"""
Ref-YoutubeVOS data loader
"""
from pathlib import Path
import torch
from torch.autograd.grad_mode import F
from torch.utils.data import Dataset
import datasets.transforms_video as T
import os
from PIL import Image
import json
import numpy as np
import random
from datasets.categories import ytvos_category_dict as category_dict
class YTVOSDataset(Dataset):
"""
A dataset class for the Refer-Youtube-VOS dataset which was first introduced in the paper:
"URVOS: Unified Referring Video Object Segmentation Network with a Large-Scale Benchmark"
(see https://link.springer.com/content/pdf/10.1007/978-3-030-58555-6_13.pdf).
The original release of the dataset contained both 'first-frame' and 'full-video' expressions. However, the first
dataset is not publicly available anymore as now only the harder 'full-video' subset is available to download
through the Youtube-VOS referring video object segmentation competition page at:
https://competitions.codalab.org/competitions/29139
Furthermore, for the competition the subset's original validation set, which consists of 507 videos, was split into
two competition 'validation' & 'test' subsets, consisting of 202 and 305 videos respectively. Evaluation can
currently only be done on the competition 'validation' subset using the competition's server, as
annotations were publicly released only for the 'train' subset of the competition.
"""
def __init__(self, img_folder: Path, ann_file: Path, transforms, return_masks: bool,
num_frames: int, max_skip: int):
self.img_folder = img_folder
self.ann_file = ann_file
self._transforms = transforms
self.return_masks = return_masks # not used
self.num_frames = num_frames
self.max_skip = max_skip
# create video meta data
self.prepare_metas()
print('\n video num: ', len(self.videos), ' clip num: ', len(self.metas))
print('\n')
def prepare_metas(self):
# read object information
with open(os.path.join(str(self.img_folder), 'meta.json'), 'r') as f:
subset_metas_by_video = json.load(f)['videos']
# read expression data
with open(str(self.ann_file), 'r') as f:
subset_expressions_by_video = json.load(f)['videos']
self.videos = list(subset_expressions_by_video.keys())
self.metas = []
skip_vid_count = 0
for vid in self.videos:
vid_meta = subset_metas_by_video[vid]
vid_data = subset_expressions_by_video[vid]
vid_frames = sorted(vid_data['frames'])
vid_len = len(vid_frames)
if vid_len < 11:
#print(f"Too short video: {vid} with frame length {vid_len}")
skip_vid_count += 1
continue
for exp_id, exp_dict in vid_data['expressions'].items():
# Exclude start_idx (0, 1) and end_idx (vid_len-1, vid_len-2)
start_idx , end_idx = 2, vid_len-2
bin_size = (end_idx - start_idx) // 4
bins = []
for i in range(4):
bin_start = start_idx + i * bin_size
bin_end = bin_start + bin_size if i < 3 else end_idx
bins.append((bin_start, bin_end))
# Random sample one frame from each bin
sample_indx = []
for start_idx, end_idx in bins:
sample_indx.append(random.randint(start_idx, end_idx - 1))
sample_indx.sort() # Ensure indices are in order
for frame_id in sample_indx:
meta = {
'video': vid,
'exp': exp_dict['exp'],
'obj_id': int(exp_dict['obj_id']),
'frames': vid_frames,
'frame_id' : frame_id,
'sample_frames_id' : sample_indx,
'bins': bins,
'category': vid_meta['objects'][exp_dict['obj_id']]['category']
}
self.metas.append(meta)
print(f"skipped {skip_vid_count} short videos")
@staticmethod
def bounding_box(img):
rows = np.any(img, axis=1)
cols = np.any(img, axis=0)
rmin, rmax = np.where(rows)[0][[0, -1]]
cmin, cmax = np.where(cols)[0][[0, -1]]
return rmin, rmax, cmin, cmax # y1, y2, x1, x2
def __len__(self):
return len(self.metas)
def __getitem__(self, idx):
instance_check = False
while not instance_check:
meta = self.metas[idx] # dict
