c if标签怎么用android,android – 使用NDK将YUV解码为C/C++中的RGB-优快云博客

我正在尝试将Android相机Feed转换为位图以进行图像处理.

我有一些代码可以在原生java中将YUV转换为RGB,但是,这个过程对于实时视频来说不够快,所以我认为在应用过滤器之前我需要在C或C中转换它.我已经设置了NDK并且正在工作,所以我不知道该怎么做才将以下代码移植到C或C：

// decode Y, U, and V values on the YUV 420 buffer described as YCbCr_422_SP by Android

// David Manpearl 081201

public void decodeYUV(int[] out, byte[] fg, int width, int height)

throws NullPointerException, IllegalArgumentException {

int sz = width * height;

if (out == null)

throw new NullPointerException("buffer out is null");

if (out.length < sz)

throw new IllegalArgumentException("buffer out size " + out.length

+ " < minimum " + sz);

if (fg == null)

throw new NullPointerException("buffer 'fg' is null");

if (fg.length < sz)

throw new IllegalArgumentException("buffer fg size " + fg.length

+ " < minimum " + sz * 3 / 2);

int i, j;

int Y, Cr = 0, Cb = 0;

for (j = 0; j < height; j++) {

int pixPtr = j * width;

final int jDiv2 = j >> 1;

for (i = 0; i < width; i++) {

Y = fg[pixPtr];

if (Y < 0)

Y += 255;

if ((i & 0x1) != 1) {

final int cOff = sz + jDiv2 * width + (i >> 1) * 2;

Cb = fg[cOff];

if (Cb < 0)

Cb += 127;

else

Cb -= 128;

Cr = fg[cOff + 1];

if (Cr < 0)

Cr += 127;

else

Cr -= 128;

}

int R = Y + Cr + (Cr >> 2) + (Cr >> 3) + (Cr >> 5);

if (R < 0)

R = 0;

else if (R > 255)

R = 255;

int G = Y - (Cb >> 2) + (Cb >> 4) + (Cb >> 5) - (Cr >> 1)

+ (Cr >> 3) + (Cr >> 4) + (Cr >> 5);

if (G < 0)

G = 0;

else if (G > 255)

G = 255;

int B = Y + Cb + (Cb >> 1) + (Cb >> 2) + (Cb >> 6);

if (B < 0)

B = 0;

else if (B > 255)

B = 255;

out[pixPtr++] = 0xff000000 + (B << 16) + (G << 8) + R;

}

…

decodeYUV(argb8888, data, camSize.width, camSize.height);

Bitmap bitmap = Bitmap.createBitmap(argb8888, camSize.width,

camSize.height, Config.ARGB_8888);

有谁知道如何做到这一点？

非常感谢！

更新

这是我有多远：

JNIEXPORT void JNICALL Java_com_twothreetwo_zoomplus_ZoomPlus_YUVtoRGB(JNIEnv * env, jobject obj, jintArray rgb, jbyteArray yuv420sp, jint width, jint height)

{

int sz;

int i;

int j;

int Y;

int Cr = 0;

int Cb = 0;

int pixPtr = 0;

int jDiv2 = 0;

int R = 0;

int G = 0;

int B = 0;

int cOff;

sz = width * height;

//if(out == null) throw new NullPointerException("buffer 'out' is null");

//if(out.length < sz) throw new IllegalArgumentException("buffer 'out' size " + out.length + " < minimum " + sz);

//if(fg == null) throw new NullPointerException("buffer 'fg' is null");

//if(fg.length < sz) throw new IllegalArgumentException("buffer 'fg' size " + fg.length + " < minimum " + sz * 3/ 2);

for(j = 0; j < height; j++) {

pixPtr = j * width;

jDiv2 = j >> 1;

for(i = 0; i < width; i++) {

Y = yuv420sp[pixPtr]; if(Y < 0) Y += 255;

if((i & 0x1) != 1) {

cOff = sz + jDiv2 * width + (i >> 1) * 2;

Cb = yuv420sp[cOff];

if(Cb < 0) Cb += 127; else Cb -= 128;

Cr = yuv420sp[cOff + 1];

if(Cr < 0) Cr += 127; else Cr -= 128;

}

R = Y + Cr + (Cr >> 2) + (Cr >> 3) + (Cr >> 5);

if(R < 0) R = 0; else if(R > 255) R = 255;

G = Y - (Cb >> 2) + (Cb >> 4) + (Cb >> 5) - (Cr >> 1) + (Cr >> 3) + (Cr >> 4) + (Cr >> 5);

if(G < 0) G = 0; else if(G > 255) G = 255;

B = Y + Cb + (Cb >> 1) + (Cb >> 2) + (Cb >> 6);

if(B < 0) B = 0; else if(B > 255) B = 255;

rgb[pixPtr++] = 0xff000000 + (B << 16) + (G << 8) + R;

}

但我得到以下C错误：

apps/zoomplusndk/jni/zoomplusndk.c:53: warning: dereferencing 'void *' pointer

apps/zoomplusndk/jni/zoomplusndk.c:53: error: void value not ignored as it ought to be

apps/zoomplusndk/jni/zoomplusndk.c:56: warning: dereferencing 'void *' pointer

apps/zoomplusndk/jni/zoomplusndk.c:56: error: void value not ignored as it ought to be

apps/zoomplusndk/jni/zoomplusndk.c:58: warning: dereferencing 'void *' pointer

apps/zoomplusndk/jni/zoomplusndk.c:58: error: void value not ignored as it ought to be

apps/zoomplusndk/jni/zoomplusndk.c:67: warning: dereferencing 'void *' pointer

apps/zoomplusndk/jni/zoomplusndk.c:67: error: invalid use of void expression

第53行是Y = yuv420sp [pixPtr]; if(Y <0)Y = 255;

解决方法:

这是你的代码更正：

#include

int* rgbData;

int rgbDataSize = 0;

JNIEXPORT void JNICALL Java_mk_g6_transparency_CameraPreview_YUVtoRBG(JNIEnv * env, jobject obj, jintArray rgb, jbyteArray yuv420sp, jint width, jint height)

{