Add frame numbers

Adding frame numbers to video frames can be useful for precise reference. Use the Frames.draw_framenumbers() method on a Frames object:

>>> import birdwatcher as bw
>>> vfs = bw.VideoFileStream('myvideo.mp4')
>>> (vfs.iter_frames()
...    .draw_framenumbers()
...    .tovideo('myvideo_numberedframes', framerate=vfs.avgframerate))

See Resize video for some explanation on the VideoFileStream.iter_frames() method. For even more explanation see our tutorial notebook 1_videoframes