Example creating WAVE file by hand in Python (8-bit)

create_wave_file_by_hand_8bit.py

import sys
import math
import struct
import array

# Writing a WAVE file, the silly but educational way
duration   = 2      # seconds
samplerate = 44100  # how many samples per second
nchannels  = 1  # 1 channel, mono audio -- for stereo, we'd use 2 channels

num_of_samples  = duration * samplerate
block_align     = nchannels * 1          # 1 byte per sample (8-bit)
data_size       = num_of_samples * block_align

out = sys.stdout.buffer

# 1st: the RIFF header, which says "hey, i am a wave file!"
out.write(b'RIFF')
out.write(struct.pack('<I', 36 + data_size))
out.write(b'WAVE')

# 2nd: the format chunk, specifying audio signal parameters
out.write(b'fmt ')
out.write(struct.pack('<I', 16))        # chunk size
out.write(struct.pack('<H', 1))         # PCM
out.write(struct.pack('<H', nchannels))
out.write(struct.pack('<I', samplerate))
out.write(struct.pack('<I', block_align * samplerate))  # byte rate
out.write(struct.pack('<H', block_align))
out.write(struct.pack('<H', 8))         # bit depth: this works the "resolution" of our audio signal

# 3rd: finally, the data chunk
out.write(b'data')
out.write(struct.pack('<I', data_size))

# --- audio samples ---
volume  = 0.5
samples = array.array('B')  # unsigned byte, 8-bit

def scale_sample(value: float) -> int:
    # For simplicity, we'll use 8-bit PCM samples, which are stored as
    # unsigned bytes (0 to 255) where 128 is silence (the midpoint)
    to_scale = (value + 1) / 2        # remap [-1, 1] -> [0, 1]
    return int(max(0, min(255, round(to_scale * 255))))

for frame_idx in range(num_of_samples):
    t   = frame_idx / samplerate
    # here we generate a sine wave signal...
    signal = volume * math.sin(2 * math.pi * (220 + 0.01 * frame_idx) * t)
    samples.append(scale_sample(signal))

out.write(samples.tobytes())