gstreamer/gst/rtp/gstrtptheoradepay.c

/* GStreamer
 * Copyright (C) <2006> Wim Taymans <wim.taymans@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., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include <gst/tag/tag.h>
#include <gst/rtp/gstrtpbuffer.h>

#include <string.h>
#include "gstrtptheoradepay.h"

GST_DEBUG_CATEGORY_STATIC (rtptheoradepay_debug);
#define GST_CAT_DEFAULT (rtptheoradepay_debug)

static GstStaticPadTemplate gst_rtp_theora_depay_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("application/x-rtp, "
        "media = (string) \"video\", "
        "clock-rate = (int) 90000, " "encoding-name = (string) \"THEORA\""
        /* All required parameters 
         *
         * "sampling = (string) { "YCbCr-4:2:0", "YCbCr-4:2:2", "YCbCr-4:4:4" } "
         * "width = (string) [1, 1048561] (multiples of 16) "
         * "height = (string) [1, 1048561] (multiples of 16) "
         * "delivery-method = (string) { inline, in_band, out_band/<specific_name> } " 
         * "configuration = (string) ANY" 
         */
        /* All optional parameters
         *
         * "configuration-uri =" 
         */
    )
    );

static GstStaticPadTemplate gst_rtp_theora_depay_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-theora")
    );

#define gst_rtp_theora_depay_parent_class parent_class
G_DEFINE_TYPE (GstRtpTheoraDepay, gst_rtp_theora_depay,
    GST_TYPE_RTP_BASE_DEPAYLOAD);

static gboolean gst_rtp_theora_depay_setcaps (GstRTPBaseDepayload * depayload,
    GstCaps * caps);
static GstBuffer *gst_rtp_theora_depay_process (GstRTPBaseDepayload * depayload,
    GstBuffer * buf);
static gboolean gst_rtp_theora_depay_packet_lost (GstRTPBaseDepayload *
    depayload, GstEvent * event);

static void gst_rtp_theora_depay_finalize (GObject * object);

static void
gst_rtp_theora_depay_class_init (GstRtpTheoraDepayClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;
  GstRTPBaseDepayloadClass *gstrtpbasedepayload_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;
  gstrtpbasedepayload_class = (GstRTPBaseDepayloadClass *) klass;

  gobject_class->finalize = gst_rtp_theora_depay_finalize;

  gstrtpbasedepayload_class->process = gst_rtp_theora_depay_process;
  gstrtpbasedepayload_class->set_caps = gst_rtp_theora_depay_setcaps;
  gstrtpbasedepayload_class->packet_lost = gst_rtp_theora_depay_packet_lost;

  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&gst_rtp_theora_depay_sink_template));
  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&gst_rtp_theora_depay_src_template));

  gst_element_class_set_static_metadata (gstelement_class,
      "RTP Theora depayloader", "Codec/Depayloader/Network/RTP",
      "Extracts Theora video from RTP packets (draft-01 of RFC XXXX)",
      "Wim Taymans <wim.taymans@gmail.com>");

  GST_DEBUG_CATEGORY_INIT (rtptheoradepay_debug, "rtptheoradepay", 0,
      "Theora RTP Depayloader");
}

static void
gst_rtp_theora_depay_init (GstRtpTheoraDepay * rtptheoradepay)
{
  rtptheoradepay->adapter = gst_adapter_new ();
}

static void
gst_rtp_theora_depay_finalize (GObject * object)
{
  GstRtpTheoraDepay *rtptheoradepay = GST_RTP_THEORA_DEPAY (object);

  g_object_unref (rtptheoradepay->adapter);

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

static gboolean
gst_rtp_theora_depay_parse_configuration (GstRtpTheoraDepay * rtptheoradepay,
    GstBuffer * confbuf)
{
  GstBuffer *buf;
  guint32 num_headers;
  GstMapInfo map;
  guint8 *data;
  gsize size;
  gint i, j;

  gst_buffer_map (confbuf, &map, GST_MAP_READ);
  data = map.data;
  size = map.size;

  GST_DEBUG_OBJECT (rtptheoradepay, "config size %" G_GSIZE_FORMAT, size);

