NeMo out, GGUF in: how parakeet.cpp ports NVIDIA ASR to C++
NVIDIA's Parakeet speech models used to mean a Python stack: NeMo, PyTorch, and a GPU you kept warm. A new C++ port collapses that to one binary and one file. From NeMo to GGUF: What the Port Covers parakeet.cpp is a C++17 inference port that runs NVIDIA's Parakeet automatic speech recognition (ASR) models on the ggml tensor library — the same engine behind whisper.cpp and llama.cpp — with no Python, no NeMo, and no ONNX at inference time. The project is maintained by Ettore Di Giacinto (@mudler), author of LocalAI, and its first tagged release, v0.1.0, landed on May 30, 2026 . The code is MIT-licensed; the model weights keep their original NVIDIA Parakeet licenses. This is a community project, not an official NVIDIA release. The port covers the offline Parakeet families — CTC, RNNT, TDT and hybrid TDT-CTC — in 110M, 0.6B and 1.1B sizes, plus a streaming 120M model with end-of-utterance detection . Two checkpoints anchor most use: parakeet-tdt-0.6b-v2 , the English default that reports 6.05% average WER on the Hugging Face Open ASR Leaderboard and was released 05/01/2025 , and parakeet-tdt-0.6b-v3 , which extends the same 600M FastConformer-TDT architecture to 25 European languages with automatic language detection, released 08/14/2025 . Inference runs on CPU, CUDA, HIP (AMD ROCm), Vulkan and Metal (Apple Silicon) — the same ggml backend matrix as whisper.cpp and llama.cpp — so deployment reduces to one binary plus one GGUF file . The hard part was mapping Parakeet's RNNT/TDT decoders onto a static-graph tensor library. An earlier work-in-progress port surfaced on Hacker News in mid-2025, where the author flagged how far there was to go: "The GGML build is roughly 1000x slower than the MLX Python version" — jason-ni, reporting an early Parakeet-on-ggml experiment (source: Hacker News, 2025 ; see also the jason-ni port ). The mudler release is the matured answer to that decoder-on-static-graph problem, and as of June 2026 Parakeet is not yet merged into mainline whis