cvbase

Introduction

cvbase is a miscellaneous set of tools which maybe helpful for computer vision research. It comprises the following parts.

• IO helpers
• Image/Video operations
• OpenCV wrappers for python2/3 and opencv 2/3
• Timer
• Progress visualization
• Plotting tools
• Object detection utils

Try and start with

pip install cvbase

See documentation for more features and usage.

Some popular features

There are some popular features such as progress visualization, timer, video to frames/frames to videos.

• Progress visualization

  If you want to apply a method to a list of items and track the progress, track_progress is a good choice. It will display a progress bar to tell the progress and ETA.

  import cvbase as cvb
  
  def func(item):
      # do something
      pass
  
  tasks = [item_1, item_2, ..., item_n]
  
  cvb.track_progress(func, tasks)
  

  The output is like the following.

  There is another method track_parallel_progress, which wraps multiprocessing and progress visualization.

  import cvbase as cvb
  
  def func(item):
      # do something
      pass
  
  tasks = [item_1, item_2, ..., item_n]
  
  cvb.track_parallel_progress(func, tasks, 8)
  # 8 workers
  

• Timer

  It is convinient to computer the runtime of a code block with Timer.

  import time
  
  with cvb.Timer():
      # simulate some code block
      time.sleep(1)
  

  Or try a more flexible way.

  timer = cvb.Timer()
  # code block 1 here
  print(timer.since_start())
  # code block 2 here
  print(timer.since_last_check())
  print(timer.since_start())
  

• Video/Frames conversion

  To split a video into frames.

  video = cvb.VideoReader('video_file.mp4')
  video.cvt2frames('frame_dir')
  

  Besides cvt2frames, VideoReader wraps many other useful methods to operate a video like a list object, like

  video = cvb.VideoReader('video_file.mp4')
  len(video)  # get total frame number
  video[5]  # get the 6th frame
  for img in video:  # iterate over all frames
      print(img.shape)
  

  To generate a video from frames, use the frames2video method.

  video = cvb.frames2video('frame_dir', 'out_video_file.avi', fps=30)
  

• Video editing (needs ffmpeg)

  To cut a video.

  cvb.cut_video('input.mp4', 'output.mp4', start=3, end=10)
  

  To join two video clips.

  cvb.concat_video(['clip1.mp4', 'clip2.mp4'], 'output.mp4')
  

  To resize a video.

  cvb.resize_video('input.mp4', 'resized.mp4', (360, 240))
  # or
  cvb.resize_video('input.mp4', 'resized.mp4', ratio=2)
  

  To convert the format of a video.

  cvb.convert_video('input.avi', 'output.mp4', vcodec='h264')