YUV420P的格式以及转换为RGB565的代码（Android摄像头的输出一般为YUV420P）

static void cvt_420p_to_rgb565(int width,int height,constunsignedchar*src,unsignedshort*dst)
{
int line, col, linewidth;
int y, u, v, yy, vr, ug, vg, ub;
int r, g, b;
const unsigned char *py,*pu,*pv;

linewidth = width >> 1;
py = src;
pu = py + (width * height);
pv = pu + (width * height)/ 4;

y = *py++;
yy = y << 8;
u = *pu - 128;
ug = 88 * u;
ub = 454 * u;
v = *pv - 128;
vg = 183 * v;
vr = 359 * v;

for (line = 0;line< height;line++){
    for (col = 0; col < width; col++){
      r = (yy + vr) >> 8;
      g = (yy - ug - vg)>> 8;
      b = (yy + ub ) >> 8;

      if (r < 0) r = 0;
      if (r > 255) r = 255;
      if (g < 0) g = 0;
      if (g > 255) g = 255;
      if (b < 0) b = 0;
      if (b > 255) b = 255;
      *dst++ = (((unsignedshort)r>>3)<<11)|(((unsignedshort)g>>2)<<5)|(((unsignedshort)b>>3)<<0);

      y = *py++;
      yy = y << 8;
      if (col & 1) {
    pu++;
    pv++;

    u = *pu - 128;
    ug = 88 * u;
    ub = 454 * u;
    v = *pv - 128;
    vg = 183 * v;
    vr = 359 * v;
      }
    }
    if ((line & 1)== 0){
      pu -= linewidth;
      pv -= linewidth;
    }
}
}

http://www.elautoctrl.info/wordpress/archives/921

http://blog.csdn.net/dotphoenix/article/details/6431351

extra:

Android手机你应该用little endian:
pSwsContext = sws_getContext(nWidth, nHeight, PIX_FMT_YUV420P, nWidth, nHeight
, PIX_FMT_RGB565LE, SWS_BICUBIC, NULL, NULL, NULL);

刚好手头有一个例子，就顺便给你一个例子吧：
SwsContext *img_convert_ctx = sws_getContext(codecContext->width, codecContext->height,

PIX_FMT_YUV420P,
mReqWidth,mReqHeight,
PIX_FMT_RGB565LE,
SWS_BICUBIC, NULL, NULL, NULL);
LOGD("sws_getContext return =%d",img_convert_ctx);

if(img_convert_ctx){

AVFrame *picture;

avcodec_get_frame_defaults(picture);

picture->data[0] = (uint8_t*)mRGB565Data;

picture->data[1] = 0;

picture->data[2] = 0;

picture->linesize[0] = mReqWidth;

picture->linesize[1] = 0;

picture->linesize[2] = 0;

sws_scale(img_convert_ctx, frame.data, frame.linesize,

0, codecContext->height, picture->data,

picture->linesize);

result = 0;

}

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