updated examples, added container.close()

I took code from example as a base and got a memory leak. Reason: there is no close method for the container.

I verified on small video: 2sec, 360:

without close:

with close:

Simplified code:

import av
import av.datasets
import psutil

current_process = psutil.Process()

get_mem_uss = lambda: current_process.memory_full_info().uss

PATH = '...'


def read_frames(path):
    container = av.open(path)
    return [frame.to_ndarray(format='yuv420p') for frame in container.decode(video=0)]


started_with = get_mem_uss()
for i in range(15000):
    read_frames(PATH)
    if i % 50:
        print(f'Used memory {(get_mem_uss() - started_with) / 1024 / 1024}')