将预览帧转换为位图 [英] Converting preview frame to bitmap

问题描述

我知道这个主题多次出现，但是无论如何我都无法使它正常工作... 我想将视图框架从预览保存为jpeg文件.看起来或多或少(代码已简化-无需附加逻辑，异常等)……

I know the subject was on the board many times, but i can not get it work anyhow... I want to save view frames from preview to jpeg files. It looks more or less(code is simplified- without additional logic, exception etc) like this...

public void onPreviewFrame(byte[] data, Camera camera) {
  int width = camera.getParameters().getPreviewSize().width;
  int height = camera.getParameters().getPreviewSize().height;


  final int[] rgb = decodeYUV420SP(data, width, height);

  Bitmap bmp = Bitmap.createBitmap(rgb, width, height,Bitmap.Config.ARGB_8888);

  String filename="/sdcard/file" + (index++)+ ".jpg"; 
  FileOutputStream out;
  out = new FileOutputStream(filename);
  bmp.compress(Bitmap.CompressFormat.JPEG, 90, out);
  out.flush();
  out.close();
  out=null;

 }

这是我尝试转换颜色的方法之一(我相信这是从这块木板上来的)

Here is the one of the methods i tried to convert colors(from this board i believe)

public int[] decodeYUV420SP( byte[] yuv420sp, int width, int height) {   

    final int frameSize = width * height;   

    int rgb[]=new int[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);   


        }   
    }   
    return rgb;   
    } 

问题是图片总是看起来像三张奇怪的绿色图片" ... 我是新用户，所以我无法发布它:(

The problem is that the picture always looks like three 'strange green pictures'... I ama new user so i can't post it:(

我不知道它是否与大小有关，但是我被卡住了... 你能支持我吗?

I dont know if it has something to do with the size or what but i am stuck... Can you support me with it?

推荐答案

，因为我发现从PreviewSize读取的宽度和高度是错误的.... 换句话说，该转换出错了，因为它基于错误的值. 在使用一种新的设置预览设置的方式后(一切以google提供的示例为例)，一切正常.

as I found out the width and height read from PreviewSize were wrong.... In other words the conversion went wrong because it was based on false values. After use a new way of setting the preview settings(from example deleivered by google) everything works fine.

很抱歉上面的快速回答很久.

Sorry for the quick answer above and long delay.

前一段时间，我现在无法挖掘代码，但我认为我曾经使用过:

It was while ago and I can not dig the code now, but i think that I used:

http://developer.android. com/reference/android/hardware/Camera.Parameters.html#getSupportedPreviewSizes()

并从列表中获取第一个元素，并使用设置值

and took the first element from the list and set the values with

http://developer .android.com/reference/android/hardware/Camera.Parameters.html#setPreviewSize(int，int)

我存储了宽度和高度，并用它来变换图片.

i stored the width and height and used it to transform picture.

它不知道这是否是最好的解决方案，但是解决了.

It dont know if it was the best solution, but it worked out.

这篇关于将预览帧转换为位图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！