video_compress_kit #

Hardware-accelerated video & image compression for Flutter — zero binary bloat, no bundled FFmpeg.

Built by ikolvi.com.

Features #

Video #

• Compress videos with five quality presets (or custom bitrate/resolution)
• H.264 profile selection — Baseline, Main, or High
• Bitrate modes — VBR, CBR, or Constant Quality (CRF-like)
• BT.709 color standard for HD / 4K content
• Faststart — moov atom at front for faster streaming (both platforms)
• Per-session progress & cancellation — run multiple compressions concurrently
• Audio passthrough — copies audio track without re-encoding
• Estimate file size — predict output size before compressing

Image #

• Compress images — JPEG, PNG, WebP output
• Resize — constrain to max width / height with proportional scaling
• EXIF metadata — strip or preserve orientation, GPS, camera info

General #

• Get media info — resolution, duration, bitrate, file size
• Extract thumbnails — single-frame JPEG at any timestamp
• Zero binary bloat — uses only native OS APIs

Installation #

dependencies:
  video_compress_kit: ^0.0.1

No extra setup — platform implementations are auto-endorsed.

Video Compression #

Basic usage #

import 'package:video_compress_kit/video_compress_kit.dart';

final kit = VideoCompressKit();

final result = await kit.compressVideo(
  '/path/to/video.mp4',
  sessionId: 'upload-1',  // unique per concurrent operation
  config: const CompressionConfig(quality: VideoQuality.medium),
);

print('Output: ${result.outputPath}  (${result.fileSize} bytes)');

Per-session progress #

Each compression is identified by a sessionId. Progress events include both the session ID and progress value (0.0–1.0):

kit.compressionProgress.listen((event) {
  final id = event['sessionId'] as String;
  final pct = (event['progress'] as double) * 100;
  print('$id: ${pct.toStringAsFixed(1)}%');
});

Filter progress for a specific session:

kit.compressionProgress
  .where((e) => e['sessionId'] == 'upload-1')
  .listen((e) => print('${e['progress']}'));

Per-session cancellation #

// Cancel a specific session
await kit.cancelCompression(sessionId: 'upload-1');

// Cancel ALL active sessions
await kit.cancelCompression();

Concurrent compressions #

final job1 = kit.compressVideo('/path/a.mp4', sessionId: 'job-1');
final job2 = kit.compressVideo('/path/b.mp4', sessionId: 'job-2');

// Both run in parallel with independent progress and cancellation
final results = await Future.wait([job1, job2]);

Quality presets #

Values are estimates from the built-in bits-per-pixel model. Actual sizes vary with content complexity and frame rate.

Estimate file size before compressing #

final info = await kit.getMediaInfo(path);
final estimate = kit.estimateFileSize(info: info, quality: VideoQuality.medium);
print('≈ ${(estimate / 1024 / 1024).toStringAsFixed(1)} MB');

Custom configuration #

const config = CompressionConfig(
  quality: VideoQuality.medium,   // base preset
  bitrate: 3000000,               // override: 3 Mbps
  width: 1280,                    // override: 1280 px
  height: 720,                    // override: 720 px
  frameRate: 30,
  includeAudio: true,
  deleteOrigin: false,
  outputPath: '/custom/output.mp4',
);

Advanced codec options #

Fine-tune the H.264 encoder beyond simple presets:

final result = await kit.compressVideo(
  '/path/to/video.mp4',
  sessionId: 'hq-job',
  config: CompressionConfig(
    quality: VideoQuality.high,
    h264Profile: H264Profile.high,       // best compression efficiency
    bitrateMode: BitrateMode.cq,         // constant quality (CRF-like)
    cqQuality: 70,                       // 0–100 (higher = better quality)
    colorStandard: ColorStandard.bt709,  // HD color space
    faststart: true,                     // moov atom at front (both platforms)
  ),
);

H.264 Profile

Android: Requires API 23+. If null, the platform default is used.
iOS: All profiles supported on modern devices.

Bitrate Mode

CQ mode is the closest equivalent to CRF (x264). Use the cqQuality parameter (0–100) to control quality. On Android, uses BITRATE_MODE_CQ (falls back to VBR if hardware doesn't support it). On iOS, uses AVVideoQualityKey.

Color Standard

Android: Requires API 24+.
iOS: Applied via pixel buffer attributes.

Faststart

faststart: true moves the moov atom to the beginning of the MP4 file, enabling progressive download and faster streaming start — equivalent to ffmpeg -movflags +faststart.

Image Compression #

Basic usage #

final result = await kit.compressImage(
  '/path/to/photo.jpg',
  config: ImageCompressionConfig(
    quality: 80,
    maxWidth: 1920,
    maxHeight: 1080,
    format: ImageFormat.jpeg,
  ),
);

print('${result.outputPath} — ${result.fileSize} bytes');
print('Dimensions: ${result.width}×${result.height}');

Output formats #

All configuration options #

WebP example #

final result = await kit.compressImage(
  '/path/to/photo.jpg',
  config: ImageCompressionConfig(
    quality: 75,
    format: ImageFormat.webp,
    keepExif: false,
  ),
);

EXIF preservation #

// Keep original EXIF data (orientation, GPS, camera info)
final result = await kit.compressImage(
  '/path/to/photo.jpg',
  config: ImageCompressionConfig(keepExif: true),
);

Android: Uses ExifInterface to copy EXIF tags.
iOS: Uses ImageIO (CGImageSource / CGImageDestination) to copy metadata.

Other APIs #

Get media info #

final info = await kit.getMediaInfo('/path/to/video.mp4');
print('Resolution: ${info.width}×${info.height}');
print('Duration:   ${info.duration}s');
print('Bitrate:    ${info.bitrate} bps');
print('File size:  ${info.fileSize} bytes');

Extract thumbnail #

// Get a JPEG frame at 2 seconds with 90% quality
final bytes = await kit.getThumbnail(
  '/path/to/video.mp4',
  quality: 90,
  position: 2000,  // milliseconds
);

Complete API Reference #

VideoCompressKit methods #

CompressionConfig fields #

Exported types #

Supported Platforms #

Architecture #

This is a federated Flutter plugin. App developers only import this package; platform implementations are resolved automatically at build time.

video_compress_kit              ← you import this
  └─ video_compress_kit_platform_interface
       ├─ video_compress_kit_android
       └─ video_compress_kit_ios

License #

MIT — see LICENSE.