (GstRTSPMediaFactory * factory,
    const GstRTSPUrl * url)
{
  GstRTSPMediaFactoryReplay *self = GST_RTSP_MEDIA_FACTORY_REPLAY (factory);

  return gst_replay_bin_new (self->uri, self->num_loops, self,
      "GstRTSPMediaFactoryReplay");
}

static gboolean
payloader_filter (GstPluginFeature * feature, FilterData * data)
{
  const gchar *klass;
  GstElementFactory *fact;
  GList **list = NULL;

  /* we only care about element factories */
  if (G_UNLIKELY (!GST_IS_ELEMENT_FACTORY (feature)))
    return FALSE;

  if (gst_plugin_feature_get_rank (feature) < GST_RANK_MARGINAL)
    return FALSE;

  fact = GST_ELEMENT_FACTORY_CAST (feature);

  klass = gst_element_factory_get_metadata (fact, GST_ELEMENT_METADATA_KLASS);

  if (strstr (klass, "Decoder"))
    list = &data->decode;
  else if (strstr (klass, "Demux"))
    list = &data->demux;
  else if (strstr (klass, "Parser") && strstr (klass, "Codec"))
    list = &data->demux;
  else if (strstr (klass, "Payloader") && strstr (klass, "RTP"))
    list = &data->payload;

  if (list) {
    GST_LOG ("adding %s", GST_OBJECT_NAME (fact));
    *list = g_list_prepend (*list, gst_object_ref (fact));
  }

  return FALSE;
}

static GList *
gst_rtsp_media_factory_replay_get_demuxers (GstRTSPMediaFactoryReplay * factory)
{
  return factory->demuxers;
}

static GList *
gst_rtsp_media_factory_replay_get_payloaders (GstRTSPMediaFactoryReplay *
    factory)
{
  return factory->payloaders;
}

static GList *
gst_rtsp_media_factory_replay_get_decoders (GstRTSPMediaFactoryReplay * factory)
{
  return factory->decoders;
}

static GstRTSPMediaFactory *
gst_rtsp_media_factory_replay_new (const gchar * uri, gint64 num_loops)
{
  GstRTSPMediaFactory *factory;

  factory =
      GST_RTSP_MEDIA_FACTORY (g_object_new
      (GST_TYPE_RTSP_MEDIA_FACTORY_REPLAY, "uri", uri, "num-loops", num_loops,
          NULL));

  return factory;
}