how to increase/decrease playback speed on .wav file?

i'm trying to increase/decrease the pitch(or speed) on a few .wav files in pydub. I tried using sound.set_frame_rate (i multiplied the original frame rate, but nothing changed). Does anyone know how this can be done? (preferably without downloading additional external libraries). thanks.

Solution

sound.set_frame_rate() does a conversion, it should not cause any "chipmunk effect", but what you can do is change the frame rate (without a conversion) and then convert the audio from there back to a normal frame rate (like 44.1 kHz, "CD quality")

from pydub import AudioSegment
sound = AudioSegment.from_file(…)

def speed_change(sound, speed=1.0):
    # Manually override the frame_rate. This tells the computer how many
    # samples to play per second
    sound_with_altered_frame_rate = sound._spawn(sound.raw_data, overrides={
        "frame_rate": int(sound.frame_rate * speed)
    })

    # convert the sound with altered frame rate to a standard frame rate
    # so that regular playback programs will work right. They often only
    # know how to play audio at standard frame rate (like 44.1k)
    return sound_with_altered_frame_rate.set_frame_rate(sound.frame_rate)

slow_sound = speed_change(sound, 0.75)
fast_sound = speed_change(sound, 2.0)