fix: forward ref_image_args to the video pipeline (#2177)

docs/edit.md

@@ -85,6 +85,9 @@ If presets are insufficient, you can manually configure the following parameters
 | `vlm_max_size` | int | Maximum VLM input size; interpreted according to `vlm_resize_mode`. | Integer |
 | `vlm_min_size` | int | Minimum VLM input size; interpreted according to `vlm_resize_mode`. | Integer |
 | `vlm_size` | int | Shortcut to set both VLM min and max size to the same value. | Integer |
+| `ref_image_size` | string | MiniMax-H3 reference image sizing before VAE encoding. `match` scales each reference down to the generation's pixel area; `max` uses a 2048 px short edge. Only references above the limit are downscaled; each axis is then snapped to the nearest 32 px multiple (an axis of at least 16 px grows by at most 16 px, and references are never narrower than 32 px). | `match`, `max` |
+
+`ref_image_size` applies to `vid_gen` with MiniMax-H3 Ref2VA. Reference latents are attended to at every sampling step, so `max` can be several times slower.
 
 ### Preset Default Values
 

docs/image_preprocessing.md

@@ -128,7 +128,8 @@ To disable reference resizing before VAE encoding, use
 `--ref-image-args "resize_before_vae=false"` or the server field
 `"ref_image_args": "resize_before_vae=false"`. This is separate from
 `target=ref,mode=none`, which only skips input geometry. Model constraints
-still apply.
+still apply; MiniMax-H3 requires 32-pixel-aligned references and warns instead
+of honoring the switch.
 
 ## Server requests
 

docs/minimax_h3.md

@@ -80,8 +80,20 @@ latents condition the diffusion transformer. Paired video and audio references
 share the same timeline. Ref2VA cannot be combined with `--init-img` or
 `--end-img` in one request.
 
-Reference images keep their aspect ratio and are only downscaled when their
-pixel area exceeds the requested generation canvas.
+Reference images keep their aspect ratio and are only downscaled when they
+exceed the configured limit; neither mode scales a reference up. The limit is
+selected by `ref_image_size`. The default, `match`, uses the pixel area of the
+requested generation canvas. Pass `--ref-image-args "ref_image_size=max"` (or
+`ref_image_size` in `sd_vid_gen_params_t.ref_image_args`) to use a 2048 px short
+edge instead, which preserves more identity detail at a higher sampling cost:
+reference latents are attended at every sampling step.
+
+Whichever limit applies, each axis is then snapped to the nearest 32-pixel
+multiple. An axis of at least 16 pixels can therefore grow by up to 16 pixels
+past the scaled size (a 48-pixel axis becomes 64), and references are never
+narrower than 32 pixels.
+`resize_before_vae=false` is not supported here; MiniMax-H3 keeps references on
+the 32-pixel grid and reports a warning.
 
 The C API exposes the same inputs through `ref_images`, `ref_videos`, and
 `ref_audios` in `sd_vid_gen_params_t`. Each `sd_ref_video_t` supplies its own