gst/rtp/gstrtpvorbispay.c - mtk-gst-plugins-good-debian - Git at Google

 /* 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., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */

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

 #include <string.h>

 #include <gst/rtp/gstrtpbuffer.h>

 #include "fnv1hash.h"
 #include "gstrtpvorbispay.h"

 GST_DEBUG_CATEGORY_STATIC (rtpvorbispay_debug);
 #define GST_CAT_DEFAULT (rtpvorbispay_debug)

 /* references:
  * http://www.rfc-editor.org/rfc/rfc5215.txt
  */

 static GstStaticPadTemplate gst_rtp_vorbis_pay_src_template =
 GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS ("application/x-rtp, "
         "media = (string) \"audio\", "
         "payload = (int) " GST_RTP_PAYLOAD_DYNAMIC_STRING ", "
         "clock-rate = (int) [1, MAX ], " "encoding-name = (string) \"VORBIS\""
         /* All required parameters
          *
          * "encoding-params = (string) <num channels>"
          * "configuration = (string) ANY"
          */
     )
     );

 static GstStaticPadTemplate gst_rtp_vorbis_pay_sink_template =
 GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS ("audio/x-vorbis")
     );

 #define gst_rtp_vorbis_pay_parent_class parent_class
 G_DEFINE_TYPE (GstRtpVorbisPay, gst_rtp_vorbis_pay, GST_TYPE_RTP_BASE_PAYLOAD);

 static gboolean gst_rtp_vorbis_pay_setcaps (GstRTPBasePayload * basepayload,
     GstCaps * caps);
 static GstStateChangeReturn gst_rtp_vorbis_pay_change_state (GstElement *
     element, GstStateChange transition);
 static GstFlowReturn gst_rtp_vorbis_pay_handle_buffer (GstRTPBasePayload * pad,
     GstBuffer * buffer);
 static gboolean gst_rtp_vorbis_pay_sink_event (GstRTPBasePayload * payload,
     GstEvent * event);

 static void
 gst_rtp_vorbis_pay_class_init (GstRtpVorbisPayClass * klass)
 {
   GstElementClass *gstelement_class;
   GstRTPBasePayloadClass *gstrtpbasepayload_class;

   gstelement_class = (GstElementClass *) klass;
   gstrtpbasepayload_class = (GstRTPBasePayloadClass *) klass;

   gstelement_class->change_state = gst_rtp_vorbis_pay_change_state;

   gstrtpbasepayload_class->set_caps = gst_rtp_vorbis_pay_setcaps;
   gstrtpbasepayload_class->handle_buffer = gst_rtp_vorbis_pay_handle_buffer;
   gstrtpbasepayload_class->sink_event = gst_rtp_vorbis_pay_sink_event;

   gst_element_class_add_pad_template (gstelement_class,
       gst_static_pad_template_get (&gst_rtp_vorbis_pay_src_template));
   gst_element_class_add_pad_template (gstelement_class,
       gst_static_pad_template_get (&gst_rtp_vorbis_pay_sink_template));

   gst_element_class_set_static_metadata (gstelement_class,
       "RTP Vorbis depayloader",
       "Codec/Payloader/Network/RTP",
       "Payload-encode Vorbis audio into RTP packets (RFC 5215)",
       "Wim Taymans <wimi.taymans@gmail.com>");

   GST_DEBUG_CATEGORY_INIT (rtpvorbispay_debug, "rtpvorbispay", 0,
       "Vorbis RTP Payloader");
 }

 static void
 gst_rtp_vorbis_pay_init (GstRtpVorbisPay * rtpvorbispay)
 {
   /* needed because of GST_BOILERPLATE */
 }

 static void
 gst_rtp_vorbis_pay_clear_packet (GstRtpVorbisPay * rtpvorbispay)
 {
   if (rtpvorbispay->packet)
     gst_buffer_unref (rtpvorbispay->packet);
   rtpvorbispay->packet = NULL;
 }

 static void
 gst_rtp_vorbis_pay_cleanup (GstRtpVorbisPay * rtpvorbispay)
 {
   g_list_foreach (rtpvorbispay->headers, (GFunc) gst_mini_object_unref, NULL);
   g_list_free (rtpvorbispay->headers);
   rtpvorbispay->headers = NULL;

   gst_rtp_vorbis_pay_clear_packet (rtpvorbispay);
 }

 static gboolean
 gst_rtp_vorbis_pay_setcaps (GstRTPBasePayload * basepayload, GstCaps * caps)
 {
   GstRtpVorbisPay *rtpvorbispay;

   rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);

   rtpvorbispay->need_headers = TRUE;

   return TRUE;
 }

 static void
 gst_rtp_vorbis_pay_reset_packet (GstRtpVorbisPay * rtpvorbispay, guint8 VDT)
 {
   guint payload_len;
   GstRTPBuffer rtp = { NULL };

   GST_LOG_OBJECT (rtpvorbispay, "reset packet");

   rtpvorbispay->payload_pos = 4;
   gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_READ, &rtp);
   payload_len = gst_rtp_buffer_get_payload_len (&rtp);
   gst_rtp_buffer_unmap (&rtp);
   rtpvorbispay->payload_left = payload_len - 4;
   rtpvorbispay->payload_duration = 0;
   rtpvorbispay->payload_F = 0;
   rtpvorbispay->payload_VDT = VDT;
   rtpvorbispay->payload_pkts = 0;
 }

 static void
 gst_rtp_vorbis_pay_init_packet (GstRtpVorbisPay * rtpvorbispay, guint8 VDT,
     GstClockTime timestamp)
 {
   GST_LOG_OBJECT (rtpvorbispay, "starting new packet, VDT: %d", VDT);

   if (rtpvorbispay->packet)
     gst_buffer_unref (rtpvorbispay->packet);