video, exp, obj_id, category, frames, frame_id, sample_frames_id, bins = \
meta['video'], meta['exp'], meta['obj_id'], meta['category'], meta['frames'], metas['frame_id'], metas['sample_frames_id'], meta['bins']
# clean up the caption
exp = " ".join(exp.lower().split())
category_id = category_dict[category]
vid_len = len(frames)
# num_frames = self.num_frames
# read frames and masks
imgs, labels, boxes, masks, valid = [], [], [], [], []
for frame_indx in sample_frames_id:
frame_name = frames[frame_indx]
img_path = os.path.join(str(self.img_folder), 'JPEGImages', video, frame_name + '.jpg')
mask_path = os.path.join(str(self.img_folder), 'Annotations', video, frame_name + '.png')
img = Image.open(img_path).convert('RGB')
mask = Image.open(mask_path).convert('P')
# create the target
label = torch.tensor(category_id)
mask = np.array(mask)
mask = (mask==obj_id).astype(np.float32) # 0,1 binary
if (mask > 0).any():
y1, y2, x1, x2 = self.bounding_box(mask)
box = torch.tensor([x1, y1, x2, y2]).to(torch.float)
valid.append(1)
else: # some frame didn't contain the instance
box = torch.tensor([0, 0, 0, 0]).to(torch.float)
valid.append(0)
mask = torch.from_numpy(mask)
# append
imgs.append(img)
labels.append(label)
masks.append(mask)
boxes.append(box)
# transform
w, h = img.size
labels = torch.stack(labels, dim=0)
boxes = torch.stack(boxes, dim=0)
boxes[:, 0::2].clamp_(min=0, max=w)
boxes[:, 1::2].clamp_(min=0, max=h)
masks = torch.stack(masks, dim=0)
target = {
'frames_idx': torch.tensor(sample_frames_id), # [T,]
'labels': labels, # [T,]
'boxes': boxes, # [T, 4], xyxy
'masks': masks, # [T, H, W]
'valid': torch.tensor(valid), # [T,]
'caption': exp,
'orig_size': torch.as_tensor([int(h), int(w)]),
'size': torch.as_tensor([int(h), int(w)])
}
# "boxes" normalize to [0, 1] and transform from xyxy to cxcywh in self._transform
if self._transforms:
imgs, target = self._transforms(imgs, target)
imgs = torch.stack(imgs, dim=0) # [T, 3, H, W]
else:
imgs = np.array(imgs)
imgs = torch.tensor(imgs.transpose(0, 3, 1, 2))
# FIXME: handle "valid", since some box may be removed due to random crop
if torch.any(target['valid'] == 1): # at leatst one instance
instance_check = True
else:
idx = random.randint(0, self.__len__() - 1)
return imgs, target
def make_coco_transforms(image_set, max_size=640):
normalize = T.Compose([
T.ToTensor(),
T.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
])
scales = [288, 320, 352, 392, 416, 448, 480, 512]
if image_set == 'train':
return T.Compose([
T.RandomHorizontalFlip(),
T.PhotometricDistort(),
T.RandomSelect(
T.Compose([
T.RandomResize(scales, max_size=max_size),
T.Check(),
]),
T.Compose([
T.RandomResize([400, 500, 600]),
T.RandomSizeCrop(384, 600),
T.RandomResize(scales, max_size=max_size),
T.Check(),
])
),
normalize,
])
# we do not use the 'val' set since the annotations are inaccessible
if image_set == 'val':
return T.Compose([
T.RandomResize([360], max_size=640),
normalize,
])
raise ValueError(f'unknown {image_set}')
def build(image_set, args):
root = Path(args.ytvos_path)
assert root.exists(), f'provided YTVOS path {root} does not exist'
PATHS = {
"train": (root / "train", root / "meta_expressions" / "train" / "meta_expressions.json"),
"val": (root / "valid", root / "meta_expressions" / "valid" / "meta_expressions.json"), # not used actually
}
img_folder, ann_file = PATHS[image_set]
# dataset = YTVOSDataset(img_folder, ann_file, transforms=make_coco_transforms(image_set, max_size=args.max_size), return_masks=args.masks,
# num_frames=args.num_frames, max_skip=args.max_skip)
dataset = YTVOSDataset(img_folder, ann_file, transforms=None, return_masks=args.masks,
num_frames=args.num_frames, max_skip=args.max_skip)
return dataset