rtpbuffer: Add function to transform a GstBuffer into a GstBufferList

Add a new function called gst_rtp_buffer_list_from_buffer() that takes
a GstBuffer containing a RTP packets and spits out a GstBufferList
containing two buffers, one with the header and the other with the payload.

docs/libs/gst-plugins-base-libs-sections.txt

@@ -1288,6 +1288,7 @@ gst_rtp_buffer_new_take_data
 gst_rtp_buffer_new_copy_data
 gst_rtp_buffer_new_allocate
 gst_rtp_buffer_new_allocate_len
+gst_rtp_buffer_list_from_buffer
 
 gst_rtp_buffer_calc_header_len
 gst_rtp_buffer_calc_packet_len

gst-libs/gst/rtp/gstrtpbuffer.c

@@ -2022,3 +2022,38 @@ gst_rtp_buffer_list_add_extension_twobytes_header (GstBufferListIterator * it,
 
   return retval;
 }
+
+/**
+ * gst_rtp_buffer_list_from_buffer:
+ * @buffer: a #GstBuffer containing a RTP packet
+ *
+ * Splits a #GstBuffer into a #GstBufferList containing separate
+ * buffers for the header and data sections.
+ *
+ * Returns: a #GstBufferList
+ */
+
+GstBufferList *
+gst_rtp_buffer_list_from_buffer (GstBuffer * buffer)
+{
+  GstBufferList *bufferlist;
+  GstBuffer *sub;
+  GstBufferListIterator *it;
+  guint8 *payload;
+
+  bufferlist = gst_buffer_list_new ();
+
+  it = gst_buffer_list_iterate (bufferlist);
+  gst_buffer_list_iterator_add_group (it);
+
+  payload = gst_rtp_buffer_get_payload (buffer);
+  sub = gst_buffer_create_sub (buffer, 0, payload - GST_BUFFER_DATA (buffer));
+  gst_buffer_list_iterator_add (it, sub);
+
+  sub = gst_rtp_buffer_get_payload_buffer (buffer);
+  gst_buffer_list_iterator_add (it, sub);
+
+  gst_buffer_list_iterator_free (it);
+
+  return bufferlist;
+}

gst-libs/gst/rtp/gstrtpbuffer.h

@@ -45,6 +45,9 @@ GstBuffer*      gst_rtp_buffer_new_copy_data         (gpointer data, guint len);
 GstBuffer*      gst_rtp_buffer_new_allocate          (guint payload_len, guint8 pad_len, guint8 csrc_count);
 GstBuffer*      gst_rtp_buffer_new_allocate_len      (guint packet_len, guint8 pad_len, guint8 csrc_count);
 
+GstBufferList*  gst_rtp_buffer_list_from_buffer      (GstBuffer * buffer);
+
+
 guint           gst_rtp_buffer_calc_header_len       (guint8 csrc_count);
 guint           gst_rtp_buffer_calc_packet_len       (guint payload_len, guint8 pad_len, guint8 csrc_count);
 guint           gst_rtp_buffer_calc_payload_len      (guint packet_len, guint8 pad_len, guint8 csrc_count);