   /* new packet allocate max packet size */
   rtpvorbispay->packet =
       gst_rtp_buffer_new_allocate_len (GST_RTP_BASE_PAYLOAD_MTU
       (rtpvorbispay), 0, 0);
   gst_rtp_vorbis_pay_reset_packet (rtpvorbispay, VDT);
   GST_BUFFER_TIMESTAMP (rtpvorbispay->packet) = timestamp;
 }

 static GstFlowReturn
 gst_rtp_vorbis_pay_flush_packet (GstRtpVorbisPay * rtpvorbispay)
 {
   GstFlowReturn ret;
   guint8 *payload;
   guint hlen;
   GstRTPBuffer rtp = { NULL };

   /* check for empty packet */
   if (!rtpvorbispay->packet || rtpvorbispay->payload_pos <= 4)
     return GST_FLOW_OK;

   GST_LOG_OBJECT (rtpvorbispay, "flushing packet");

   gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_WRITE, &rtp);

   /* fix header */
   payload = gst_rtp_buffer_get_payload (&rtp);
   /*
    *  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 |VDT|# pkts.|
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    *
    * F: Fragment type (0=none, 1=start, 2=cont, 3=end)
    * VDT: Vorbis data type (0=vorbis, 1=config, 2=comment, 3=reserved)
    * pkts: number of packets.
    */
   payload[0] = (rtpvorbispay->payload_ident >> 16) & 0xff;
   payload[1] = (rtpvorbispay->payload_ident >> 8) & 0xff;
   payload[2] = (rtpvorbispay->payload_ident) & 0xff;
   payload[3] = (rtpvorbispay->payload_F & 0x3) << 6 |
       (rtpvorbispay->payload_VDT & 0x3) << 4 |
       (rtpvorbispay->payload_pkts & 0xf);

   gst_rtp_buffer_unmap (&rtp);

   /* shrink the buffer size to the last written byte */
   hlen = gst_rtp_buffer_calc_header_len (0);
   gst_buffer_resize (rtpvorbispay->packet, 0, hlen + rtpvorbispay->payload_pos);

   GST_BUFFER_DURATION (rtpvorbispay->packet) = rtpvorbispay->payload_duration;

   /* push, this gives away our ref to the packet, so clear it. */
   ret =
       gst_rtp_base_payload_push (GST_RTP_BASE_PAYLOAD (rtpvorbispay),
       rtpvorbispay->packet);
   rtpvorbispay->packet = NULL;

   return ret;
 }

 static gboolean
 gst_rtp_vorbis_pay_finish_headers (GstRTPBasePayload * basepayload)
 {
   GstRtpVorbisPay *rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);
   GList *walk;
   guint length, size, n_headers, configlen;
   gchar *cstr, *configuration;
   guint8 *data, *config;
   guint32 ident;
   gboolean res;

   GST_DEBUG_OBJECT (rtpvorbispay, "finish headers");

   if (!rtpvorbispay->headers)
     goto no_headers;

   /* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    * |                     Number of packed headers                  |
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    * |                          Packed header                        |
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    * |                          Packed header                        |
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    * |                          ....                                 |
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    *
    * We only construct a config containing 1 packed header like this:
    *
    *  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                         |
    * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    */

   /* we need 4 bytes for the number of headers (which is always 1), 3 bytes for
    * the ident, 2 bytes for length, 1 byte for n. of headers. */
   size = 4 + 3 + 2 + 1;

   /* count the size of the headers first and update the hash */
   length = 0;
   n_headers = 0;
   ident = fnv1_hash_32_new ();
   for (walk = rtpvorbispay->headers; walk; walk = g_list_next (walk)) {
     GstBuffer *buf = GST_BUFFER_CAST (walk->data);
     GstMapInfo map;
     guint bsize;

     bsize = gst_buffer_get_size (buf);
     length += bsize;
     n_headers++;

     /* count number of bytes needed for length fields, we don't need this for
      * the last header. */
     if (g_list_next (walk)) {
       do {
         size++;
         bsize >>= 7;
       } while (bsize);
     }
     /* update hash */
     gst_buffer_map (buf, &map, GST_MAP_READ);
     ident = fnv1_hash_32_update (ident, map.data, map.size);
     gst_buffer_unmap (buf, &map);
   }

   /* packet length is header size + packet length */
   configlen = size + length;
   config = data = g_malloc (configlen);

   /* number of packed headers, we only pack 1 header */
   data[0] = 0;
   data[1] = 0;
   data[2] = 0;
   data[3] = 1;

   ident = fnv1_hash_32_to_24 (ident);
   rtpvorbispay->payload_ident = ident;
   GST_DEBUG_OBJECT (rtpvorbispay, "ident 0x%08x", ident);

   /* take lower 3 bytes */
   data[4] = (ident >> 16) & 0xff;
   data[5] = (ident >> 8) & 0xff;
   data[6] = ident & 0xff;

   /* store length of all vorbis headers */
   data[7] = ((length) >> 8) & 0xff;
   data[8] = (length) & 0xff;

   /* store number of headers minus one. */
   data[9] = n_headers - 1;
   data += 10;

   /* store length for each header */
   for (walk = rtpvorbispay->headers; walk; walk = g_list_next (walk)) {
     GstBuffer *buf = GST_BUFFER_CAST (walk->data);
     guint bsize, size, temp;
     guint flag;

     /* only need to store the length when it's not the last header */
     if (!g_list_next (walk))
       break;

     bsize = gst_buffer_get_size (buf);

     /* calc size */
     size = 0;
     do {
       size++;
       bsize >>= 7;
     } while (bsize);
     temp = size;

     bsize = gst_buffer_get_size (buf);
     /* write the size backwards */
     flag = 0;
     while (size) {
       size--;
       data[size] = (bsize & 0x7f) | flag;
       bsize >>= 7;
       flag = 0x80;              /* Flag bit on all bytes of the length except the last */
     }
     data += temp;
   }

