CSM-1B — GGUF (ggml-quantised)
GGUF / ggml conversion of sesame/csm-1b (Conversational Speech Model) for use with CrispStrobe/CrispASR.
CSM-1B is a TTS model that generates speech from text using a two-stage transformer architecture:
- Backbone (Llama-3.2 1B, 16 layers): generates first-codebook Mimi tokens autoregressively
- Depth decoder (Llama-3.2 100M, 4 layers): fills remaining 31 codebooks per frame
- Mimi codec (Kyutai, 8-layer transformer + SEANet): converts 32-codebook RVQ tokens to 24 kHz PCM
Released under Apache 2.0 license.
Files
| File | Quant | Size | Notes |
|---|---|---|---|
csm-1b-f16.gguf | F16 | 3.4 GB | Full precision — reference quality |
csm-1b-q8_0.gguf | Q8_0 | 1.9 GB | Recommended — identical ASR roundtrip |
csm-1b-q4_k.gguf | Q4_K | 1.1 GB | Smallest — minor quality loss |
Quick start
# 1. Build CrispASR
git clone https://github.com/CrispStrobe/CrispASR
cd CrispASR
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j --target crispasr-cli
# 2. Download model
huggingface-cli download cstr/csm-1b-GGUF csm-1b-q8_0.gguf --local-dir .
# 3. Synthesize
./build/bin/crispasr --backend csm -m csm-1b-q8_0.gguf \
--tts "Hello, how are you today?" \
--tts-output hello.wav --seed 42
Or with auto-download:
./build/bin/crispasr -m csm --auto-download \
--tts "The quick brown fox jumps over the lazy dog." \
--tts-output fox.wav
Parameters
| Parameter | Default | Description |
|---|---|---|
--seed N | 0 | RNG seed (0 = non-deterministic) |
-tp N | 0.9 | Sampling temperature |
--tts-output PATH | — | Output WAV path (24 kHz mono) |
Architecture details
- Text tokenizer: Llama-3.2 BPE (128,256 tokens)
- Audio codec: Mimi (32 codebooks, 2048 entries each, 12.5 Hz frame rate)
- Backbone: 16-layer Llama with GQA (32 heads, 8 KV heads), SwiGLU, RMSNorm, RoPE theta=500,000
- Depth decoder: 4-layer Llama (8 heads, 2 KV heads), position-specific codebook heads
- Sample rate: 24,000 Hz
Conversion
python models/convert-csm-to-gguf.py \
--input sesame/csm-1b \
--output csm-1b-f16.gguf
# Quantize
./build/bin/crispasr-quantize csm-1b-f16.gguf csm-1b-q8_0.gguf q8_0
./build/bin/crispasr-quantize csm-1b-f16.gguf csm-1b-q4_k.gguf q4_k
Acknowledgements
- SesameAILabs/csm — original model and inference code
- Kyutai/mimi — audio codec
Provenance and EU AI Act Art. 53 note
- Upstream model: sesame/csm-1b — published by
sesame. - Upstream licence:
apache-2.0. 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.