Index-Echo-S2ST-2B FP4 Quantized Speech-to-Speech Translation Model Released on Hugging Face

IndexTeam released Index-Echo-S2ST-2B-FP4, an NVFP4 (W4A4) quantized version of the Index-Echo-S2ST-2B speech-to-speech translation model, with only the text LLM backbone quantized and the audio components kept in BF16.

On a fixed corpus, perplexity rose from 5.9332 to 6.4980 (+9.52%), while zh->en and en->zh generations matched the original. Full FP4 acceleration requires an NVIDIA Blackwell GPU, and the model loads via compressed-tensors in vLLM or transformers.