Java / Kotlin MP3Gain Wrapper

JKMP3GainWrapper is an Mp3Gain wrapper written in Kotlin, but should be fully compatible to Java.

Building and Requirements

In order to build a *.jar file JKMP3GainWrapper requires:

• Gradle - is used to resolve dependencies and build a jar file.
• JDK 8+ - JKMP3GainWrapper is developed with Oracle JDK 8 but should also work with OpenJDK.
  
  

To build JKMP3GainWrapper use the following command:

gradle clean build

The *.jar file can be found in the build/libs directory afterwards. Even though, easier is it to directly install it into your maven repository using

gradle install

If you don't want to build it yourself, there is also an already compiled version JKMP3GainWrapper-1.0.jar

How to use it

It is just a simple wrapper for MP3Gain. In order to run, it needs a working MP3Gain installation or binary (mp3gain.exe for windows or mp3gain for e.g. linux based OS'). To instantiate simply use the constructor and provide the path to the MP3Gain binary and optionally change the targetDB and the timestamp option. Per default the target DB is 89. Per default the timestamps of your MP3 file will not be overwritten. Even if MP3Gain writes a new tag, the last modified date of the file itself remains unchanged.

// Java
MP3Gain g = new MP3Gain("path/to/MP3Gain/binary")
// Kotlin
val g = MP3Gain("path/to/MP3Gain/binary")

most methods offer an additional parameter called MP3GainThread. This class extends runnable and gets the Error Inputstream of MP3Gain as a parameter and is started by each method itself. Using this thread GUIs for example can show current process.

Afterwards the following methods can be used. It should be mentioned that it only works with up to 15 files, don't ask me why.

// Java
Boolean deleteStoredTagInfo(List<String> files)
// Kotlin
fun deleteStoredTagInfo(files: List<String>): Boolean

deletes the stored MP3Gain Tags (parameter: -s d)

// Java
List<UndoMp3GainChange> undoMp3gainChanges(List<String> files, MP3GainThread thread)
// Kotlin
fun undoMp3gainChanges(files: List<String>, thread: MP3GainThread? = null): List<UndoMP3GainChange>

Undo the changes for the given Files (parameter: -u)

// Java
List<ApplyGainChange> applyTrackGain(List<String>files, Boolean untilNoClipping, MP3GainThread thread) 
// Kotlin
fun applyTrackGain(files: List<String>, untilNoClipping: Boolean = false, thread: MP3GainThread? = null): List<ApplyGainChange>

applies the track gain so that it will be normalized to default gain. If untilNoClipping is true, the default gain will be ignored and automatically lowered until no clipping occurs. (parameter: -r -o [-p] [-k] [-d x])

// Java
List<ApplyGainChange> applyAlbumGain(List<String> files, Boolean untilNoClipping, MP3GainThread thread)
// Kotlin
fun applyAlbumGain(files: List<String>, untilNoClipping: Boolean = false, thread: MP3GainThread? = null): List<ApplyGainChange>

applies the album gain so that it will be normalized to default gain (parameter: -a -o [-p] [-k] [-d x])

// Java
List<RecommendedGainChange> analyzeGain(List<String> files, MP3GainThread thread) 
// Kotlin
fun analyzeGain(files: List<String>, thread: MP3GainThread? = null): List<RecommendedGainChange>

reads the tag info for the given files. Containing DB and Gain Changes for Track and Album (parameter: -s r / -s c)

// Java
List<AddGainChange> addGain(List<String> files, Integer gain, MP3GainThread thread) 
// Kotlin
fun addGain(files: List<String>, gain: Int, thread: MP3GainThread? = null): List<AddGainChange>

adds a given gain value to the file. 1 gain = 1.5 DB (parameter: -g x)

Copyright

Copyright (c) 2018 Christian Feier (Christian.Feier@gmail.com). See licence.txt for details.