| --- |
| license: other |
| license_name: minimax-h3-community |
| license_link: LICENSE |
| base_model: |
| - FastVideo/FastVideo-FastH3-4-step-Preview-v1-VSA-DataFree |
| tags: |
| - text-to-video |
| - audio |
| - apple-silicon |
| - metal |
| - int8 |
| - fasth3 |
| - vsa |
| --- |
| |
| # FastH3 VSA · H3ddle INT8 ConvRot |
|
|
| This repository contains the learned-VSA FastH3 Preview v1 transformer converted |
| for H3ddle's native Apple-Silicon Metal engine. It is published with permission |
| from the MiniMax/Hailuo team and remains subject to the included MiniMax H3 |
| Community License Agreement. |
|
|
| ## Use in H3ddle |
|
|
| **FastH3 · VSA is included in |
| [H3ddle](https://github.com/AlexanderIstomin/h3ddle)'s managed model catalog.** Users do not |
| need to download this repository manually, merge checkpoints, run a conversion |
| script, or configure a model folder. In H3ddle, open **Models**, choose |
| **FastH3 · VSA** under **Video**, and select **Install**. The app downloads and |
| verifies this pinned transformer and reuses shared H3 components that are |
| already installed. |
|
|
| The source checkpoint is |
| [`FastVideo/FastVideo-FastH3-4-step-Preview-v1-VSA-DataFree`](https://huggingface.co/FastVideo/FastVideo-FastH3-4-step-Preview-v1-VSA-DataFree) |
| at revision `b65818d41939b5085451074fe8ca8b799f8d4921`. |
|
|
| ## Package |
|
|
| `diffusion_models/minimax_h3_fl2va_pruned_int8_convrot.safetensors` |
|
|
| - Size: `22,966,486,018` bytes |
| - SHA-256: `53335dfb80a09e9de0ef8dce2ef36b5b91e9167044b4da7a3a1219746f474f40` |
| - H3ddle profile: `fasth3` |
| - Serving schedule: exactly four calls |
| - Attention: learned VSA, format 2, tile size 64, sparsity 0.9 |
| - Conditioning: text-to-video with jointly generated audio only |
|
|
| The conversion keeps H3ddle's input-major INT8 ConvRot transformer core, |
| translates Diffusers' value-first SwiGLU layout to the native engine's |
| gate-first layout, preserves the trained four-call AdaLN function as exact |
| lookup rows, and includes all 50 learned VSA compression-gate projections. |
|
|
| This file is not a Diffusers checkpoint. Use it with H3ddle/h3.c and the shared |
| MiniMax H3 text encoder, video VAE, audio VAE, tokenizer, and configuration |
| files expected by the app's managed model manifest. |
|
|
| ## Apple Silicon performance |
|
|
| A controlled 512×512, 124-frame comparison on a 32 GB M1 Pro used the same |
| prompt, soundscape, seed, and cache settings. The measured outputs were |
| 5.175-second H.264 clips at 24 fps with stereo AAC: |
|
|
| | H3 model | Released passes | Attention | End-to-end time | Compared with VSA | Evidence | |
| | --- | ---: | --- | ---: | ---: | --- | |
| | Standard | 20 | Dense | ~4,253 s (~70.9 min) | ~6.11× slower | Schedule-normalized estimate | |
| | Turbo | 8 | Dense | ~1,782 s (~29.7 min) | ~2.56× slower | Schedule-normalized estimate | |
| | FastH3 Dense | 4 | Dense | 958.174 s (16.0 min) | 1.377× slower | Measured conversion baseline | |
| | **FastH3 · VSA** | **4** | **Learned VSA, 90% sparse** | **696.043 s (11.6 min)** | **Baseline** | **Measured** | |
|
|
| The Standard and Turbo rows are estimates, not completed matched runs. They |
| subtract the 134.439-second fixed pipeline cost observed in a phase-instrumented |
| matched-shape receipt, scale only the measured dense transformer work from four |
| passes to the released 8- and 20-pass schedules, and then add the fixed cost |
| back. The FastH3 Dense and VSA rows are direct end-to-end measurements. |
|
|
| These are local M1 Pro results, not projections for every Apple-Silicon device. |
| The direct four-call comparison is a 27.4% end-to-end reduction, or 1.377× |
| throughput, for learned VSA versus Dense. |
|
|
| The native deterministic VSA GPU/CPU test measured cosine similarity |
| `0.999998633`, mean absolute error `0.000065549`, and maximum error |
| `0.000706643` after BF16 output rounding. |
|
|
| ## Limitations |
|
|
| FastH3 Preview v1 supports 124–362 frames and requires a short edge of at least |
| 480 pixels. It does not support still-image generation, start/end frames, |
| ordered image references, or video inpainting. H3ddle enforces these constraints |
| in both the app and the native engine. |
|
|