   /* copy header data */
   for (walk = rtpvorbispay->headers; walk; walk = g_list_next (walk)) {
     GstBuffer *buf = GST_BUFFER_CAST (walk->data);

     gst_buffer_extract (buf, 0, data, gst_buffer_get_size (buf));
     data += gst_buffer_get_size (buf);
   }

   /* serialize to base64 */
   configuration = g_base64_encode (config, configlen);
   g_free (config);

   /* configure payloader settings */
   cstr = g_strdup_printf ("%d", rtpvorbispay->channels);
   gst_rtp_base_payload_set_options (basepayload, "audio", TRUE, "VORBIS",
       rtpvorbispay->rate);
   res =
       gst_rtp_base_payload_set_outcaps (basepayload, "encoding-params",
       G_TYPE_STRING, cstr, "configuration", G_TYPE_STRING, configuration, NULL);
   g_free (cstr);
   g_free (configuration);

   return res;

   /* ERRORS */
 no_headers:
   {
     GST_DEBUG_OBJECT (rtpvorbispay, "finish headers");
     return FALSE;
   }
 }

 static gboolean
 gst_rtp_vorbis_pay_parse_id (GstRTPBasePayload * basepayload, guint8 * data,
     guint size)
 {
   GstRtpVorbisPay *rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);
   guint8 channels;
   gint32 rate, version;

   if (G_UNLIKELY (size < 16))
     goto too_short;

   if (G_UNLIKELY (memcmp (data, "\001vorbis", 7)))
     goto invalid_start;
   data += 7;

   if (G_UNLIKELY ((version = GST_READ_UINT32_LE (data)) != 0))
     goto invalid_version;
   data += 4;

   if (G_UNLIKELY ((channels = *data++) < 1))
     goto invalid_channels;

   if (G_UNLIKELY ((rate = GST_READ_UINT32_LE (data)) < 1))
     goto invalid_rate;

   /* all fine, store the values */
   rtpvorbispay->channels = channels;
   rtpvorbispay->rate = rate;

   return TRUE;

   /* ERRORS */
 too_short:
   {
     GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
         ("Identification packet is too short, need at least 16, got %d", size),
         (NULL));
     return FALSE;
   }
 invalid_start:
   {
     GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
         ("Invalid header start in identification packet"), (NULL));
     return FALSE;
   }
 invalid_version:
   {
     GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
         ("Invalid version, expected 0, got %d", version), (NULL));
     return FALSE;
   }
 invalid_rate:
   {
     GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
         ("Invalid rate %d", rate), (NULL));
     return FALSE;
   }
 invalid_channels:
   {
     GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
         ("Invalid channels %d", channels), (NULL));
     return FALSE;
   }
 }

 static GstFlowReturn
 gst_rtp_vorbis_pay_handle_buffer (GstRTPBasePayload * basepayload,
     GstBuffer * buffer)
 {
   GstRtpVorbisPay *rtpvorbispay;
   GstFlowReturn ret;
   guint newsize;
   GstMapInfo map;
   gsize size;
   guint8 *data;
   guint packet_len;
   GstClockTime duration, newduration, timestamp;
   gboolean flush;
   guint8 VDT;
   guint plen;
   guint8 *ppos, *payload;
   gboolean fragmented;
   GstRTPBuffer rtp = { NULL };

   rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);

   gst_buffer_map (buffer, &map, GST_MAP_READ);
   data = map.data;
   size = map.size;
   duration = GST_BUFFER_DURATION (buffer);
   timestamp = GST_BUFFER_TIMESTAMP (buffer);

   GST_LOG_OBJECT (rtpvorbispay, "size %" G_GSIZE_FORMAT
       ", duration %" GST_TIME_FORMAT, size, GST_TIME_ARGS (duration));

   if (G_UNLIKELY (size < 1 || size > 0xffff))
     goto wrong_size;

   /* find packet type */
   if (data[0] & 1) {
     /* header */
     if (data[0] == 1) {
       /* identification, we need to parse this in order to get the clock rate. */
       if (G_UNLIKELY (!gst_rtp_vorbis_pay_parse_id (basepayload, data, size)))
         goto parse_id_failed;
       VDT = 1;
     } else if (data[0] == 3) {
       /* comment */
       VDT = 2;
     } else if (data[0] == 5) {
       /* setup */
       VDT = 1;
     } else
       goto unknown_header;
   } else
     /* data */
     VDT = 0;

   if (rtpvorbispay->need_headers) {
     /* we need to collect the headers and construct a config string from them */
     if (VDT != 0) {
       GST_DEBUG_OBJECT (rtpvorbispay, "collecting header");
       /* append header to the list of headers */
       gst_buffer_unmap (buffer, &map);
       rtpvorbispay->headers = g_list_append (rtpvorbispay->headers, buffer);
       ret = GST_FLOW_OK;
       goto done;
     } else {
       if (!gst_rtp_vorbis_pay_finish_headers (basepayload))
         goto header_error;
       rtpvorbispay->need_headers = FALSE;
     }
   }

   /* size increases with packet length and 2 bytes size eader. */
   newduration = rtpvorbispay->payload_duration;
   if (duration != GST_CLOCK_TIME_NONE)
     newduration += duration;

   newsize = rtpvorbispay->payload_pos + 2 + size;
   packet_len = gst_rtp_buffer_calc_packet_len (newsize, 0, 0);

