Android 视频缩放/放大

1. 原理

不直接改变Codec输出的视频宽高比，而是改变视频播放器窗口的大小。

2. 设置Window

需要将Window设置未可以超出屏幕尺寸

mWindow.setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);  

mSurfaceHolder.setFixedSize(mVideoWidth, mVideoHeight); 

4. 改变Surface窗口大小

ViewGroup.LayoutParams layoutParams = (ViewGroup.LayoutParams) mSurface.getLayoutParams();    if (scale > 4.0f) {        scale = 4.0f;    } else if (scale < 0.25f) {        scale = 0.25f;    }    layoutParams.width = (int) (windowWidth * scale);    layoutParams.height = (int) (windowHeight * scale);        mSurface.setLayoutParams(layoutParams);