--- trunk/xvidcore/src/motion/motion_comp.c	2002/04/13 16:30:02	118
+++ branches/dev-api-4/xvidcore/src/motion/motion_comp.c	2003/03/22 13:41:11	935
@@ -1,348 +1,1080 @@
-// 14.04.2002	bframe compensation
+// 30.10.2002	corrected qpel chroma rounding
+// 04.10.2002	added qpel support to MBMotionCompensation
+// 01.05.2002   updated MBMotionCompensationBVOP
+// 14.04.2002   bframe compensation
+
+#include <stdio.h>
 
 #include "../encoder.h"
 #include "../utils/mbfunctions.h"
 #include "../image/interpolate8x8.h"
+#include "../image/reduced.h"
 #include "../utils/timer.h"
 #include "motion.h"
 
+#ifndef ABS
 #define ABS(X) (((X)>0)?(X):-(X))
+#endif
+#ifndef SIGN
 #define SIGN(X) (((X)>0)?1:-1)
+#endif
 
-static __inline void compensate8x8_halfpel(
-				int16_t * const dct_codes,
-				uint8_t * const cur,
-				const uint8_t * const ref,
-				const uint8_t * const refh,
-				const uint8_t * const refv,
-				const uint8_t * const refhv,
-				const uint32_t x, const uint32_t y,
-				const int32_t dx,  const int dy,
-				const uint32_t stride)
-{
-	int32_t ddx,ddy;
-
-	switch ( ((dx&1)<<1) + (dy&1) )   // ((dx%2)?2:0)+((dy%2)?1:0)
-    {
-    case 0 :
-		ddx = dx/2;
-		ddy = dy/2;
-		transfer_8to16sub(dct_codes, cur + y*stride + x, 
-				ref + (y+ddy)*stride + x+ddx, stride);
-		break;
+#ifndef RSHIFT
+#define RSHIFT(a,b) ((a) > 0 ? ((a) + (1<<((b)-1)))>>(b) : ((a) + (1<<((b)-1))-1)>>(b))
+#endif
 
-    case 1 :
-		ddx = dx/2;
-		ddy = (dy-1)/2;
-		transfer_8to16sub(dct_codes, cur + y*stride + x, 
-				refv + (y+ddy)*stride + x+ddx, stride);
-		break;
+/* assume b>0 */
+#ifndef RDIV
+#define RDIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
+#endif
 
-    case 2 :
-		ddx = (dx-1)/2;
-		ddy = dy/2;
-		transfer_8to16sub(dct_codes, cur + y*stride + x, 
-				refh + (y+ddy)*stride + x+ddx, stride);
-		break;
 
-	default :	// case 3:
-		ddx = (dx-1)/2;
-		ddy = (dy-1)/2;
-		transfer_8to16sub(dct_codes, cur + y*stride + x, 
-				refhv + (y+ddy)*stride + x+ddx, stride);
-		break;
-    }
+/* This is borrowed from	decoder.c   */
+static __inline int gmc_sanitize(int value, int quarterpel, int fcode)
+{
+	int length = 1 << (fcode+4);
+
+//	if (quarterpel) value *= 2;
+
+	if (value < -length)
+		return -length;
+	else if (value >= length)
+		return length-1;
+	else return value;
 }
 
+/* And this is borrowed from   bitstream.c  until we find a common solution */
+
+static uint32_t __inline
+log2bin(uint32_t value)
+{
+/* Changed by Chenm001 */
+#if !defined(_MSC_VER)
+	int n = 0;
+
+	while (value) {
+		value >>= 1;
+		n++;
+	}
+	return n;
+#else
+	__asm {
+		bsr eax, value
+		inc eax
+	}
+#endif
+}
 
 
-void MBMotionCompensation(
-	MACROBLOCK * const mb,
-	const uint32_t i,
-	const uint32_t j,
-	const IMAGE * const ref,
-	const IMAGE * const refh,
-	const IMAGE * const refv,
-	const IMAGE * const refhv,
-	IMAGE * const cur,
-	int16_t *dct_codes,
-	const uint32_t width, 
-	const uint32_t height,
-	const uint32_t edged_width,
-	const uint32_t rounding)
+static __inline void
+compensate16x16_interpolate(int16_t * const dct_codes,
+							uint8_t * const cur,
+							const uint8_t * const ref,
+							const uint8_t * const refh,
+							const uint8_t * const refv,
+							const uint8_t * const refhv,
+							uint8_t * const tmp,
+							uint32_t x,
+							uint32_t y,
+							const int32_t dx,
+							const int32_t dy,
+							const int32_t stride,
+							const int quarterpel,
+							const int reduced_resolution,
+							const int32_t rounding)
 {
-	static const uint32_t roundtab[16] =
-		{ 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2 };
+	const uint8_t * ptr;
 