   /* check buffer filled against length and max latency */
   flush = gst_rtp_base_payload_is_filled (basepayload, packet_len, newduration);
   /* we can store up to 15 vorbis packets in one RTP packet. */
   flush |= (rtpvorbispay->payload_pkts == 15);
   /* flush if we have a new VDT */
   if (rtpvorbispay->packet)
     flush |= (rtpvorbispay->payload_VDT != VDT);
   if (flush)
     gst_rtp_vorbis_pay_flush_packet (rtpvorbispay);

   /* create new packet if we must */
   if (!rtpvorbispay->packet) {
     gst_rtp_vorbis_pay_init_packet (rtpvorbispay, VDT, timestamp);
   }

   gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_WRITE, &rtp);
   payload = gst_rtp_buffer_get_payload (&rtp);
   ppos = payload + rtpvorbispay->payload_pos;
   fragmented = FALSE;

   ret = GST_FLOW_OK;

   /* put buffer in packet, it either fits completely or needs to be fragmented
    * over multiple RTP packets. */
   while (size) {
     plen = MIN (rtpvorbispay->payload_left - 2, size);

     GST_LOG_OBJECT (rtpvorbispay, "append %u bytes", plen);

     /* data is copied in the payload with a 2 byte length header */
     ppos[0] = (plen >> 8) & 0xff;
     ppos[1] = (plen & 0xff);
     memcpy (&ppos[2], data, plen);

     size -= plen;
     data += plen;

     rtpvorbispay->payload_pos += plen + 2;
     rtpvorbispay->payload_left -= plen + 2;

     if (fragmented) {
       if (size == 0)
         /* last fragment, set F to 0x3. */
         rtpvorbispay->payload_F = 0x3;
       else
         /* fragment continues, set F to 0x2. */
         rtpvorbispay->payload_F = 0x2;
     } else {
       if (size > 0) {
         /* fragmented packet starts, set F to 0x1, mark ourselves as
          * fragmented. */
         rtpvorbispay->payload_F = 0x1;
         fragmented = TRUE;
       }
     }
     if (fragmented) {
       gst_rtp_buffer_unmap (&rtp);
       /* fragmented packets are always flushed and have ptks of 0 */
       rtpvorbispay->payload_pkts = 0;
       ret = gst_rtp_vorbis_pay_flush_packet (rtpvorbispay);

       if (size > 0) {
         /* start new packet and get pointers. VDT stays the same. */
         gst_rtp_vorbis_pay_init_packet (rtpvorbispay,
             rtpvorbispay->payload_VDT, timestamp);
         gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_WRITE, &rtp);
         payload = gst_rtp_buffer_get_payload (&rtp);
         ppos = payload + rtpvorbispay->payload_pos;
       }
     } else {
       /* unfragmented packet, update stats for next packet, size == 0 and we
        * exit the while loop */
       rtpvorbispay->payload_pkts++;
       if (duration != GST_CLOCK_TIME_NONE)
         rtpvorbispay->payload_duration += duration;
     }
   }

   if (rtp.buffer)
     gst_rtp_buffer_unmap (&rtp);

   gst_buffer_unmap (buffer, &map);
   gst_buffer_unref (buffer);

 done:
   return ret;

   /* ERRORS */
 wrong_size:
   {
     GST_ELEMENT_WARNING (rtpvorbispay, STREAM, DECODE,
         ("Invalid packet size (1 < %" G_GSIZE_FORMAT " <= 0xffff)", size),
         (NULL));
     gst_buffer_unmap (buffer, &map);
     gst_buffer_unref (buffer);
     return GST_FLOW_OK;
   }
 parse_id_failed:
   {
     gst_buffer_unmap (buffer, &map);
     gst_buffer_unref (buffer);
     return GST_FLOW_ERROR;
   }
 unknown_header:
   {
     GST_ELEMENT_WARNING (rtpvorbispay, STREAM, DECODE,
         (NULL), ("Ignoring unknown header received"));
     gst_buffer_unmap (buffer, &map);
     gst_buffer_unref (buffer);
     return GST_FLOW_OK;
   }
 header_error:
   {
     GST_ELEMENT_WARNING (rtpvorbispay, STREAM, DECODE,
         (NULL), ("Error initializing header config"));
     gst_buffer_unmap (buffer, &map);
     gst_buffer_unref (buffer);
     return GST_FLOW_OK;
   }
 }

 static gboolean
 gst_rtp_vorbis_pay_sink_event (GstRTPBasePayload * payload, GstEvent * event)
 {
   GstRtpVorbisPay *rtpvorbispay = GST_RTP_VORBIS_PAY (payload);

   switch (GST_EVENT_TYPE (event)) {
     case GST_EVENT_FLUSH_STOP:
       gst_rtp_vorbis_pay_clear_packet (rtpvorbispay);
       break;
     default:
       break;
   }
   /* false to let parent handle event as well */
   return GST_RTP_BASE_PAYLOAD_CLASS (parent_class)->sink_event (payload, event);
 }

 static GstStateChangeReturn
 gst_rtp_vorbis_pay_change_state (GstElement * element,
     GstStateChange transition)
 {
   GstRtpVorbisPay *rtpvorbispay;
   GstStateChangeReturn ret;

   rtpvorbispay = GST_RTP_VORBIS_PAY (element);

   switch (transition) {
     default:
       break;
   }

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

   switch (transition) {
     case GST_STATE_CHANGE_PAUSED_TO_READY:
       gst_rtp_vorbis_pay_cleanup (rtpvorbispay);
       break;
     default:
       break;
   }
   return ret;
 }

 gboolean
 gst_rtp_vorbis_pay_plugin_init (GstPlugin * plugin)
 {
   return gst_element_register (plugin, "rtpvorbispay",
       GST_RANK_SECONDARY, GST_TYPE_RTP_VORBIS_PAY);
 }
	/* 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., 59 Temple Place - Suite 330,
	* Boston, MA 02111-1307, USA.
	*/

