Show HN: We compressed a 31B video+audio diffusion model to 14B, 6 steps, INT8

jiant

Hi HN, I’m Jian, one of the engineers on this. MiniMax-H3 is an open model that generates video and audio together, but its transformer is ~31B parameters and sampling takes a long trajectory, so it’s slow and heavy to run locally. HyperFlow H3 Flash is our compressed version. What we changed: Pruning + low-rank factorization: dropped 3 of 50 blocks and factored 102 linear layers, down to 13.7B params. Two-time (t, r) conditioning: each step knows both the current noise level and where it should land, so it samples in 4–8 steps without CFG. W8A8 INT8 with a Hadamard rotation on 180 linear layers. End-to-end numbers for a 5.2 s clip at 1344×768, 6 steps: 8.7 s on 4× B200, 36 s on 1× H200, 92 s on an RTX 5090, 266 s on an RTX 3090. The Q4_K_M GGUF is 9.1 GB and runs in ComfyUI on 24 GB cards. 16 GB GPUs aren’t measured yet. To be clear about “real time”: our package does 8.7 s for a 5.2 s clip on 4× B200. Real-time playback speed uses NVIDIA’s SOL-H3 runtime, which supports the model from day 0. License: code is Apache-2.0 (ComfyUI nodes GPL-3.0). The weights are a derivative of MiniMax-H3 under its Community License, which does not cover the US, EU, UK or South Korea without MiniMax’s authorization. Please check before using. Demos and an overview: https://www.videorebirth.com/lp/hyperflow-flash Happy to answer questions about the compression or the numbers.

xrd

I see references to comfyui in the readme. Is that the easiest way to run it? I've always found it a bit cumbersome to use and wish I had something like a simple CLI tool to use it like llama.cpp. Perhaps that's not possible with a video diffusion model?

swiftcoder

This is very cool, I wish they would make quality+time comparisons between the various quantisations though

ricardobeat

Their product page has sample videos: https://www.videorebirth.com/lp/hyperflow-flash

kodablah

Am curious how this compares perf/quality wise with FastVideo's FastH3 trim/omni which I have been using pretty well with a basic laptop NVidia card (e.g. 5s 480p video w/ audio in 90s).