Module flac_codec 

Simplified FLAC codec using fixed linear prediction + Rice coding.

This module implements a lightweight FLAC-style encoder/decoder based on fixed predictors (order 0-4) rather than full LPC analysis. It is useful for educational purposes and lightweight lossless audio compression.

Fixed predictor formulas

Order	Residual formula
0	r[i] = s[i]
1	r[i] = s[i] - s[i-1]
2	r[i] = s[i] - 2*s[i-1] + s[i-2]
3	r[i] = s[i] - 3*s[i-1] + 3*s[i-2] - s[i-3]
4	r[i] = s[i] - 4*s[i-1] + 6*s[i-2] - 4*s[i-3] + s[i-4]

Rice coding

Residuals are zigzag-folded (signed → unsigned) then split into a unary quotient and binary remainder using a Rice parameter k.

Structs

FlacEncoderConfig

FLAC encoder configuration.

FlacFrameHeader

FLAC frame header.

FlacStreamInfo

FLAC stream info metadata.

Functions

decode_flac_frame

Decode a FLAC-style frame back to i16 samples.

encode_flac_frame

Encode i16 samples into a single FLAC-style frame.