Chatterbox Turbo — all-CoreML (ANE-optimized)

On-device Apple Silicon build of ResembleAI Chatterbox Turbo for iOS 18+ / macOS 15+, arm64. The entire pipeline is CoreML — T3 prefill

• decode run fully on the Apple Neural Engine as one weight-shared multifunction model, and the S3Gen audio synth is three CoreML packages (encoder on ANE, CFM + vocoder on the GPU).

Sibling repos: iliasaz/chatterbox-nano-coreml (smaller, faster) and iliasaz/chatterbox-multilingual-coreml (23 languages).

Links

• Upstream model — ResembleAI/chatterbox-turbo by Resemble AI.
• Runtime — iliasaz/chatterbox-coreml, the Swift package + demo app that loads this repo.
• Watermarking — iliasaz/perth-coreml (Swift) / weights. Every utterance the runtime generates is watermarked with Perth, as upstream chatterbox does.

Artifacts

Pipeline

text → GPT-2 BPE → host-assemble inputs_embeds + position_ids + masks
     → T3LM "prefill" function (CoreML, ANE)  — writes shared KV state
     → T3LM "decode" function (CoreML, ANE)   — autoregressive, reads/writes same state
     → S3Encoder (ANE) → S3CFM (GPU) → S3Vocoder (GPU)  — 24 kHz waveform

All attention masks (attn_mask, write_mask, decode update_mask) are built on the Swift host and passed in — constructing them inside the stateful 24-layer prefill graph fails the ANE compile, so keeping mask construction off the model is what makes the prefill ANE-compilable. The prefill's attention is also hand-decomposed rather than fused: on iPhone the ANE's fused attention kernel silently drops attn_mask for q_len >> 1.

On-device numbers (iPhone 17 Pro Max, iOS 26.5, warm)

The compiled .mlmodelc is persisted once and reused across launches, so the one-time ANE compile isn't paid every launch. The runtime also overlaps chunk N+1 decode (ANE) with chunk N synth (GPU) for faster multi-chunk throughput.

License

MIT. These weights are a CoreML format conversion of ResembleAI/chatterbox-turbo, which Resemble AI publishes under the MIT licence; the conversion inherits those terms, and copyright in the weights stays with Resemble AI — no claim of ownership is made over them here. Redistribute with attribution to Resemble AI.

The Swift runtime that loads them is separately MIT-licensed; see the LICENSE and NOTICE files in iliasaz/chatterbox-coreml.