通常用Camera 采集视频 得到预览数据，使用mediaCodec获取视频数据，用mediaMuxer进行音视频的混流，
如果想要添加水印很简单：
1、拿到相机预览的帧数据
2、将帧数据转为Bitmap
3、在Bitmap上添加水印(文字或者图片)
4、将图片转为帧数据
然后继续混流，效果如下：
拿相机预览的数据很简单：
关键在第二步，帧数据转为bitmap常规是这样做的 但是这种做法很耗时会导致视频卡顿：
YuvImage image = new YuvImage(dst, ImageFormat.NV21, CameraSettings.SRC_IMAGE_WIDTH,CameraSettings.SRC_IMAGE_HEIGHT, null)
ByteArrayOutputStream stream = new ByteArrayOutputStream();
image.compressToJpeg(new Rect(0, 0, CameraSettings.SRC_IMAGE_WIDTH,CameraSettings.SRC_IMAGE_HEIGHT), 100, stream);
Bitmap bitmapAll = BitmapFactory.decodeByteArray(stream.toByteArray(), 0, stream.size());
比较好的做法是使用 RenderScript的内联函数 可以更加高效的将帧数据转为bitmap：
public class MyClass {
private RenderScript rs;
private ScriptIntrinsicYuvToRGB yuvToRgbIntrinsic;
private Type.Builder yuvType, rgbaType;
private Allocation in, out;
public MyClass(Context context) {
rs = RenderScript.create(context);
yuvToRgbIntrinsic = ScriptIntrinsicYuvToRGB.create(rs, Element.U8_4(rs));
}
public Bitmap nv21ToBitmap(byte[] nv21, int width, int height){
if (yuvType == null){
yuvType = new Type.Builder(rs, Element.U8(rs)).setX(nv21.length);
in = Allocation.createTyped(rs, yuvType.create(), Allocation.USAGE_SCRIPT);
rgbaType = new Type.Builder(rs, Element.RGBA_8888(rs)).setX(width).setY(height);
out = Allocation.createTyped(rs, rgbaType.create(), Allocation.USAGE_SCRIPT);
}
in.copyFrom(nv21);
yuvToRgbIntrinsic.setInput(in);
yuvToRgbIntrinsic.forEach(out);
Bitmap bmpout = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
out.copyTo(bmpout);
return bmpout;
}
}
所以第二步、第三步可以这样使用：
private byte[] dealByte(byte[] dst) {
// YuvImage image = new YuvImage(dst, ImageFormat.NV21, CameraSettings.SRC_IMAGE_WIDTH,CameraSettings.SRC_IMAGE_HEIGHT, null)
// ByteArrayOutputStream stream = new ByteArrayOutputStream();
// image.compressToJpeg(new Rect(0, 0, CameraSettings.SRC_IMAGE_WIDTH,CameraSettings.SRC_IMAGE_HEIGHT), 100, stream);
// Bitmap bitmapAll = BitmapFactory.decodeByteArray(stream.toByteArray(), 0, stream.size());
Bitmap bitmapAll = myClass.nv21ToBitmap(dst, CameraSettings.SRC_IMAGE_WIDTH,
CameraSettings.SRC_IMAGE_HEIGHT);
Bitmap bitmapAllNew=bitmapAll.copy(Bitmap.Config.ARGB_8888,true);
Canvas canvas = new Canvas(bitmapAllNew);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.WHITE);
paint.setTextSize(80);
canvas.drawText("毕哥制作", CameraSettings.SRC_IMAGE_WIDTH/2, 100, paint);
byte[] newBytes = bitmapToNv21(bitmapAllNew,CameraSettings.SRC_IMAGE_WIDTH, CameraSettings.SRC_IMAGE_HEIGHT);
if(newBytes!=null){
return newBytes;
}else{
return null;
}
}
bitmap转为帧数据
public static byte[] bitmapToNv21(Bitmap src, int width, int height) {
if (src != null && src.getWidth() >= width && src.getHeight() >= height) {
int[] argb = new int[width * height];
src.getPixels(argb, 0, width, 0, 0, width, height);
return argbToNv21(argb, width, height);
} else {
return null;
}
}
最后再将帧数据 通过mediaCodec编码，再用mediaMuxer进行音视频混流即可