# OpenMOSS Team releases MOSS-TTS, an 8B Apache 2.0 voice cloning and long-form TTS

> MOSS-TTS is an 8B (and 1.7B) open TTS family with cloning, up to an hour of long-form audio and duration control.

Published 2026-02-06

Canonical: https://shipped.anth.us/open-weights/openmoss-moss-tts/

OpenMOSS Team released MOSS-TTS, a family led by an 8B flagship (MossTTSDelay, recommended for production) and a 1.7B MossTTSLocal (recommended for research). The card lists 20 languages but its table shows 19. Features include zero-shot voice cloning from reference audio, long-form generation described as up to one hour in a single run, token-level duration control (about 12.5 audio tokens per second), Pinyin and IPA pronunciation input, and code-switching within one utterance. Siblings include MOSS-TTSD for dialogue, MOSS-VoiceGenerator for voice design, MOSS-SoundEffect and MOSS-TTS-Realtime, which reports 180 ms time to first byte.

Self-reported Seed-TTS-eval: MossTTSDelay scores 1.84 English word error rate and 1.37 Chinese character error rate. The card calls these state of the art, but its own table shows Qwen3-TTS at 1.5 on English and GLM-TTS-RL at 0.89 on Chinese, both better.

The licence is Apache-2.0. Practical notes: it needs trust_remote_code, the README recommends Transformers 5.0.0, and only one reference audio is supported. The card gives no release date; the date used is the Hugging Face repo creation date, and the linked report is listed as published 18 March.

Useful family. The card's own table keeps the claims honest.

## Sources
- [OpenMOSS Team model card on Hugging Face](https://huggingface.co/OpenMOSS Team-Team/MOSS-TTS)
- [Hugging Face repo metadata (creation date)](https://huggingface.co/api/models/OpenMOSS Team-Team/MOSS-TTS)

## Editor's first pass (AI-assisted)
- Real 4: Apache 2.0 weights, though the card needs trust_remote_code and pinned torch.
- Useful 4: Long-form output, duration control and cloning cover narration and dubbing work.
- Notable 3.5: A broad family with dialogue, sound effects and realtime siblings.
- Novel 3.5: Token-level duration control is uncommon, the rest is familiar.