Question

如何从实际的相机源代码中读取预览帧？我试图在android中修改相机应用程序的实际源代码来读取预览帧。任何人都可以帮助我。

Answer 1

您不必更改读取帧的实际源代码。实现Camera.PreviewCallback接口应该足够了。它从相机返回原始数据。

Answer 2

在搞乱相机应用程序的来源之前，请尝试以下示例： CameraPreview 然后实现Camera.PreviewCallback。捕获的帧在YUV420SP中，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);
            }
        }
    }

我怎样才能从实际的开源android相机中读取预览帧

2 个答案: