yuv_to_png #

A high-performance Flutter plugin for converting YUV camera image data to PNG format, optimized for Android applications.

Overview #

This plugin provides efficient YUV to PNG conversion with minimal dependencies and optimized performance. Perfect for processing camera frames in Flutter applications.

Key Features:

• ✅ Zero OpenCV dependency - smaller APK size (~ 24 mb saved per ABI)
• ✅ Fast conversion using libyuv library
• ✅ Automatic camera orientation handling (front/back)
• ✅ Support for YUV420 and NV21 formats
• ✅ Built-in rotation and mirroring for camera images
• ✅ Performance tracking with timing metrics

Installation #

Add this to your pubspec.yaml:

dependencies:
  yuv_to_png: ^1.0.1

Usage #

Basic Usage #

import 'package:yuv_to_png/yuv_to_png.dart';
import 'package:camera/camera.dart';

// Convert camera image to PNG
Uint8List png = YuvToPng.yuvToPng(
  cameraImage,
  lensDirection: cameraController.description.lensDirection,
);

// Display the image
Image.memory(png)

if there is an error you can use the next function to check if the image data is corrupted or not

        await precacheImage(Image.memory(imagedata).image, context,
        onError: (exception, stackTrace) {
      print('Failed to load image: $exception');
      imageRendered = false;
    });

if image data is corrupted you could simply use recurssion untill we get correct image data

The PNG data can then be used to display the image in Flutter using Image.memory() or as shown in the example application.

Optional #

Error Handling #

try {
  Uint8List png = YuvToPng.yuvToPng(cameraImage, lensDirection: lensDirection);

  // Verify image data is valid
  await precacheImage(
    Image.memory(png).image,
    context,
    onError: (exception, stackTrace) {
      print('Failed to load image: $exception');
    }
  );
} catch (e) {
  print('Conversion error: $e');
}

Supported Formats #

• YUV420 (planar format with separate Y, U, V planes)
• NV21 (semi-planar format with interleaved UV)

Both formats are commonly used by Android camera APIs.

Performance #

Typical conversion times on modern Android devices:

• YUV → PNG: ~80-100ms (720p image)
• Includes: YUV conversion, rotation, mirroring, and PNG encoding

Technical Details #

Architecture #

• YUV Conversion: libyuv library (fast, optimized)
• PNG Encoding: stb_image_write.h (zero dependencies)
• Image Processing: libyuv for rotation and mirroring
• Platform: Android only (API 24+)

Conversion Pipeline #

1. YUV → RGBA (using libyuv)
2. Mirror (front camera only)
3. Rotate 90° clockwise (or 270° for front camera)
4. RGBA → PNG encoding

Important Notes #

⚠️ Camera Orientation: The lensDirection parameter is crucial for correct image orientation. Always pass the correct camera lens direction to ensure proper rotation and mirroring.

⚠️ Android Only: This plugin currently supports Android only, as YUV camera formats are primarily used on Android devices.

⚠️ First Run: When running the example app for the first time, use flutter run (debug mode). Running flutter run --release on the first build may fail. After the initial successful debug build, release mode will work properly.

Roadmap #

Future features under consideration:

• ❌ upon request methods or improvements

Contact #

For questions or support, connect with me on:

LinkedIn

License #

MIT

Changelog #

See CHANGELOG.md for detailed version history and updates.