NVIDIA · Open multilingual ASR

NVIDIA Nemotron 3.5 Transcribe 30B-A4B

Nemotron 3.5 Transcribe is an open-weight, offline speech and audio model from NVIDIA. It covers transcription in 40 languages, speech translation, contextual and speaker-attributed transcription, timestamp prediction, language identification and audio question answering, with recordings of up to one hour and a 65,536-token context. NVIDIA reports a mean WER of 4.71 on nine English Open ASR Leaderboard sets (next best open-weight model, Qwen3-ASR-1.7B, 4.94), 10.98 on long-form ASR (Parakeet-TDT-0.6B-v3 13.37) and 4.62 on seven multilingual languages (Qwen3-ASR-1.7B 6.49). It also reports a mean cpWER of 15.80 on multi-speaker sessions, against 16.83 for DiCoW v3.3 + DiariZen. It is a speech-augmented language model with a Mamba-2–Transformer hybrid mixture-of-experts backbone and a Transformer ASR encoder plus speaker encoder; 34B parameters in total, about 4.3B active. Weights are released in BF16, FP8 and NVFP4 under the OpenMDW-1.1 licence, and NVIDIA says the model runs on one H100 80 GB via vLLM or Hugging Face Transformers. NVIDIA's faster serving optimisations, reported at up to 2,238 seconds of audio per second on one RTX PRO 6000 Blackwell GPU, are not yet in the open-source release.