REW to ReaEQ Converter

Note: This project and its documentation were generated with the assistance of AI.

A simple Python script that converts Room EQ Wizard (REW) filter export text files into Reaper ReaEQ preset library (.RPL) files.

Features

• Parses standard REW EQ text files.
• Supports Include: directives for recursive configuration file parsing from Equalizer APO.
• Converts Peak (PK), Low Shelf (LS/LSC), and High Shelf (HS/HSC) filters.
• Automatically translates REW's Q-factor to ReaEQ's Bandwidth (in octaves).
• Generates a ready-to-import .RPL file base64-encoded structure for Cockos Reaper.

Usage

Run the script from the command line, providing the input REW text file and the desired output .RPL file path:

python rew_to_reaeq.py <input_rew_file.txt> <output_preset.RPL>

Example

python rew_to_reaeq.py configs/config.txt outputs/main.RPL

RPL Data Structure

The .RPL preset file generated by this script contains a Base64-encoded binary chunk representing the ReaEQ state. The script encodes it using the following internal binary structure (all numeric types are little-endian):

Note: This structure was analyzed with the assistance of AI. It may not be 100% correct for all edge cases, but it has been tested and works with the provided examples.

Overall Structure

Field	Size	Description
Header	48 bytes	Standard Cockos ReaEQ preset header signature.
Chunk Size	4 bytes	Calculated as 8 + (num_bands * stride) + len(suffix).
Sub-Header	8 bytes	Magic bytes 01 00 00 00 00 00 10 00.
Stride	4 bytes	Size of each band's data (33 bytes).
Number of Bands	4 bytes	The total count of EQ bands.
Band Data	n * 33 bytes	Sequence of band structures (see below).
Suffix	16 bytes	Standard trailing magic bytes (two ints 1, 1 and one double 1.0).

Band Data Breakdown (33 bytes per band)

Attribute	Data Type	Size	Description
Type	int	4 bytes	0 = Low Shelf, 1 = High Shelf, 8 = Band/Peak.
Enabled	int	4 bytes	1 = ON, 0 = OFF.
Frequency	double	8 bytes	Frequency in Hz.
Gain	double	8 bytes	Gain in linear scale ($10^{gain_{dB} / 20}$).
Bandwidth	double	8 bytes	Bandwidth in octaves.
Flags	byte	1 byte	Typically 0.

Project Structure

• rew_to_reaeq.py: The main conversion script.
• configs/: Directory for input REW filter text files.
• outputs/: Directory where the generated .RPL files are saved.