# hmp3

**Repository Path**: ghoul_code/hmp3

## Basic Information

- **Project Name**: hmp3
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2026-04-30
- **Last Updated**: 2026-04-30

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# hmp3 - Helix MP3 Encoder, with some additions

This repository contains a version of the Helix MP3 Encoder with some maintenance work applied to build on modern systems. This targets mostly Linux-based machines (tested on x86-64 and ARM), but project files for Visual Studio 2015 are also included.

## On the license of the Helix MP3 Encoder

This repository contains a source code copy of the Helix MP3 Encoder in the directory [./hmp3](./hmp3). Please study [./hmp3/LICENSE.txt](./hmp3/LICENSE.txt) for licensing information.

## On the license of other files in this repository

Files in this repository outside of the [./hmp3](./hmp3) directory are licensed under the terms of the MIT License, unless noted otherwise.

## Compiling

A Makefile tested on Linux is provided in this directory. With the usual build systems installed, a simple `make` should create a `hmp3` program binary in `builds/release`, along with compiled object files.

A binary with debug symbols can be generated with `make debug`.

## Documentation

The encoder is documented over at the [HydrogenAudio Wiki page of the Helix MP3 encoder](https://wiki.hydrogenaud.io/index.php?title=Helix_MP3_Encoder).

## Use examples

* Create a ~128 kbps VBR MP3 file:
  
  `hmp3 input.wav output.mp3`

* Create a 128 kbps CBR MP3 file:
  
  `hmp3 input.wav output.mp3 -B64`

  (Note that `-B` denotes the bitrate **per channel**, thus stereo input files are being encoded with 128 kbps.)

* Create a ~185 kbps VBR MP3 file, encode frequencies above 16 kHz, with a highpass filter of 19 kHz applied:
  
  `hmp3 input.wav output.mp3 -V100 -HF2 -F19000`