Hunyuan Video 15 Latent Upscale With Model

HunyuanVideo 1.5 got small - 8.3B against the original 13B - and stayed good by doing a trick: it renders at a modest resolution, then a dedicated super-resolution network lifts the latent to your target. This node is that second stage. Hunyuan Video 15 Latent Upscale With Model takes your sampled latent, resizes it with an interpolation method, and then runs it through a learned latent-upscale model so the upsampled result has actual detail instead of just more pixels. It's why 1.5's official workflows produce 720p that doesn't look like a stretched 480p.

Five inputs, one output:

• model - the LATENT_UPSCALE_MODEL, loaded with Load Latent Upscale Model. This is the SR network, and it's a real model - separate download from the main checkpoint.
• samples - your sampled LATENT.
• upscale_method - default bilinear. The interpolation used before the model refines. bicubic is a reasonable alternative; nearest-exact is the fastest and least smooth. It's a pre-filter, not the upscaler.
• width / height - default 1280×720, the target size. Set 0 on one axis to preserve aspect ratio from the other. Steps of 8.
• crop - disabled or center, what to do if the aspect ratio doesn't line up with the target.
• Output: the upscaled LATENT, ready for VAE decode.

Mechanically the source does this: interpolate the latent to width/16 × height/16, pass it through model.resample_latent(), and hand back the result. The /16 (not /8) reflects 1.5's latent being twice as compressed spatially as the original Hunyuan's - the SR model operates on that coarser latent and fills in what interpolation can't.

The two model flavors

The Load Latent Upscale Model node auto-detects what you give it, and the Hunyuan 1.5 release ships two kinds: the 720p SR model (for the 480p→720p step in the standard I2V/T2V workflow) and the 1080p SR model (a further upscale to 1080p). Pick the one that matches your target. Both go in models/latent_upscale_models.

Where it fits

It's the tail of the official HunyuanVideo 1.5 T2V/I2V workflows: Empty HunyuanVideo 1.5 Latent → sampler → this node → VAE decode → video output. Generate at 480p/720p, upscale in latent, decode once. The step-distilled I2V models made this pairing the community's fast path - 8–12 steps plus the SR pass got 1.5 demos genuinely competitive with Wan on speed.

Troubleshooting

• "Latent upscale model" not in the dropdown - the files aren't downloaded. This is the single most common failure for 1.5 workflows, and it's not your wiring: the models are separate downloads and people regularly miss them. Grab the SR model from the HunyuanVideo-1.5 release and drop it in ComfyUI/models/latent_upscale_models/.
• Degradation after the upscale. A recurring r/StableDiffusion thread shows output degrading mid-video after the latent upscaler - faces and fine detail going mushy as the clip progresses. The usual culprits: upscaling too aggressively in one step (step it: 480→720→1080), or the source latent being too noisy/long for one SR pass. If your clip degrades, shorten it and upscale in stages.
• Compatibility: this is the 1.5 node. The original HunyuanVideo 1.0 doesn't use it - its latent is different (16 channels, 8× spatial, against 1.5's 32 channels, 16×), so don't bolt this onto a 1.0 workflow.

If your card can't run 1.5's SR model in one shot, remember it's optional: you can sample, decode, and upscale in pixel space with a regular image upscaler. You lose the latent-space coherence, but you gain the ability to render at all.