在部分机型上camera2预览帧转换有问题

[JcmeLs]

比如米10至尊纪念版里会出现预览帧半绿屏

[Shouheng88]

哦，这个时预览的数据，我看下吧

[JcmeLs]

Google在TensorFlow的demo里有个效率很高的算法

public class ImageUtils {
  // This value is 2 ^ 18 - 1, and is used to clamp the RGB values before their ranges
  // are normalized to eight bits.
  static final int kMaxChannelValue = 262143;

  @SuppressWarnings("unused")
  private static final Logger LOGGER = new Logger();
  
  private static int YUV2RGB(int y, int u, int v) {
    // Adjust and check YUV values
    y = (y - 16) < 0 ? 0 : (y - 16);
    u -= 128;
    v -= 128;

    // This is the floating point equivalent. We do the conversion in integer
    // because some Android devices do not have floating point in hardware.
    // nR = (int)(1.164 * nY + 2.018 * nU);
    // nG = (int)(1.164 * nY - 0.813 * nV - 0.391 * nU);
    // nB = (int)(1.164 * nY + 1.596 * nV);
    int y1192 = 1192 * y;
    int r = (y1192 + 1634 * v);
    int g = (y1192 - 833 * v - 400 * u);
    int b = (y1192 + 2066 * u);

    // Clipping RGB values to be inside boundaries [ 0 , kMaxChannelValue ]
    r = r > kMaxChannelValue ? kMaxChannelValue : (r < 0 ? 0 : r);
    g = g > kMaxChannelValue ? kMaxChannelValue : (g < 0 ? 0 : g);
    b = b > kMaxChannelValue ? kMaxChannelValue : (b < 0 ? 0 : b);

    return 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
  }

  public static int[] convertYUV420ToARGB8888(
      byte[] yData,
      byte[] uData,
      byte[] vData,
      int width,
      int height,
      int yRowStride,
      int uvRowStride,
      int uvPixelStride,
      int[] out) {
    int yp = 0;
    for (int j = 0; j < height; j++) {
      int pY = yRowStride * j;
      int pUV = uvRowStride * (j >> 1);

      for (int i = 0; i < width; i++) {
        int uv_offset = pUV + (i >> 1) * uvPixelStride;

        out[yp++] = YUV2RGB(0xff & yData[pY + i], 0xff & uData[uv_offset], 0xff & vData[uv_offset]);
      }
    }
    return out;
  }
  
}