'coreader' methods of 'VideoFileClip' and 'AudioFileClip' are buggy

[mondeja]

These methods were created at #1332 and fdc51d2, but IMHO I think that are a misunderstanding of how copy.copy and copy.deepcopy works in Python.

• coreader methods currently does a shallow copy (like copy.copy) but only taking into account filename parameter.
• Clip.copy method is working like copy.deepcopy, but even for AudioClip the mask and audio attributes are checked in the instance.

Actual Behavior

The coreader functionality is not working. It's implemented as return AudioFileClip(self.filename, self.buffersize), but AudioFileClip accepts buffersize as a kwarg argument, so it's not taking the buffersize. The same applies to VideoFileClip.

The documentation of coreader methods are very poor, what are they supposed to do? I think that should be added an example, if they are really implemented and are not bad copy.copy-like code.

Steps to Reproduce the Problem

>>> from moviepy.editor import *
>>> clip = AudioFileClip('media/crunching.mp3', buffersize=1000)
>>> clip_2 = clip.coreader()
>>> clip.buffersize
1000
>>> clip_2.buffersize
200000

Expected behaviour

I'm not sure, are a failed copy, I'm thinking in two possible cases:

• New instance with only filename as the same argument
• New instance with filename and buffersize as same arguments

I suspect that are just weird copy code, and copy method should be used instead (ovewriting it in AudioClip to because a deepcopy in those are not needed).

Specifications

• Python Version: 3.8.5
• Moviepy Version: master
• Platform Name: Ubuntu
• Platform Version: 20.04

[tburrows13]

I have no opinion on the coreader methods. Feel free to scrap them, fix them, rename them, or implement proper copy methods if you like.

I've never used .coreader(), and I don't really know when I would.