osu!academy covered this in Episode 15: Audio Encoding (4:02). That episode also contains how to install and use Audacity with LAME's .mp3
export ability.
This article serves as guide to help you do minor edits to your audio files for beatmapping purposes. By expanding it, you can help fellow beatmappers to create suitable audio files for any need.
By no means is this the software that you can only use, rather this only lists from those who had added them here. If you know of other tools that could be used and can explain how to use them for the described sections below, please add them.
Audacity is a free, open-source audio editing and recording software. It uses the LAME encoding library to be able to export audio in the MP3 audio format and is built into Audacity on Windows and macOS.
Linux users should refer to the Audacity Reference Manual for more information, as certain Linux distributions may not provide LAME when installing Audacity, but most do provide it.
For information on compression in general, see: Compressing files
Install and open Audacity, then follow these steps:
.mp3
file that you want to lower the bit rate on.Ctrl
+ Shift
+ E
, then in Save as type:
select MP3 Files
, or:
File
, then Export
, then Export as MP3
.Format Options
, change the following settings:
Bit Rate Mode
: Preset
Quality
: Medium, 145-185 kbps
Save
and a dialog will appear to enter metadata.OK
once done entering metadata.Install and open Audacity then follow these steps:
.mp3
file that you want to loop.Ctrl
+ C
, or
Edit
Copy
Ctrl
+ V
, or
Edit
Paste
Ctrl
+ Shift
+ E
, then in Save as type:
select MP3 Files
, or:
File
, then Export
, then Export as MP3
.Format Options
, change the following settings:
Bit Rate Mode
: Preset
Quality
: Medium, 145-185 kbps
Save
and a dialog will appear to enter metadata.OK
once done entering metadata.Install and open Audacity, then follow these steps:
.mp3
file that you want to crop.Delete
.Effect
.Fade Out
.Ctrl
+ Shift
+ E
, then in Save as type:
select MP3 Files
, or:
File
, then Export
, then Export as MP3
.Format Options
, change the following settings:
Bit Rate Mode
: Preset
Quality
: Medium, 145-185 kbps
Save
and a dialog will appear to enter metadata.OK
once done entering metadata.mp3DirectCut is a free-to-use audio editing software that can directly edit MP3 files without re-encoding, often preventing loss of quality. It is recommended when needing to raise/lower the volume or crop the audio.
Install and open mp3DirectCut, then follow these steps:
.mp3
file that you want to loop.Ctrl
+ C
, or
Edit
Copy
Ctrl
+ V
, or
Edit
Paste
Ctrl
+ W
, or
File
.Save complete audio...
.Save
.Install and open mp3DirectCut, then follow these steps:
.mp3
file that you want to crop.Delete
.Ctrl
+ F
, or
Edit
.Simple fade to/from position
.Ctrl
+ W
, or
File
.Save complete audio...
.Save
.Install and open mp3DirectCut, then follow these steps:
.mp3
file that you want to adjust.Ctrl
+ A
to select all.Ctrl
+ G
, or
Edit
Gain...
Lock Sliders
checkbox.OK
.Ctrl
+ W
, or
File
.Save complete audio...
.Save
.