As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/indextts-2/

# IndexTTS-2 / IndexTTS-2.5 (bilibili)

bilibili (Index Team), IndexTTS family. Status: current. Type: speech and audio. Released: 2025-09-08.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| Hugging Face | `IndexTeam/IndexTTS-2` |  | https://huggingface.co/IndexTeam/IndexTTS-2 |
| GitHub |  |  | https://github.com/index-tts/index-tts |

## Pricing

- Price not published.
- Last checked: 2026-09-29

## Specs

- Input: text, audio
- Output: audio
- Context window: not published
- Max output: not published
- Open weights: yes
- Licence: bilibili Model Use License Agreement (commercial use by request)

## Where it stands

- Newer speech and audio models in the registry since its release: 86. The 5 newest:
  - NVIDIA Nemotron 3.5 Transcribe (30B-A4B) (2026-10-28) https://postcutoff.com/m/nemotron-3-5-transcribe/
  - Hy-SimulMT-30B-A3B (2026-10-22) https://postcutoff.com/m/hy-simulmt-30b-a3b/
  - Eleven Realtime v1 Max / Mini (2026-10-20) https://postcutoff.com/m/eleven-realtime-v1-max/
  - Voxtral Mini Transcribe 3 (+ Mini Transcribe Realtime 3) (2026-10-20) https://postcutoff.com/m/voxtral-mini-transcribe-3/
  - Voxtral Small Transcribe 3 (2026-10-20) https://postcutoff.com/m/voxtral-small-transcribe-3/
- Weights are public. Licence: bilibili Model Use License Agreement. See the licence for commercial terms.

## What stands out

- Precise duration control in an autoregressive TTS: Lets users specify the exact number of speech tokens (useful for dubbing/lip-sync) while keeping AR naturalness, and disentangles speaker timbre from emotion (emotion from a separate reference audio or text). Source: https://huggingface.co/IndexTeam/IndexTTS-2
- IndexTTS-2.5 multilingual (found after launch): 2026-08-10 release adds Japanese, Spanish and Arabic to Chinese/English; speed 0.5-2x, Pinyin/CMU/Kana pronunciation control, RTF ~0.2 on RTX 4090. Source: https://github.com/index-tts/index-tts

## Notes

The IndexTTS2 paper (arXiv June 2025) presents duration control as novel for AR TTS; 'first' not independently verified, so not flagged. Weights released 2025-09-08. Commercial use: contact indexspeech@bilibili.com.

Sources: https://github.com/index-tts/index-tts , https://huggingface.co/IndexTeam/IndexTTS-2

Model page: https://postcutoff.com/m/indextts-2/