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我有一个有〜8000帧的视频(.mp4)。我有一个csv,告诉我需要抓取视频中每个帧的时间以及要抓取的帧数。 number_of_frames in video = 8000
times是一个数组像[0.004, 0.005, ... 732s]
在给出的数据中的最后一次是在732s。因此FPS = 8000/732 = ~10
使用opencv和python或moviepy提取图像
我希望能够在这些特定时间从视频中提取图像帧。然后将这些图像路径写入.csv文件。
我试过多种方法: 第一种方法(OpenCV的):
with open('./data/driving.csv', 'w') as csvfile:
fieldnames = ['image_path', 'time', 'speed']
writer = csv.DictWriter(csvfile, fieldnames = fieldnames)
writer.writeheader()
vidcap = cv2.VideoCapture('./data/drive.mp4')
for idx, item in enumerate(ground_truth):
# set video capture to specific time frame
# multiply time by 1000 to convert to milliseconds
vidcap.set(cv2.CAP_PROP_POS_MSEC, item[0] * 1000)
# read in the image
success, image = vidcap.read()
if success:
image_path = os.path.join('./data/IMG/', str(item[0]) +
'.jpg')
# save image to IMG folder
cv2.imwrite(image_path, image)
# write row to driving.csv
writer.writerow({'image_path': image_path,
'time':item[0],
'speed':item[1],
})
这种做法却并没有给我想要的帧的总数。它只给了我对应于FPS = 25视频的帧数。我相信我的FPS = 8000/732s = 10.928s。
我然后使用moviepy捕捉到类似的风格每个图像的尝试:
from moviepy.editor import VideoFileClip
clip1 = VideoFileClip('./data/drive.mp4')
with open('./data/driving.csv', 'w') as csvfile:
fieldnames = ['image_path', 'time', 'speed']
writer = csv.DictWriter(csvfile, fieldnames = fieldnames)
writer.writeheader()
# Path to raw image folder
abs_path_to_IMG = os.path.join('./data/IMG/')
for idx, item in enumerate(ground_truth):
image_path = os.path.join('./data/IMG/', str(item[0]) + '.jpg')
clip1.save_frame(image_path, t = item[0])
# write row to driving.csv
writer.writerow({'image_path': image_path,
'time':item[0],
'speed':item[1],
})
但是这种方法也不能工作,由于某种原因,我捕捉视频数百倍的最后一帧。