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

	#include <string.h>

	#include <gst/rtp/gstrtpbuffer.h>

	#include "fnv1hash.h"
	#include "gstrtpvorbispay.h"

	GST_DEBUG_CATEGORY_STATIC (rtpvorbispay_debug);
	#define GST_CAT_DEFAULT (rtpvorbispay_debug)

	/* references:
	* http://www.rfc-editor.org/rfc/rfc5215.txt
	*/

	static GstStaticPadTemplate gst_rtp_vorbis_pay_src_template =
	GST_STATIC_PAD_TEMPLATE ("src",
	GST_PAD_SRC,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS ("application/x-rtp, "
	"media = (string) \"audio\", "
	"payload = (int) " GST_RTP_PAYLOAD_DYNAMIC_STRING ", "
	"clock-rate = (int) [1, MAX ], " "encoding-name = (string) \"VORBIS\""
	/* All required parameters
	*
	* "encoding-params = (string) <num channels>"
	* "configuration = (string) ANY"
	*/
	)
	);

	static GstStaticPadTemplate gst_rtp_vorbis_pay_sink_template =
	GST_STATIC_PAD_TEMPLATE ("sink",
	GST_PAD_SINK,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS ("audio/x-vorbis")
	);

	#define gst_rtp_vorbis_pay_parent_class parent_class
	G_DEFINE_TYPE (GstRtpVorbisPay, gst_rtp_vorbis_pay, GST_TYPE_RTP_BASE_PAYLOAD);

	static gboolean gst_rtp_vorbis_pay_setcaps (GstRTPBasePayload * basepayload,
	GstCaps * caps);
	static GstStateChangeReturn gst_rtp_vorbis_pay_change_state (GstElement *
	element, GstStateChange transition);
	static GstFlowReturn gst_rtp_vorbis_pay_handle_buffer (GstRTPBasePayload * pad,
	GstBuffer * buffer);
	static gboolean gst_rtp_vorbis_pay_sink_event (GstRTPBasePayload * payload,
	GstEvent * event);

	static void
	gst_rtp_vorbis_pay_class_init (GstRtpVorbisPayClass * klass)
	{
	GstElementClass *gstelement_class;
	GstRTPBasePayloadClass *gstrtpbasepayload_class;

	gstelement_class = (GstElementClass *) klass;
	gstrtpbasepayload_class = (GstRTPBasePayloadClass *) klass;

	gstelement_class->change_state = gst_rtp_vorbis_pay_change_state;

	gstrtpbasepayload_class->set_caps = gst_rtp_vorbis_pay_setcaps;
	gstrtpbasepayload_class->handle_buffer = gst_rtp_vorbis_pay_handle_buffer;
	gstrtpbasepayload_class->sink_event = gst_rtp_vorbis_pay_sink_event;

	gst_element_class_add_pad_template (gstelement_class,
	gst_static_pad_template_get (&gst_rtp_vorbis_pay_src_template));
	gst_element_class_add_pad_template (gstelement_class,
	gst_static_pad_template_get (&gst_rtp_vorbis_pay_sink_template));

	gst_element_class_set_static_metadata (gstelement_class,
	"RTP Vorbis depayloader",
	"Codec/Payloader/Network/RTP",
	"Payload-encode Vorbis audio into RTP packets (RFC 5215)",
	"Wim Taymans <wimi.taymans@gmail.com>");

	GST_DEBUG_CATEGORY_INIT (rtpvorbispay_debug, "rtpvorbispay", 0,
	"Vorbis RTP Payloader");
	}

	static void
	gst_rtp_vorbis_pay_init (GstRtpVorbisPay * rtpvorbispay)
	{
	/* needed because of GST_BOILERPLATE */
	}

	static void
	gst_rtp_vorbis_pay_clear_packet (GstRtpVorbisPay * rtpvorbispay)
	{
	if (rtpvorbispay->packet)
	gst_buffer_unref (rtpvorbispay->packet);
	rtpvorbispay->packet = NULL;
	}

	static void
	gst_rtp_vorbis_pay_cleanup (GstRtpVorbisPay * rtpvorbispay)
	{
	g_list_foreach (rtpvorbispay->headers, (GFunc) gst_mini_object_unref, NULL);
	g_list_free (rtpvorbispay->headers);
	rtpvorbispay->headers = NULL;

	gst_rtp_vorbis_pay_clear_packet (rtpvorbispay);
	}

	static gboolean
	gst_rtp_vorbis_pay_setcaps (GstRTPBasePayload * basepayload, GstCaps * caps)
	{
	GstRtpVorbisPay *rtpvorbispay;

	rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);

	rtpvorbispay->need_headers = TRUE;

	return TRUE;
	}

	static void
	gst_rtp_vorbis_pay_reset_packet (GstRtpVorbisPay * rtpvorbispay, guint8 VDT)
	{
	guint payload_len;
	GstRTPBuffer rtp = { NULL };

	GST_LOG_OBJECT (rtpvorbispay, "reset packet");

	rtpvorbispay->payload_pos = 4;
	gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_READ, &rtp);
	payload_len = gst_rtp_buffer_get_payload_len (&rtp);
	gst_rtp_buffer_unmap (&rtp);
	rtpvorbispay->payload_left = payload_len - 4;
	rtpvorbispay->payload_duration = 0;
	rtpvorbispay->payload_F = 0;
	rtpvorbispay->payload_VDT = VDT;
	rtpvorbispay->payload_pkts = 0;
	}

	static void
	gst_rtp_vorbis_pay_init_packet (GstRtpVorbisPay * rtpvorbispay, guint8 VDT,
	GstClockTime timestamp)
	{
	GST_LOG_OBJECT (rtpvorbispay, "starting new packet, VDT: %d", VDT);

	if (rtpvorbispay->packet)
	gst_buffer_unref (rtpvorbispay->packet);