  /* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                     Number of packed headers                  |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                          Packed header                        |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                          Packed header                        |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                          ....                                 |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   */
  if (size < 4)
    goto too_small;

  num_headers = GST_READ_UINT32_BE (data);
  size -= 4;
  data += 4;

  GST_DEBUG_OBJECT (rtptheoradepay, "have %u headers", num_headers);

  /*  0                   1                   2                   3
   *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                   Ident                       | length       ..
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * ..              | n. of headers |    length1    |    length2   ..
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * ..              |             Identification Header            ..
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * .................................................................
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * ..              |         Comment Header                       ..
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * .................................................................
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * ..                        Comment Header                        |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                          Setup Header                        ..
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * .................................................................
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * ..                         Setup Header                         |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   */
  for (i = 0; i < num_headers; i++) {
    guint32 ident;
    guint16 length;
    guint8 n_headers, b;
    GstRtpTheoraConfig *conf;
    guint *h_sizes;
    guint extra = 1;

    if (size < 6)
      goto too_small;

    ident = (data[0] << 16) | (data[1] << 8) | data[2];
    length = (data[3] << 8) | data[4];
    n_headers = data[5];
    size -= 6;
    data += 6;

    GST_DEBUG_OBJECT (rtptheoradepay,
        "header %d, ident 0x%08x, length %u, left %" G_GSIZE_FORMAT, i, ident,
        length, size);

    /* FIXME check if we already got this ident */

    /* length might also include count of following size fields */
    if (size < length && size + 1 != length)
      goto too_small;

    /* read header sizes we read 2 sizes, the third size (for which we allocate
     * space) must be derived from the total packed header length. */
    h_sizes = g_newa (guint, n_headers + 1);
    for (j = 0; j < n_headers; j++) {
      guint h_size;

      h_size = 0;
      do {
        if (size < 1)
          goto too_small;
        b = *data++;
        size--;
        extra++;
        h_size = (h_size << 7) | (b & 0x7f);
      } while (b & 0x80);
      GST_DEBUG_OBJECT (rtptheoradepay, "headers %d: size: %u", j, h_size);
      h_sizes[j] = h_size;
      length -= h_size;
    }
    /* last header length is the remaining space */
    GST_DEBUG_OBJECT (rtptheoradepay, "last header size: %u", length);
    h_sizes[j] = length;

    GST_DEBUG_OBJECT (rtptheoradepay, "preparing headers");
    conf = g_new0 (GstRtpTheoraConfig, 1);
    conf->ident = ident;

    for (j = 0; j <= n_headers; j++) {
      guint h_size;

      h_size = h_sizes[j];
      if (size < h_size) {
        if (j != n_headers || size + extra != h_size) {
          goto too_small;
        } else {
          /* otherwise means that overall length field contained total length,
           * including extra fields */
          h_size -= extra;
        }
      }

      GST_DEBUG_OBJECT (rtptheoradepay, "reading header %d, size %u", j,
          h_size);

      buf = gst_buffer_new_and_alloc (h_size);
      gst_buffer_fill (buf, 0, data, h_size);
      conf->headers = g_list_append (conf->headers, buf);
      data += h_size;
      size -= h_size;
    }
    rtptheoradepay->configs = g_list_append (rtptheoradepay->configs, conf);
  }

  gst_buffer_unmap (confbuf, &map);
  return TRUE;

  /* ERRORS */
too_small:
  {
    GST_DEBUG_OBJECT (rtptheoradepay, "configuration too small");
    gst_buffer_unmap (confbuf, &map);
    return FALSE;
  }
}

static gboolean
gst_rtp_theora_depay_parse_inband_configuration (GstRtpTheoraDepay *
    rtptheoradepay, guint ident, guint8 * configuration, guint size,
    guint length)
{
  GstBuffer *confbuf;
  GstMapInfo map;

  if (G_UNLIKELY (size < 4))
    return FALSE;

