Parakeet TDT+CTC 1.1B — GGUF (ggml-quantised)
GGUF / ggml conversions of nvidia/parakeet-tdt_ctc-1.1b for use with the crispasr CLI from CrispStrobe/CrispASR.
The largest hybrid Parakeet — 1.1 B parameters, 42-layer FastConformer encoder with both TDT and CTC heads. The hybrid head gives you two decode strategies on the same encoder: native TDT word timestamps (default), or CTC if you need shallow-fusion biasing.
- English, mixed-case + punctuation output (vocab includes uppercase + punctuation tokens, unlike the pure
parakeet-tdt-1.1b) - Hybrid TDT+CTC — default decode is TDT; pass
--parakeet-decoder ctcfor the CTC head - CC-BY-4.0 licence
This repo provides three quantisations, all converted from the same .nemo checkpoint via the convert-parakeet-to-gguf.py script and quantised with crispasr-quantize.
Files
| File | Size | Notes |
|---|---|---|
parakeet-tdt_ctc-1.1b.gguf | 2.15 GB | F16, full precision |
parakeet-tdt_ctc-1.1b-q8_0.gguf | 1.27 GB | Q8_0, near-lossless |
parakeet-tdt_ctc-1.1b-q4_k.gguf | 810 MB | Q4_K — recommended default |
Smoke test on samples/jfk.wav (11 s clip, M1 Metal):
| Quant | Time | Realtime | Output |
|---|---|---|---|
| F16 | 0.74 s | 14.8× | "And so my fellow Americans, ask not what your country can do for you, ask what you can do for your country." |
| Q8_0 | 2.12 s | 5.2× | (identical) |
| Q4_K | 2.67 s | 4.1× | (identical) |
Note: this checkpoint's Q4_K/Q8_0 run slower than the pure
parakeet-tdt-1.1bquants on M1 (CTC + TDT both wired in, plus a per-tensor q4_0 fallback on the joint head). F16 is the fastest precision here.
Quick Start
# 1. Build the runtime
git clone https://github.com/CrispStrobe/CrispASR
cd CrispASR
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j$(nproc) --target crispasr
# 2a. Auto-download via the registry key
./build/bin/crispasr -m parakeet-tdt_ctc-1.1b --auto-download -f your-audio.wav
# 2b. Or explicit download + load
hf download cstr/parakeet-tdt_ctc-1.1b-GGUF \
parakeet-tdt_ctc-1.1b-q4_k.gguf --local-dir .
./build/bin/crispasr -m parakeet-tdt_ctc-1.1b-q4_k.gguf -f your-audio.wav
# 2c. Switch to the CTC head (e.g. when adding hotword biasing)
./build/bin/crispasr -m parakeet-tdt_ctc-1.1b --parakeet-decoder ctc -f your-audio.wav
When to pick this over the other Parakeet variants
| Scenario | Pick |
|---|---|
| English 1.1B with proper casing + punctuation in output | tdt_ctc-1.1b (this repo) |
| English 1.1B, lowercase output, faster Q4_K/Q8_0 | cstr/parakeet-tdt-1.1b-GGUF |
| English, best WER per FLOP | cstr/parakeet-tdt-0.6b-v2-GGUF |
| Multilingual (25 EU languages) | cstr/parakeet-tdt-0.6b-v3-GGUF |
| Tight RAM | cstr/parakeet-tdt_ctc-110m-GGUF |
Model architecture
| Component | Details |
|---|---|
| Encoder | 42-layer FastConformer, d=1024, 8 heads, head_dim=128, FFN=4096, conv kernel=9 |
| Subsampling | Conv2d dw_striding stack, 8× temporal (100 → 12.5 fps) |
| Predictor | 2-layer LSTM, hidden 640 |
| Joint head | enc(1024 → 640) + pred(640 → 640) → ReLU → linear(640 → 1029) — TDT, 5 durations |
| CTC head | linear(1024 → 1025) |
| Vocab | 1024 SentencePiece tokens (English, mixed case + punctuation) + blank |
| Audio | 16 kHz mono, 80 mel bins, n_fft=512, hop=160, win=400 |
| Parameters | ~1.1 B |
Same 42-layer encoder as parakeet-tdt-1.1b, but with an added CTC head and a mixed-case + punctuated vocab.
Attribution
- Original model:
nvidia/parakeet-tdt_ctc-1.1b(CC-BY-4.0). NVIDIA NeMo team. - GGUF conversion + ggml runtime:
CrispStrobe/CrispASR.
License
CC-BY-4.0, inherited from the base model.
Provenance and EU AI Act Art. 53 note
- Upstream model: nvidia/parakeet-tdt_ctc-1.1b — published by
nvidia. - Upstream licence:
cc-by-4.0. This repository redistributes under the same terms; it grants no rights the upstream licence does not. - What was done here: format conversion and/or quantisation only (GGUF/GGML). No training, no fine-tuning, no merging, no distillation, no change to architecture, vocabulary or capability. Only the numeric representation of the upstream weights differs.
- Training data: documented — where it is documented at all — by the upstream provider; see the upstream model card. No training data was used, added or selected by this repository.
- Provider status: under Regulation (EU) 2024/1689 the upstream authors remain the provider of this model. Converting the serialisation format does not make this repository the provider of a new general-purpose AI model, and no such claim is made. Questions about training content, copyright policy or model capability belong upstream.