[Model] Nano Nemotron VL - fast media preprocessing (#35657)

Signed-off-by: Natan Bagrov <nbagrov@nvidia.com>

vllm/model_executor/models/nano_nemotron_vl.py

@@ -17,11 +17,11 @@ from functools import cached_property
 from typing import Annotated, Any, Literal, TypeAlias, TypeVar
 
 import einops
+import numpy as np
 import numpy.typing as npt
 import regex as re
 import torch
 import torch.nn as nn
-import torchvision.transforms as T
 from PIL import Image
 from transformers import BatchFeature, PretrainedConfig, TensorType
 
@@ -214,7 +214,12 @@ NanoNemotronVLVideoInputs: TypeAlias = (
 
 
 def dynamic_preprocess(
-    image, *, image_size=512, max_num_tiles=12, use_thumbnail=True, idx=0
+    image,
+    *,
+    image_size=512,
+    max_num_tiles=12,
+    use_thumbnail=True,
+    idx=0,
 ):
     orig_width, orig_height = image.size
 
@@ -227,35 +232,44 @@ def dynamic_preprocess(
         image_size=image_size,
         use_thumbnail=False,
     )
-    # resize the image
-    resized_img = image.resize((target_width, target_height))
-    processed_images = []
-    for i in range(blocks):
-        box = (
-            (i % (target_width // image_size)) * image_size,
-            (i // (target_width // image_size)) * image_size,
-            ((i % (target_width // image_size)) + 1) * image_size,
-            ((i // (target_width // image_size)) + 1) * image_size,
-        )
-        # split the image
-        split_img = resized_img.crop(box)
-        processed_images.append(split_img)
-    assert len(processed_images) == blocks
-    if use_thumbnail and len(processed_images) != 1:
-        thumbnail_img = image.resize((image_size, image_size))
-        processed_images.append(thumbnail_img)
-
-    processed_images = [
-        img.convert("RGB") if img.mode != "RGB" else img for img in processed_images
-    ]
-    processed_images = [
-        T.Resize((image_size, image_size), interpolation=T.InterpolationMode.BICUBIC)(
-            img
+
+    image = np.asarray(
+        image.convert("RGB") if image.mode != "RGB" else image, dtype=np.uint8
     )
-        for img in processed_images
-    ]
-    processed_images = [T.ToTensor()(img) for img in processed_images]
-    return processed_images
+
+    image = torch.from_numpy(image).unsqueeze(0)  # (1, H, W, 3)
+    image = image.permute(0, 3, 1, 2)  # (1, 3, H, W)
+
+    resized_img = torch.nn.functional.interpolate(
+        image,
+        size=(target_height, target_width),
+        mode="bicubic",
+        align_corners=False,
+        antialias=True,
+    )
+    B, C, H, W = resized_img.shape
+    hp, wp = H // image_size, W // image_size
+    patches = (
+        resized_img.reshape(B, C, hp, image_size, wp, image_size)
+        .permute(0, 2, 4, 1, 3, 5)
+        .reshape(B * hp * wp, C, image_size, image_size)
+        / 255.0
+    )
+
+    if use_thumbnail and patches.shape[0] > 1:
+        thumb = (
+            torch.nn.functional.interpolate(
+                image,
+                size=(image_size, image_size),
+                mode="bicubic",
+                align_corners=False,
+                antialias=True,
+            )
+            / 255.0
+        )
+        patches = torch.cat([patches, thumb], dim=0)
+
+    return list(patches)
 
 
 def image_to_pixel_values(
@@ -287,22 +301,21 @@ def video_to_pixel_values(
 ) -> torch.Tensor:
     assert max_num_tiles == 1, "Video modality always uses one tile"
 
