| # Reference Video Fade (experimental) |
|
|
| ## Why it exists |
|
|
| MiniMax H3 does not reduce a Ref2VA video to poses. Core VAE-encodes the |
| complete 24 fps reference and packs its latent rows into the same transformer |
| sequence as text, reference pictures/audio, and the target AV streams. Those |
| video rows remain available at every DiT block and every sampling evaluation. |
|
|
| That strong path explains why a simple character-swap prompt can reproduce the |
| reference camera, action, and timing so closely. It also means source color, |
| background, framing, and texture can influence the target even though source |
| pixels are not directly composited into the output. |
|
|
| Dropping every second or third input frame is not a safe strength control. It |
| changes reference speed, duration, and temporal coordinates. Repeating frames |
| keeps duration but introduces stepped motion. Reference Video Fade therefore |
| keeps the complete video and schedules its transformer contribution instead. |
|
|
| ## What the node does |
|
|
| **MiniMax H3 Reference Video Fade (Experimental)** is an opt-in MODEL patch. |
| During early denoising, native reference-video rows remain at full value |
| strength. After `fade_start`, their value contribution follows a half-cosine |
| curve toward `end_strength`: |
|
|
| ```text |
| strength = 1 progress <= fade_start |
| u = (progress - fade_start) / (1 - fade_start) |
| strength = end + (1-end) × 0.5 × (1 + cos(pi×u)) progress > fade_start |
| ``` |
|
|
| `progress` is measured against the complete sigma schedule from 0 at the first |
| sampling level to 1 at the end. The node modifies only H3 attention V slices |
| belonging to native `video` and `video_audio` reference blocks. H3's V tensor |
| is already fresh scratch memory, so the slices are scaled in place without a |
| sequence-sized mask, a duplicate model, or a second attention pass. |
|
|
| The following remain unchanged: |
|
|
| - native still-picture references; |
| - Qwen text and visual-presentation tokens; |
| - native reference audio; |
| - continuation guides or AV-prefix masks; |
| - target video and target audio rows. |
|
|
| The reference video is still completely encoded and supplied to H3. This is a |
| smooth reduction of its attention value contribution, not a hard removal. Its |
| Q/K rows and Qwen presentation can still carry weaker semantic influence. |
|
|
| ## Relationship to continuation color control |
|
|
| Reference Video Fade and **Color-Stable Drift AV** act on different inputs and |
| can be used together: |
|
|
| - Reference Video Fade reduces late denoising influence from an external |
| native Ref2VA motion video. It is the control to test when source framing, |
| background, or color keeps leaking into the generated scene. |
| - Color-Stable Drift AV corrects the disposable previous-scene prefix used for |
| chain continuation. It does not alter the external motion reference, source |
| audio, or saved scene latent. |
|
|
| Use Reference Video Fade alone to diagnose motion-reference leakage. Add |
| Color-Stable Drift AV only when chained scenes also develop their own |
| scene-to-scene color drift. Neither feature modifies the final assembled video. |
|
|
| ## Presets |
|
|
| | Preset | Full reference through | End strength | |
| |---|---:|---:| |
| | `full` | 100% | 100% (true bypass) | |
| | `balanced` | 67% | 20% | |
| | `freer` | 50% | 15% | |
| | `early_only` | 50% | 0% | |
| | `custom` | `custom_fade_start` | `custom_end_strength` | |
|
|
| Start with `balanced`. Use `freer` when the reference reproduces source color, |
| background, or camera too literally. `early_only` is an aggressive diagnostic, |
| not a recommended default. |
|
|
| ## Wiring |
|
|
| For one sampler/model: |
|
|
| ```text |
| H3 MODEL → other backend/model patches → Reference Video Fade → sampler |
| ``` |
|
|
| In a Context Loop Drift-Control graph, the faded MODEL may feed Chain Context's |
| MODEL input; use Chain Context's MODEL output for sampling. |
|
|
| For split-sigma sampling, connect the original **unsplit** schedule to |
| `full_sigmas`. If the split switches models, put one Reference Video Fade node |
| on each model branch and connect the same `full_sigmas` to every copy. This |
| prevents the second half from restarting the fade at progress zero. |
|
|
| Place the node after an attention-backend selector when possible. It chains an |
| already installed optimized-attention override, including SolAttn or Comfy |
| Kitchen, instead of replacing it. |
|
|
| ## Scope and limitations |
|
|
| - All native `video` and `video_audio` reference blocks are faded. Core does |
| not preserve Tagged-reference role names in the packed payload, so a graph |
| with several native reference videos fades all of them. Still pictures are |
| never selected. |
| - This is value gating, not an exact target-query-to-reference-key attention |
| mask. It is deliberately the low-memory implementation suitable for H3's |
| very long packed sequence. |
| - It does not fade the 2 fps Qwen presentation derived from the reference |
| video. Prompts can therefore retain semantic awareness after the native |
| latent-video contribution has weakened. |
| - Results are model-, sampler-, schedule-, and prompt-dependent. Treat the |
| presets as experimental comparisons and keep the rest of the graph fixed. |
|
|
