Can't write to a callback stream [PaErrorCode -9976]

[Davis8483]

I'm trying to get the current audio level of the wav file thats playing using a callback function. When ran it results in, sounddevice.PortAudioError: Can't write to a callback stream [PaErrorCode -9976]

The audio plays correctly when the callback parameter is removed.

Here's the code...

import soundfile as sf
import sounddevice as sd
import numpy as np

path_to_audio = "add audio path here"

def print_audio_level(outdata, frames, time, status):
    # Calculate the audio level as the RMS of the audio data
    audio_level = 20 * np.log10(np.sqrt(np.mean(np.square(outdata))))

    # Print the current audio level
    print("Current audio level:", audio_level, "dB")

# Read the audio file using soundfile
audio, sample_rate = sf.read(path_to_audio)

audio = audio.astype(np.float32)

# Set up the audio playback stream
playback_stream = sd.OutputStream(samplerate=sample_rate, channels=1, callback=print_audio_level)

# Start the audio playback stream
playback_stream.start()

# Play the audio file
playback_stream.write(audio)

# Stop the audio stream (wait for playback to finish)
playback_stream.stop()

# Close the audio stream
playback_stream.close()

[mgeier]

The error message says it all.

But maybe it's not clear what a "callback stream" is?

A callback stream is a stream with a callback function.

Your stream has a callback function, and you are trying to write to it.

But you can't.

The audio plays correctly when the callback parameter is removed.

Exactly, because then it ceases to be a callback stream and you can write to it.