	/* new packet allocate max packet size */
	rtpvorbispay->packet =
	gst_rtp_buffer_new_allocate_len (GST_RTP_BASE_PAYLOAD_MTU
	(rtpvorbispay), 0, 0);
	gst_rtp_vorbis_pay_reset_packet (rtpvorbispay, VDT);
	GST_BUFFER_TIMESTAMP (rtpvorbispay->packet) = timestamp;
	}

	static GstFlowReturn
	gst_rtp_vorbis_pay_flush_packet (GstRtpVorbisPay * rtpvorbispay)
	{
	GstFlowReturn ret;
	guint8 *payload;
	guint hlen;
	GstRTPBuffer rtp = { NULL };

	/* check for empty packet */
	if (!rtpvorbispay->packet \|\| rtpvorbispay->payload_pos <= 4)
	return GST_FLOW_OK;

	GST_LOG_OBJECT (rtpvorbispay, "flushing packet");

	gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_WRITE, &rtp);

	/* fix header */
	payload = gst_rtp_buffer_get_payload (&rtp);
	/*
	* 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 \|VDT\|# pkts.\|
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	*
	* F: Fragment type (0=none, 1=start, 2=cont, 3=end)
	* VDT: Vorbis data type (0=vorbis, 1=config, 2=comment, 3=reserved)
	* pkts: number of packets.
	*/
	payload[0] = (rtpvorbispay->payload_ident >> 16) & 0xff;
	payload[1] = (rtpvorbispay->payload_ident >> 8) & 0xff;
	payload[2] = (rtpvorbispay->payload_ident) & 0xff;
	payload[3] = (rtpvorbispay->payload_F & 0x3) << 6 \|
	(rtpvorbispay->payload_VDT & 0x3) << 4 \|
	(rtpvorbispay->payload_pkts & 0xf);

	gst_rtp_buffer_unmap (&rtp);

	/* shrink the buffer size to the last written byte */
	hlen = gst_rtp_buffer_calc_header_len (0);
	gst_buffer_resize (rtpvorbispay->packet, 0, hlen + rtpvorbispay->payload_pos);

	GST_BUFFER_DURATION (rtpvorbispay->packet) = rtpvorbispay->payload_duration;

	/* push, this gives away our ref to the packet, so clear it. */
	ret =
	gst_rtp_base_payload_push (GST_RTP_BASE_PAYLOAD (rtpvorbispay),
	rtpvorbispay->packet);
	rtpvorbispay->packet = NULL;

	return ret;
	}

	static gboolean
	gst_rtp_vorbis_pay_finish_headers (GstRTPBasePayload * basepayload)
	{
	GstRtpVorbisPay *rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);
	GList *walk;
	guint length, size, n_headers, configlen;
	gchar cstr, configuration;
	guint8 data, config;
	guint32 ident;
	gboolean res;

	GST_DEBUG_OBJECT (rtpvorbispay, "finish headers");

	if (!rtpvorbispay->headers)
	goto no_headers;

	/* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	* \| Number of packed headers \|
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	* \| Packed header \|
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	* \| Packed header \|
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	* \| .... \|
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	*
	* We only construct a config containing 1 packed header like this:
	*
	* 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 \|
	* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	*/

	/* we need 4 bytes for the number of headers (which is always 1), 3 bytes for
	* the ident, 2 bytes for length, 1 byte for n. of headers. */
	size = 4 + 3 + 2 + 1;

	/* count the size of the headers first and update the hash */
	length = 0;
	n_headers = 0;
	ident = fnv1_hash_32_new ();
	for (walk = rtpvorbispay->headers; walk; walk = g_list_next (walk)) {
	GstBuffer *buf = GST_BUFFER_CAST (walk->data);
	GstMapInfo map;
	guint bsize;

	bsize = gst_buffer_get_size (buf);
	length += bsize;
	n_headers++;

	/* count number of bytes needed for length fields, we don't need this for
	* the last header. */
	if (g_list_next (walk)) {
	do {
	size++;
	bsize >>= 7;
	} while (bsize);
	}
	/* update hash */
	gst_buffer_map (buf, &map, GST_MAP_READ);
	ident = fnv1_hash_32_update (ident, map.data, map.size);
	gst_buffer_unmap (buf, &map);
	}

	/* packet length is header size + packet length */
	configlen = size + length;
	config = data = g_malloc (configlen);

	/* number of packed headers, we only pack 1 header */
	data[0] = 0;
	data[1] = 0;
	data[2] = 0;
	data[3] = 1;

	ident = fnv1_hash_32_to_24 (ident);
	rtpvorbispay->payload_ident = ident;
	GST_DEBUG_OBJECT (rtpvorbispay, "ident 0x%08x", ident);

	/* take lower 3 bytes */
	data[4] = (ident >> 16) & 0xff;
	data[5] = (ident >> 8) & 0xff;
	data[6] = ident & 0xff;

	/* store length of all vorbis headers */
	data[7] = ((length) >> 8) & 0xff;
	data[8] = (length) & 0xff;

	/* store number of headers minus one. */
	data[9] = n_headers - 1;
	data += 10;

	/* store length for each header */
	for (walk = rtpvorbispay->headers; walk; walk = g_list_next (walk)) {
	GstBuffer *buf = GST_BUFFER_CAST (walk->data);
	guint bsize, size, temp;
	guint flag;

	/* only need to store the length when it's not the last header */
	if (!g_list_next (walk))
	break;

	bsize = gst_buffer_get_size (buf);

	/* calc size */
	size = 0;
	do {
	size++;
	bsize >>= 7;
	} while (bsize);
	temp = size;

	bsize = gst_buffer_get_size (buf);
	/* write the size backwards */
	flag = 0;
	while (size) {
	size--;
	data[size] = (bsize & 0x7f) \| flag;
	bsize >>= 7;
	flag = 0x80; /* Flag bit on all bytes of the length except the last */
	}
	data += temp;
	}

