How do I set audio stream's frame_size?

[makerjackie]

Overview

I want to get AudioFrame with duration 20ms (160 samples / sample rate 8000 ) from a wavfile.

but with code

container = av.open('8k.wav')
for frame in container.decode(audio=0):
    print(frame.samples)

I get 2048 which is 0.256 ms

Research

• I found a stream_option in av.open docs but have no idea how to use it
• I found av.audio.codeccontext.AudioCodecContext.frame_size, but I don't know how to change it too (I get 0 when I print it)

I have done the following:

• Checked the PyAV documentation
• Searched on Google
• Searched on Stack Overflow
• Looked through old GitHub issues
• Asked on PyAV Gitter
• ... and waited 72 hours for a response.