Frame processing points

//==========================================\
标准有in memory相反的函数：
// ABGR little endian (rgba in memory)

如：
ABGRToARGB
ABGRToI420

BGRAToARGB
RGBAToARGB
......

glreadPixels(....GL_RGBA..)内存中真正是rgba格式；
调用带有上面标记的函数需要使用：ABGRTo...,
绝不能使用：RGBATo...

如ABGRToARGB调用后dest内存区域真正格式是：bgra，即RB互换；
但名字ARGB并无混淆，可以继续调用其他函数没问题，如：ARGBToNV21，dest内存区域真格式是：nv21

//==========================================\
Start & stride:
PStart=帧起始
size=w*h

RGBA:
PStart; stride: w * 4
I420:
Y: PStart; stride: w
U: PStart+size; stride: w/ 2
V: PStart +size* 5/ 4; stride: w/ 2
NV21
Y: PStart; stride: w
VU: PStart+size; stride: w

//==========================================\
保存帧函数：
C++:

＃include<sstream>       

int writeData2File( const void *buf, int size, int cnt) {
    stringstream ss;
        ss << cnt;
        string s1 = "/mnt/sdcard/origin_20180109_";
        string s = ss.str();
        string s2 = ".rgba";
        string sss = s1 + s + s2;

        FILE *fp1 = fopen(sss.c_str(), "a+");
        if (fp1==0) { printf("can't open file\n"); return -1;}
        fseek(fp1, 0, SEEK_END);
        fwrite(buf, size * 4, 1, fp1);
        fclose(fp1);
       return 0;
}

int writeData2File(const char *filename, const void *data, int size)
{
    if (filename == nullptr || data == nullptr || size <= 0)
    {
        return -1;
    }

    FILE *fp = fopen(filename, "wb+");
    if (fp == NULL)
    {
//        LOGE("Can not open file : %s!", filename);
        return -1;
    }

    fwrite(data, size, 1, fp);
    fclose(fp);

    return 0;
}

Java

void saveYUVBytes2SDcard(byte[] yuvBytes) {
        final String fileName = "Frame_" + System.currentTimeMillis() + ".yuv";
        File file = new File(Environment.getExternalStorageDirectory(), fileName);
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(file.getAbsolutePath());
            fos.write(yuvBytes);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    void saveYUVBytes2Png2SDcard(byte[] yuvBytes, int w, int h) {
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            final Bitmap bitmap = convertYUVBytes2Bmp(yuvBytes, w, h);
            final String fileName = "Frame_" + System.currentTimeMillis() + ".png";
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        saveBmp2PNGSDCard(fileName, bitmap);
                    } catch (IOException e) {
                        e.printStackTrace();
                    } finally {
                        if (bitmap != null) {
                            bitmap.recycle();
//                            bitmap = null;
                        }
                    }
                }
            }).start();
        }
    }

    Bitmap convertYUVBytes2Bmp(byte[] yuv, int mWidth, int mHeight) {
        YuvImage image = new YuvImage(yuv, ImageFormat.NV21, mWidth, mHeight, null);
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        image.compressToJpeg(new Rect(0, 0, mWidth, mHeight), 100, stream);
        Bitmap bmp = BitmapFactory.decodeByteArray(stream.toByteArray(), 0, stream.size());
        try {
            stream.flush();
            stream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return bmp;
    }

    private void saveBmp2PNGSDCard(String filename, Bitmap bmp) throws IOException {
        File file = new File(Environment.getExternalStorageDirectory(), filename);
        BufferedOutputStream bos = null;
        try {
            bos = new BufferedOutputStream(new FileOutputStream(file));
            bmp.compress(Bitmap.CompressFormat.PNG, 90, bos);
            bmp.recycle();
            bmp = null;
        } finally {
            if (bos != null) bos.close();
        }

        final String info = "Save frame to:" +
                Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + filename;
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(Activity.this, info, Toast.LENGTH_LONG).show();
            }
        });
    }