RTPTransceiver

Represents a combination of an RTPSender and an RTPReceiver that share a common mid.

Overview

RTPTransceiver represents a combination of an RTPSender and an RTPReceiver that share a common mid. It manages the bidirectional flow of media data in a WebRTC connection.

Type Definition

type RTPTransceiver struct {
    mid                    atomic.Value // string
    sender                 atomic.Value // *RTPSender
    receiver               atomic.Value // *RTPReceiver
    direction              atomic.Value // RTPTransceiverDirection
    currentDirection       atomic.Value // RTPTransceiverDirection
    currentRemoteDirection atomic.Value // RTPTransceiverDirection
    codecs                 []RTPCodecParameters
    kind                   RTPCodecType
    api                    *API
    mu                     sync.RWMutex
}

Methods

SetCodecPreferences

Sets the preferred list of supported codecs. If codecs is empty or nil, resets to default from MediaEngine.

func (t *RTPTransceiver) SetCodecPreferences(codecs []RTPCodecParameters) error

codecs · []RTPCodecParameters

List of codec parameters to set as preferences. Pass empty slice or nil to reset to defaults.

error · error

Returns error if codec is not supported by the MediaEngine

Example

// Set H.264 as the preferred video codec
codecs := []webrtc.RTPCodecParameters{
    {
        RTPCodecCapability: webrtc.RTPCodecCapability{
            MimeType:  webrtc.MimeTypeH264,
            ClockRate: 90000,
        },
        PayloadType: 102,
    },
}

err := transceiver.SetCodecPreferences(codecs)
if err != nil {
    panic(err)
}

Sender

Returns the RTPTransceiver’s RTPSender if it has one.

func (t *RTPTransceiver) Sender() *RTPSender

sender · *RTPSender

The associated RTPSender, or nil if none exists

SetSender

Sets the RTPSender and Track to the current transceiver.

func (t *RTPTransceiver) SetSender(s *RTPSender, track TrackLocal) error

s · *RTPSender · required

The RTPSender to associate with this transceiver

track · TrackLocal · required

The local track to send

Receiver

Returns the RTPTransceiver’s RTPReceiver if it has one.

func (t *RTPTransceiver) Receiver() *RTPReceiver

receiver · *RTPReceiver

The associated RTPReceiver, or nil if none exists

SetMid

Sets the RTPTransceiver’s mid. If it was already set, returns an error.

func (t *RTPTransceiver) SetMid(mid string) error

mid · string · required

The media ID to set for this transceiver

error · error

Returns error if mid is already set

Mid

Gets the Transceiver’s mid value. When not already set, this value will be set in CreateOffer or CreateAnswer.

func (t *RTPTransceiver) Mid() string

mid · string

The media ID, or empty string if not yet set

Kind

Returns the RTPTransceiver’s kind (audio or video).

func (t *RTPTransceiver) Kind() RTPCodecType

kind · RTPCodecType

The codec type (RTPCodecTypeAudio or RTPCodecTypeVideo)

Direction

Returns the RTPTransceiver’s current direction.

func (t *RTPTransceiver) Direction() RTPTransceiverDirection

direction · RTPTransceiverDirection

The current direction (sendrecv, sendonly, recvonly, or inactive)

Show RTPTransceiverDirection Values

• RTPTransceiverDirectionSendrecv - Send and receive
• RTPTransceiverDirectionSendonly - Send only
• RTPTransceiverDirectionRecvonly - Receive only
• RTPTransceiverDirectionInactive - Neither send nor receive
• RTPTransceiverDirectionUnknown - Direction unknown

Stop

Irreversibly stops the RTPTransceiver.

func (t *RTPTransceiver) Stop() error

error · error

Returns error if stopping the sender or receiver fails

Example

transceiver := pc.AddTransceiverFromKind(webrtc.RTPCodecTypeVideo)

// Later...
if err := transceiver.Stop(); err != nil {
    panic(err)
}

After calling Stop(), the transceiver’s direction is set to inactive and cannot be changed.

Usage Examples

Creating and Configuring a Transceiver

// Add a transceiver for video
transceiver, err := pc.AddTransceiverFromKind(webrtc.RTPCodecTypeVideo, webrtc.RTPTransceiverInit{
    Direction: webrtc.RTPTransceiverDirectionSendrecv,
})
if err != nil {
    panic(err)
}

// Check the transceiver properties
fmt.Println("Mid:", transceiver.Mid())
fmt.Println("Kind:", transceiver.Kind())
fmt.Println("Direction:", transceiver.Direction())

Setting Codec Preferences

// Prefer VP8 over other video codecs
codecs := []webrtc.RTPCodecParameters{
    {
        RTPCodecCapability: webrtc.RTPCodecCapability{
            MimeType:  webrtc.MimeTypeVP8,
            ClockRate: 90000,
        },
        PayloadType: 96,
    },
}

if err := transceiver.SetCodecPreferences(codecs); err != nil {
    panic(err)
}

Accessing Sender and Receiver

// Get the sender
sender := transceiver.Sender()
if sender != nil {
    track := sender.Track()
    fmt.Println("Sender track:", track)
}

// Get the receiver
receiver := transceiver.Receiver()
if receiver != nil {
    track := receiver.Track()
    fmt.Println("Receiver track:", track)
}

See Also

• RTPSender - Manages outbound RTP streams
• RTPReceiver - Manages inbound RTP streams
• TrackLocal - Local media track interface
• TrackRemote - Remote media track