http://blog.csdn.net/qingxinguayu/article/details/1642430
X264中Color Space Converter问题, 附解决图像倒立代码
X264的编码输入一般以I420格式为主,但是x264也支持了RGB24,RGB32及YUVU,YV12(晕~~
就YUV都整出了这么多大同小异格式来)等格式,当然支持的意思就是x264里
面把这些格式转换成了I420了,具体转换工作(Color Space Converter)在csp.c里完成.
但是在windows下,RGB的存放顺序是upside down,如果直接使用rgb_to_i420,则图像是
倒立的.因此需要修改,以便图像不再倒立。
具体修改就是
#define RGB_TO_I420( name, POS_R, POS_G, POS_B, S_RGB ) /
static void name( x264_frame_t *frm, x264_image_t *img, /
int i_width, int i_height ) /
{ /
uint8_t *src = img->plane[0]+i_width*(i_height-1)*3;/
int i_src= img->i_stride[0]; /
int i_y = frm->i_stride[0]; /
uint8_t *y = frm->plane[0]; /
uint8_t *u = frm->plane[1]; /
uint8_t *v = frm->plane[2]; /
/
if( img->i_csp & X264_CSP_VFLIP ) /
{ /
src += ( i_height - 1 ) * i_src; /
i_src = -i_src; /
} /
/
for( ; i_height > 0; i_height -= 2 ) /
{ /
uint8_t *ss = src; /
uint8_t *yy = y; /
uint8_t *uu = u; /
uint8_t *vv = v; /
int w; /
/
for( w = i_width; w > 0; w -= 2 ) /
{ /
int cr = 0,cg = 0,cb = 0; /
int r, g, b; /
/
/* Luma */ /
cr = r = *(ss+POS_R); /
cg = g = *(ss+POS_G); /
cb = b = *(ss+POS_B); /
/
yy[0] = Y_ADD + ((Y_R * r + Y_G * g + Y_B * b) >> BITS); /
cr+= r = *(ss+POS_R-i_src); /
cg+= g = *(ss+POS_G-i_src); /
cb+= b = *(ss+POS_B-i_src); /
yy[i_y] = Y_ADD + ((Y_R * r + Y_G * g + Y_B * b) >> BITS); /
yy++; /
ss += S_RGB; /
/
cr+= r = *(ss+POS_R); /
cg+= g = *(ss+POS_G); /
cb+= b = *(ss+POS_B); /
/
yy[0] = Y_ADD + ((Y_R * r + Y_G * g + Y_B * b) >> BITS); /
/
cr+= r = *(ss+POS_R-i_src); /
cg+= g = *(ss+POS_G-i_src); /
cb+= b = *(ss+POS_B-i_src); /
yy[i_y] = Y_ADD + ((Y_R * r + Y_G * g + Y_B * b) >> BITS); /
yy++; /
ss += S_RGB; /
/
/* Chroma */ /
*uu++ = (uint8_t)(U_ADD + ((-U_R * cr - U_G * cg + U_B * cb) >> (B
ITS+2)) ); /
*vv++ = (uint8_t)(V_ADD + (( V_R * cr - V_G * cg - V_B * cb) >> (B
ITS+2)) ); /
} /
/
src -= 2*i_src; /
y += 2*frm->i_stride[0]; /
u += frm->i_stride[1]; /
v += frm->i_stride[2]; /
} /
}
这样就解决了windows下图像倒立的问题，实际上也是一段RGB24 ->YUV420的代码. 供
有需要的人参考.