> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fluidinference.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Streaming ASR

> Real-time streaming transcription with Parakeet EOU and end-of-utterance detection.

## Overview

`StreamingEouAsrManager` provides real-time streaming ASR with End-of-Utterance detection using the Parakeet EOU 120M model.

## Quick Start

```swift theme={null}
let manager = StreamingEouAsrManager(chunkSize: .ms160, eouDebounceMs: 1280)
try await manager.loadModels(modelDir: modelsURL)

// Process audio incrementally
_ = try await manager.process(audioBuffer: buffer1)
_ = try await manager.process(audioBuffer: buffer2)

// Get final transcript
let transcript = try await manager.finish()

// Reset for next utterance
await manager.reset()
```

## Configuration

```swift theme={null}
let manager = StreamingEouAsrManager(
    chunkSize: .ms320,        // .ms160, .ms320, or .ms1600
    eouDebounceMs: 1280       // Minimum silence before EOU triggers
)
```

## EOU Callback

```swift theme={null}
manager.setEouCallback { transcript in
    print("End of utterance: \(transcript)")
}
```

## API

| Method                  | Description                                       |
| ----------------------- | ------------------------------------------------- |
| `loadModels(modelDir:)` | Load CoreML models from directory                 |
| `process(audioBuffer:)` | Process audio incrementally                       |
| `finish()`              | Finalize and return transcript                    |
| `reset()`               | Reset state for next utterance                    |
| `appendAudio(_:)`       | Append audio without processing (VAD integration) |

## Benchmarks

[LibriSpeech test-clean](https://huggingface.co/datasets/openslr/librispeech_asr) (2,620 files, 5.4h audio):

| Chunk Size | Latency            | WER  | RTFx  |
| ---------- | ------------------ | ---- | ----- |
| 160ms      | Lowest             | \~8% | \~5x  |
| 320ms      | Balanced           | \~5% | \~12x |
| 1600ms     | Highest throughput | —    | —     |

320ms is the recommended default — best accuracy/latency tradeoff.

## CLI

```bash theme={null}
# Transcribe a file
swift run fluidaudio parakeet-eou --input audio.wav --use-cache

# Benchmark
swift run fluidaudio parakeet-eou --benchmark --chunk-size 160 --max-files 100 --use-cache
```