Tuesday, September 26, 2023

Flutter video trimmer package

This Flutter plugin plays audio from URLs, files, assets, DASH/HLS streams and playlists. Furthermore, it can clip, concatenate, loop, shuffle and compose audio into complex arrangements with gapless playback. This plugin can be used with audio_service to play audio in the background and control playback from the lock screen, Android notifications, the iOS Control Center, and headset buttons.


  • read from URL
  • read from file
  • read from asset
  • request headers
  • DASH
  • HLS
  • buffer status/position
  • play/pause/seek
  • set volume
  • set speed
  • clip audio
  • playlists
  • looping
  • custom shuffle order
  • compose audio
  • gapless playback
  • report player errors
  • Handle phonecall interruptions

Please consider reporting any bugs you encounter here or submitting pull requests here.




final player = AudioPlayer();
var duration = await player.setUrl('https://foo.com/bar.mp3');
var duration = await player.setFilePath('/path/to/file.mp3');
var duration = await player.setAsset('path/to/asset.mp3');


var duration = await player.setUrl('https://foo.com/bar.mp3',
    headers: {'header1': 'value1', 'header2': 'value2'});

Standard controls:

player.play(); // Usually you don't want to wait for playback to finish.
await player.seek(Duration(seconds: 10));
await player.pause();

Clipping audio:

await player.setClip(start: Duration(seconds: 10), end: Duration(seconds: 20));
await player.play(); // Waits until the clip has finished playing

Adjusting audio:

await player.setSpeed(2.0); // Double speed
await player.setVolume(0.5); // Halve volume

Gapless playlists:

await player.setAudioSource(
    // Start loading next item just before reaching it.
    useLazyPreparation: true, // default
    // Customise the shuffle algorithm.
    shuffleOrder: DefaultShuffleOrder(), // default
    // Specify the items in the playlist.
    children: [
  // Playback will be prepared to start from track1.mp3
  initialIndex: 0, // default
  // Playback will be prepared to start from position zero.
  initialPosition: Duration.zero, // default
await player.seekToNext();
await player.seekToPrevious();
// Jump to the beginning of track3.mp3.
await player.seek(Duration(milliseconds: 0), index: 2);

Looping and shuffling:

await player.setLoopMode(LoopMode.off); // no looping (default)
await player.setLoopMode(LoopMode.all); // loop playlist
await player.setLoopMode(LoopMode.one); // loop current item
await player.setShuffleModeEnabled(true); // shuffle playlist

Composing audio sources:

  // Loop child 4 times
    count: 4,
    // Play children one after the other
    child: ConcatenatingAudioSource(
      children: [
        // Play a regular media file
        // Play a DASH stream
        // Play an HLS stream
        // Play a segment of the child
          child: ProgressiveAudioSource(Uri.parse("https://w.xyz/p.mp3")),
          start: Duration(seconds: 25),
          end: Duration(seconds: 30),

Managing resources:

// Set the audio source but manually load audio at a later point.
await player.setUrl('https://a.b/c.mp3', preload: false);
// Acquire platform decoders and start loading audio.
var duration = await player.load();
// Unload audio and release decoders until needed again.
await player.stop();
// Permanently release decoders/resources used by the player.
await player.dispose();

Catching player errors:

try {
  await player.setUrl("https://s3.amazonaws.com/404-file.mp3");
} on PlayerException catch (e) {
  // iOS/macOS: maps to NSError.code
  // Android: maps to ExoPlayerException.type
  // Web: maps to MediaError.code
  print("Error code: ${e.code}");
  // iOS/macOS: maps to NSError.localizedDescription
  // Android: maps to ExoPlaybackException.getMessage()
  // Web: a generic message
  print("Error message: ${e.message}");
} on PlayerInterruptedException catch (e) {
  // This call was interrupted since another audio source was loaded or the
  // player was stopped or disposed before this audio source could complete
  // loading.
  print("Connection aborted: ${e.message}");
} catch (e) {
  // Fallback for all errors

Listening to state changes:

player.playerStateStream.listen((state) {
  if (state.playing) ... else ...
  switch (state.processingState) {
    case ProcessingState.idle: ...
    case ProcessingState.loading: ...
    case ProcessingState.buffering: ...
    case ProcessingState.ready: ...
    case ProcessingState.completed: ...

