arikawa/voice

Voice

Terminology

• Discord Gateway - The standard Discord Gateway users connect to and receive update events from
• Discord Voice Gateway - The Discord Voice gateway that allows voice connections to be configured
• Voice Server - What the Discord Voice Gateway allows connection to for sending of Opus voice packets over UDP
• Voice Packet - Opus encoded UDP packet that contains audio
• Application - Could be a custom Discord Client or Bot (nothing that is within this package)
• Library - Code within this package

Connection Flow

• The application would get a new *Voice instance by calling NewVoice()
• When the application wants to connect to a voice channel they would call JoinChannel() on the stored *Voice instance

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• The library sends a Voice State Update to the Discord Gateway.
• The library waits until it receives a Voice Server Update from the Discord Gateway.
• Once a Voice Server Update event is received, a new connection is opened to the Discord Voice Gateway.

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• The Discord Voice Gateway will first send a Hello Event which will be used to create a new *heart.PacemakerLoop and start sending heartbeats to the Discord Voice Gateway.
• Afterwards, an Identify Command or Resume Command is sent to the Discord Voice Gateway depending on whether the library is reconnecting.

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• The Discord Voice Gateway should then respond with a Ready Event once the connection is opened, providing the required information to connect to a Voice Server.
• Using the information provided in the Ready Event, a new UDP connection is opened to the Voice Server and IP Discovery occurs.
• After IP Discovery returns the Application's external ip and port it connected to the Voice Server with, the library sends a Select Protocol Event to the Discord Voice Gateway.
• The library waits until it receives a Session Description Event from the Discord Voice Gateway.
• Once the Session Description Event is received, Speaking Events and Voice Packets can begin to be sent to the Discord Voice Gateway and Voice Server respectively.

Usage

• The application would get a new *Voice instance by calling NewVoice() and keep it stored for when it needs to open voice connections.
• When the application wants to connect to a voice channel they would call JoinChannel() on the stored *Voice instance.
• JoinChannel() will block as it follows the Connection Flow, returning an error if one occurs and a *voice.Session if it was successful.
• The application should now call (*voice.Session).Speaking() with the wanted voice flag (voicegateway.Microphone, voicegateway.Soundshare, or voicegateway.Priority).
• The application can now send Voice Packets using the (*voice.Session).Write() method which will be sent to the Voice Server. (*voice.Session) also implements io.Writer.
• When the application wants to stop sending Voice Packets they should call (*voice.Session).StopSpeaking(), then any required voice cleanup (closing streams, etc.), then (*voice.Session).Disconnect()

Examples

Check the integration tests at voice/integration_test.go.