range_coding_cython

A range coding lib implemented in Cython.

Install

pip install range_coding_cython

Usage

import numpy as np
from range_coding_cython import encode_nxk, decode_nxk

# Example usage
syms = np.array([0, 1, 2, 3, 3, 3], dtype=np.uint32)

cdf = [0.0, 0.1, 0.3, 0.6, 1.0]
PRECISION = 16
cdf_table = np.array([cdf]) * (1 << PRECISION) # (1, alphabet_size + 1)
cdf_table = cdf_table.astype(np.uint32)

cdf_indices = np.array([0, 0, 0, 0, 0, 0], dtype=np.uint32)

# Encode
data = bytearray()
data = encode_nxk(syms, cdf_table, cdf_indices, data)

# Decode
buff = np.zeros_like(symbols)
dec_syms = decode_nxk(buff, cdf_table, cdf_indices, data)

# Check if the decoded symbols match the original symbols
assert np.array_equal(dec_syms, syms)

References

• Range Coding
• Arithmetic Coder
• NeuralCompression
• Yet-Another-Entropy-Coding-Library