// See also:
// - durationStream
// - positionStream
// - bufferedPositionStream
// - sequenceStateStream
// - sequenceStream
// - currentIndexStream
// - icyMetadataStream
// - playingStream
// - processingStateStream
// - loopModeStream
// - shuffleModeEnabledStream
// - volumeStream
// - speedStream
// - playbackEventStream

The state model

The state of the player consists of two orthogonal states: playing and processingState. The playing state typically maps to the app’s play/pause button and only ever changes in response to direct method calls by the app. By contrast, processingState reflects the state of the underlying audio decoder and can change both in response to method calls by the app and also in response to events occurring asynchronously within the audio processing pipeline. The following diagram depicts the valid state transitions:


This state model provides a flexible way to capture different combinations of states such as playing+buffering vs paused+buffering, and this allows state to be more accurately represented in an app’s UI. It is important to understand that even when playing == true, no sound will actually be audible unless processingState == ready which indicates that the buffers are filled and ready to play. This makes intuitive sense when imagining the playing state as mapping onto an app’s play/pause button:

  • When the user presses “play” to start a new track, the button will immediately reflect the “playing” state change although there will be a few moments of silence while the audio is loading (while processingState == loading) but once the buffers are finally filled (i.e. processingState == ready), audio playback will begin.
  • When buffering occurs during playback (e.g. due to a slow network connection), the app’s play/pause button remains in the playing state, although temporarily no sound will be audible while processingState == buffering. Sound will be audible again as soon as the buffers are filled again and processingState == ready.
  • When playback reaches the end of the audio stream, the player remains in the playing state with the seek bar positioned at the end of the track. No sound will be audible until the app seeks to an earlier point in the stream. Some apps may choose to display a “replay” button in place of the play/pause button at this point, which calls seek(Duration.zero). When clicked, playback will automatically continue from the seek point (because it was never paused in the first place). Other apps may instead wish to listen for the processingState == completed event and programmatically pause and rewind the audio at that point.

Apps that wish to react to both orthogonal states through a single combined stream may listen to playerStateStream. This stream will emit events that contain the latest value of both playing and processingState.

Configuring the audio session

If your app uses audio, you should tell the operating system what kind of usage scenario your app has and how your app will interact with other audio apps on the device. Different audio apps often have unique requirements. For example, when a navigator app speaks driving instructions, a music player should duck its audio while a podcast player should pause its audio. Depending on which one of these three apps you are building, you will need to configure your app’s audio settings and callbacks to appropriately handle these interactions.

just_audio will by default choose settings that are appropriate for a music player app which means that it will automatically duck audio when a navigator starts speaking, but should pause when a phone call or another music player starts. If you are building a podcast player or audio book reader, this behaviour would not be appropriate. While the user may be able to comprehend the navigator instructions while ducked music is playing in the background, it would be much more difficult to understand the navigator instructions while simultaneously listening to an audio book or podcast.

You can use the audio_session package to change the default audio session configuration for your app. E.g. for a podcast player, you may use:

final session = await AudioSession.instance;
await session.configure(AudioSessionConfiguration.speech());

Note: If your app uses a number of different audio plugins, e.g. for audio recording, or text to speech, or background audio, it is possible that those plugins may internally override each other’s audio session settings, so it is recommended that you apply your own preferred configuration using audio_session after all other audio plugins have loaded. You may consider asking the developer of each audio plugin you use to provide an option to not overwrite these global settings and allow them be managed externally.

Platform specific configuration


If you wish to connect to non-HTTPS URLS, add the following attribute to the application element of your AndroidManifest.xml file:

    <application ... android:usesCleartextTraffic="true">

If you need access to the player’s AudioSession ID, you can listen to AudioPlayer.androidAudioSessionIdStream. Note that the AudioSession ID will change whenever you set new AudioAttributes.


Regardless of whether your app uses the microphone, Apple will require you to add the following key to your Info.plist file. The message will simply be ignored if your app doesn’t use the microphone:

<string>... explain why you use (or don't use) the microphone ...</string>

If you wish to connect to non-HTTPS URLS, add the following to your Info.plist file:



To allow your macOS application to access audio files on the Internet, add the following to your DebugProfile.entitlements and Release.entitlements files:


If you wish to connect to non-HTTPS URLS, add the following to your Info.plist file: