66 lines
3.8 KiB
Markdown
66 lines
3.8 KiB
Markdown
# ComfyUI-StepByStep-Sampler
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A set of custom nodes for ComfyUI designed to analyze and compare the image generation process step-by-step. It quantifies changes in latent variables (using metrics like PSNR/SSIM) and provides a dedicated viewer for intuitive inspection. Furthermore, since sampling automatically stops once image generation converges, image generation can be performed with the optimal number of steps.
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[](https://github.com/TakkunRed/ComfyUI-StepByStep-Sampler/blob/main/LICENSE)
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[](https://github.com/comfyanonymous/ComfyUI)
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## Node description
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### 1. Step-by-Step Sampler
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Hooks into the generation process to capture intermediate images at specified intervals by VAE encoding the latent state. It can be integrated with `Preview Image` or `Save Image` nodes to display or output the progression as a sequence.
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Calculates the amount of change from the previous step using MSE, RMSE, L1, PSNR, or SSIM, allowing you to monitor convergence numerically.
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Draws step counts and difference values directly onto the images, making it easy to track the step number and the delta from the preceding frame.
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Since sampling automatically stops once image generation converges, image generation can be performed with the optimal number of steps.
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Outputs the final result as a standard `LATENT` (similar to KSampler), but can also output the VAE-encoded image via the `LAST_IMAGE` socket.
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<img src="images/StepByStep_Sampler.png">
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### 2. Step-by-Step Player
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Visualizes the image list output from the `STEP_IMAGES` socket of the `Step-by-Step Sampler`. Use the slider or the Play button to view the generation process as an animation.
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<img src="images/StepByStepImage.png" width="50%">
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### 3. Step-by-Step Comparer
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A side-by-side visualization tool for the `STEP_IMAGES` output. It allows you to compare two different steps (e.g., Step 5 vs. Step 20) using an interactive split-screen slider.
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<img src="images/comparer.png">
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## Installation
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Manual Install
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```
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Bash
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cd ComfyUI/custom_nodes
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git clone https://github.com/TakkunRed/ComfyUI-StepByStep-Sampler.git
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```
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## How to Use
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### Workflow Integration
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* Add the Step-by-Step Sampler node.
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* Connect `model`, `positive`, `negative`, `latent_image`, and `vae` to the respective inputs.
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* Connect the `STEP_IMAGES` output to the `StepStepPlayer` or `StepStepComparer` node. You can also connect it to `Preview Image` or `Save Image`.
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* Turning on `auto_stop` will stop sampling based on the `stop_threshold`.
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* Run Queue Prompt as usual, and the generation process will appear in the viewers.
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### Viewer Controls
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* `Player`: Change steps using the bottom slider or use the "Play" button for auto-playback.
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* `Comparer`: Select two steps to compare using the sliders, and drag the vertical bar on the image to reveal the differences between side A and side B.
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### Step-by-Step Sampler Settings
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* `save_interval`: Determines how often images are saved (e.g., set to 1 to capture every step).
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* `show_overlay`: Toggles the on-image display of step numbers and difference metrics.
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* `diff_method`: Selects the algorithm for calculating step-to-step changes:
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* Metric Characteristics (at convergence):
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```
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MSE → 0 (Emphasizes large changes)
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RMSE → 0 (MSE scaled back to L1 range)
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L1 → 0 (Simple, robust against outliers)
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PSNR → ∞ (Higher dB means closer to previous step; 40dB+ is a typical convergence target)
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SSIM → 1.0 (Structural Similarity Index; 0.99+ is a typical convergence target)
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```
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* `auto_stop`: Enable/Disable automatic convergence stop
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* `stop_threshhold`: Threshold for determining convergence
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## License
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MIT |