Asterisk.Sdk.VoiceAi 1.15.3

Asterisk.Sdk.VoiceAi

Voice AI pipeline for Asterisk.Sdk — orchestration layer for STT, TTS, and conversation with turn-taking and barge-in detection.

Installation

dotnet add package Asterisk.Sdk.VoiceAi

Quick Start

// Implement your conversation handler (called once per user utterance)
public class MyHandler : IConversationHandler
{
    public ValueTask<string> HandleAsync(
        string transcript, ConversationContext context, CancellationToken ct)
    {
        return ValueTask.FromResult($"You said: {transcript}");
    }
}

// Register in DI
services.AddAudioSocketServer(opts => opts.Port = 9092);
services.AddVoiceAiPipeline<MyHandler>(opts =>
{
    opts.InputFormat = AudioFormat.Slin16Mono8kHz;
    opts.OutputFormat = AudioFormat.Slin16Mono8kHz;
    opts.EndOfUtteranceSilence = TimeSpan.FromMilliseconds(600);
});

// Subscribe to pipeline events
var pipeline = app.Services.GetRequiredService<VoiceAiPipeline>();
pipeline.Events.Subscribe(evt => Console.WriteLine(evt));

Features

• VoiceAiPipeline — full VAD → STT → IConversationHandler → TTS loop per AudioSocket session
• Barge-in detection: cancels TTS playback when the caller speaks
• IConversationHandler — scoped per session; implement to plug in any LLM or business logic
• ISessionHandler — low-level interface; implement for fully custom session handling
• VoiceAiSessionBroker — hosted service that routes AudioSocketSession instances to the active handler
• Observable Events stream (SpeechStartedEvent, TranscriptReceivedEvent, BargInDetectedEvent, etc.)
• Native AOT compatible

Custom STT / TTS Providers

When writing your own SpeechRecognizer or SpeechSynthesizer subclass, override ProviderName with a stable literal to avoid the per-utterance GetType().Name allocation on the pipeline hot path (used as a tag on STT/TTS activities):

public sealed class MyCustomRecognizer : SpeechRecognizer
{
    public override string ProviderName => "MyCustom";

    public override IAsyncEnumerable<SpeechRecognitionResult> StreamAsync(
        IAsyncEnumerable<ReadOnlyMemory<byte>> audioFrames,
        AudioFormat format,
        CancellationToken ct = default)
    {
        // ...
    }
}

If you don't override ProviderName the default falls back to GetType().Name — functional, but incurs one reflection call per utterance.

Observability

• Metrics: VoiceAiMetrics (sessions started/completed/failed, session duration), SpeechRecognitionMetrics (transcriptions started/completed/failed, latency), SpeechSynthesisMetrics (syntheses started/completed/failed, latency, characters).
• Tracing: VoiceAiActivitySource — session / recognition / synthesis spans.
• Health: VoiceAiHealthCheck, SttHealthCheck, TtsHealthCheck auto-registered by AddVoiceAiPipeline<THandler>().
• Discover names via AsteriskTelemetry.ActivitySourceNames / MeterNames from Asterisk.Sdk.Hosting.

Documentation

See the main README for full documentation.