> ## Documentation Index
> Fetch the complete documentation index at: https://docs.runanywhere.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# STT Options
> Configure Speech-to-Text transcription
## Overview
The STT API provides various options to customize transcription behavior, from language selection to word-level timestamps.
## Options Reference
```typescript theme={null}
interface STTOptions {
/** Language code for transcription */
language?: string
/** Enable punctuation in output */
punctuation?: boolean
/** Enable speaker diarization (multi-speaker) */
diarization?: boolean
/** Enable word-level timestamps */
wordTimestamps?: boolean
/** Audio sample rate (default: 16000) */
sampleRate?: number
}
```
## Language Support
Specify the language code to improve accuracy:
```typescript theme={null}
// English
const english = await RunAnywhere.transcribe(audioBase64, { language: 'en' })
// Spanish
const spanish = await RunAnywhere.transcribe(audioBase64, { language: 'es' })
// French
const french = await RunAnywhere.transcribe(audioBase64, { language: 'fr' })
// Auto-detect (slower)
const auto = await RunAnywhere.transcribe(audioBase64)
```
### Supported Languages
| Code | Language | Code | Language |
| ---- | -------- | ---- | ---------- |
| `en` | English | `ja` | Japanese |
| `es` | Spanish | `ko` | Korean |
| `fr` | French | `pt` | Portuguese |
| `de` | German | `ru` | Russian |
| `it` | Italian | `zh` | Chinese |
| `nl` | Dutch | `ar` | Arabic |
| `pl` | Polish | `hi` | Hindi |
Language-specific models (e.g., `whisper-tiny.en`) only support that language but are more
accurate and faster.
## Punctuation
Add punctuation to transcription output:
```typescript theme={null}
// Without punctuation (default for some models)
const noPunct = await RunAnywhere.transcribe(audioBase64, {
language: 'en',
punctuation: false,
})
// "hello how are you today"
// With punctuation
const withPunct = await RunAnywhere.transcribe(audioBase64, {
language: 'en',
punctuation: true,
})
// "Hello, how are you today?"
```
## Word Timestamps
Get timing information for each word:
```typescript theme={null}
const result = await RunAnywhere.transcribe(audioBase64, {
language: 'en',
wordTimestamps: true,
})
console.log('Transcription:', result.text)
// Each segment contains word-level timing
for (const segment of result.segments) {
console.log(`[${segment.startTime.toFixed(2)}s - ${segment.endTime.toFixed(2)}s] ${segment.text}`)
}
```
### Use Cases
* **Subtitles/Captions**: Sync text with video
* **Karaoke**: Highlight words as they're spoken
* **Search**: Jump to specific moments in audio
* **Accessibility**: Show words as they're spoken
### Example: Subtitle Generator
```typescript theme={null}
interface Subtitle {
start: number
end: number
text: string
}
async function generateSubtitles(audioBase64: string): Promise {
const result = await RunAnywhere.transcribe(audioBase64, {
language: 'en',
wordTimestamps: true,
})
return result.segments.map((segment) => ({
start: segment.startTime,
end: segment.endTime,
text: segment.text.trim(),
}))
}
// Convert to SRT format
function toSRT(subtitles: Subtitle[]): string {
return subtitles
.map((sub, i) => {
const start = formatSRTTime(sub.start)
const end = formatSRTTime(sub.end)
return `${i + 1}\n${start} --> ${end}\n${sub.text}\n`
})
.join('\n')
}
function formatSRTTime(seconds: number): string {
const h = Math.floor(seconds / 3600)
const m = Math.floor((seconds % 3600) / 60)
const s = Math.floor(seconds % 60)
const ms = Math.floor((seconds % 1) * 1000)
return `${h.toString().padStart(2, '0')}:${m.toString().padStart(2, '0')}:${s.toString().padStart(2, '0')},${ms.toString().padStart(3, '0')}`
}
```
## Speaker Diarization
Identify different speakers in the audio:
```typescript theme={null}
const result = await RunAnywhere.transcribe(audioBase64, {
language: 'en',
diarization: true,
})
// Segments include speaker IDs
for (const segment of result.segments) {
console.log(`[Speaker ${segment.speakerId}]: ${segment.text}`)
}
```
Speaker diarization is computationally expensive and may not be available on all models. Check
model documentation for support.
## Sample Rate
Specify the audio sample rate if different from the default:
```typescript theme={null}
// Standard 16kHz (default, recommended for STT)
const standard = await RunAnywhere.transcribeBuffer(samples)
// Higher quality 44.1kHz (will be downsampled internally)
const highQuality = await RunAnywhere.transcribeBuffer(samples, {
sampleRate: 44100,
})
```
`transcribeBuffer()` accepts a `Float32Array` of PCM audio samples. The sample rate defaults to
16000 Hz if not specified in options.
For best results, record audio at 16kHz mono. Higher sample rates will be downsampled, which adds
processing overhead.
## Model Loading Options
Configure model loading:
```typescript theme={null}
// Load STT model with specific type
await RunAnywhere.loadSTTModel(modelPath, 'whisper')
// Check if model is loaded
const isLoaded = await RunAnywhere.isSTTModelLoaded()
// Unload when done
await RunAnywhere.unloadSTTModel()
```
## Combining Options
```typescript theme={null}
// Full-featured transcription
const result = await RunAnywhere.transcribe(audioBase64, {
language: 'en',
punctuation: true,
wordTimestamps: true,
})
// Access all result data
console.log('Text:', result.text)
console.log('Language:', result.language)
console.log('Confidence:', result.confidence)
console.log('Duration:', result.duration, 'seconds')
console.log('Segments:', result.segments.length)
// Alternatives (if available)
if (result.alternatives.length > 0) {
console.log('Alternatives:')
result.alternatives.forEach((alt, i) => {
console.log(` ${i + 1}. ${alt.text} (confidence: ${alt.confidence})`)
})
}
```
## Performance vs Accuracy
| Option | Impact on Speed | Impact on Accuracy |
| -------------------- | -------------------------------------------------------- | --------------------------------------------------- |
| `language` specified | Faster | Better |
| `wordTimestamps` | Slower | Same |
| `diarization` | Much slower | Same |
| `punctuation` | Minimal | Same |
For best performance, always specify the `language` option rather than relying on auto-detection.
## Related
Basic transcription
Real-time transcription
Voice Activity Detection