Fish Audio S2-Pro

Fish Audio S2-Pro is a text-to-speech model served through /v1/audio/speech. It supports plain TTS, voice cloning with a reference clip, and streaming audio chunks.

Prerequisites

Install sglang-omni by following Installation, then download the model:

hf download fishaudio/s2-pro

Server Configuration

sgl-omni serve \
  --model-path fishaudio/s2-pro \
  --config examples/configs/s2pro_tts.yaml \
  --port 8000

Synthesize Speech

Plain TTS:

curl -X POST http://localhost:8000/v1/audio/speech \
  -H "Content-Type: application/json" \
  -d '{"input": "Hello, how are you?"}' \
  --output output.wav

Voice cloning:

curl -X POST http://localhost:8000/v1/audio/speech \
  -H "Content-Type: application/json" \
  -d '{
    "input": "Get the trust fund to the bank early.",
    "references": [{
      "audio_path": "https://huggingface.co/datasets/zhaochenyang20/seed-tts-eval-mini/resolve/main/en/prompt-wavs/common_voice_en_10119832.wav",
      "text": "We asked over twenty different people, and they all said it was his."
    }]
  }' \
  --output output.wav

Streaming:

curl -N -X POST http://localhost:8000/v1/audio/speech \
  -H "Content-Type: application/json" \
  -d '{
    "input": "Get the trust fund to the bank early.",
    "references": [{
      "audio_path": "https://huggingface.co/datasets/zhaochenyang20/seed-tts-eval-mini/resolve/main/en/prompt-wavs/common_voice_en_10119832.wav",
      "text": "We asked over twenty different people, and they all said it was his."
    }],
    "stream": true,
    "response_format": "pcm"
  }' \
  --output output.pcm

Request Parameters

Parameter	Type	Default	Description
input	string	required	Text to synthesize
voice	string	default	Voice identifier for non-reference requests
response_format	string	wav	Output audio format
speed	float	1.0	Playback speed multiplier
stream	bool	false	Stream raw PCM audio chunks
references	list	null	Reference clip for voice cloning; each item has audio_path and text
ref_audio / ref_text	string	null	Shorthand for references[0].audio_path and references[0].text
max_new_tokens	int	2048	Maximum generated semantic tokens
temperature	float	0.8	Sampling temperature
top_p	float	0.8	Top-p sampling
top_k	int	30	Top-k sampling; must be -1 or between 1 and 30
repetition_penalty	float	1.1	Repetition penalty

Known Limitations

• top_k is constrained to -1 or 1..30; keep requests inside this range because invalid values currently fail the S2-Pro pipeline instead of returning a clean parameter error.

• Reference quality strongly affects cloned voice quality.

• Use streaming for interactive playback; CLI inspection of raw audio responses is awkward.