package org.jcodec.scale;

import org.jcodec.common.model.Picture;

public class Yuv422pToYuv420p implements Transform {
  public void transform(Picture src, Picture dst) {
    int lumaSize = src.getWidth() * src.getHeight();
    System.arraycopy(src.getPlaneData(0), 0, dst.getPlaneData(0), 0, lumaSize);
    copyAvg(src.getPlaneData(1), dst.getPlaneData(1), src.getPlaneWidth(1), src.getPlaneHeight(1));
    copyAvg(src.getPlaneData(2), dst.getPlaneData(2), src.getPlaneWidth(2), src.getPlaneHeight(2));
  }
  
  private void copyAvg(byte[] src, byte[] dst, int width, int height) {
    int offSrc = 0, offDst = 0;
    for (int y = 0; y < height / 2; y++) {
      for (int x = 0; x < width; x++, offDst++, offSrc++)
        dst[offDst] = (byte)(src[offSrc] + src[offSrc + width] + 1 >> 1); 
      offSrc += width;
    } 
  }
}