tutorials/utility/seedvr2

[giscus[bot]]

tutorials/utility/seedvr2

Learn how to upscale images and videos using SeedVR2, a one-step diffusion-based restoration model from ByteDance Seed

https://docs.comfy.org/tutorials/utility/seedvr2

[blenderdeluxe]

The output with two workflows
SeedVR2 3B Int8: Upscale Image
SeedVR2 7B Int8: Upscale Image

is black with my RTX 3090

someone more?

[lin-bot23]

Thanks for reporting this! Black output from the SeedVR2 Int8 upscale workflows on a 3090 is not something we've seen in our testing, so a few more details would really help us narrow it down:

1. Environment: ComfyUI Desktop or manual install? Which ComfyUI version (latest stable or nightly)?
2. Models: Can you confirm both files are fully downloaded? They should be models/vae/seedvr2_ema_vae_fp16.safetensors and models/diffusion_models/seedvr2_3b_int8_convrot.safetensors (or the 7B variant). A partial/truncated download often produces exactly this symptom.
3. Log output: Could you share the console/terminal output around the run? Any errors or warnings (model load failures, dtype/quantization warnings, OOM)?
4. Run behavior: Does the workflow run to completion? Roughly how long does it take? Does the ImageCompare node show the before image but a black after?
5. Input image: Does the input image preview correctly in the LoadImage node before you run?
6. Both workflows: Do both the 3B and 7B variants fail identically, or does one work?

Black output usually points to either a missing/mismatched model file or something failing silently during sampling or decode, and the log should tell us which. Thanks!

[lin-bot23]

One more thing worth checking: have you installed the SageAttention custom node or enabled sage attn as your attention backend? We have seen black or corrupted outputs traced to the SageAttention backend, particularly with quantized models on certain GPUs (the fallback path or dtype handling can silently produce garbage). If you have it installed, try disabling it / switching the attention backend back to the default and re-running. That would be a very useful data point!

[gabrielmtzcarrillo]

when I get black images, sometimes it's related to the preview flag of comfyui, disable live previews

[lin-bot23]

Thanks @gabrielmtzcarrillo, that's a great tip! Disabling live previews is indeed worth trying when outputs come back black, especially with quantized models. I've noted it as a troubleshooting suggestion for this workflow.