+	if (!reduced_resolution) {
 
-	if (mb->mode == MODE_INTER || mb->mode == MODE_INTER_Q)
-	{
-		int32_t dx = mb->mvs[0].x;
-		int32_t dy = mb->mvs[0].y;
+		if(quarterpel) {
+			if ((dx&3) | (dy&3)) {
+				interpolate16x16_quarterpel(tmp - y * stride - x,
+											(uint8_t *) ref, tmp + 32,
+											tmp + 64, tmp + 96, x, y, dx, dy, stride, rounding);
+				ptr = tmp;
+			} else ptr =  ref + (y + dy/4)*stride + x + dx/4; // fullpixel position
+
+		} else ptr = get_ref(ref, refh, refv, refhv, x, y, 1, dx, dy, stride);
+
+		transfer_8to16sub(dct_codes, cur + y * stride + x,
+							ptr, stride);
+		transfer_8to16sub(dct_codes+64, cur + y * stride + x + 8,
+							ptr + 8, stride);
+		transfer_8to16sub(dct_codes+128, cur + y * stride + x + 8*stride,
+							ptr + 8*stride, stride);
+		transfer_8to16sub(dct_codes+192, cur + y * stride + x + 8*stride+8,
+							ptr + 8*stride + 8, stride);
+
+	} else { //reduced_resolution
+
+		x *= 2; y *= 2;
+
+		ptr = get_ref(ref, refh, refv, refhv, x, y, 1, dx, dy, stride);
 
-		compensate8x8_halfpel(&dct_codes[0*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i,     16*j,     dx, dy, edged_width);
-		compensate8x8_halfpel(&dct_codes[1*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i + 8, 16*j,     dx, dy, edged_width);
-		compensate8x8_halfpel(&dct_codes[2*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i,     16*j + 8, dx, dy, edged_width);
-		compensate8x8_halfpel(&dct_codes[3*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i + 8, 16*j + 8, dx, dy, edged_width);
-
-		dx = (dx & 3) ? (dx >> 1) | 1 : dx / 2;
-		dy = (dy & 3) ? (dy >> 1) | 1 : dy / 2;
-
-		/* uv-image-based compensation
-		   compensate8x8_halfpel(dct_codes[4], cur->u, ref->u, refh->u, refv->u, refhv->u,
-		   8*i, 8*j, dx, dy, edged_width/2);
-		   compensate8x8_halfpel(dct_codes[5], cur->v, ref->v, refh->v, refv->v, refhv->v,
-		   8*i, 8*j, dx, dy, edged_width/2);		*/
-
-		/* uv-block-based compensation */
-		interpolate8x8_switch(refv->u, ref->u, 8*i, 8*j, dx, dy, edged_width/2, rounding);
-		transfer_8to16sub(&dct_codes[4*64], 
-				  cur->u + 8*j*edged_width/2 + 8*i, 
-				  refv->u + 8*j*edged_width/2 + 8*i, edged_width/2);
-
-		interpolate8x8_switch(refv->v, ref->v, 8*i, 8*j, dx, dy, edged_width/2, rounding);
-		transfer_8to16sub(&dct_codes[5*64], 
-				  cur->v + 8*j*edged_width/2 + 8*i, 
-				  refv->v + 8*j*edged_width/2 + 8*i, edged_width/2);
+		filter_18x18_to_8x8(dct_codes, cur+y*stride + x, stride);
+		filter_diff_18x18_to_8x8(dct_codes, ptr, stride);
 
