MODEL PROFILE

s2-pro

fishaudio · s2-pro

**Fish Audio S2 Pro** is a leading text-to-speech (TTS) model with fine-grained inline control of prosody and emotion. Trained on over 10M+ hours of audio data across 80+ languages, the system combines reinforcement learning alignment with a dual-autoregressive architecture. The release includes model weights, fine-tuning code, and an SGLang-based streaming inference engine. S2 Pro builds on a decoder-only transformer combined with an RVQ-based audio codec (10 codebooks, ~21 Hz frame rate) using a **Dual-Autoregressive (Dual-AR)** architecture: - **Slow AR** (4B parameters): Operates along the time axis and predicts the primary semantic codebook. - **Fast AR** (400M parameters): Generates the remaining 9 residual codebooks at each time step, reconstructing fine-grained acoustic detail.

Speech synthesislicense:other
Context windowNot disclosed
Input → OutputText → Audio
Model weightsNot verified
Profile updated2026/10/31 03:08:17
OVERVIEW

Model overview

**Fish Audio S2 Pro** is a leading text-to-speech (TTS) model with fine-grained inline control of prosody and emotion. Trained on over 10M+ hours of audio data across 80+ languages, the system combines reinforcement learning alignment with a dual-autoregressive architecture. The release includes model weights, fine-tuning code, and an SGLang-based streaming inference engine. S2 Pro builds on a decoder-only transformer combined with an RVQ-based audio codec (10 codebooks, ~21 Hz frame rate) using a **Dual-Autoregressive (Dual-AR)** architecture: - **Slow AR** (4B parameters): Operates along the time axis and predicts the primary semantic codebook. - **Fast AR** (400M parameters): Generates the remaining 9 residual codebooks at each time step, reconstructing fine-grained acoustic detail.

Key features

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PRICING & COST

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INDEPENDENT BENCHMARKS

Public benchmarks & run configuration

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Sources & traceability

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