WAV audio file handling in SciPy - Step-by-Step Execution

Concept Flow - WAV audio file handling

Import scipy.io.wavfile

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Read WAV file with read()

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Get sample rate and data array

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Process or analyze data

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Write data back with write()

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Save new WAV file

This flow shows how to read a WAV file, get its sample rate and data, optionally process it, and then save it back.

Execution Sample

SciPy

from scipy.io import wavfile
sample_rate, data = wavfile.read('input.wav')
print(sample_rate, data.shape)
wavfile.write('output.wav', sample_rate, data)

Reads a WAV file, prints sample rate and data shape, then writes the same data to a new file.

Execution Table

Step	Action	Result	Data Type/Value
1	Import wavfile from scipy.io	Module ready	wavfile module
2	Read 'input.wav' using wavfile.read()	Returns sample rate and data array	sample_rate=44100, data=array(shape=(441000,))
3	Print sample_rate and data.shape	Outputs sample rate and data shape	44100 (441000,)
4	Write data to 'output.wav' with wavfile.write()	File saved with same sample rate and data	output.wav created
5	End of script	Process complete	No errors

💡 All steps executed successfully; WAV file read and written.

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
sample_rate	undefined	44100	44100	44100	44100
data	undefined	array(shape=(441000,))	array(shape=(441000,))	array(shape=(441000,))	array(shape=(441000,))

Key Moments - 3 Insights

Why do we get two outputs from wavfile.read()?

wavfile.read() returns the sample rate (how many samples per second) and the data array (the actual sound samples). See execution_table step 2.

What does the data array shape mean?

The shape shows how many samples and channels the audio has. For example, (441000,) means 441000 samples in one channel (mono). See variable_tracker for data shape.

Can we write the data back without changes?

Yes, wavfile.write() saves the data with the given sample rate. This is shown in execution_table step 4.

Visual Quiz - 3 Questions

Look at the execution table, what is the sample rate after reading the WAV file?

A 22050

B 48000

C 44100

D None

💡 Hint

Check execution_table row 2 under 'Data Type/Value' for sample_rate.

At which step is the WAV file data shape printed?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Look at execution_table rows and find where print happens.

If the data array had shape (441000, 2), what would that mean?

A Stereo audio with 441000 samples per channel

B Mono audio with 441000 samples

C Audio with 2 samples total

D Sample rate is 2 Hz

💡 Hint

Refer to key_moments about data array shape meaning.

Concept Snapshot

Use scipy.io.wavfile to read and write WAV files.
read() returns sample rate and data array.
Data array shape shows samples and channels.
write() saves data with sample rate.
Useful for audio processing and analysis.

Full Transcript

This lesson shows how to handle WAV audio files using scipy.io.wavfile in Python. First, import wavfile. Then read a WAV file with wavfile.read(), which gives you the sample rate and the audio data array. The sample rate tells how many samples per second the audio has. The data array contains the sound samples, and its shape tells you how many samples and channels are present. You can print these values to understand the audio file. Finally, you can write the audio data back to a new WAV file using wavfile.write(), keeping the same sample rate and data. This process is useful for audio analysis and processing tasks.