Pydub

Audio files are a widespread means of transferring information. So let’s see how to work with audio files using Python. Python provides a module called pydub to work with audio files. pydub is a Python library to work with only .wav files. By using this library we can play, split, merge, edit our .wav audio files.pydub is built on top of other audio libraries, such as FFmpeg and Audioop, making it easy to use and compatible with a wide range of audio formats.

Installation

pip install pydub        

Following are some functionalities that can be performed by pydub:

1. Playing audio file.
2. We can get certain information of file like length channels.
3. Increase/Decrease volume of given .wav file.
4. Merging two or more audio files.
5. Exporting an audio file.
6. Splitting an audio file.

Here are some of the key features and modules of pydub:

AudioSegment Class:

• The core of pydub is the AudioSegment class. It represents audio data and provides methods for various audio operations.
• You can create AudioSegment instances from audio files, audio data in memory, or even generate synthetic audio.

File Formats:

pydub supports a wide range of audio file formats, including MP3, WAV, AAC, FLAC, OGG, and more. You can specify the format when importing audio and export audio to different formats.

Audio Manipulation:

• pydub allows you to perform various audio manipulation tasks, such as slicing, concatenating, fading in/out, changing volume, and changing speed.
• It provides methods like slice(), concatenate(), fade(), set_frame_rate(), set_channels(), set_sample_width(), and more.

Format Conversion:

You can easily convert audio between different formats using export() with the desired format.

Playback:

While pydub is primarily used for audio processing, it also provides a basic playback feature that allows you to play audio in your Python code.

Integration with FFmpeg:

pydub relies on the FFmpeg library to support many audio formats. It can automatically convert between formats that FFmpeg supports.

Here's an overview of some key modules and classes within pydub

• pydub.AudioSegment: The main class for representing audio data. It provides methods for manipulating audio, such as slicing, concatenation, and format conversion.
• pydub.AudioSegment.from_file(): A method to create an AudioSegment instance from an audio file.
• pydub.AudioSegment.from_ogg(), pydub.AudioSegment.from_mp3(), etc.: Methods for creating AudioSegment instances from specific audio formats.
• pydub.AudioSegment.export(): Method to export an AudioSegment to a different audio format.
• pydub.playback.play(): A basic audio playback function that allows you to play audio directly from Python.
• pydub.utils.make_chunks(): A utility function to split an AudioSegment into smaller chunks.
• pydub.silence.detect_silence(): A function to detect silence in an AudioSegment.
• pydub.effects.fade(): A function to apply fade-in and fade-out effects to an AudioSegment.
• pydub.generators: A module containing various audio generators for creating synthetic audio data.
• pydub.exceptions: A module containing exceptions that can be raised during audio operations.
• pydub.playback.AudioPlayer: A class for more advanced audio playback control.

Here's a simple example of using pydub to load an audio file, apply a fade-in effectand export it in a different format:

AudioSegment Class:

from pydub import AudioSegment

# Create an AudioSegment instance from audio file
audio = AudioSegment.from_file("input.mp3")

# Slice audio from 10 to 20 seconds
sliced_audio = audio[10000:20000]

# Export the sliced audio to a different format
sliced_audio.export("output.wav", format="wav")
        

File Formats:

from pydub import AudioSegment

# Create an AudioSegment instance from an MP3 file
audio = AudioSegment.from_mp3("input.mp3")

# Export the audio to an OGG file
audio.export("output.ogg", format="ogg")
        

Format Conversion:

from pydub import AudioSegment

# Create an AudioSegment instance from an MP3 file
audio = AudioSegment.from_mp3("input.mp3")

# Export the audio to a WAV file
audio.export("output.wav", format="wav")
        

Playback:

from pydub import AudioSegment, playback

# Create an AudioSegment instance from an audio file
audio = AudioSegment.from_file("input.mp3")

# Play the audio
playback.play(audio)
        

Audio Manipulation:

