nemo-nano-codec-22khz-1.89kbps-21.5fps

NeMo NanoCodec 22 kHz / 1.89 kbps / 21.5 fps — MLX (safetensors)

MLX-ready safetensors conversion of NVIDIA's NeMo NanoCodec (nvidia/nemo-nano-codec-22khz-1.89kbps-21.5fps), the 22.05 kHz / 21.5 fps / 1.89 kbps variant. It is a neural audio codec using finite scalar quantization (GroupFSQ, 8 groups × FSQ levels [8, 7, 6, 6], 32 embed dims) with a HiFi-GAN encoder/decoder.

This repo exists so Swift-MLX / MLX consumers can load the codec weights directly — the upstream distribution ships a .nemo archive that requires the NeMo/PyTorch stack (Linux-only in practice). The tensors here are extracted from that archive verbatim (weight-norm kept in the modern parametrizations.weight.{original0,original1} layout; no numerics changed). It is the codec layer of the Gepard-1.0 streaming-TTS port (xocialize/mlx-gepard-swift).

Contents

Parity

Converted and validated against the NeMo reference (CPU fp32) as part of the Gepard port:

• decode (32-ch codes → waveform): max|Δ| 6.7e-6, SI-SNR 104 dB, corr 1.000000
• encode (waveform → codes): 99.5% packed integer-exact (residual = FSQ knife-edge boundary flips + ≤1 tail frame — the documented conv-edge convention).

License / Terms of Use

Governed by the NVIDIA Open Model License Agreement (v. June 14, 2024) — see the bundled PDF and NOTICE. The model is commercially usable; redistribution of the model and derivatives is permitted with the §3.1 obligations (ship a copy of the Agreement and the Notice below).

Licensed by NVIDIA Corporation under the NVIDIA Open Model License

The conversion tooling and the consuming Swift port are Apache-2.0; only these weights carry the NVIDIA Open Model License.

Citation

NeMo NanoCodec — https://arxiv.org/abs/2508.05835