最近有个需求就是给定一个视频，截取某一特定时间的那帧图片。最后决定使用python＋opencv 环境：
- python3（
pip install opencv-python)
核心代码：
def get_frame_from_video(video_name, frame_time, img_dir, img_name):
"""
get a specific frame of a video by time in milliseconds
:param video_name: video name
:param frame_time: time of the desired frame
:param img_dir: path which use to store output image
:param img_name: name of output image
:return: None
"""
vidcap = cv2.VideoCapture(video_name)
# Current position of the video file in milliseconds.
vidcap.set(cv2.CAP_PROP_POS_MSEC, frame_time - 1)
# read(): Grabs, decodes and returns the next video frame
success, image = vidcap.read()
if not os.path.exists(img_dir):
os.makedirs(img_dir)
if success:
# save frame as JPEG file
cv2.imwrite(img_dir + sep + img_name, image)
# cv2.imshow("frame%s" % frame_time, image)
# cv2.waitKey()
