uclmmbase-rtp.html

UCL Common Code Library Routines common to a number of multimedia tools. The library originates

                                             <A
HREF="uclmmbase-rtp.html#RTCP-APP-CALLBACK"
>rtcp_app_callback</A
> appcallback);</PRE
></TD
></TR
></TABLE
><P
>Checks RTCP timer and sends RTCP data when nececessary.  The
interval between RTCP packets is randomized over an interval that
depends on the session bandwidth, the number of participants, and
whether the local participant is a sender.  This function should be
called at least once per second, and can be safely called more
frequently.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1167"
></A
><P
></P
><TABLE
BORDER="0"
WIDTH="100%"
BGCOLOR="#FFD0D0"
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CLASS="CALSTABLE"
><TBODY
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><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>session</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the session pointer (returned by <A
HREF="uclmmbase-rtp.html#RTP-INIT"
>rtp_init</A
>())</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>rtp_ts</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the current time expressed in units of the media timestamp.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>appcallback</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> a callback to create an APP RTCP packet, if needed.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN1185"
></A
><H3
><A
NAME="RTP-UPDATE"
></A
>rtp_update ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>void        rtp_update                      (struct <GTKDOCLINK
HREF="RTP"
>rtp</GTKDOCLINK
> *session);</PRE
></TD
></TR
></TABLE
><P
>Trawls through the internal data structures and performs
housekeeping.  This function should be called at least once per
second.  It uses an internal timer to limit the number of passes
through the data structures to once per second, it can be safely
called more frequently.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1192"
></A
><P
></P
><TABLE
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WIDTH="100%"
BGCOLOR="#FFD0D0"
CELLSPACING="0"
CELLPADDING="4"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>session</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the session pointer (returned by <A
HREF="uclmmbase-rtp.html#RTP-INIT"
>rtp_init</A
>())</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN1202"
></A
><H3
><A
NAME="RTP-MY-SSRC"
></A
>rtp_my_ssrc ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
><GTKDOCLINK
HREF="UINT32-T"
>uint32_t</GTKDOCLINK
>    rtp_my_ssrc                     (struct <GTKDOCLINK
HREF="RTP"
>rtp</GTKDOCLINK
> *session);</PRE
></TD
></TR
></TABLE
><P
></P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1210"
></A
><P
></P
><TABLE
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WIDTH="100%"
BGCOLOR="#FFD0D0"
CELLSPACING="0"
CELLPADDING="4"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>session</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> The RTP Session.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><I
CLASS="EMPHASIS"
>Returns</I
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> The SSRC we are currently using in this session. Note that our
SSRC can change at any time (due to collisions) so applications must not
store the value returned, but rather should call this function each time 
they need it.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN1223"
></A
><H3
><A
NAME="RTP-ADD-CSRC"
></A
>rtp_add_csrc ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>int         rtp_add_csrc                    (struct <GTKDOCLINK
HREF="RTP"
>rtp</GTKDOCLINK
> *session,
                                             <GTKDOCLINK
HREF="UINT32-T"
>uint32_t</GTKDOCLINK
> csrc);</PRE
></TD
></TR
></TABLE
><P
>Adds <TT
CLASS="PARAMETER"
><I
>csrc</I
></TT
> to list of contributing sources used in SDES items.
Used by mixers and transcoders.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1232"
></A
><P
></P
><TABLE
BORDER="0"
WIDTH="100%"
BGCOLOR="#FFD0D0"
CELLSPACING="0"
CELLPADDING="4"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>session</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the session pointer (returned by <A
HREF="uclmmbase-rtp.html#RTP-INIT"
>rtp_init</A
>()) </TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>csrc</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> Constributing SSRC identifier</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><I
CLASS="EMPHASIS"
>Returns</I
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> TRUE.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN1250"
></A
><H3
><A
NAME="RTP-DEL-CSRC"
></A
>rtp_del_csrc ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>int         rtp_del_csrc                    (struct <GTKDOCLINK
HREF="RTP"
>rtp</GTKDOCLINK
> *session,
                                             <GTKDOCLINK
HREF="UINT32-T"
>uint32_t</GTKDOCLINK
> csrc);</PRE
></TD
></TR
></TABLE
><P
>Removes <TT
CLASS="PARAMETER"
><I
>csrc</I
></TT
> from list of contributing sources used in SDES items.
