ortp-rtpsession-api.html

ortp协议栈（实时传输协议）

></TT
> with timestamp <TT
CLASS="PARAMETER"
><I
>userts</I
></TT
>. This is a high level function that uses
<A
HREF="ortp-rtpsession-api.html#RTP-SESSION-CREATE-PACKET"
>rtp_session_create_packet</A
>() and <A
HREF="ortp-rtpsession-api.html#RTP-SESSION-SENDM-WITH-TS"
>rtp_session_sendm_with_ts</A
>() to send the data.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN451"><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"
> a rtp session.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>buffer</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>	a buffer containing the data to be sent in a rtp packet.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>len</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>		the length of the data buffer, in bytes.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>userts</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>	the timestamp of the data to be sent. Refer to the rfc to know what it is.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>Returns</I
></SPAN
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the number of bytes sent over the network.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN476"
></A
><H3
><A
NAME="RTP-SESSION-RECV-WITH-TS"
></A
>rtp_session_recv_with_ts ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>gint        rtp_session_recv_with_ts        (<A
HREF="ortp-rtpsession-api.html#RTPSESSION"
>RtpSession</A
> *session,
                                             gchar *buffer,
                                             gint len,
                                             guint32 time,
                                             gint *have_more);</PRE
></TD
></TR
></TABLE
><P
>Tries to read the bytes of the incoming rtp stream related to timestamp <TT
CLASS="PARAMETER"
><I
>time</I
></TT
>. In case 
where the user supplied buffer <TT
CLASS="PARAMETER"
><I
>buffer</I
></TT
> is not large enough to get all the data 
related to timestamp <TT
CLASS="PARAMETER"
><I
>time</I
></TT
>, then *( <TT
CLASS="PARAMETER"
><I
>have_more</I
></TT
>) is set to 1 to indicate that the application
should recall the function with the same timestamp to get more data.</P
><P
> When the rtp session is scheduled (see <A
HREF="ortp-rtpsession-api.html#RTP-SESSION-SET-SCHEDULING-MODE"
>rtp_session_set_scheduling_mode</A
>() ), and the 
blocking mode is on (see <A
HREF="ortp-rtpsession-api.html#RTP-SESSION-SET-BLOCKING-MODE"
>rtp_session_set_blocking_mode</A
>() ), then the calling thread
is suspended until the timestamp given as argument expires, whatever a received packet 
fits the query or not.</P
><P
>Important note: it is clear that the application cannot know the timestamp of the first
packet of the incoming stream, because it can be random. The <TT
CLASS="PARAMETER"
><I
>time</I
></TT
> timestamp given to the
function is used relatively to first timestamp of the stream. In simple words, 0 is a good
value to start calling this function.</P
><P
>This function internally calls <A
HREF="ortp-rtpsession-api.html#RTP-SESSION-RECVM-WITH-TS"
>rtp_session_recvm_with_ts</A
>() to get a rtp packet. The content
of this packet is then copied into the user supplied buffer in an intelligent manner:
the function takes care of the size of the supplied buffer and the timestamp given in  
argument. Using this function it is possible to read continous audio data (e.g. pcma,pcmu...)