  /* transform inline to out-of-band and parse that one */
  confbuf = gst_buffer_new_and_alloc (size + 9);
  gst_buffer_map (confbuf, &map, GST_MAP_WRITE);
  /* 1 header */
  GST_WRITE_UINT32_BE (map.data, 1);
  /* write Ident */
  GST_WRITE_UINT24_BE (map.data + 4, ident);
  /* write sort-of-length */
  GST_WRITE_UINT16_BE (map.data + 7, length);
  /* copy remainder */
  memcpy (map.data + 9, configuration, size);
  gst_buffer_unmap (confbuf, &map);

  return gst_rtp_theora_depay_parse_configuration (rtptheoradepay, confbuf);
}

static gboolean
gst_rtp_theora_depay_setcaps (GstRTPBaseDepayload * depayload, GstCaps * caps)
{
  GstStructure *structure;
  GstRtpTheoraDepay *rtptheoradepay;
  GstCaps *srccaps;
  const gchar *configuration;
  gboolean res;

  rtptheoradepay = GST_RTP_THEORA_DEPAY (depayload);

  rtptheoradepay->needs_keyframe = FALSE;

  structure = gst_caps_get_structure (caps, 0);

  /* read and parse configuration string */
  configuration = gst_structure_get_string (structure, "configuration");
  if (configuration) {
    GstBuffer *confbuf;
    guint8 *data;
    gsize size;

    /* deserialize base64 to buffer */
    data = g_base64_decode (configuration, &size);

    confbuf = gst_buffer_new ();
    gst_buffer_append_memory (confbuf,
        gst_memory_new_wrapped (0, data, size, 0, size, data, g_free));

    if (!gst_rtp_theora_depay_parse_configuration (rtptheoradepay, confbuf))
      goto invalid_configuration;
  }

  /* set caps on pad and on header */
  srccaps = gst_caps_new_empty_simple ("video/x-theora");
  res = gst_pad_set_caps (depayload->srcpad, srccaps);
  gst_caps_unref (srccaps);

  /* Clock rate is always 90000 according to draft-barbato-avt-rtp-theora-01 */
  depayload->clock_rate = 90000;

  return res;

  /* ERRORS */
invalid_configuration:
  {
    GST_ERROR_OBJECT (rtptheoradepay, "invalid configuration specified");
    return FALSE;
  }
}

static gboolean
gst_rtp_theora_depay_switch_codebook (GstRtpTheoraDepay * rtptheoradepay,
    guint32 ident)
{
  GList *walk;
  gboolean res = FALSE;

  for (walk = rtptheoradepay->configs; walk; walk = g_list_next (walk)) {
    GstRtpTheoraConfig *conf = (GstRtpTheoraConfig *) walk->data;

    if (conf->ident == ident) {
      GList *headers;

      /* FIXME, remove pads, create new pad.. */

      /* push out all the headers */
      for (headers = conf->headers; headers; headers = g_list_next (headers)) {
        GstBuffer *header = GST_BUFFER_CAST (headers->data);

        gst_buffer_ref (header);
        gst_rtp_base_depayload_push (GST_RTP_BASE_DEPAYLOAD (rtptheoradepay),
            header);
      }
      /* remember the current config */
      rtptheoradepay->config = conf;
      res = TRUE;
    }
  }
  if (!res) {
    /* we don't know about the headers, figure out an alternative method for
     * getting the codebooks. FIXME, fail for now. */
  }
  return res;
}

static GstBuffer *
gst_rtp_theora_depay_process (GstRTPBaseDepayload * depayload, GstBuffer * buf)
{
  GstRtpTheoraDepay *rtptheoradepay;
  GstBuffer *outbuf;
  GstFlowReturn ret;
  gint payload_len;
  guint8 *payload, *to_free = NULL;
  guint32 header, ident;
  guint8 F, TDT, packets;
  GstRTPBuffer rtp = { NULL };
  guint length;

  rtptheoradepay = GST_RTP_THEORA_DEPAY (depayload);

  gst_rtp_buffer_map (buf, GST_MAP_READ, &rtp);

  payload_len = gst_rtp_buffer_get_payload_len (&rtp);

  GST_DEBUG_OBJECT (depayload, "got RTP packet of size %d", payload_len);

