video_ultra_player 1.1.0

Native gapless timeline player plugin backed by platform video composition and a single Flutter texture.

video_ultra_player

A Flutter plugin for previewing and exporting a native media timeline made from local video and image files.

video_ultra_player builds one native composition per timeline, renders it into a single Flutter Texture, and can export the same timeline as an MP4 file. This avoids the visible flash or gap that often appears when switching between multiple Flutter video players at clip boundaries.

Features

• Gapless native timeline preview in one Flutter Texture.
• MP4 export for the same list of timeline clips.
• Video and image clips in the same timeline.
• Playback controls: play, pause, seek, volume, and dispose.
• Timeline state stream with global position, local clip position, clip index, playing state, and total duration.
• Per-clip pan/crop with normalized alignment values.
• iOS implementation backed by AVFoundation.
• Android implementation backed by AndroidX Media3.

Platform support

Platform	Preview	Export	Native implementation
iOS	Yes	Yes	AVFoundation, FlutterTexture, AVAssetExportSession
Android	Yes	Yes	Media3 CompositionPlayer, Transformer, SurfaceTexture
Web	No	No	Not implemented
macOS / Windows / Linux	No	No	Not implemented

Getting started

Add the package to your app:

flutter pub add video_ultra_player

Then import it:

import 'package:video_ultra_player/video_ultra_player.dart';

The plugin works with local file paths. If your media comes from assets, downloads, a camera capture, or the photo library, copy or resolve it to a local file path before calling load or exportTimeline.

Basic usage

Create a player and define the timeline:

final player = NativeTimelinePlayer();

final clips = <TimelineClip>[
  const TimelineClip(
    path: '/local/path/intro.mp4',
    type: MediaType.video,
  ),
  const TimelineClip(
    path: '/local/path/title-card.png',
    type: MediaType.image,
    duration: Duration(seconds: 2),
    scale: 1.2,
  ),
  const TimelineClip(
    path: '/local/path/outro.mp4',
    type: MediaType.video,
  ),
];

Load the native composition and render the texture:

final textureId = await player.load(clips);

AspectRatio(
  aspectRatio: 16 / 9,
  child: Texture(textureId: textureId),
);

Control playback:

await player.play();
await player.pause();
await player.seekTo(const Duration(milliseconds: 1500));
await player.setVolume(0.8);

Listen to timeline state:

StreamBuilder<TimelinePlayerState>(
  stream: player.stateStream,
  builder: (context, snapshot) {
    final state = snapshot.data ?? const TimelinePlayerState.initial();

    return Text(
      'Clip ${state.clipIndex + 1} - '
      '${state.globalPosition.inMilliseconds} ms',
    );
  },
);

Apply pan/crop to a clip:

await player.setClipAlignment(
  state.clipIndex,
  0.4,
  -0.2,
);

Alignment values use the -1.0..1.0 range for both axes. To export the same pan/crop result, keep your TimelineClip list updated with the latest Alignment values before calling exportTimeline.

Dispose the player when it is no longer needed:

@override
void dispose() {
  player.dispose();
  super.dispose();
}

Exporting MP4

Use exportTimeline to render the timeline to a local MP4 file:

final outputPath = await player.exportTimeline(
  clips,
  outputPath: '/local/path/final-video.mp4',
);

If outputPath is omitted, the native platform creates a temporary output file and returns its path.

exportTimeline does not require load to be called first. It only needs a non-empty list of TimelineClips with valid local file paths.

Loading videos from the gallery

Gallery picking is intentionally not built into this plugin. Use a picker package in your app, then pass the returned local paths to video_ultra_player.

Example using image_picker:

dependencies:
  image_picker: ^1.2.2
  video_ultra_player: ^1.0.0

import 'package:image_picker/image_picker.dart';
import 'package:video_ultra_player/video_ultra_player.dart';

final picker = ImagePicker();
final player = NativeTimelinePlayer();

final videos = await picker.pickMultiVideo();
if (videos.isNotEmpty) {
  final clips = videos
      .map(
        (video) => TimelineClip(
          path: video.path,
          type: MediaType.video,
        ),
      )
      .toList();

  final textureId = await player.load(clips);

  final outputPath = await player.exportTimeline(clips);
}

If your app opens the iOS photo library, add a usage description to the app's ios/Runner/Info.plist:

<key>NSPhotoLibraryUsageDescription</key>
<string>Select videos from your library to preview and export them.</string>

API reference

TimelineClip

const TimelineClip({
  required String path,
  required MediaType type,
  Duration? duration,
  Alignment alignment = Alignment.center,
  double scale = 1.0,
})

Property	Description
path	Local file path for the media item.
type	MediaType.video or MediaType.image.
duration	Optional segment duration. Recommended for images.
alignment	Initial pan/crop alignment for the clip.
scale	Clip scale used for crop/zoom. Must be greater than zero.

TimelinePlayerState

Property	Description
globalPosition	Current position in the full timeline.
clipIndex	Index of the active clip.
localPosition	Current position inside the active clip.
isPlaying	Whether the native player is currently playing.
totalDuration	Total duration of the timeline.

NativeTimelinePlayer

Member	Description
load(List<TimelineClip>)	Builds the native preview composition and returns a textureId.
exportTimeline(List<TimelineClip>, {String? outputPath})	Exports the timeline to MP4 and returns the output path.
play()	Starts playback.
pause()	Pauses playback.
seekTo(Duration)	Seeks to a global timeline position.
setVolume(double)	Sets volume from 0.0 to 1.0.
setClipAlignment(int, double, double)	Updates pan/crop alignment for a clip.
stateStream	Broadcast stream of TimelinePlayerState.
textureId	Current Flutter texture id after load.
dispose()	Releases native player and texture resources.

Example app

The example/ app demonstrates:

• Loading bundled sample assets.
• Selecting multiple videos from the gallery with image_picker.
• Rendering the native timeline in a Flutter Texture.
• Playback, scrubbing, volume, and pan/crop.
• Exporting the loaded timeline to MP4.

Run it with:

cd example
flutter run

Technical notes

• load and exportTimeline reject empty clip lists.
• Playback methods and stateStream require load to complete first.
• exportTimeline is independent from the preview player and can be called without loading a texture.
• Image clips use a default duration of 2 seconds when no duration is provided.
• iOS image clips are converted to temporary MP4 segments before composition.
• Android rebuilds the Media3 composition when live pan/crop changes because Media3 effects are immutable.
• The plugin returns local output paths; it does not save exported files to the user's gallery or share sheet.

Development

Run package checks:

flutter analyze
flutter test

Run example checks:

cd example
flutter test
flutter build apk --debug
flutter build ios --debug --simulator

For implementation details, see flow/native-timeline-player.md.