android – 将预览帧转换为位图

我知道这个主题很多次都在董事会上,但无论如何我都无法工作……
我想保存从预览到jpeg文件的视图帧.它看起来或多或少(代码简化 – 没有额外的逻辑,例外等)像这样……

public void onPreviewFrame(byte[] data,Camera camera) {
  int width = camera.getParameters().getPreviewSize().width;
  int height = camera.getParameters().getPreviewSize().height;


  final int[] rgb = decodeYUV420SP(data,width,height);

  Bitmap bmp = Bitmap.createBitmap(rgb,height,Bitmap.Config.ARGB_8888);

  String filename="/sdcard/file" + (index++)+ ".jpg"; 
  FileOutputStream out;
  out = new FileOutputStream(filename);
  bmp.compress(Bitmap.CompressFormat.JPEG,90,out);
  out.flush();
  out.close();
  out=null;

 }

这是我尝试转换颜色的方法之一(我相信这个板)

public int[] decodeYUV420SP( byte[] yuv420sp,int width,int height) {   

    final int frameSize = width * height;   

    int rgb[]=new int[width*height];   
    for (int j = 0,yp = 0; j < height; j++) {   
        int uvp = frameSize + (j >> 1) * width,u = 0,v = 0;   
        for (int i = 0; i < width; i++,yp++) {   
            int y = (0xff & ((int) yuv420sp[yp])) - 16;   
            if (y < 0) y = 0;   
            if ((i & 1) == 0) {   
                v = (0xff & yuv420sp[uvp++]) - 128;   
                u = (0xff & yuv420sp[uvp++]) - 128;   
            }   

            int y1192 = 1192 * y;   
            int r = (y1192 + 1634 * v);   
            int g = (y1192 - 833 * v - 400 * u);   
            int b = (y1192 + 2066 * u);   

            if (r < 0) r = 0; else if (r > 262143) r = 262143;   
            if (g < 0) g = 0; else if (g > 262143) g = 262143;   
            if (b < 0) b = 0; else if (b > 262143) b = 262143;   

            rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) &    
    0xff00) | ((b >> 10) & 0xff);   


        }   
    }   
    return rgb;   
    }

问题是图片总是看起来像三个“奇怪的绿色图片”……
我是新用户所以我不能发布它:(

我不知道它是否与尺寸有什么关系或者我被卡住了…
你可以用它支持我吗？

解决方法

或者,如果由于某种原因需要位图,和/或想要在不创建YUVImage并压缩为JPEG的情况下执行此操作,则可以使用方便的RenderScript’ScriptIntrinsicYuvToRGB'(API 17)：

@Override 
public void onPreviewFrame(byte[] data,Camera camera) { 
   Bitmap bitmap = Bitmap.createBitmap(r.width(),r.height(),Bitmap.Config.ARGB_8888);
    Allocation bmData = renderScriptNV21ToRGBA8888(
        mContext,r.width(),data);
    bmData.copyTo(bitmap);
}

public Allocation renderScriptNV21ToRGBA8888(Context context,int height,byte[] nv21) {
  RenderScript rs = RenderScript.create(context);
  ScriptIntrinsicYuvToRGB yuvToRgbIntrinsic = ScriptIntrinsicYuvToRGB.create(rs,Element.U8_4(rs));

  Type.Builder yuvType = new Type.Builder(rs,Element.U8(rs)).setX(nv21.length);
  Allocation in = Allocation.createTyped(rs,yuvType.create(),Allocation.USAGE_SCRIPT);

  Type.Builder rgbaType = new Type.Builder(rs,Element.RGBA_8888(rs)).setX(width).setY(height);
  Allocation out = Allocation.createTyped(rs,rgbaType.create(),Allocation.USAGE_SCRIPT);

  in.copyFrom(nv21);

  yuvToRgbIntrinsic.setInput(in);
  yuvToRgbIntrinsic.forEach(out);
  return out;
}