  /* we need at least 4 bytes for the packet header */
  if (G_UNLIKELY (payload_len < 4))
    goto packet_short;

  payload = gst_rtp_buffer_get_payload (&rtp);

  header = GST_READ_UINT32_BE (payload);
  /*
   *  0                   1                   2                   3
   *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |                     Ident                     | F |TDT|# pkts.|
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   *
   * F: Fragment type (0=none, 1=start, 2=cont, 3=end)
   * TDT: Theora data type (0=theora, 1=config, 2=comment, 3=reserved)
   * pkts: number of packets.
   */
  TDT = (header & 0x30) >> 4;
  if (G_UNLIKELY (TDT == 3))
    goto ignore_reserved;

  ident = (header >> 8) & 0xffffff;
  F = (header & 0xc0) >> 6;
  packets = (header & 0xf);

  GST_DEBUG_OBJECT (depayload, "ident: 0x%08x, F: %d, TDT: %d, packets: %d",
      ident, F, TDT, packets);

  if (TDT == 0) {
    gboolean do_switch = FALSE;

    /* we have a raw payload, find the codebook for the ident */
    if (!rtptheoradepay->config) {
      /* we don't have an active codebook, find the codebook and
       * activate it */
      do_switch = TRUE;
    } else if (rtptheoradepay->config->ident != ident) {
      /* codebook changed */
      do_switch = TRUE;
    }
    if (do_switch) {
      if (!gst_rtp_theora_depay_switch_codebook (rtptheoradepay, ident))
        goto switch_failed;
    }
  }

  /* skip header */
  payload += 4;
  payload_len -= 4;

  /* fragmented packets, assemble */
  if (F != 0) {
    GstBuffer *vdata;
    guint headerskip;

    if (F == 1) {
      /* if we start a packet, clear adapter and start assembling. */
      gst_adapter_clear (rtptheoradepay->adapter);
      GST_DEBUG_OBJECT (depayload, "start assemble");
      rtptheoradepay->assembling = TRUE;
    }

    if (!rtptheoradepay->assembling)
      goto no_output;

    /* first assembled packet, reuse 2 bytes to store the length */
    headerskip = (F == 1 ? 4 : 6);
    /* skip header and length. */
    vdata = gst_rtp_buffer_get_payload_subbuffer (&rtp, headerskip, -1);

    GST_DEBUG_OBJECT (depayload, "assemble theora packet");
    gst_adapter_push (rtptheoradepay->adapter, vdata);

    /* packet is not complete, we are done */
    if (F != 3)
      goto no_output;

    /* construct assembled buffer */
    payload_len = gst_adapter_available (rtptheoradepay->adapter);
    payload = gst_adapter_take (rtptheoradepay->adapter, payload_len);

    /* use this length */
    length = payload_len - 2;

    to_free = payload;
  } else {
    /* read length from data */
    length = 0;
  }

  GST_DEBUG_OBJECT (depayload, "assemble done, payload_len %d", payload_len);

  /* we not assembling anymore now */
  rtptheoradepay->assembling = FALSE;
  gst_adapter_clear (rtptheoradepay->adapter);

  /* payload now points to a length with that many theora data bytes.
   * Iterate over the packets and send them out.
   *
   *  0                   1                   2                   3
   *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |             length            |          theora data         ..
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * ..                        theora data                           |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * |            length             |   next theora packet data    ..
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   * ..                        theora data                           |
   * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+*
   */
  while (payload_len >= 2) {
    if (length == 0)
      length = GST_READ_UINT16_BE (payload);

    payload += 2;
    payload_len -= 2;

    GST_DEBUG_OBJECT (depayload, "read length %u, avail: %d", length,
        payload_len);

    /* skip packet if something odd happens */
    if (G_UNLIKELY (length > payload_len))
      goto length_short;

    /* handle in-band configuration */
    if (G_UNLIKELY (TDT == 1)) {
      GST_DEBUG_OBJECT (rtptheoradepay, "in-band configuration");
      if (!gst_rtp_theora_depay_parse_inband_configuration (rtptheoradepay,
              ident, payload, payload_len, length))
        goto invalid_configuration;
      goto no_output;
    }

