android– 使用NDK将YUV解码为CC++中的RGB

概述我正在尝试将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

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 *' pointerapps/zoomplusndk/jni/zoomplusndk.c:53: error: voID value not ignored as it ought to beapps/zoomplusndk/jni/zoomplusndk.c:56: warning: dereferencing 'voID *' pointerapps/zoomplusndk/jni/zoomplusndk.c:56: error: voID value not ignored as it ought to beapps/zoomplusndk/jni/zoomplusndk.c:58: warning: dereferencing 'voID *' pointerapps/zoomplusndk/jni/zoomplusndk.c:58: error: voID value not ignored as it ought to beapps/zoomplusndk/jni/zoomplusndk.c:67: warning: dereferencing 'voID *' pointerapps/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 <jni.h>#include <androID/log.h>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){    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;    int w = wIDth;    int h = height;    sz = w * h;    jbyte* yuv = yuv420sp;    if(rgbDataSize < sz) {        int tmp[sz];        rgbData = &tmp[0];        rgbDataSize = sz;        __androID_log_write(ANDROID_LOG_INFO, "JNI", "alloc");    }    for(j = 0; j < h; j++) {             pixPtr = j * w;             jdiv2 = j >> 1;             for(i = 0; i < w; i++) {                     Y = yuv[pixPtr];                     if(Y < 0) Y += 255;                     if((i & 0x1) != 1) {                             cOff = sz + jdiv2 * w + (i >> 1) * 2;                             Cb = yuv[cOff];                             if(Cb < 0) Cb += 127; else Cb -= 128;                             Cr = yuv[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;                     rgbData[pixPtr++] = 0xff000000 + (B << 16) + (G << 8) + R;             }    }    (*env)->SetIntArrayRegion(env, rgb, 0, sz, ( jint * ) &rgbData[0] );}

它也在http://dl.dropbox.com/u/49855874/yuv-decoder.c在线

我的测试：

> 640×480的相机预览在HTC Desire上处理~20ms
>相机预览为320×240,HTC Desire处理~6ms

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