	/* copy header data */
	for (walk = rtpvorbispay->headers; walk; walk = g_list_next (walk)) {
	GstBuffer *buf = GST_BUFFER_CAST (walk->data);

	gst_buffer_extract (buf, 0, data, gst_buffer_get_size (buf));
	data += gst_buffer_get_size (buf);
	}

	/* serialize to base64 */
	configuration = g_base64_encode (config, configlen);
	g_free (config);

	/* configure payloader settings */
	cstr = g_strdup_printf ("%d", rtpvorbispay->channels);
	gst_rtp_base_payload_set_options (basepayload, "audio", TRUE, "VORBIS",
	rtpvorbispay->rate);
	res =
	gst_rtp_base_payload_set_outcaps (basepayload, "encoding-params",
	G_TYPE_STRING, cstr, "configuration", G_TYPE_STRING, configuration, NULL);
	g_free (cstr);
	g_free (configuration);

	return res;

	/* ERRORS */
	no_headers:
	{
	GST_DEBUG_OBJECT (rtpvorbispay, "finish headers");
	return FALSE;
	}
	}

	static gboolean
	gst_rtp_vorbis_pay_parse_id (GstRTPBasePayload * basepayload, guint8 * data,
	guint size)
	{
	GstRtpVorbisPay *rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);
	guint8 channels;
	gint32 rate, version;

	if (G_UNLIKELY (size < 16))
	goto too_short;

	if (G_UNLIKELY (memcmp (data, "\001vorbis", 7)))
	goto invalid_start;
	data += 7;

	if (G_UNLIKELY ((version = GST_READ_UINT32_LE (data)) != 0))
	goto invalid_version;
	data += 4;

	if (G_UNLIKELY ((channels = *data++) < 1))
	goto invalid_channels;

	if (G_UNLIKELY ((rate = GST_READ_UINT32_LE (data)) < 1))
	goto invalid_rate;

	/* all fine, store the values */
	rtpvorbispay->channels = channels;
	rtpvorbispay->rate = rate;

	return TRUE;

	/* ERRORS */
	too_short:
	{
	GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
	("Identification packet is too short, need at least 16, got %d", size),
	(NULL));
	return FALSE;
	}
	invalid_start:
	{
	GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
	("Invalid header start in identification packet"), (NULL));
	return FALSE;
	}
	invalid_version:
	{
	GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
	("Invalid version, expected 0, got %d", version), (NULL));
	return FALSE;
	}
	invalid_rate:
	{
	GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
	("Invalid rate %d", rate), (NULL));
	return FALSE;
	}
	invalid_channels:
	{
	GST_ELEMENT_ERROR (basepayload, STREAM, DECODE,
	("Invalid channels %d", channels), (NULL));
	return FALSE;
	}
	}

	static GstFlowReturn
	gst_rtp_vorbis_pay_handle_buffer (GstRTPBasePayload * basepayload,
	GstBuffer * buffer)
	{
	GstRtpVorbisPay *rtpvorbispay;
	GstFlowReturn ret;
	guint newsize;
	GstMapInfo map;
	gsize size;
	guint8 *data;
	guint packet_len;
	GstClockTime duration, newduration, timestamp;
	gboolean flush;
	guint8 VDT;
	guint plen;
	guint8 ppos, payload;
	gboolean fragmented;
	GstRTPBuffer rtp = { NULL };

	rtpvorbispay = GST_RTP_VORBIS_PAY (basepayload);

	gst_buffer_map (buffer, &map, GST_MAP_READ);
	data = map.data;
	size = map.size;
	duration = GST_BUFFER_DURATION (buffer);
	timestamp = GST_BUFFER_TIMESTAMP (buffer);

	GST_LOG_OBJECT (rtpvorbispay, "size %" G_GSIZE_FORMAT
	", duration %" GST_TIME_FORMAT, size, GST_TIME_ARGS (duration));

	if (G_UNLIKELY (size < 1 \|\| size > 0xffff))
	goto wrong_size;

	/* find packet type */
	if (data[0] & 1) {
	/* header */
	if (data[0] == 1) {
	/* identification, we need to parse this in order to get the clock rate. */
	if (G_UNLIKELY (!gst_rtp_vorbis_pay_parse_id (basepayload, data, size)))
	goto parse_id_failed;
	VDT = 1;
	} else if (data[0] == 3) {
	/* comment */
	VDT = 2;
	} else if (data[0] == 5) {
	/* setup */
	VDT = 1;
	} else
	goto unknown_header;
	} else
	/* data */
	VDT = 0;

	if (rtpvorbispay->need_headers) {
	/* we need to collect the headers and construct a config string from them */
	if (VDT != 0) {
	GST_DEBUG_OBJECT (rtpvorbispay, "collecting header");
	/* append header to the list of headers */
	gst_buffer_unmap (buffer, &map);
	rtpvorbispay->headers = g_list_append (rtpvorbispay->headers, buffer);
	ret = GST_FLOW_OK;
	goto done;
	} else {
	if (!gst_rtp_vorbis_pay_finish_headers (basepayload))
	goto header_error;
	rtpvorbispay->need_headers = FALSE;
	}
	}

	/* size increases with packet length and 2 bytes size eader. */
	newduration = rtpvorbispay->payload_duration;
	if (duration != GST_CLOCK_TIME_NONE)
	newduration += duration;

	newsize = rtpvorbispay->payload_pos + 2 + size;
	packet_len = gst_rtp_buffer_calc_packet_len (newsize, 0, 0);

