NAME

       Net::SIP::SDP - Parsing and manipulation of SDP data for SIP

SYNOPSIS

         my $sdp = Net::SIP::SDP->new( sdp_string );
         my @media = $sdp->get_media;

DESCRIPTION

       Net::SIP::SDP can parse and manipulate SDP data.

       It's not a general purpose SDP class (like Net::SDP) but designed to work with SDP data
       contained in SIP packets and for easy extraction and manipulation (for NAT etc) of media
       information contained in the SDP.

       The class is also designed for easy creation of SDP bodies in the context of the rest of
       Net::SIP::*.

EXAMPLES

         # creation based on media data
         my $sdp = Net::SIP::SDP->new(
               { addr => '192.168.0.1' },
               { port => 2012, proto => 'RTP/AVP', media => 'audio', fmt => 0 },
               { port => 2014, proto => 'RTP/AVP', media => 'video', fmt => 0 },
         );

         # parse from string
         my $sdp = Net::SIP::SDP->new( sdp_string );

         # extract all media data
         my @media = $sdp->get_media;

         # and replace them with new addr + port (for NAT)
         my @new_media,;
         foreach (@media) {
               my ($port,@socks) = create_rtp_sockets( '192.168.178.1', $_->{range} );
               push @new_media, [ '192.168.178.1', $port ];
               ...
         }
         $sdp->replace_media_listen( @new_media );

CONSTRUCTOR

       new Default constructor.  Depending on kind of arguments branches into new_from_string or
           new_from_parts.  See there.

       new_from_string ( STRING )
           Creates object from STRING containing the SDP data.  Raises an exception (e.g. die())
           if SDP is invalid.

       new_from_parts ( \%GLOBAL, @MEDIA )
           Creates object from specification.  %GLOBAL describes the global keys, usually only a
           common "addr" for all media but any of the keys defined in RFC2327 can be used.

           @MEDIA is a list of hash references, one hash for each media part. These hashes can
           contain as keys the one-letter keys specified in RFC2327 and/or special keys for
           constructing the 'c' and 'm' line:

           addr - The address, used in the 'c' line.
           port -  The port number
           range - Range of ports, for RTP/AVP defaults to 2, else 1
           media - The media typ, e.g. 'audio','video',...
           proto - Transport protocol, ususally 'RTP/AVP' or 'udp'

           If the SDP should contain multiple values for the same key in the same media section
           on can specifiy the value for the key as a \@list instead of a string (this is often
           the case for 'a' lines).

METHODS

       as_string
           Returns string representation for object.

       content_type
           Returns 'application/sdp'

       get_media
           Returns list of all media described in the SDP. If the caller expects an array the
           result will be a list, otherwise a reference to a list.

           Each element of the list is a hash with the following keys:

           addr - IP4/IP6 address for media
           port - Start port
           range - Range for ports
           proto - Media proto, usually 'RTP/AVP' or 'udp'
           media - Media typ, usually 'audio', 'video' or 'data'
           fmt - Format info from media line as \@list, e.g "[ 0,10,5 ]".
           lines - All lines from media description as \@list of [ key,value ].

           WARNING! You should never manipulate the values you got from this function, because
           this might affect the objects internals.

       replace_media_listen ( NEW_MEDIA )
           Replaces the exisisting media in the object with new media. Useful for NAT.

           NEW_MEDIA is ether an array or a reference to an array. Each element in the list
           consists of the new [ addr,port ] mapping for the matching media entry.

           The number of entries in the list should be the same as the number of media entries in
           the object ( see get_media ). If this is not the case it will "die()".

       name2int ( NAME, INDEX )
           Returns the RTP payload id for NAME (e.g. "telephone-event/8000").  INDEX is the index
           into the list of media information, matching the list returned from get_media. INDEX
           can also be 'audio','video'.., which will then lookup at the first matching entry in
           the media list.