diff -r 9b2c3c7a1a9c -r 567bb019e3e3 gst_plugins_base/gst-libs/gst/rtp/README --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gst_plugins_base/gst-libs/gst/rtp/README Tue Aug 31 15:30:33 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.