    /* create buffer for packet */
    if (G_UNLIKELY (to_free)) {
      outbuf =
          gst_buffer_new_wrapped_full (0, to_free, (payload - to_free) + length,
          payload - to_free, length, to_free, g_free);
      to_free = NULL;
    } else {
      outbuf = gst_buffer_new_and_alloc (length);
      gst_buffer_fill (outbuf, 0, payload, length);
    }

    if (payload_len > 0 && (payload[0] & 0xC0) == 0x0) {
      rtptheoradepay->needs_keyframe = FALSE;
    } else {
      GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT);
    }

    payload += length;
    payload_len -= length;
    /* make sure to read next length */
    length = 0;

    ret = gst_rtp_base_depayload_push (depayload, outbuf);
    if (ret != GST_FLOW_OK)
      break;
  }

  g_free (to_free);

  if (rtptheoradepay->needs_keyframe)
    goto request_keyframe;

  gst_rtp_buffer_unmap (&rtp);
  return NULL;

no_output:
  {
    gst_rtp_buffer_unmap (&rtp);
    return NULL;
  }
  /* ERORRS */
switch_failed:
  {
    GST_ELEMENT_WARNING (rtptheoradepay, STREAM, DECODE,
        (NULL), ("Could not switch codebooks"));
    goto request_config;
  }
packet_short:
  {
    GST_ELEMENT_WARNING (rtptheoradepay, STREAM, DECODE,
        (NULL), ("Packet was too short (%d < 4)", payload_len));
    goto request_keyframe;
  }
ignore_reserved:
  {
    GST_WARNING_OBJECT (rtptheoradepay, "reserved TDT ignored");
    gst_rtp_buffer_unmap (&rtp);
    return NULL;
  }
length_short:
  {
    GST_ELEMENT_WARNING (rtptheoradepay, STREAM, DECODE,
        (NULL), ("Packet contains invalid data"));
    goto request_keyframe;
  }
invalid_configuration:
  {
    /* fatal, as we otherwise risk carrying on without output */
    GST_ELEMENT_ERROR (rtptheoradepay, STREAM, DECODE,
        (NULL), ("Packet contains invalid configuration"));
    goto request_config;
  }
request_config:
  {
    gst_pad_push_event (GST_RTP_BASE_DEPAYLOAD_SINKPAD (depayload),
        gst_event_new_custom (GST_EVENT_CUSTOM_UPSTREAM,
            gst_structure_new ("GstForceKeyUnit",
                "all-headers", G_TYPE_BOOLEAN, TRUE, NULL)));
    gst_rtp_buffer_unmap (&rtp);
    return NULL;
  }
request_keyframe:
  {
    rtptheoradepay->needs_keyframe = TRUE;
    gst_pad_push_event (GST_RTP_BASE_DEPAYLOAD_SINKPAD (depayload),
        gst_event_new_custom (GST_EVENT_CUSTOM_UPSTREAM,
            gst_structure_new_empty ("GstForceKeyUnit")));
    gst_rtp_buffer_unmap (&rtp);
    return NULL;
  }
}

gboolean
gst_rtp_theora_depay_plugin_init (GstPlugin * plugin)
{
  return gst_element_register (plugin, "rtptheoradepay",
      GST_RANK_SECONDARY, GST_TYPE_RTP_THEORA_DEPAY);
}

static gboolean
gst_rtp_theora_depay_packet_lost (GstRTPBaseDepayload * depayload,
    GstEvent * event)
{
  GstRtpTheoraDepay *rtptheoradepay = GST_RTP_THEORA_DEPAY (depayload);
  guint seqnum = 0;

  gst_structure_get_uint (gst_event_get_structure (event), "seqnum", &seqnum);
  GST_LOG_OBJECT (depayload, "Requested keyframe because frame with seqnum %u"
      " is missing", seqnum);
  rtptheoradepay->needs_keyframe = TRUE;

  gst_pad_push_event (GST_RTP_BASE_DEPAYLOAD_SINKPAD (depayload),
      gst_event_new_custom (GST_EVENT_CUSTOM_UPSTREAM,
          gst_structure_new_empty ("GstForceKeyUnit")));

  return TRUE;
}