非整数倍率YUV422图像的自由缩放DSP算法
下面的代码,实现将一幅YUV422的双通道图片(640x480大小),取中间区域(560x400大小)使用插值的办法放大至(640x480)。这个算法可以用来实现将图片外围区域截掉。- #define X_RATIO (8)
- #define Y_RATIO (6)
- PUBLIC void YUVScale(JINF_YUV_CHN_T *const yuv_ptr,const uint32 Width,const uint32 Height)
- {
- uint8 *const src_y_ptr = (uint16 *)yuv_ptr->y_chn_ptr;
- uint8 *const src_uv_ptr = (uint16 *)yuv_ptr->u_chn_ptr;
- uint32 x,y,w,h=0,xl,yl,dx,dy;
- if ((Width%(X_RATIO<<1)!=0)||(Height%(Y_RATIO<<1)!=0))
- {
- TRACE("%s Width=%d,Height=%d",__func__,Width,Height);
- return;
- }
- ASSERT(PNULL != yuv_ptr);
- xl=(Width-(Width/X_RATIO))>>1;
- yl=(Height-(Height/Y_RATIO))>>1;
- dx=Width / (X_RATIO<<1);
- dy=Height / (Y_RATIO<<1);
- for (y=0; y<yl; y++,h++)
- {
- w = 0;
- for (x=0; x<xl; x+=2,w+=2)
- {
- CopyPixel:
- //2 Quadrant 2
- src_y_ptr[h*Width+w] = src_y_ptr[(dy+y)*Width+dx+x];
- src_y_ptr[h*Width+w+1] = src_y_ptr[(dy+y)*Width+dx+x+1];
- src_uv_ptr[h*Width+w] = src_uv_ptr[(dy+y)*Width+dx+x];
- src_uv_ptr[h*Width+w+1] = src_uv_ptr[(dy+y)*Width+dx+x+1];
- //2 Quadrant 1
- src_y_ptr[h*Width+(Width-w-1)] = src_y_ptr[(dy+y)*Width+(Width-dx-x-1)];
- src_y_ptr[h*Width+(Width-w-2)] = src_y_ptr[(dy+y)*Width+(Width-dx-x-2)];
- src_uv_ptr[h*Width+(Width-w-1)] = src_uv_ptr[(dy+y)*Width+(Width-dx-x-1)];
- src_uv_ptr[h*Width+(Width-w-2)] = src_uv_ptr[(dy+y)*Width+(Width-dx-x-2)];
- //2 Quadrant 4
- src_y_ptr[(Height-h-1)*Width+(Width-w-1)] = src_y_ptr[(Height-dy-y-1)*Width+(Width-dx-x-1)];
- src_y_ptr[(Height-h-1)*Width+(Width-w-2)] = src_y_ptr[(Height-dy-y-1)*Width+(Width-dx-x-2)];
- src_uv_ptr[(Height-h-1)*Width+(Width-w-1)] = src_uv_ptr[(Height-dy-y-1)*Width+(Width-dx-x-1)];
- src_uv_ptr[(Height-h-1)*Width+(Width-w-2)] = src_uv_ptr[(Height-dy-y-1)*Width+(Width-dx-x-2)];
- //2 Quadrant 3
- src_y_ptr[(Height-h-1)*Width+w] = src_y_ptr[(Height-dy-y-1)*Width+dx+x];
- src_y_ptr[(Height-h-1)*Width+w+1] = src_y_ptr[(Height-dy-y-1)*Width+dx+x+1];
- src_uv_ptr[(Height-h-1)*Width+w] = src_uv_ptr[(Height-dy-y-1)*Width+dx+x];
- src_uv_ptr[(Height-h-1)*Width+w+1] = src_uv_ptr[(Height-dy-y-1)*Width+dx+x+1];
- if (
- ((w+2) % (X_RATIO<<1))==
- ((X_RATIO<<1)-2)
- )
- {
- w+=2;
- goto CopyPixel;
- }
- }
- if (((h+1) % (Y_RATIO))==(Y_RATIO-1))
- {
- h++;
- memcpy(src_y_ptr+h*Width,src_y_ptr+(h-1)*Width,Width);
- memcpy(src_uv_ptr+h*Width,src_uv_ptr+(h-1)*Width,Width);
- memcpy(src_y_ptr+(Height-h-1)*Width,src_y_ptr+(Height-h)*Width,Width);
- memcpy(src_uv_ptr+(Height-h-1)*Width,src_uv_ptr+(Height-h)*Width,Width);
- }
- }
- }
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