Voice Cloning Implementation in Mobile Applications
Voice cloning in mobile — record voice sample on device, send to provider API, create clone, synthesize new phrases with that voice. Technically not complex, but requires recording quality, legal restrictions, and voice profile UI.
Providers and APIs
ElevenLabs — de facto standard for voice cloning. Instant Voice Cloning needs minimum 1 minute audio. Professional — 30+ minutes for high quality. API simple: POST /v1/voices/add with multipart audio files, response gives voice_id used in TTS requests.
Resemble AI — slightly lower quality, cheaper. Supports streaming synthesis.
PlayHT — supports cloning from 5–10 seconds (noticeably lower quality).
For Russian, ElevenLabs works well with 2–5 minutes clean speech.
Recording Requirements
Clone quality directly depends on sample. Minimum requirements:
- Sample rate: 44100 Hz or 48000 Hz
- Format: WAV (uncompressed) or FLAC. MP3 with compression artifacts degrades clone
- Noise: SNR > 20 dB. Quiet room, not kitchen with fridge
- Duration: 60+ seconds for Instant Cloning, better 3–5 minutes
iOS: record via AVAudioEngine with format AVAudioFormat(commonFormat: .pcmFormatFloat32, sampleRate: 44100, channels: 1, interleaved: false), convert to WAV via AVAudioFile:
func exportToWAV(pcmBuffer: AVAudioPCMBuffer, destinationURL: URL) throws {
let settings: [String: Any] = [
AVFormatIDKey: kAudioFormatLinearPCM,
AVSampleRateKey: 44100.0,
AVNumberOfChannelsKey: 1,
AVLinearPCMBitDepthKey: 16,
AVLinearPCMIsFloatKey: false,
AVLinearPCMIsBigEndianKey: false
]
let file = try AVAudioFile(forWriting: destinationURL, settings: settings)
try file.write(from: pcmBuffer)
}
Android: AudioRecord with ENCODING_PCM_16BIT, 44100 Hz, record to WAV by adding 44-byte header before PCM data.
Uploading Voice to ElevenLabs
func uploadVoice(audioURLs: [URL], name: String) async throws -> String {
var request = URLRequest(url: URL(string: "https://api.elevenlabs.io/v1/voices/add")!)
request.httpMethod = "POST"
request.setValue(apiKey, forHTTPHeaderField: "xi-api-key")
let boundary = UUID().uuidString
request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")
var body = Data()
// Name field
body.append("--\(boundary)\r\nContent-Disposition: form-data; name=\"name\"\r\n\r\n\(name)\r\n".data(using: .utf8)!)
// Audio files
for (i, url) in audioURLs.enumerated() {
let audioData = try Data(contentsOf: url)
body.append("--\(boundary)\r\nContent-Disposition: form-data; name=\"files\"; filename=\"sample_\(i).wav\"\r\nContent-Type: audio/wav\r\n\r\n".data(using: .utf8)!)
body.append(audioData)
body.append("\r\n".data(using: .utf8)!)
}
body.append("--\(boundary)--\r\n".data(using: .utf8)!)
request.httpBody = body
let (data, _) = try await URLSession.shared.data(for: request)
let response = try JSONDecoder().decode(VoiceResponse.self, from: data)
return response.voice_id
}
voice_id save locally (Keychain / SharedPreferences) — needed for all subsequent TTS requests with this voice.
Voice Profile Management
App should allow:
- Create multiple voice profiles (own voice, character voice, narrator voice)
- Rename and delete (
DELETE /v1/voices/{voice_id}) - Test clone quality — play test phrase immediately after creation
Storage: voice_id + metadata in local DB. Audio samples after successful upload can delete from device — stored with provider.
Legal and Ethical Restrictions
ElevenLabs requires confirmation user clones own voice or has explicit owner consent. ToS forbids cloning without consent. Implement mandatory consent checkbox, save timestamp in DB.
In some jurisdictions (EU, some US states), biometric use without consent has regulatory risks. Account for this in data retention policy design.
Common Mistakes
Recording via AVAudioSession.sharedInstance().setCategory(.record) without setting preferredSampleRate: 44100 — on some devices system picks 16000 Hz, noticeably worse clone.
Sending uncompressed WAV on screen for 3-minute recording — ~30 MB. Need background upload via URLSession.background.
Timeline
Recording screen + upload to ElevenLabs + clone TTS — 5–8 days. Full flow with profile management, quality recorder UI (waveform, volume, noise), test clone playback — 2–3 weeks.