--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_base/gst-libs/gst/rtp/README Fri Apr 16 15:15:52 2010 +0300
@@ -0,0 +1,66 @@
+The RTP libraries
+---------------------
+
+ RTP Buffers
+ -----------
+ The real time protocol as described in RFC 3550 requires the use of special
+ packets containing an additional RTP header of at least 12 bytes. GStreamer
+ provides some helper functions for creating and parsing these RTP headers.
+ The result is a normal #GstBuffer with an additional RTP header.
+
+ RTP buffers are usually created with gst_rtp_buffer_new_allocate() or
+ gst_rtp_buffer_new_allocate_len(). These functions create buffers with a
+ preallocated space of memory. It will also ensure that enough memory
+ is allocated for the RTP header. The first function is used when the payload
+ size is known. gst_rtp_buffer_new_allocate_len() should be used when the size
+ of the whole RTP buffer (RTP header + payload) is known.
+
+ When receiving RTP buffers from a network, gst_rtp_buffer_new_take_data()
+ should be used when the user would like to parse that RTP packet. (TODO Ask
+ Wim what the real purpose of this function is as it seems to simply create a
+ duplicate GstBuffer with the same data as the previous one). The
+ function will create a new RTP buffer with the given data as the whole RTP
+ packet. Alternatively, gst_rtp_buffer_new_copy_data() can be used if the user
+ wishes to make a copy of the data before using it in the new RTP buffer. An
+ important function is gst_rtp_buffer_validate() that is used to verify that
+ the buffer a well formed RTP buffer.
+
+ It is now possible to use all the gst_rtp_buffer_get_*() or
+ gst_rtp_buffer_set_*() functions to read or write the different parts of the
+ RTP header such as the payload type, the sequence number or the RTP
+ timestamp. The use can also retreive a pointer to the actual RTP payload data
+ using the gst_rtp_buffer_get_payload() function.
+
+ RTP Base Payloader Class (GstBaseRTPPayload)
+ --------------------------------------------
+
+ All RTP payloader elements (audio or video) should derive from this class.
+
+ RTP Base Audio Payloader Class (GstBaseRTPAudioPayload)
+ -------------------------------------------------------
+
+ This base class can be tested through it's children classes. Here is an
+ example using the iLBC payloader (frame based).
+
+ For 20ms mode :
+
+ GST_DEBUG="basertpaudiopayload:5" gst-launch-0.10 fakesrc sizetype=2
+ sizemax=114 datarate=1900 ! audio/x-iLBC, mode=20 ! rtpilbcpay
+ max-ptime="40000000" ! fakesink
+
+ For 30ms mode :
+
+ GST_DEBUG="basertpaudiopayload:5" gst-launch-0.10 fakesrc sizetype=2
+ sizemax=150 datarate=1662 ! audio/x-iLBC, mode=30 ! rtpilbcpay
+ max-ptime="60000000" ! fakesink
+
+ Here is an example using the uLaw payloader (sample based).
+
+ GST_DEBUG="basertpaudiopayload:5" gst-launch-0.10 fakesrc sizetype=2
+ sizemax=150 datarate=8000 ! audio/x-mulaw ! rtppcmupay max-ptime="6000000" !
+ fakesink
+
+ RTP Base Depayloader Class (GstBaseRTPDepayload)
+ ------------------------------------------------
+
+ All RTP depayloader elements (audio or video) should derive from this class.