| --- |
| license: other |
| license_name: ltx-2-community-license-agreement |
| license_link: https://github.com/Lightricks/LTX-2/blob/main/LICENSE |
| base_model: Lightricks/LTX-2.3 |
| tags: |
| - ltx-2 |
| - video |
| - comfyui |
| - int8 |
| - quantized |
| --- |
| |
| # LTX-2.3 22B dev — INT8 tensorwise (+ConvRot), stock-ComfyUI native |
|
|
| Offline INT8 quantization of `Lightricks/LTX-2.3` (`ltx-2.3-22b-dev.safetensors`), |
| produced with [Comfy-Org/comfy-quants](https://github.com/Comfy-Org/comfy-quants) |
| (`export-model-int8-tensorwise`). Loads **natively in stock ComfyUI >= v0.27.0** |
| (`QUANT_ALGOS["int8_tensorwise"]`, SM >= 7.5 / Turing+) — no custom node required. |
|
|
| ## Contents |
|
|
| Single-file bundle (drop into `models/checkpoints/`, load via `CheckpointLoaderSimple`; |
| `LTXAVTextEncoderLoader` and `LTXVAudioVAELoader` read the text-embedding projection / |
| audio VAE / vocoder from the same file). Text encoder (Gemma-3-12B) not included — |
| use e.g. `Comfy-Org/ltx-2` `gemma_3_12B_it_fp4_mixed.safetensors`. |
|
|
| ## Quantization contract |
|
|
| - 1,496 quantized Linears (blocks 2–45 incl. `to_gate_logits`; blocks 0/1/46/47 kept |
| bf16) — **layer-for-layer identical to the official `Lightricks/LTX-2.3-fp8` / |
| `-nvfp4` releases**. |
| - Per layer: `int8` weight + `float32 [out,1]` scale + `comfy_quant` marker |
| `{"format": "int8_tensorwise", "convrot": true, "convrot_groupsize": 256}` |
| (byte-exact to stock ComfyUI's own save path). All 1,496 layers ConvRot-rotated. |
| - Quant math bit-faithful to comfy-kitchen >= 0.2.15 (`quantize_int8_convrot_weight`). |
| - VAE / audio VAE / vocoder / text-embedding projection copied verbatim (bf16/f32). |
|
|
| ## Measured (RTX PRO 6000 Blackwell, 512²×49f+audio, 20 steps, torch 2.10.0+cu130) |
|
|
| | | bf16 | this artifact | |
| |---|---|---| |
| | Disk | 46.1 GB | **29.2 GB** | |
| | Peak VRAM (full pipeline) | 53.7 GB | **38.6 GB (−28%)** | |
| | Sampling speed | 2.37 it/s | **2.73 it/s (1.15×)** | |
| | Video PSNR vs bf16 | — | **45.4 dB** | |
|
|
| Best fidelity and the only faster-than-bf16 format among fp8/mxfp8/nvfp4/int8 on this |
| model. |
|
|
| ## License |
|
|
| Inherits the **LTX-2 Community License Agreement** from the base model (free below |
| $10M annual revenue; derivatives must remain under the same license). See the license |
| link above and the `license` field embedded in the checkpoint metadata. |
|
|
