PiD Super-Resolution Decode | InvokeAI Documentation
PiD Super-Resolution Decode
PiD (Pixel Diffusion Decoder) is an alternative way to turn a model’s latents into an image. Instead of the usual VAE decode, it runs a short pixel-space diffusion that produces a 4× super-resolved result in a single, few-step pass — so a 512×512 generation comes out as a detailed 2048×2048 image.
Because it decodes in pixel space and is conditioned on your prompt, PiD often recovers finer texture and edge detail than a plain VAE decode followed by an upscaler.
Supported models
PiD works with these base models:
| Base model | PiD decoder to install |
|---|---|
| FLUX.1 | PiD Decoder FLUX |
| FLUX.2 Klein (4B / 9B) | PiD Decoder FLUX.2 |
| Stable Diffusion 3 | PiD Decoder SD3 |
| SDXL | PiD Decoder SDXL |
| Z-Image / Z-Image Turbo | PiD Decoder FLUX (Z-Image shares FLUX.1’s VAE) |
| Qwen-Image | PiD Decoder Qwen-Image |
What you need to install
PiD needs two extra models, both available in Model Manager → Starter Models:
- A PiD Decoder for your base model (e.g. PiD Decoder FLUX (2K)). Some bases offer a 2K and a 2K-to-4K preset; SDXL and Qwen-Image ship only the 2K-to-4K preset.
- The Gemma 2 2B (PiD caption encoder) — PiD uses it to condition the decode on your prompt. It installs automatically as a dependency of any PiD decoder, and is shared across all of them.
Each PiD decoder is roughly 5 GB and the shared Gemma-2 encoder is roughly 5 GB.
Enabling PiD
Open the Generation settings for a supported model and expand the advanced options. You’ll find a PiD control with three modes:
Standard VAE decode. No PiD models required.
Generate at the requested size, decode 4× with PiD, then downscale the result back to the requested size. This is the safe default and works everywhere — the output matches your bounding box exactly, so it composites cleanly on the Canvas.
Treat the requested dimensions as the 4× target: the image is generated at target ÷ 4 and PiD’s full 4× output is used directly (no downscale), preserving all of the added detail. Great when you want a large, highly-detailed result.
When PiD mode is not Off, pick your PiD Decoder and Gemma-2 Encoder below the mode selector. The PiD Steps control (default 4) sets how many decode steps run — the released checkpoints are trained for 4.
PiD is available in both the Generate tab (text-to-image) and on the Canvas (image-to-image), in both Fit and Native modes.
Tips & limitations
- Turn off “Scale Before Processing” on the Canvas when using PiD — PiD already decodes at 4×, so pre-scaling would inflate the work and is blocked.
- Inpaint / Outpaint are not supported with PiD yet; use text-to-image or image-to-image.
- SDXL Refiner cannot be combined with PiD — disable one of them.
- PiD’s memory use scales with the output resolution. A 2048px output needs only a little more headroom than a normal decode, but Native mode at large target sizes (e.g. a 4096px result) is significantly heavier.
- Turbo variants (e.g. Z-Image Turbo) work as usual — the low step count / no-CFG only affects generation; PiD’s own step count is separate.