with for example a standart buffer of size of 160 with timestamp incrementing by 160 while the incoming
stream has a different packet size.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN499"><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"
> a rtp session.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>buffer</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>	a user supplied buffer to write the data.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>len</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>		the length in bytes of the user supplied buffer.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>time</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>	the timestamp wanted.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>have_more</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the address of an integer to indicate if more data is availlable for the given timestamp.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>Returns</I
></SPAN
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> if a packet was availlable with the corresponding timestamp supplied in argument 
then the number of bytes written in the user supplied buffer is returned. If no packets
are availlable, either because the sender has not started to send the stream, or either
because silence packet are not transmitted, or either because the packet was lost during
network transport, then the function returns zero.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN528"
></A
><H3
><A
NAME="RTP-SESSION-SENDM-WITH-TS"
></A
>rtp_session_sendm_with_ts ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>gint        rtp_session_sendm_with_ts       (<A
HREF="ortp-rtpsession-api.html#RTPSESSION"
>RtpSession</A
> *session,
                                             mblk_t *mp,
                                             guint32 userts);</PRE
></TD
></TR
></TABLE
><P
>Send the rtp datagram <TT
CLASS="PARAMETER"
><I
>mp</I
></TT
> to the destination set by <A
HREF="ortp-rtpsession-api.html#RTP-SESSION-SET-REMOTE-ADDR"
>rtp_session_set_remote_addr</A
>() 
with timestamp <TT
CLASS="PARAMETER"
><I
>timestamp</I
></TT
>. For audio data, the timestamp is the number
of the first sample resulting of the data transmitted. See rfc1889 for details.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN541"><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"
> a rtp session.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>mp</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>	a rtp packet presented as a mblk_t.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>userts</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>&nbsp;</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>Returns</I
></SPAN
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> the number of bytes sent over the network.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN562"
></A
><H3
><A
NAME="RTP-SESSION-RECVM-WITH-TS"
></A
>rtp_session_recvm_with_ts ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>mblk_t*     rtp_session_recvm_with_ts       (<A
HREF="ortp-rtpsession-api.html#RTPSESSION"
>RtpSession</A
> *session,
                                             guint32 user_ts);</PRE
></TD
></TR
></TABLE
><P
>Try to get a rtp packet presented as a mblk_t structure from the rtp session.
The <TT
CLASS="PARAMETER"
><I
>user_ts</I
></TT
> parameter is relative to the first timestamp of the incoming stream. In other
words, the application does not have to know the first timestamp of the stream, it can
simply call for the first time this function with <TT
CLASS="PARAMETER"
><I
>user_ts</I
></TT
>=0, and then incrementing it
as it want. The RtpSession takes care of synchronisation between the stream timestamp
and the user timestamp given here.</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN573"><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"
> a rtp session.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>user_ts</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>	a timestamp.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>Returns</I
></SPAN
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> a rtp packet presented as a mblk_t.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></DIV
><HR><DIV
CLASS="REFSECT2"
><A
NAME="AEN590"
></A
><H3
><A
NAME="RTP-SESSION-CREATE-PACKET"
></A
>rtp_session_create_packet ()</H3
><TABLE
BORDER="0"
BGCOLOR="#D6E8FF"
WIDTH="100%"
CELLPADDING="6"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>mblk_t*     rtp_session_create_packet       (<A
HREF="ortp-rtpsession-api.html#RTPSESSION"
>RtpSession</A
> *session,
                                             gint header_size,
                                             char *payload,
                                             gint payload_size);</PRE
></TD
></TR
></TABLE
><P
>Allocates a new rtp packet. In the header, ssrc and payload_type according to the session's
context. Timestamp and seq number are not set, there will be set when the packet is going to be
sent with <A
HREF="ortp-rtpsession-api.html#RTP-SESSION-SENDM-WITH-TS"
>rtp_session_sendm_with_ts</A
>().</P
><P
></P
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN601"><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"
>		a rtp session.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>header_size</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>	the rtp header size. For standart size (without extensions), it is RTP_FIXED_HEADER_SIZE</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>payload</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
>data to be copied into the rtp packet.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><TT
CLASS="PARAMETER"
><I
>payload_size</I
></TT
>&nbsp;:</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> size of data carried by the rtp packet.</TD
></TR
><TR
><TD
WIDTH="20%"
ALIGN="RIGHT"
VALIGN="TOP"
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>Returns</I
></SPAN
> :</TD
><TD
WIDTH="80%"
ALIGN="LEFT"
VALIGN="TOP"
> a rtp packet in a mblk_t (message block) structure.</TD
></TR
></TBODY
></TABLE
><P
></P
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