MiniMax-H3 FL2VA — Turbo 4-step v1.2 (768p) · NVFP4 SVDQuant (vLLM-Omni)

vLLM-Omni serialized DiT for MiniMax-H3 FL2VA (First-&-Last-frame → Video + Audio), with the Turbo 4-step v1.2 768p LoRA fused in, quantized with SVDQuant NVFP4.

• Format: vLLM-Omni serialized SVDQuant — FL2VA/transformer/ (MiniMaxH3DiTModel, 50 layers, 3 shards).
• Quantization: SVDQuant, precision NVFP4, rank-32 low-rank correction, activation W4A4, curve-basis AdaLN rank-16. modules_to_not_convert: token_refiner, adaln_proj, condition_proj.
• Source: bf16 FL2VA transformer + turbo-4step v1.2 LoRA fused (rank-128, α=8) — no fp4 was ever dequantized; only bf16 base + bf16 LoRA as inputs.
• Size: ~12.3 GiB (3 shards, 1785 tensors).

Requirements

• vLLM-Omni with SVDQuant enabled and SM120 (consumer Blackwell) in the capability gate — see the patch below, or use the pre-built image.
• Text encoder: pottokao/MiniMax-H3-TextEncoder-Qwen3VL-32B-abliterated-NVFP4-AWQ (W4A16_NVFP4, the vLLM-Omni path) — not the GGUF (that one is for ComfyUI).

Running on consumer Blackwell — SM120 (RTX 50xx) & SM121 (GB10 / DGX Spark)

Upstream vLLM-Omni (v0.28.0) gates SVDQuant-NVFP4 to SM103 (B300) only and treats a present quant_config as online quantization, which forces the whole DiT onto the GPU at build time (OOM on 16 GB). Two tiny changes fix both; the same NVFP4 tensor-core path runs unchanged on SM120 (RTX 5070 Ti / 5060 Ti) and SM121 (GB10 / DGX Spark).

Pre-built image (no patching needed) — shipped in this repo under docker/:

hf download pottokao/MiniMax-H3-FL2VA-turbo-4step-v1.2-768p-NVFP4-SVDQuant-vLLM-Omni \
    docker/h3-vllm-omni-nvfp4-0.28.0-sm120.tar.gz --local-dir .
docker load < docker/h3-vllm-omni-nvfp4-0.28.0-sm120.tar.gz   # → h3-vllm-omni-nvfp4:0.28.0-sm120

Built on RTX 5060 Ti (consumer Blackwell / SM120), x86_64. Base: vllm/vllm-openai:v0.28.0.

What is patched — vllm_omni_0.28.0_sm120_svdquant.patch (93 lines, 3 files)

1. vllm_omni/quantization/svdquant_config.py
   • _SUPPORTED_CAPABILITIES = {(10, 3)} → {(10, 3), (12, 0), (12, 1)} — admit SM120 (RTX 50xx) and SM121 (GB10).
   • DiffusionSVDQuantConfig.__init__: add self.is_checkpoint_quantized = True — mark the serialized checkpoint as offline so the diffusion loader allows CPU-offload instead of forcing the DiT onto the accelerator (this is what lets it fit 16 GB).
   • error-string update (SM103 → SM103/SM120).
2. vllm_omni/diffusion/model_loader/host_weight_plan.py
   • add _needs_post_load_quant_processing() and, in build_checkpoint_mmap_plan, fall back to the ordinary loader for SVDQuant checkpoints. SVDQuant renames/reshapes params in process_weights_after_loading (qweight→weight, scale swizzle+pad, input_global_scale_inv/ alpha creation); the direct-mmap plan binds the pre-processing names and would stream a layer missing its kernel runtime params.
3. tests/diffusion/quantization/test_svdquant_linear.py — capability-gate test update.

--- a/vllm_omni/quantization/svdquant_config.py
+++ b/vllm_omni/quantization/svdquant_config.py
@@
-_SUPPORTED_CAPABILITIES = {(10, 3)}
+# SM103 (B300) upstream-validated; SM120 (RTX 50xx) and SM121 (GB10 / DGX Spark)
+# run the same NVFP4 tensor-core path via vLLM CUTLASS/FlashInfer kernels;
+# validated on RTX 5070 Ti and GB10 with MiniMax-H3 SVDQuant-NVFP4.
+_SUPPORTED_CAPABILITIES = {(10, 3), (12, 0), (12, 1)}
@@ class DiffusionSVDQuantConfig
         self.modules_to_not_convert = modules_to_not_convert or []
+        # Offline serialized checkpoint: weights are already quantized on disk.
+        # Without this flag the loader assumes *online* quant and forces the whole
+        # DiT onto the accelerator at build time (OOM on 16 GB).
+        self.is_checkpoint_quantized = True

Build it yourself

# layer 1: official vLLM-Omni CUDA image from the patched v0.28.0 checkout
git clone --branch v0.28.0 <vllm-omni> vllm-omni-src
cd vllm-omni-src && git apply vllm_omni_0.28.0_sm120_svdquant.patch
docker build -f docker/Dockerfile.cuda -t vllm-omni:0.28.0-sm120 .
# layer 2: H3 exporter + example
docker build -f Dockerfile.h3 -t h3-vllm-omni-nvfp4:0.28.0-sm120 .

Run

docker run --rm --gpus all --ipc=host \
  -v $PWD/FL2VA:/models/FL2VA \
  h3-vllm-omni-nvfp4:0.28.0-sm120 \
  python3 /opt/h3/smoke_gen.py --model /models/FL2VA --quant @/opt/h3/quant_svdquant.json --out /out

Related

• ComfyUI path (rotated-NVFP4, nunchaku loader): pottokao/MiniMax-H3-FL2VA-turbo-4step-v1.2-768p-NVFP4-rotated-T1

Abliterated / uncensored pipeline component for the MiniMax-H3 text-to-video / image-to-video stack.