ffMetadataEx

Module that contains the FFmpeg libraries required for OuterTune FFmpeg tag extractor and FFmpeg audio decoders.

Usage

1. Install an OuterTune version with ffMetadataEx, look for the apk with "full" in its name. For example: OuterTune-0.9.0-full-universal-release-60.apk`. These builds are provided with stable releases (not beta or alpha).

2. Select the scanner implementation. Open the OuterTune app and navigate to Settings --> Library & Content -> Local media -> Metadata extractor, and select FFmpeg.

3. Select the decoder preference. Open the OuterTune app and navigate to Settings --> Player and audio -> Advanced -> Audio decoder, and select a decoder preference.

Developer use

Audio metadata is accessible through the AudioMetadata class.

Code example

Extract metadata

val ffmpeg = FFmpegWrapper()
val data: AudioMetadata? = ffmpeg.getFullAudioMetadata("file path of audio file")

// get metadata tags
var title: String? = data.title
var artists: String? = data.artist

// get audio information
var codec: String? = data.codec
var type: String? = data.codecType
var sampleRate: Int = data.sampleRate
var duration: Long = data.duration // duration is in milliseconds

For any additional tag information that does not have an associated field, they can be accessible via extrasRaw field

// Array of strings, in format of: <key>:<value>
data.extrasRaw.forEach {
    val tag = it.substringBefore(':')
    when (tag) {
        // read date
        "DATE", "date" -> date = it.substringAfter(':')
    }
}

For more examples, see the OuterTune implementation

Audio decoders via nextlib

If you only need the decoder functionality, you are likely better off using nextlib directly. All the documentation and guides are on their GitHub. ffMetadataEx does not support any video features.

Building

1. First you will need to setup the Android NDK

2. Import this module into your app project:

   • Building for OuterTune: Resolve the git submodule, then proceed with step 3.
   • For other projects: Import the module and its code into your project manually, then setup Proguard correctly.

3. FFmpeg is used to extract metadata from local files. Those binaries must be resolved in one of two ways:

   • a) Build libraries yourself. Clone ffmpeg-android-maker into <project root>/ffmpeg-android-maker, run the build script. Note: It may be helpful to modify the FFmpeg build script disable unneeded FFmpeg features to reduce app size, see here for an example.

   • b) Use prebuilt FFmpeg libraries. Clone prebuilt ffmpeg-android-maker into <project root>/ffmpeg-android-maker.

4. Gradle sync, then start the build as you normally would. If you are building for OuterTune, you will need to build with the "full" build variant.

Attribution

nextlib for audio decoders

FFmpeg information for OuterTune releases

See modules information