-    # Convert each frame to a single resized tile tensor consistent
-    # with image path
-    frames_tensors: list[torch.Tensor] = []
-    for frame in video:
-        pil_frame = dynamic_preprocess(
-            Image.fromarray(frame, mode="RGB"),
-            image_size=input_size,
-            max_num_tiles=max_num_tiles,
-            use_thumbnail=use_thumbnail,
-            idx=0,
+    # (num_frames, H, W, C) -> (num_frames, C, H, W)
+    video_tensor = torch.from_numpy(video).permute(0, 3, 1, 2)
+
+    if video_tensor.shape[2] != input_size or video_tensor.shape[3] != input_size:
+        video_tensor = torch.nn.functional.interpolate(
+            video_tensor,
+            size=(input_size, input_size),
+            mode="bicubic",
+            align_corners=False,
+            antialias=True,
         )
-        # dynamic_preprocess returns tensors already; take the single tile
-        assert len(pil_frame) >= 1
-        frames_tensors.append(pil_frame[-1])
 
-    return torch.stack(frames_tensors)
+    video_tensor = video_tensor / 255.0
+
+    return video_tensor
 
 
 def input_conditioner(x, norm_mean, norm_std):
@@ -346,12 +359,6 @@ class DynamicResolutionImageTiler:
         self._factor_max = factor_max
         self.norm_mean = torch.tensor(norm_mean).reshape(3, 1, 1)
         self.norm_std = torch.tensor(norm_std).reshape(3, 1, 1)
-        self._transform = T.Compose(
-            [
-                T.Lambda(lambda img: img.convert("RGB") if img.mode != "RGB" else img),
-                T.ToTensor(),
-            ]
-        )
         assert downsample_ratio < 1
         reduction_factor = 1 / downsample_ratio
         assert reduction_factor == 2.0
@@ -441,15 +448,25 @@ class DynamicResolutionImageTiler:
         patch_size: tuple[int, int]
 
     def apply_params(self, params: DynamicResolutionParams) -> list[torch.Tensor]:
-        resized_img = params.media.resize(
-            (
-                params.patch_size[0] * self._patch_size,
+        target_size = (
             params.patch_size[1] * self._patch_size,
+            params.patch_size[0] * self._patch_size,
         )
+        image = np.asarray(
+            params.media.convert("RGB") if params.media.mode != "RGB" else params.media,
+            dtype=np.uint8,
         )
-        processed_images = [resized_img]
-
-        return [self._transform(img) for img in processed_images]
+        resized_img = (
+            torch.nn.functional.interpolate(
+                torch.from_numpy(image).unsqueeze(0).permute(0, 3, 1, 2),
+                size=target_size,
+                mode="bicubic",
+                align_corners=False,
+                antialias=True,
+            )
+            / 255.0
+        )
+        return list(resized_img)
 
     def process_media(
         self,
@@ -803,6 +820,7 @@ class BaseNanoNemotronVLProcessor(ABC):
             image_repl = self.get_image_repl(feature_size, num_patches)
             parts[i] = parts[i].replace("<image>", image_repl.full)
         text = ["".join(parts)]
+
         return text, image_inputs
 
     def _make_batch_input(self, input_item: Any | list[Any] | None = None):
@@ -922,14 +940,14 @@ class NanoNemotronVLProcessor(BaseNanoNemotronVLProcessor):
             frames_indices_lst = [
                 metadata["frames_indices"] for metadata in video_metadata_lst
             ]
-
+            video_num_patches = torch.tensor(
+                [len(item) for item in pixel_values_lst_video]
+            )
             video_inputs = {
                 "pixel_values_flat_video": input_conditioner(
                     torch.cat(pixel_values_lst_video), self.norm_mean, self.norm_std
                 ),
-                "video_num_patches": torch.tensor(
-                    [len(item) for item in pixel_values_lst_video]
-                ),
+                "video_num_patches": video_num_patches,
                 "frames_indices": frames_indices_lst,
                 "frame_duration_ms": torch.tensor(frame_duration_ms_lst),
             }
@@ -985,6 +1003,7 @@ class NanoNemotronVLProcessor(BaseNanoNemotronVLProcessor):
                     video_repl.full, skip_special_tokens=False
                 )
                 text = [t.replace("<video>", video_repl_text, 1) for t in text]
+
         return text, video_inputs
 
     def _preprocess_audio(