Android -- 获取摄像头帧数据解码

由于Android下摄像头预览数据只能 ImageFormat.NV21 格式的，所以解码时要经过一翻周折.

Camera mCamera = Camera.open();Camera.Parameters p = mCamera.getParameters();p.setPreviewFormat(ImageFormat.NV21);/*这是唯一值，也可以不设置。有些同学可能设置成 PixelFormat 下面的一个值，其实是不对的，具体的可以看官方文档*/mCamera.setParameters(p);mCamera.startPreview();

下面是解码核心部分：

@Overridepublic void onPreviewFrame(byte[] data, Camera camera) {        Size size = camera.getParameters().getPreviewSize();        try{YuvImage image = new YuvImage(data, ImageFormat.NV21, size.width, size.height, null);if(image!=null){ByteArrayOutputStream stream = new ByteArrayOutputStream();image.compressToJpeg(new Rect(0, 0, size.width, size.height), 80, stream);Bitmap bmp = BitmapFactory.decodeByteArray(stream.toByteArray(), 0, stream.size());stream.close();}}catch(Exception ex){Log.e("Sys","Error:"+ex.getMessage());}}

代码很简单。就是把YUV数据转成 Bitmap 就行了，系统提供 YuvImage 类。

yuv420sp转RGB

/*** 解码* * @param rgb* @param yuv420sp* @param width* @param height*/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);}}}