Deadlock on creating audio segment if another python thread reads from stdin

[ggolda]

Steps to reproduce

Looks like pydub attempts to read the stdin in the scenario below in audio_segment.py (https://github.com/jiaaro/pydub/blob/master/pydub/audio_segment.py#L766). If another python thread is currently trying to read from stdin, pydub gets stuck forever in a deadlock state.

This is reproduceable only when python is run as a child subprocess of another process (e.g. if you spawn it from another program or run in a jupyter playbook) and tested on windows, probably linux handles simultaneous stdin reads better.

Reading from stdin is a common pattern on windows (sadly) to handle graceful shutdowns because OS doesn't have signals like posix os.

To reproduce, run this code in a jupyter playbook:

import os, sys
import threading
import signal
from pydub import AudioSegment


def windows_graceful_shutdown_listener():
    """
    Windows doesn't have signals, so we need to listen to stdin for quit command
    """
    for line in sys.stdin:
        if line == "quit\n":
            signal.raise_signal(signal.SIGINT)


threading.Thread(target=windows_graceful_shutdown_listener, daemon=True).start()

video_uri = "C:/path/to/file/video.mp4"

audio_file = AudioSegment.from_file(video_uri, start_second=0, duration=10)
audio_file.set_frame_rate(16000)
audio_file.export("test.wav", format="wav")

Expected behavior

pydub shouldn't hang and complete the work, or at least throw a timeout exception if it can not read from stdin.

Actual behavior

pydub hangs in a deadlock state indefinitely.

Your System configuration

• Python version: 3.12.4
• Pydub version: 0.25.1
• ffmpeg or avlib?: ffmpeg
• ffmpeg/avlib version: 6.0

Is there an audio file you can include to help us reproduce?

Works on any audio or video file

[ggolda]

submitted a PR that fixes this issue