如何从实际开放源代码读取预览帧android相机

Question

如何从实际相机源代码读取预览帧？我正在尝试修改Android中用于读取预览帧的相机应用程序的实际源代码。谁能帮我这个。

Answer 1

您不应该更改读取帧的实际源代码。实施Camera.PreviewCallback接口应该就足够了。它从相机返回原始数据。

Answer 2

在搞乱相机应用程序的源之前，试试这里的例子： CameraPreview 然后实现Camera.PreviewCallback。 捕获的帧来自YUV420SP，因此您必须将其转换为rgb才能将其转换为彩色位图并在屏幕上显示。 像这样：

 @Override 
     public void onPreviewFrame(byte[] data, Camera camera) { 

     int imageWidth = camera.getParameters().getPreviewSize().width ; 
     int imageHeight =camera.getParameters().getPreviewSize().height ; 
     int RGBData[] = new int[imageWidth* imageHeight]; 
     byte[] mYUVData = new byte[data.length];  
     System.arraycopy(data, 0, mYUVData, 0, data.length); 
     decodeYUV420SP(RGBData, mYUVData, imageWidth, imageHeight); 

     Bitmap bitmap = Bitmap.createBitmap(imageWidth, imageHeight, Bitmap.Config.ARGB_8888); 
     bitmap.setPixels(RGBData, 0, imageWidth, 0, 0, imageWidth, imageHeight); 
    } 

    static public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) { 
      final int frameSize = 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); 
      } 
     } 
    }