	/* check buffer filled against length and max latency */
	flush = gst_rtp_base_payload_is_filled (basepayload, packet_len, newduration);
	/* we can store up to 15 vorbis packets in one RTP packet. */
	flush \|= (rtpvorbispay->payload_pkts == 15);
	/* flush if we have a new VDT */
	if (rtpvorbispay->packet)
	flush \|= (rtpvorbispay->payload_VDT != VDT);
	if (flush)
	gst_rtp_vorbis_pay_flush_packet (rtpvorbispay);

	/* create new packet if we must */
	if (!rtpvorbispay->packet) {
	gst_rtp_vorbis_pay_init_packet (rtpvorbispay, VDT, timestamp);
	}

	gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_WRITE, &rtp);
	payload = gst_rtp_buffer_get_payload (&rtp);
	ppos = payload + rtpvorbispay->payload_pos;
	fragmented = FALSE;

	ret = GST_FLOW_OK;

	/* put buffer in packet, it either fits completely or needs to be fragmented
	* over multiple RTP packets. */
	while (size) {
	plen = MIN (rtpvorbispay->payload_left - 2, size);

	GST_LOG_OBJECT (rtpvorbispay, "append %u bytes", plen);

	/* data is copied in the payload with a 2 byte length header */
	ppos[0] = (plen >> 8) & 0xff;
	ppos[1] = (plen & 0xff);
	memcpy (&ppos[2], data, plen);

	size -= plen;
	data += plen;

	rtpvorbispay->payload_pos += plen + 2;
	rtpvorbispay->payload_left -= plen + 2;

	if (fragmented) {
	if (size == 0)
	/* last fragment, set F to 0x3. */
	rtpvorbispay->payload_F = 0x3;
	else
	/* fragment continues, set F to 0x2. */
	rtpvorbispay->payload_F = 0x2;
	} else {
	if (size > 0) {
	/* fragmented packet starts, set F to 0x1, mark ourselves as
	* fragmented. */
	rtpvorbispay->payload_F = 0x1;
	fragmented = TRUE;
	}
	}
	if (fragmented) {
	gst_rtp_buffer_unmap (&rtp);
	/* fragmented packets are always flushed and have ptks of 0 */
	rtpvorbispay->payload_pkts = 0;
	ret = gst_rtp_vorbis_pay_flush_packet (rtpvorbispay);

	if (size > 0) {
	/* start new packet and get pointers. VDT stays the same. */
	gst_rtp_vorbis_pay_init_packet (rtpvorbispay,
	rtpvorbispay->payload_VDT, timestamp);
	gst_rtp_buffer_map (rtpvorbispay->packet, GST_MAP_WRITE, &rtp);
	payload = gst_rtp_buffer_get_payload (&rtp);
	ppos = payload + rtpvorbispay->payload_pos;
	}
	} else {
	/* unfragmented packet, update stats for next packet, size == 0 and we
	* exit the while loop */
	rtpvorbispay->payload_pkts++;
	if (duration != GST_CLOCK_TIME_NONE)
	rtpvorbispay->payload_duration += duration;
	}
	}

	if (rtp.buffer)
	gst_rtp_buffer_unmap (&rtp);

	gst_buffer_unmap (buffer, &map);
	gst_buffer_unref (buffer);

	done:
	return ret;

	/* ERRORS */
	wrong_size:
	{
	GST_ELEMENT_WARNING (rtpvorbispay, STREAM, DECODE,
	("Invalid packet size (1 < %" G_GSIZE_FORMAT " <= 0xffff)", size),
	(NULL));
	gst_buffer_unmap (buffer, &map);
	gst_buffer_unref (buffer);
	return GST_FLOW_OK;
	}
	parse_id_failed:
	{
	gst_buffer_unmap (buffer, &map);
	gst_buffer_unref (buffer);
	return GST_FLOW_ERROR;
	}
	unknown_header:
	{
	GST_ELEMENT_WARNING (rtpvorbispay, STREAM, DECODE,
	(NULL), ("Ignoring unknown header received"));
	gst_buffer_unmap (buffer, &map);
	gst_buffer_unref (buffer);
	return GST_FLOW_OK;
	}
	header_error:
	{
	GST_ELEMENT_WARNING (rtpvorbispay, STREAM, DECODE,
	(NULL), ("Error initializing header config"));
	gst_buffer_unmap (buffer, &map);
	gst_buffer_unref (buffer);
	return GST_FLOW_OK;
	}
	}

	static gboolean
	gst_rtp_vorbis_pay_sink_event (GstRTPBasePayload * payload, GstEvent * event)
	{
	GstRtpVorbisPay *rtpvorbispay = GST_RTP_VORBIS_PAY (payload);

	switch (GST_EVENT_TYPE (event)) {
	case GST_EVENT_FLUSH_STOP:
	gst_rtp_vorbis_pay_clear_packet (rtpvorbispay);
	break;
	default:
	break;
	}
	/* false to let parent handle event as well */
	return GST_RTP_BASE_PAYLOAD_CLASS (parent_class)->sink_event (payload, event);
	}

	static GstStateChangeReturn
	gst_rtp_vorbis_pay_change_state (GstElement * element,
	GstStateChange transition)
	{
	GstRtpVorbisPay *rtpvorbispay;
	GstStateChangeReturn ret;

	rtpvorbispay = GST_RTP_VORBIS_PAY (element);

	switch (transition) {
	default:
	break;
	}

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

	switch (transition) {
	case GST_STATE_CHANGE_PAUSED_TO_READY:
	gst_rtp_vorbis_pay_cleanup (rtpvorbispay);
	break;
	default:
	break;
	}
	return ret;
	}

	gboolean
	gst_rtp_vorbis_pay_plugin_init (GstPlugin * plugin)
	{
	return gst_element_register (plugin, "rtpvorbispay",
	GST_RANK_SECONDARY, GST_TYPE_RTP_VORBIS_PAY);
	}