将 YUV420 转换为 RGB 抖动

Question

const shift = (0xFF << 24);
Future<Image> convertYUV420toImageColor(CameraImage image) async {
      try {
        final int width = image.width;
        final int height = image.height;
        final int uvRowStride = image.planes[1].bytesPerRow;
        final int uvPixelStride = image.planes[1].bytesPerPixel;

        print("uvRowStride: " + uvRowStride.toString());
        print("uvPixelStride: " + uvPixelStride.toString());

        // imgLib -> Image package from https://pub.dartlang.org/packages/image
        var img = imglib.Image(width, height); // Create Image buffer

        // Fill image buffer with plane[0] from YUV420_888
        for(int x=0; x < width; x++) {
          for(int y=0; y < height; y++) {
            final int uvIndex = uvPixelStride * (x/2).floor() + uvRowStride*(y/2).floor();
            final int index = y * width + x;

            final yp = image.planes[0].bytes[index];
            final up = image.planes[1].bytes[uvIndex];
            final vp = image.planes[2].bytes[uvIndex];
            // Calculate pixel color
            int r = (yp + vp * 1436 / 1024 - 179).round().clamp(0, 255);
            int g = (yp - up * 46549 / 131072 + 44 -vp * 93604 / 131072 + 91).round().clamp(0, 255);
            int b = (yp + up * 1814 / 1024 - 227).round().clamp(0, 255);     
            // color: 0x FF  FF  FF  FF 
            //           A   B   G   R
            img.data[index] = shift | (b << 16) | (g << 8) | r;
          }
        }

        imglib.PngEncoder pngEncoder = new imglib.PngEncoder(level: 0, filter: 0);
        List<int> png = pngEncoder.encodeImage(img);
        muteYUVProcessing = false;
        return Image.memory(png);  
      } catch (e) {
        print(">>>>>>>>>>>> ERROR:" + e.toString());
      }
      return null;
  }

我一直在关注如何将相机图像转换为颤振中的图像？将 YUV 转换为 RGB，以通过 WebSockets 发送图像以进行 ML 预测。虽然可以转换，但生成的图像旋转了 90 度，性能有点慢。我怎样才能旋转它？

Answer 1

代替 img.data[index] = shift | (b << 16) | (g << 8) | r;

和

if (img.boundsSafe(height-y, x)){ 
 img.setPixelRgba(height-y, x, r , g ,b ,shift); 
} 

并替换var img = imglib.Image(width, height);

和

var img = imglib.Image(height, width);