Subject: Wan 2.1 GGUF with 5D patch_embedding fails on older builds – request for compatibility note

[desirel-dev]

Subject: Wan 2.1 GGUF with 5D patch_embedding fails on older builds – request for compatibility note

Hi leejet,

First of all, thank you for the amazing work on stable-diffusion.cpp — I use sd-server daily on Windows with Vulkan (Intel Iris Xe) and it's the only backend that runs reliably on my hardware.

I'm hitting a loader mismatch with Wan 2.1 1.3B models exported by current community converters.

Environment:

sd-server.exe commit bb84971 (pre-September 2025 build)
Model: wan2.1-i2v-1.3b-480p-q8_0.gguf (from city96 / calcuis)
Command: --diffusion-model wan2.1-i2v-1.3b-480p-q8_0.gguf --t5xxl umt5-xxl-encoder-Q4_K_M.gguf --vae wan_2.1_vae.safetensors

Error:
Code

[ERROR] ggml_extend.hpp:70 - gguf_init_from_reader: tensor 'patch_embedding.weight' has invalid number of dimensions: 5 > 4
[ERROR] ggml_extend.hpp:70 - gguf_init_from_reader: failed to read tensor info
[ERROR] stable-diffusion.cpp:1416 - model metadata validation failed

The GGUF contains patch_embedding.weight with shape [2, 2, 1, 48, 1536] (5D), while the loader in this build expects max 4D. I understand that Wan 2.1 support (including 5D tensors) was added on 2025-09-14, but many users still use older prebuilt binaries.

Would it be possible to either:

Add a clear note in the README/releases that Wan 2.1 GGUFs require build >= 2025-09-14 due to 5D patch_embedding, or
Consider a small backport that gracefully reports "model requires newer build with 5D support" instead of the generic dimension error?

I'm happy to test any patch on Windows/Vulkan if helpful.

Thanks again for your work, and for maintaining such a lightweight project.

Best regards,