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Internal Project Voice Sample Preview

This is an internal authenticated backend route used by the VoiceCheap app. It is not part of the public API key surface.

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Route

  • Method: POST
  • Path: /speech/project-voice-sample-preview
  • Auth: Bearer access token required

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Request body

{
  "projectId": "project_123",
  "speakerNumber": 0,
  "voiceCloningSettings": {
    "stability": 0.6,
    "similarity": 0.8,
    "speakerBoost": 0.6
  }
}

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Response

{
  "speakerNumber": 0,
  "audioBase64": "<base64-mp3>",
  "mimeType": "audio/mpeg"
}

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Behavior

  • Resolves the project and checks the requester has access.
  • Downloads the stored original audio.
  • Cuts and concatenates the selected speaker audio from the project transcription.
  • Caps source speech at 5 minutes per speaker.
  • Creates a temporary cloned voice, generates one preview sentence in the first target language, then deletes the temporary voice.
  • Returns the preview as base64 MP3 data for immediate playback in the app.

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Rate limiting

  • This route is intentionally low-rate-limit.
  • 429 response:
{
  "code": "PROJECT_VOICE_SAMPLE_RATE_LIMIT_REACHED",
  "message": "Voice previews are limited right now. Please wait a few minutes before generating another sample."
}

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Project data changes

Project creation now stores persisted examples on the dubbing project under voicePreviewSamples[]: 
[
  {
    "speakerNumber": 0,
    "audioUrl": "https://...",
    "targetLanguage": "french",
    "createdAt": 1741950000000
  }
]
Stored voicePreviewSamples[].audioUrl files are deleted when the project is deleted.