what is the difference between on_attributes_changed event, and on_participant_connected event?

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whenever the callback/handler function is called for the on_attributes_changed event, what is passed in as an argument?

When the

on_attributes_changed

event fires, the callback function gets a couple of handy arguments: •

changed_attributes

: This is a dictionary (or map) showing which attributes have changed and their new values. If an attribute was deleted, you'll see it as an empty string. •

participant

: This is the participant object whose attributes just got updated. If you'd like me to walk you through more details or share some examples for a particular SDK, just give me a shout! Sources: callback_test.go | src/room/Room.ts | livekit-rtc/livekit/rtc/room.py | livekit/src/room/participant/mod.rs | livekit-android-sdk/src/main/java/io/livekit/android/room/participant/Parti...

What are the different keys in the changed_attributes dictionary?

The

changed_attributes

dictionary in the

on_attributes_changed

event holds app-specific key-value pairs, where both keys and values are strings. The keys tell you which attributes have changed, and the values show their updated state. Here are some examples of keys you might see: • Application-Specific Keys: For instance,

captions_language

to set the language for captions. • SIP-Related Keys: ◦ `sip.callStatus`: The current status of the SIP call (like "active" or "dialing"). ◦ `sip.callID`: The identifier for the SIP call. ◦ `sip.phoneNumber`: The phone number tied to the SIP call. ◦ `sip.trunkID`: The identifier for the SIP trunk. ◦ `sip.trunkPhoneNumber`: The phone number of the trunk. These keys are totally up to your app, so feel free to customize them however fits your needs. If you want me to walk you through more examples or clarify anything, just let me know—I'm here to help! Sources: src/room/events.ts | livekit-rtc/livekit/rtc/room.py | server/main.py | telephony/sip_lifecycle.py

what are the possible values, and their meanings, for the sip.callStatus key?

The

sip.callStatus

key tells you what's going on with a SIP call right now. Here’s a quick rundown of the possible values and what they mean: •

active

: The participant is connected, and the call is up and running. •

automation

: For outbound calls using DTMF (Dual-Tone Multi-Frequency), this means the call is connected but still dialing those DTMF numbers. Once all numbers are dialed, it switches to

active

. •

dialing

: The call is in the process of dialing and waiting for someone to pick up. •

hangup

: Someone on the call has ended it. •

ringing

: For incoming calls, this means the phone is ringing. When the SIP participant picks up and subscribes to any remote audio tracks, it changes to

active

. If you want, I’m happy to share more details or examples on how to use this in your app—just let me know! Sources: SIP participant | LiveKit Docs | Making calls using SIP | LiveKit Docs

Difference between remotePartiicpant and Participant?

Let's break down the difference between

Participant

and

RemoteParticipant

so it’s a bit easier to understand: •

Participant

: Think of this as the base class that represents anyone or anything in a LiveKit session. It includes the basics like identity, metadata, attributes, and managing tracks. You can’t create a

Participant

directly—it’s more like the foundation for other participant types. •

RemoteParticipant

: This one is a special kind of

Participant

that represents users who are joining the session remotely. It comes with extra tools to handle things like: ◦ Managing subscriptions for remote tracks. ◦ Controlling volume for remote audio tracks. ◦ Handling events such as

TrackSubscribed

,

TrackUnsubscribed

, and

TrackSubscriptionFailed

. ◦ Using

RemoteTrackPublication

objects to manage track publications. So, in a nutshell,

Participant

is the general role, and

RemoteParticipant

is tailored specifically for managing remote users in your session. If you want me to explain anything more or have questions, just let me know—I’m here to help! Sources: Rooms, participants, and tracks | LiveKit Docs | lib/src/participant/participant.dart | src/room/Room.ts