# Which VAE memory options (slicing, tiling, frame-wise decoding) do the diffusers docs and source support for Wan, LTX-Video, HunyuanVideo and CogVideoX at v0.41.0, and where do docs and code disagree?

- id: art_01M5NP05VJ0FSG8T4CQ3MDWPQ8
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T06, T09 · tags: none
- updated: 2026-10-24T00:47:01.995Z
- url: https://veyrul.com/articles/art_01M5NP05VJ0FSG8T4CQ3MDWPQ8

At v0.41.0 the memory guide says AutoencoderKLWan supports neither slicing nor tiling (same sentence at an older commit from 2025-08-19), but AutoencoderKLWan in the same tag defines enable_tiling and has use_slicing/use_tiling branches in encode/decode, and the shared AutoencoderMixin only raises NotImplementedError when the attributes are missing. The docs/code conflict is unresolved from reading alone (not executed). Other VAEs differ in defaults: HunyuanVideo's VAE decodes frame-wise by default and the HunyuanVideo page example calls vae.enable_tiling(); LTX's VAE has frame-wise off by default; CogVideoX's page table lists 11GB with tiling plus model offload (no hardware stated). Slicing, per the docs, only helps batches larger than one, so it does not apply to a single-clip run.

At v0.41.0 the memory guide says AutoencoderKLWan supports neither slicing nor tiling (same sentence at an older commit from 2025-08-19), but AutoencoderKLWan in the same tag defines enable_tiling and has use_slicing/use_tiling branches in encode/decode, and the shared AutoencoderMixin only raises NotImplementedError when the attributes are missing. The docs/code conflict is unresolved from reading alone (not executed). Other VAEs differ in defaults: HunyuanVideo's VAE decodes frame-wise by default and the HunyuanVideo page example calls vae.enable_tiling(); LTX's VAE has frame-wise off by default; CogVideoX's page table lists 11GB with tiling plus model offload (no hardware stated). Slicing, per the docs, only helps batches larger than one, so it does not apply to a single-clip run.

Curator qualifications: Docs/code conflict confirmed at the same tag: the guide says the Wan VAE supports neither slicing nor tiling, while AutoencoderKLWan inherits AutoencoderMixin, initialises both flags and branches on them, so enable_slicing/enable_tiling will not raise. Whether the switches give correct output is unobserved. CogVideoX table figures verified (no hardware, frames, resolution or checkpoint stated). Curator addition: the same CogVideoX page says I2V height 'must be 758' and that height and width must be divisible by 16; 758 is not divisible by 16 (768 is), so the page contradicts itself (probable typo). Rights/verification notes are shown as limitations (L00 0019/ADR-0011): they restrict reuse of the cited material or record what was not verified; they are not cleared by this summary.

Limitations: [rights_conflict_record] eligible_with_conflict

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/docs/source/en/optimization/memory.md",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://huggingface.co/docs/diffusers/en/optimization/memory",
      "note": "cited at https://github.com/huggingface/diffusers/blob/f27949dad9f88a34eb22ff80956bbbb940cdbd2b/docs/source/en/optimization/memory.md; memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/src/diffusers/models/autoencoders/autoencoder_kl_wan.py",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/src/diffusers/models/autoencoders/vae.py",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/docs/source/en/api/pipelines/hunyuan_video.md",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/docs/source/en/api/pipelines/cogvideox.md",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/src/diffusers/models/autoencoders/autoencoder_kl_hunyuan_video.py",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/src/diffusers/models/autoencoders/autoencoder_kl_ltx.py",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/src/diffusers/models/autoencoders/autoencoder_kl_cogvideox.py",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/docs/source/en/api/pipelines/ltx_video.md",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/docs/source/en/api/pipelines/wan.md",
      "note": "memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188"
    },
    {
      "url": "https://github.com/huggingface/diffusers/blob/f27949dad9f88a34eb22ff80956bbbb940cdbd2b/docs/source/en/optimization/memory.md",
      "note": "observed URL (dated/alias form of the cited catalogue source; canonical identity retained)"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] At v0.41.0 the memory guide says AutoencoderKLWan supports neither slicing nor tiling (same sentence at an older commit from 2025-08-19), but AutoencoderKLWan in the same tag defines enable_tiling and has use_slicing/use_tiling branches in encode/decode, and the shared AutoencoderMixin only raises NotImplementedError when the attributes are missing. The docs/code conflict is unresolved from reading alone (not executed). Other VAEs differ in defaults: HunyuanVideo's VAE decodes frame-wise by default and the HunyuanVideo page example calls vae.enable_tiling(); LTX's VAE has frame-wise off by default; CogVideoX's page table lists 11GB with tiling plus model offload (no hardware stated). Slicing, per the docs, only helps batches larger than one, so it does not apply to a single-clip run. · locator: memory.md L192, L217; autoencoder_kl_wan.py L964, L1072-1121, L1180, L1237; vae.py L899-923 (AutoencoderMixin); cogvideox.md L176-188 · source: https://github.com/huggingface/diffusers/blob/086bf9578c0f4acbc66e48cd1e7cc26befd9e10f/docs/source/en/optimization/memory.md

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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