from pydub import AudioSegment

# Create an AudioSegment instance from an audio file
audio = AudioSegment.from_file("input.mp3")

# Apply a fade-in effect (2 seconds)
faded_audio = audio.fade_in(2000)

# Concatenate two audio segments
concatenated_audio = audio + faded_audio

# Export the concatenated audio
concatenated_audio.export("output.wav", format="wav")        

Other Functions:

pydub.utils.make_chunks():

from pydub import AudioSegment, utils

# Create an AudioSegment instance
audio = AudioSegment.from_file("input.mp3")

# Split audio into 10-second chunks
chunks = utils.make_chunks(audio, 10000)        

pydub.silence.detect_silence():

from pydub import AudioSegment, silence

# Create an AudioSegment instance
audio = AudioSegment.from_file("input.mp3")

# Detect silence (silence_threshold in dBFS, min_silence_len in milliseconds)
silent_ranges = silence.detect_silence(audio, silence_threshold=-40, min_silence_len=1000)        

pydub.effects.fade():

from pydub import AudioSegment, effects

# Create an AudioSegment instance
audio = AudioSegment.from_file("input.mp3")

# Apply a fade-out effect (2 seconds)
faded_audio = effects.fade(audio, duration=2000)        

pydub.generators:

from pydub import AudioSegment, generators

# Generate a 3-second sine wave at 440 Hz
sine_wave = generators.Sine(440).to_audio_segment(duration=3000)        

Applications:

Knowing about .wav file: for this we will use attributes of audio file object.

# import required library
from pydub import AudioSegment

# import the audio file
wav_file = AudioSegment.from_file(file="Sample.wav", format="wav")

# data type for the file
print(type(wav_file))
# OUTPUT: <class 'pydub.audio_segment.AudioSegment'>

# To find frame rate of song/file
print(wav_file.frame_rate)
# OUTPUT: 22050

# To know about channels of file
print(wav_file.channels)
# OUTPUT: 1

# Find the number of bytes per sample
print(wav_file.sample_width )
# OUTPUT : 2


# Find Maximum amplitude
print(wav_file.max)
# OUTPUT 17106

# To know length of audio file
print(len(wav_file))
# OUTPUT 60000

'''
We can change the attributes of file by
changeed_audio_segment = audio_segment.set_ATTRIBUTENAME(x)
'''
wav_file_new = wav_file.set_frame_rate(50)
print(wav_file_new.frame_rate)
        

Increasing/Decreasing volume of the file: By using ‘+’ and ‘-‘ operator.

# import required library
import pydub
from pydub.playback import play

wav_file = pydub.AudioSegment.from_file(file = "Sample.wav",
										format = "wav")
# Increase the volume by 10 dB
new_wav_file = wav_file + 10

# Reducing volume by 5
silent_wav_file = wav_file - 5

# Playing silent file
play(silent_wav_file)

# Playing original file
play(wav_file)

# Playing louder file
play(new_wav_file)

# Feel the difference!
        

Merging files: This is done using ‘+’ operator.

# import required libraries
from pydub import AudioSegment
from pydub.playback import play

wav_file_1 = AudioSegment.from_file("noice.wav")
wav_file_2 = AudioSegment.from_file("Sample.wav")

# Combine the two audio files
wav_file_3 = wav_file_1 + wav_file_2

# play the sound
play(wav_file_3)        

Exporting files: This is done using export() method.

# import required libraries
from pydub import AudioSegment
from pydub.playback import play

# importing audio file
a = AudioSegment.from_file("pzm12.wav")

# Split stereo to mono
b = a.split_to_mono()
print(b)
print(b[0].channels )


b[0].export(out_f="outNow.wav",format="wav")        

Splitting Audio: Splitting audio using split_to_mono() method.

# import required libraries
from pydub import AudioSegment
from pydub.playback import play

# importing audio file
a = AudioSegment.from_file("pzm12.wav")

# Split stereo to mono
b = a.split_to_mono()
print(b)
print(b[0].channels )


b[0].export(out_f="outNow.wav",format="wav")        

Conclusion:

These are simplified examples to demonstrate the usage of different modules and functions in pydub. You can refer to the official pydub documentation for more detailed information and additional features: https://pydub.com/