Used by mixers and transcoders.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1259"
></A
><P
></P
><TABLE
BORDER="0"
WIDTH="100%"
BGCOLOR="#FFD0D0"
CELLSPACING="0"
CELLPADDING="4"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>session</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the session pointer (returned by <A
HREF="uclmmbase-rtp.html#RTP-INIT"
>rtp_init</A
>()) </TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>csrc</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> Constributing SSRC identifier</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><I
CLASS="EMPHASIS"
>Returns</I
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> TRUE on success, FALSE if <TT
CLASS="PARAMETER"
><I
>csrc</I
></TT
> is not a valid source.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN1278"
></A
><H3
><A
NAME="RTP-SET-SDES"
></A
>rtp_set_sdes ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>int         rtp_set_sdes                    (struct <GTKDOCLINK
HREF="RTP"
>rtp</GTKDOCLINK
> *session,
                                             <GTKDOCLINK
HREF="UINT32-T"
>uint32_t</GTKDOCLINK
> ssrc,
                                             <A
HREF="uclmmbase-rtp.html#RTCP-SDES-TYPE"
>rtcp_sdes_type</A
> type,
                                             const char *value,
                                             int length);</PRE
></TD
></TR
></TABLE
><P
>Sets session description information associated with participant
<TT
CLASS="PARAMETER"
><I
>ssrc</I
></TT
>.  Under normal circumstances applications always use the
<TT
CLASS="PARAMETER"
><I
>ssrc</I
></TT
> of the local participant, this SDES information is
transmitted in receiver reports.  Setting SDES information for
other participants affects the local SDES entries, but are not
transmitted onto the network.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1289"
></A
><P
></P
><TABLE
BORDER="0"
WIDTH="100%"
BGCOLOR="#FFD0D0"
CELLSPACING="0"
CELLPADDING="4"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>session</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the session pointer (returned by <A
HREF="uclmmbase-rtp.html#RTP-INIT"
>rtp_init</A
>()) </TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>ssrc</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the SSRC identifier of a participant</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>type</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the SDES type represented by <TT
CLASS="PARAMETER"
><I
>value</I
></TT
></TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>value</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the SDES description</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>length</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the length of the description</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><I
CLASS="EMPHASIS"
>Returns</I
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> Returns TRUE if participant exists, FALSE otherwise.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN1320"
></A
><H3
><A
NAME="RTP-GET-SDES"
></A
>rtp_get_sdes ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>const char* rtp_get_sdes                    (struct <GTKDOCLINK
HREF="RTP"
>rtp</GTKDOCLINK
> *session,
                                             <GTKDOCLINK
HREF="UINT32-T"
>uint32_t</GTKDOCLINK
> ssrc,
                                             <A
HREF="uclmmbase-rtp.html#RTCP-SDES-TYPE"
>rtcp_sdes_type</A
> type);</PRE
></TD
></TR
></TABLE
><P
>Recovers session description (SDES) information on participant
identified with <TT
CLASS="PARAMETER"
><I
>ssrc</I
></TT
>.  The SDES information associated with a
source is updated when receiver reports are received.  There are
several different types of SDES information, e.g. username,
location, phone, email.  These are enumerated by <A
HREF="uclmmbase-rtp.html#RTCP-SDES-TYPE"
>rtcp_sdes_type</A
>.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN1331"
></A
><P
></P
><TABLE
BORDER="0"
WIDTH="100%"
BGCOLOR="#FFD0D0"
CELLSPACING="0"
CELLPADDING="4"
CLASS="CALSTABLE"
><TBODY
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>session</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the session pointer (returned by <A
HREF="uclmmbase-rtp.html#RTP-INIT"
>rtp_init</A
>()) </TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>ssrc</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the SSRC identifier of a participant</TD
></TR
><TR
><TD
WIDTH="2