NkSIP SDP API

Function	Description
new/2	Generates a simple base SDP record
new/0	Generates a simple base SDP record using host "auto.nksip"
empty/0	Generates an empty SDP record, using host "auto.nksip"
increment/1	Increments the SDP version by one
update/2	Updates and SDP changing all medias
is_sdp/1	Checks if term is an valid SDP
is_new/2	Checks if SDP2 is newer than SDP1
parse/1	Parses a binary SDP packet
unparse/1	Generates a binary SDP packet from an nksip_sdp:sdp() record.

Example

1> SDP = nksip_sdp:new("local", [
        {<<"audio">>, 10000, [{rtpmap, 0, "Params0"}, {rtpmap, 1, "Params1"}, sendrecv]},
        {<<"video">>, 10001, [{rtpmap, 2, "Params2"}, {rtpmap, 3, "Params3"}, sendrecv]}
   ]).
#sdp{sdp_vsn = <<"0">>,user = <<"-">>,id = 1405007035,
     vsn = 1405007035,
     address = {<<"IN">>,<<"IP4">>,<<"local">>},
     session = <<"nksip">>,info = undefined,uri = undefined,
     email = undefined,phone = undefined,
     connect = {<<"IN">>,<<"IP4">>,<<"local">>},
     bandwidth = [],
     time = [{0,0,[]}],
     zone = undefined,key = undefined,attributes = [],
     medias = [#sdp_m{media = <<"audio">>,port = 10000,
                      nports = 1,proto = <<"RTP/AVP">>,
                      fmt = [<<"0">>,<<"1">>],
                      info = undefined,connect = undefined,bandwidth = [],
                      key = undefined,...},
               #sdp_m{media = <<"video">>,port = 10001,nports = 1,
                      proto = <<"RTP/AVP">>,
                      fmt = [<<"2">>,<<"3">>],
                      info = undefined,connect = undefined,bandwidth = [],...}]}
                      
2> io:format("~s", [nksip_sdp:unparse(SDP)]).
v=0
o=- 1405007035 1405007035 IN IP4 local
s=nksip
c=IN IP4 local
t=0 0
m=audio 10000 RTP/AVP 0 1
a=rtpmap:0 Params0
a=rtpmap:1 Params1
a=sendrecv
m=video 10001 RTP/AVP 2 3
a=rtpmap:2 Params2
a=rtpmap:3 Params3
a=sendrecv
ok

API

new/2

nksip_sdp:new(Host::string()|binary(), MediaSpecs::[nksip_sdp:media_spec()]) -> 
    nksip_sdp:sdp().

Generates a simple base SDP record.

It will use the indicated Host and a MediaSpecs description to generate a new nksip_sdp:sdp() record, having several m sections, one for each media.

Each media must define a Media (like <<"audio">> or <<"video">>), a Port and a list of Attributes. Each attributes can have the form {rtpmap, Pos, Data} to define a codec (like {rtpmap, 0, <<"PCMU/8000">>}) or a standard SDP a attribute (like <<"inactive">> or <<"ptime:30">>). The class will be RTP/AVP.

If Host is "auto.nksip", NkSIP it will be changed to the current local address before sending.

new/0

nksip_sdp:new() ->
    nksip_sdp:sdp().

Generates a simple base SDP record (see new/2, using host "auto.nksip", port 1080, codec "PCMU", and inactive.

empty/0

nksip_sdp:empty() ->
    nksip_sdp:sdp().

Generates an empty SDP record, using host "auto.nksip" (see new/2). Equivalent to new(<<"auto.nksip">>, []).

increment/1

nksip_sdp:increment(nksip_sdp:sdp()) ->
    nksip_sdp:sdp().

Increments the SDP version by one.

update/2

nksip_sdp:update(nksip_sdp:sdp(), inactive | recvonly | sendonly | sendrecv) ->
    nksip_sdp:sdp().

Updates and SDP changing all medias to inactive, recvonly, sendonly or sendrecv and incrementing the SDP version.

is_sdp/1

nksip_sdp:is_sdp(term()) ->
    boolean().

Checks if term is an valid SDP.

is_new/2

nksip_sdp:is_new(SDP2::undefined|nksip_sdp:sdp(), SDP1::undefined|nksip_sdp:sdp()) ->
    boolean().

Checks if SDP2 is newer than SDP1. If any of them are undefined, returns false.

parse/1

nksip_sdp:parse(binary()) -> 
    nksip_sdp:sdp() | error.

Parses a binary SDP packet into a nksip_sdp:sdp() record or error.

unparse/1

nksip_sdp:unparse(nksip_sdp:sdp()) -> 
    binary().

Generates a binary SDP packet from an nksip_sdp:sdp() record.