Kimi-K3 / kimi_k3_vision_processing.py
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feat: add Kimi-K3 video input support
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"""Image and video processor class for Kimi-K3.
"""
import base64
import io
import json
import os
from typing import Any, Dict, Optional, Union
import numpy as np
import torch
from PIL import Image
from transformers.image_processing_utils import (BaseImageProcessor,
BatchFeature)
from transformers.utils import TensorType
from transformers.video_utils import load_video, read_video_pyav
from .media_utils import (MediaInput, TransparentBgConfig, VideoChunkInput,
_to_tensor, ensure_media_type, image_to_np,
navit_patchify, navit_resize_image, normalize,
timestamp_as_str)
class KimiK3VisionProcessor(BaseImageProcessor):
model_type = "kimi_k3"
def __init__(
self,
media_proc_cfg: dict,
**kwargs,
):
super().__init__(**kwargs)
self.media_proc_cfg = media_proc_cfg
self.num_frames_per_chunk = media_proc_cfg[
'temporal_merge_kernel_size']
@property
def _transparent_bg_config(self) -> Optional[TransparentBgConfig]:
cfg = self.media_proc_cfg.get("transparent_bg_config")
if cfg is None:
return None
if isinstance(cfg, TransparentBgConfig):
return cfg
return TransparentBgConfig(**cfg)
@property
def _transparent_bg_fill_stage(self) -> str:
return self.media_proc_cfg.get("transparent_bg_fill_stage",
"before_resize")
def media_tokens_calculator(self, media: MediaInput):
media = ensure_media_type(
media,
transparent_bg_config=self._transparent_bg_config,
transparent_bg_fill_stage=self._transparent_bg_fill_stage,
)
ret = self.get_resize_config(media)
return ret['num_tokens']
@classmethod
def make_image_prompt(cls, width: int, height: int) -> str:
"""Build the K3 image placeholder with resolution info."""
return (f"<|media_begin|>image {width}x{height}"
f"<|media_content|><|media_pad|><|media_end|>")
@classmethod
def make_chunk_prompt(cls, timestamp_text: str) -> str:
"""Build one timestamped K3 video-chunk placeholder."""
return (f"{timestamp_text}<|media_begin|>video<|media_content|>"
f"<|media_pad|><|media_end|>")
@staticmethod
def _normalize_video_source(video_source):
if isinstance(video_source, bytes):
return io.BytesIO(video_source)
if isinstance(video_source, os.PathLike):
return os.fspath(video_source)
if isinstance(video_source, str) and video_source.startswith('data:'):
header, encoded = video_source.split(',', 1)
if not header.startswith('data:video/') or ';base64' not in header:
raise ValueError(
"Video data URLs must contain base64-encoded video data.")
return io.BytesIO(base64.b64decode(encoded, validate=True))
return video_source
def split_video_chunks(self, video_source) -> list[VideoChunkInput]:
"""Decode, uniformly sample, and split a video into temporal chunks."""
config = self.media_proc_cfg
def sample_indices(metadata, **_):
total_frames = int(metadata.total_num_frames)
video_fps = float(metadata.fps or 0)
if total_frames <= 0 or video_fps <= 0:
raise ValueError(
"Video must contain frames and report a positive FPS.")
sample_fps = min(float(config['sample_fps']), video_fps)
sampled_nframes = max(
round(total_frames * sample_fps / video_fps), 1)
max_frames = config.get('max_num_frames_each_video')
if max_frames is not None:
sampled_nframes = min(sampled_nframes, int(max_frames))
sampled_nframes = min(sampled_nframes, total_frames)
return np.linspace(0, total_frames - 1,
sampled_nframes).round().astype(int)
source = self._normalize_video_source(video_source)
if isinstance(source, io.BytesIO):
sampled_frames, metadata = read_video_pyav(
source, sample_indices_fn=sample_indices)
else:
sampled_frames, metadata = load_video(
source, backend="pyav", sample_indices_fn=sample_indices)
if isinstance(sampled_frames, torch.Tensor):
sampled_frames = sampled_frames.cpu().numpy()
frames = [Image.fromarray(np.asarray(frame).astype(np.uint8))
for frame in sampled_frames]
if not frames:
raise ValueError("Video sampling did not return any frames.")
