+/**
+ * Check if the given 8x8 Block is mostly "flat"
+ */
+static inline int isHorizDC(uint8_t src[], int stride)
+{
+ int numEq= 0;
+ int y;
+ for(y=0; y<BLOCK_SIZE; y++)
+ {
+ if(((src[0] - src[1] + 1) & 0xFFFF) < 3) numEq++;
+ if(((src[1] - src[2] + 1) & 0xFFFF) < 3) numEq++;
+ if(((src[2] - src[3] + 1) & 0xFFFF) < 3) numEq++;
+ if(((src[3] - src[4] + 1) & 0xFFFF) < 3) numEq++;
+ if(((src[4] - src[5] + 1) & 0xFFFF) < 3) numEq++;
+ if(((src[5] - src[6] + 1) & 0xFFFF) < 3) numEq++;
+ if(((src[6] - src[7] + 1) & 0xFFFF) < 3) numEq++;
+ src+= stride;
+ }
+ return numEq > hFlatnessThreshold;
+}
+
+static inline int isHorizMinMaxOk(uint8_t src[], int stride, int QP)
+{
+ if(abs(src[0] - src[7]) > 2*QP) return 0;
+
+ return 1;
+}
+
+static inline void doHorizDefFilter(uint8_t dst[], int stride, int QP)
+{
+ int y;
+ for(y=0; y<BLOCK_SIZE; y++)
+ {
+ const int middleEnergy= 5*(dst[4] - dst[5]) + 2*(dst[2] - dst[5]);
+
+ if(ABS(middleEnergy) < 8*QP)
+ {
+ const int q=(dst[3] - dst[4])/2;
+ const int leftEnergy= 5*(dst[2] - dst[1]) + 2*(dst[0] - dst[3]);
+ const int rightEnergy= 5*(dst[6] - dst[5]) + 2*(dst[4] - dst[7]);
+
+ int d= ABS(middleEnergy) - MIN( ABS(leftEnergy), ABS(rightEnergy) );
+ d= MAX(d, 0);
+
+ d= (5*d + 32) >> 6;
+ d*= SIGN(-middleEnergy);
+
+ if(q>0)
+ {
+ d= d<0 ? 0 : d;
+ d= d>q ? q : d;
+ }
+ else
+ {
+ d= d>0 ? 0 : d;
+ d= d<q ? q : d;
+ }
+
+ dst[3]-= d;
+ dst[4]+= d;
+ }
+ dst+= stride;
+ }
+}
+
+/**
+ * Do a horizontal low pass filter on the 10x8 block (dst points to middle 8x8 Block)
+ * using the 9-Tap Filter (1,1,2,2,4,2,2,1,1)/16 (C version)
+ */
+static inline void doHorizLowPass(uint8_t dst[], int stride, int QP)
+{
+
+ int y;
+ for(y=0; y<BLOCK_SIZE; y++)
+ {
+ const int first= ABS(dst[-1] - dst[0]) < QP ? dst[-1] : dst[0];
+ const int last= ABS(dst[8] - dst[7]) < QP ? dst[8] : dst[7];
+
+ int sums[9];
+ sums[0] = first + dst[0];
+ sums[1] = dst[0] + dst[1];
+ sums[2] = dst[1] + dst[2];
+ sums[3] = dst[2] + dst[3];
+ sums[4] = dst[3] + dst[4];
+ sums[5] = dst[4] + dst[5];
+ sums[6] = dst[5] + dst[6];
+ sums[7] = dst[6] + dst[7];
+ sums[8] = dst[7] + last;
+
+ dst[0]= ((sums[0]<<2) + ((first + sums[2])<<1) + sums[4] + 8)>>4;
+ dst[1]= ((dst[1]<<2) + ((first + sums[0] + sums[3])<<1) + sums[5] + 8)>>4;
+ dst[2]= ((dst[2]<<2) + ((first + sums[1] + sums[4])<<1) + sums[6] + 8)>>4;
+ dst[3]= ((dst[3]<<2) + ((sums[2] + sums[5])<<1) + sums[0] + sums[7] + 8)>>4;
+ dst[4]= ((dst[4]<<2) + ((sums[3] + sums[6])<<1) + sums[1] + sums[8] + 8)>>4;
+ dst[5]= ((dst[5]<<2) + ((last + sums[7] + sums[4])<<1) + sums[2] + 8)>>4;
+ dst[6]= (((last + dst[6])<<2) + ((dst[7] + sums[5])<<1) + sums[3] + 8)>>4;
+ dst[7]= ((sums[8]<<2) + ((last + sums[6])<<1) + sums[4] + 8)>>4;
+
+ dst+= stride;
+ }
+}
+
+