mirror of
https://github.com/pion/webrtc.git
synced 2025-10-27 01:00:35 +08:00
121 lines
3.3 KiB
Go
121 lines
3.3 KiB
Go
package sdp
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import (
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"fmt"
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"math/rand"
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"strconv"
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"strings"
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)
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// SessionBuilderTrack represents a single track in a SessionBuilder
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type SessionBuilderTrack struct {
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SSRC uint32
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IsAudio bool
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}
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// SessionBuilder provides an easy way to build an SDP for an RTCPeerConnection
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type SessionBuilder struct {
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IceUsername, IcePassword, Fingerprint string
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Candidates []string
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Tracks []*SessionBuilderTrack
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}
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// BaseSessionDescription generates a default SDP response that is ice-lite, initiates the DTLS session and supports VP8, VP9 and Opus
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func BaseSessionDescription(b *SessionBuilder) *SessionDescription {
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addMediaCandidates := func(m *MediaDescription) *MediaDescription {
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m.Attributes = append(m.Attributes, b.Candidates...)
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m.Attributes = append(m.Attributes, "end-of-candidates")
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return m
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}
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audioMediaDescription := &MediaDescription{
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MediaName: "audio 9 RTP/SAVPF 111",
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ConnectionData: "IN IP4 127.0.0.1",
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Attributes: []string{
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"setup:active",
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"mid:audio",
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"sendrecv",
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"ice-ufrag:" + b.IceUsername,
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"ice-pwd:" + b.IcePassword,
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"ice-lite",
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"fingerprint:sha-256 " + b.Fingerprint,
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"rtcp-mux",
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"rtcp-rsize",
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"rtpmap:111 opus/48000/2",
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"fmtp:111 minptime=10;useinbandfec=1",
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},
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}
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videoMediaDescription := &MediaDescription{
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MediaName: "video 9 RTP/SAVPF 96 98",
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ConnectionData: "IN IP4 127.0.0.1",
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Attributes: []string{
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"setup:active",
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"mid:video",
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"sendrecv",
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"ice-ufrag:" + b.IceUsername,
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"ice-pwd:" + b.IcePassword,
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"ice-lite",
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"fingerprint:sha-256 " + b.Fingerprint,
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"rtcp-mux",
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"rtcp-rsize",
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"rtpmap:96 VP8/90000",
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"rtpmap:98 VP9/90000",
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},
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}
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mediaStreamsAttribute := "msid-semantic: WMS"
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for i, track := range b.Tracks {
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var attributes *[]string
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if track.IsAudio {
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attributes = &audioMediaDescription.Attributes
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} else {
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attributes = &videoMediaDescription.Attributes
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}
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appendAttr := func(attr string) {
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*attributes = append(*attributes, attr)
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}
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appendAttr("ssrc:" + fmt.Sprint(track.SSRC) + " cname:pion" + strconv.Itoa(i))
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appendAttr("ssrc:" + fmt.Sprint(track.SSRC) + " msid:pion" + strconv.Itoa(i) + " pion" + strconv.Itoa(i))
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appendAttr("ssrc:" + fmt.Sprint(track.SSRC) + " mslabel:pion" + strconv.Itoa(i))
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appendAttr("ssrc:" + fmt.Sprint(track.SSRC) + " label:pion" + strconv.Itoa(i))
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mediaStreamsAttribute += " pion" + strconv.Itoa(i)
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}
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sessionID := strconv.FormatUint(uint64(rand.Uint32())<<32+uint64(rand.Uint32()), 10)
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return &SessionDescription{
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ProtocolVersion: 0,
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Origin: "pion-webrtc " + sessionID + " 2 IN IP4 0.0.0.0",
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SessionName: "-",
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Timing: []string{"0 0"},
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Attributes: []string{
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"group:BUNDLE audio video",
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mediaStreamsAttribute,
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},
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MediaDescriptions: []*MediaDescription{
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addMediaCandidates(audioMediaDescription),
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addMediaCandidates(videoMediaDescription),
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},
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}
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}
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// GetCodecForPayloadType scans the SessionDescription for the given payloadType and returns the codec
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func GetCodecForPayloadType(payloadType uint8, sd *SessionDescription) (ok bool, codec string) {
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for _, m := range sd.MediaDescriptions {
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for _, a := range m.Attributes {
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if strings.Contains(a, "rtpmap:"+strconv.Itoa(int(payloadType))) {
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split := strings.Split(a, " ")
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if len(split) == 2 {
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split := strings.Split(split[1], "/")
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return true, split[0]
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}
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}
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}
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}
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return false, ""
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}
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