per_frame_limit = int(config.get('in_patch_limit_each_frame')
or config['in_patch_limit'])
total_patch_limit = config.get('in_patch_limit_video')
if total_patch_limit is not None:
per_frame_limit = min(
per_frame_limit,
max(1, round(int(total_patch_limit) / len(frames))),
)
frame_indices = metadata.frames_indices
video_fps = float(metadata.fps)
chunks = []
for start in range(0, len(frames), self.num_frames_per_chunk):
timestamp = timestamp_as_str(
frame_indices[start] / video_fps,
config['timestamp_mode'],
)
chunks.append(
VideoChunkInput(
type='video_chunk',
video_chunk=frames[start:start + self.num_frames_per_chunk],
prompt=self.make_chunk_prompt(timestamp),
in_patch_limit=per_frame_limit,
))
return chunks
def get_resize_config(self, media_input: MediaInput) -> dict:
if media_input['type'] == 'image':
w, h = media_input['image'].size
ret = navit_resize_image(
w, h, self.media_proc_cfg['patch_size'],
self.media_proc_cfg['merge_kernel_size'],
self.media_proc_cfg['in_patch_limit'],
self.media_proc_cfg['patch_limit_on_one_side'],
self.media_proc_cfg['fixed_output_tokens'])
return ret
elif media_input['type'] == 'video_chunk':
frame = media_input['video_chunk'][0]
return navit_resize_image(
frame.width, frame.height,
self.media_proc_cfg['patch_size'],
self.media_proc_cfg['merge_kernel_size'],
media_input['in_patch_limit'],
self.media_proc_cfg['patch_limit_on_one_side'],
self.media_proc_cfg['fixed_output_tokens'])
else:
raise ValueError("Unsupported type: {}".format(
media_input['type']))
def resize_image(self, image: Image.Image, new_width: int, new_height: int,
pad_width: int, pad_height: int) -> np.ndarray:
image_np = image_to_np(
image,
(new_width, new_height),
"resize",
transparent_bg_config=self._transparent_bg_config,
transparent_bg_fill_stage=self._transparent_bg_fill_stage,
)
image_np = np.pad(
image_np,
((0, pad_height), (0, pad_width), (0, 0)),
mode="constant",
constant_values=0,
)
return image_np
def preprocess(
self,
medias: list[MediaInput],
return_tensors: Optional[Union[str, TensorType]] = None,
) -> BatchFeature:
"""
Preprocess images and video chunks into model-ready tensors.
Video audio tracks are not processed.
Args:
medias: List of MediaInput.
return_tensors: Desired output format ('pt', 'np', 'tf', or None).
Returns:
BatchFeature containing 'pixel_values' and 'grid_thws' tensors.
"""
if not isinstance(medias, list):
medias = [medias]
if medias:
pixel_values = []
for item in medias:
item = ensure_media_type(
item,
transparent_bg_config=self._transparent_bg_config,
transparent_bg_fill_stage=self._transparent_bg_fill_stage,
)
resize_config = self.get_resize_config(item)
new_width, new_height, pad_width, pad_height = resize_config[
'new_width'], resize_config['new_height'], resize_config[
'pad_width'], resize_config['pad_height']
if item['type'] == 'image':
image = item['image']
image_np = self.resize_image(image, new_width, new_height,
pad_width, pad_height)
pixel_values.append(np.expand_dims(image_np, axis=0))
elif item['type'] == 'video_chunk':
pixels = [
self.resize_image(frame, new_width, new_height,
pad_width, pad_height)
for frame in item['video_chunk']
]
pixel_values.append(np.stack(pixels, axis=0))
else:
raise ValueError("Unsupported type: {}".format(
item['type']))
normalized_pixel_values = []
image_std_inv = 1.0 / np.array(self.media_proc_cfg['image_std'])
image_mean = np.array(self.media_proc_cfg['image_mean'])
for pixels in pixel_values:
pixels = normalize(pixels, image_mean, image_std_inv)
pixels_and_thw = navit_patchify(
pixels,
self.media_proc_cfg['patch_size'],
)
normalized_pixel_values.append(pixels_and_thw)
pixel_values = torch.cat([
_to_tensor(pixel_value['pixel_values'])
for pixel_value in normalized_pixel_values
])
grid_thws = torch.cat([
_to_tensor(pixel_value['grid_thw'],
dtype=torch.int64).unsqueeze(0)
for pixel_value in normalized_pixel_values
])
data = {
'pixel_values': pixel_values,
'grid_thws': grid_thws,
}
else:
data = {}
return BatchFeature(data=data, tensor_type=return_tensors)
def __repr__(self):
return f"KimiK3VisionProcessor(media_proc_cfg={self.media_proc_cfg})"
def to_dict(self) -> Dict[str, Any]:
output = super().to_dict()
output["media_proc_cfg"] = self.media_proc_cfg
if "media_processor" in output:
del output["media_processor"]
return output
@classmethod
def from_dict(cls, config_dict: Dict[str, Any], **kwargs):
config = config_dict.copy()
media_proc_cfg = config.pop("media_proc_cfg", {})
return cls(media_proc_cfg=media_proc_cfg, **config, **kwargs)
def to_json_string(self):
dictionary = self.to_dict()
for key, value in dictionary.items():
if hasattr(value, 'tolist'):
dictionary[key] = value.tolist()
return json.dumps(dictionary, indent=2, sort_keys=True) + "\n"