Microsoft.Extensions.AI speech-to-text

SmallestAIClient implements Microsoft.Extensions.AI.ISpeechToTextClient, so Pulse drops into any MEAI pipeline. GetTextAsync posts pre-recorded audio; GetStreamingTextAsync opens the realtime WebSocket and yields interim and final updates.

MEAI has no first-class notion of diarization, so Pulse knobs go in through SpeechToTextOptions.AdditionalProperties and speaker-labelled results come back out through the response's AdditionalProperties — use SmallestAISpeechToTextPropertyNames for the keys, or read RawRepresentation for the full typed payload.

Note the Meai alias: the generated SmallestAI.ISpeechToTextClient sub-client interface collides by simple name with the MEAI one, so inside the SmallestAI namespace the MEAI types must be qualified.

This example assumes using SmallestAI; is in scope and apiKey contains your SmallestAI API key.

using var client = new SmallestAIClient(apiKey);

var audio = await BuildTwoSpeakerWavAsync(client, TestContext.CancellationToken);

Meai.ISpeechToTextClient speechToText = client;

speechToText.GetService(typeof(Meai.SpeechToTextClientMetadata))

var options = new Meai.SpeechToTextOptions
{
    ModelId = SmallestAIClient.PulseModelId,
    SpeechLanguage = "en",
    AdditionalProperties = new Meai.AdditionalPropertiesDictionary
    {
        [SmallestAISpeechToTextPropertyNames.Diarize] = true,
        [SmallestAISpeechToTextPropertyNames.WordTimestamps] = true,
    },
};

using var batchAudio = new MemoryStream(audio);
var response = await speechToText.GetTextAsync(
    batchAudio,
    options,
    TestContext.CancellationToken);

var words = response.AdditionalProperties?[SmallestAISpeechToTextPropertyNames.Words] as IList<Word>;

// The same client streams the same audio over the realtime channel.
using var streamingAudio = new MemoryStream(ReadPcm(audio));
options.AdditionalProperties![SmallestAISpeechToTextPropertyNames.SampleRate] = FixtureSampleRate;

var updates = new List<Meai.SpeechToTextResponseUpdate>();
await foreach (var update in speechToText.GetStreamingTextAsync(
    streamingAudio,
    options,
    TestContext.CancellationToken))
{
    updates.Add(update);
}