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|
package sdp
import (
"fmt"
"net/url"
"strconv"
"time"
)
// Constants for SDP attributes used in JSEP
const (
AttrKeyCandidate = "candidate"
AttrKeyEndOfCandidates = "end-of-candidates"
AttrKeyIdentity = "identity"
AttrKeyGroup = "group"
AttrKeySSRC = "ssrc"
AttrKeySSRCGroup = "ssrc-group"
AttrKeyMsid = "msid"
AttrKeyMsidSemantic = "msid-semantic"
AttrKeyConnectionSetup = "setup"
AttrKeyMID = "mid"
AttrKeyICELite = "ice-lite"
AttrKeyRTCPMux = "rtcp-mux"
AttrKeyRTCPRsize = "rtcp-rsize"
AttrKeyInactive = "inactive"
AttrKeyRecvOnly = "recvonly"
AttrKeySendOnly = "sendonly"
AttrKeySendRecv = "sendrecv"
AttrKeyExtMap = "extmap"
)
// Constants for semantic tokens used in JSEP
const (
SemanticTokenLipSynchronization = "LS"
SemanticTokenFlowIdentification = "FID"
SemanticTokenForwardErrorCorrection = "FEC"
SemanticTokenWebRTCMediaStreams = "WMS"
)
// Constants for extmap key
const (
ExtMapValueTransportCC = 3
)
func extMapURI() map[int]string {
return map[int]string{
ExtMapValueTransportCC: "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01",
}
}
// API to match draft-ietf-rtcweb-jsep
// Move to webrtc or its own package?
// NewJSEPSessionDescription creates a new SessionDescription with
// some settings that are required by the JSEP spec.
//
// Note: Since v2.4.0, session ID has been fixed to use crypto random according to
// JSEP spec, so that NewJSEPSessionDescription now returns error as a second
// return value.
func NewJSEPSessionDescription(identity bool) (*SessionDescription, error) {
sid, err := newSessionID()
if err != nil {
return nil, err
}
d := &SessionDescription{
Version: 0,
Origin: Origin{
Username: "-",
SessionID: sid,
SessionVersion: uint64(time.Now().Unix()),
NetworkType: "IN",
AddressType: "IP4",
UnicastAddress: "0.0.0.0",
},
SessionName: "-",
TimeDescriptions: []TimeDescription{
{
Timing: Timing{
StartTime: 0,
StopTime: 0,
},
RepeatTimes: nil,
},
},
Attributes: []Attribute{
// "Attribute(ice-options:trickle)", // TODO: implement trickle ICE
},
}
if identity {
d.WithPropertyAttribute(AttrKeyIdentity)
}
return d, nil
}
// WithPropertyAttribute adds a property attribute 'a=key' to the session description
func (s *SessionDescription) WithPropertyAttribute(key string) *SessionDescription {
s.Attributes = append(s.Attributes, NewPropertyAttribute(key))
return s
}
// WithValueAttribute adds a value attribute 'a=key:value' to the session description
func (s *SessionDescription) WithValueAttribute(key, value string) *SessionDescription {
s.Attributes = append(s.Attributes, NewAttribute(key, value))
return s
}
// WithFingerprint adds a fingerprint to the session description
func (s *SessionDescription) WithFingerprint(algorithm, value string) *SessionDescription {
return s.WithValueAttribute("fingerprint", algorithm+" "+value)
}
// WithMedia adds a media description to the session description
func (s *SessionDescription) WithMedia(md *MediaDescription) *SessionDescription {
s.MediaDescriptions = append(s.MediaDescriptions, md)
return s
}
// NewJSEPMediaDescription creates a new MediaName with
// some settings that are required by the JSEP spec.
func NewJSEPMediaDescription(codecType string, codecPrefs []string) *MediaDescription {
return &MediaDescription{
MediaName: MediaName{
Media: codecType,
Port: RangedPort{Value: 9},
Protos: []string{"UDP", "TLS", "RTP", "SAVPF"},
},
ConnectionInformation: &ConnectionInformation{
NetworkType: "IN",
AddressType: "IP4",
Address: &Address{
Address: "0.0.0.0",
},
},
}
}
// WithPropertyAttribute adds a property attribute 'a=key' to the media description
func (d *MediaDescription) WithPropertyAttribute(key string) *MediaDescription {
d.Attributes = append(d.Attributes, NewPropertyAttribute(key))
return d
}
// WithValueAttribute adds a value attribute 'a=key:value' to the media description
func (d *MediaDescription) WithValueAttribute(key, value string) *MediaDescription {
d.Attributes = append(d.Attributes, NewAttribute(key, value))
return d
}
// WithFingerprint adds a fingerprint to the media description
func (d *MediaDescription) WithFingerprint(algorithm, value string) *MediaDescription {
return d.WithValueAttribute("fingerprint", algorithm+" "+value)
}
// WithICECredentials adds ICE credentials to the media description
func (d *MediaDescription) WithICECredentials(username, password string) *MediaDescription {
return d.
WithValueAttribute("ice-ufrag", username).
WithValueAttribute("ice-pwd", password)
}
// WithCodec adds codec information to the media description
func (d *MediaDescription) WithCodec(payloadType uint8, name string, clockrate uint32, channels uint16, fmtp string) *MediaDescription {
d.MediaName.Formats = append(d.MediaName.Formats, strconv.Itoa(int(payloadType)))
rtpmap := fmt.Sprintf("%d %s/%d", payloadType, name, clockrate)
if channels > 0 {
rtpmap += fmt.Sprintf("/%d", channels)
}
d.WithValueAttribute("rtpmap", rtpmap)
if fmtp != "" {
d.WithValueAttribute("fmtp", fmt.Sprintf("%d %s", payloadType, fmtp))
}
return d
}
// WithMediaSource adds media source information to the media description
func (d *MediaDescription) WithMediaSource(ssrc uint32, cname, streamLabel, label string) *MediaDescription {
return d.
WithValueAttribute("ssrc", fmt.Sprintf("%d cname:%s", ssrc, cname)). // Deprecated but not phased out?
WithValueAttribute("ssrc", fmt.Sprintf("%d msid:%s %s", ssrc, streamLabel, label)).
WithValueAttribute("ssrc", fmt.Sprintf("%d mslabel:%s", ssrc, streamLabel)). // Deprecated but not phased out?
WithValueAttribute("ssrc", fmt.Sprintf("%d label:%s", ssrc, label)) // Deprecated but not phased out?
}
// WithCandidate adds an ICE candidate to the media description
// Deprecated: use WithICECandidate instead
func (d *MediaDescription) WithCandidate(value string) *MediaDescription {
return d.WithValueAttribute("candidate", value)
}
// WithExtMap adds an extmap to the media description
func (d *MediaDescription) WithExtMap(e ExtMap) *MediaDescription {
return d.WithPropertyAttribute(e.Marshal())
}
// WithTransportCCExtMap adds an extmap to the media description
func (d *MediaDescription) WithTransportCCExtMap() *MediaDescription {
uri, _ := url.Parse(extMapURI()[ExtMapValueTransportCC])
e := ExtMap{
Value: ExtMapValueTransportCC,
URI: uri,
}
return d.WithExtMap(e)
}
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