+		filter_18x18_to_8x8(dct_codes+64, cur+y*stride + x + 16, stride);
+		filter_diff_18x18_to_8x8(dct_codes+64, ptr + 16, stride);
+
+		filter_18x18_to_8x8(dct_codes+128, cur+(y+16)*stride + x, stride);
+		filter_diff_18x18_to_8x8(dct_codes+128, ptr + 16*stride, stride);
+
+		filter_18x18_to_8x8(dct_codes+192, cur+(y+16)*stride + x + 16, stride);
+		filter_diff_18x18_to_8x8(dct_codes+192, ptr + 16*stride + 16, stride);
+
+		transfer32x32_copy(cur + y*stride + x, ptr, stride);
 	}
-	else	// mode == MODE_INTER4V
-	{
-		int32_t sum, dx, dy;
+}
 
-		compensate8x8_halfpel(&dct_codes[0*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i,     16*j,     mb->mvs[0].x, mb->mvs[0].y, edged_width);
-		compensate8x8_halfpel(&dct_codes[1*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i + 8, 16*j,     mb->mvs[1].x, mb->mvs[1].y, edged_width);
-		compensate8x8_halfpel(&dct_codes[2*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i,     16*j + 8, mb->mvs[2].x, mb->mvs[2].y, edged_width);
-		compensate8x8_halfpel(&dct_codes[3*64], cur->y, ref->y, refh->y, refv->y, refhv->y,
-				      16*i + 8, 16*j + 8, mb->mvs[3].x, mb->mvs[3].y, edged_width);
+static __inline void
+compensate8x8_interpolate(	int16_t * const dct_codes,
+							uint8_t * const cur,
+							const uint8_t * const ref,
+							const uint8_t * const refh,
+							const uint8_t * const refv,
+							const uint8_t * const refhv,
+							uint8_t * const tmp,
+							uint32_t x,
+							uint32_t y,
+							const int32_t dx,
+							const int32_t dy,
+							const int32_t stride,
+							const int32_t quarterpel,
+							const int reduced_resolution,
+							const int32_t rounding)
+{
+	const uint8_t * ptr;
+
+	if (!reduced_resolution) {
+
+		if(quarterpel) {
+			if ((dx&3) | (dy&3)) {
+				interpolate8x8_quarterpel(tmp - y*stride - x,
+										(uint8_t *) ref, tmp + 32,
+										tmp + 64, tmp + 96, x, y, dx, dy, stride, rounding);
+				ptr = tmp;
+			} else ptr = ref + (y + dy/4)*stride + x + dx/4; // fullpixel position
+		} else ptr = get_ref(ref, refh, refv, refhv, x, y, 1, dx, dy, stride);
 
-		sum = mb->mvs[0].x + mb->mvs[1].x + mb->mvs[2].x + mb->mvs[3].x;
-		dx = (sum ? SIGN(sum) * (roundtab[ABS(sum) % 16] + (ABS(sum) / 16) * 2) : 0);
+			transfer_8to16sub(dct_codes, cur + y * stride + x, ptr, stride);
 
-		sum = mb->mvs[0].y + mb->mvs[1].y + mb->mvs[2].y + mb->mvs[3].y;
-		dy = (sum ? SIGN(sum) * (roundtab[ABS(sum) % 16] + (ABS(sum) / 16) * 2) : 0);
+	} else { //reduced_resolution
 
-		/* uv-image-based compensation
-		   compensate8x8_halfpel(dct_codes[4], cur->u, ref->u, refh->u, refv->u, refhv->u,
-		   8*i, 8*j, dx, dy, edged_width/2);
-		   compensate8x8_halfpel(dct_codes[5], cur->v, ref->v, refh->v, refv->v, refhv->v,
-		   8*i, 8*j, dx, dy, edged_width/2);		*/
+		x *= 2; y *= 2;
 
-		/* uv-block-based compensation */
-		interpolate8x8_switch(refv->u, ref->u, 8*i, 8*j, dx, dy, edged_width/2, rounding);
-		transfer_8to16sub(&dct_codes[4*64], 
-				  cur->u + 8*j*edged_width/2 + 8*i, 
-				  refv->u + 8*j*edged_width/2 + 8*i, edged_width/2);
+		ptr = get_ref(ref, refh, refv, refhv, x, y, 1, dx, dy, stride);
 
-		interpolate8x8_switch(refv->v, ref->v, 8*i, 8*j, dx, dy, edged_width/2, rounding);
-		transfer_8to16sub(&dct_codes[5*64], 
-				  cur->v + 8*j*edged_width/2 + 8*i, 
-				  refv->v + 8*j*edged_width/2 + 8*i, edged_width/2);
+		filter_18x18_to_8x8(dct_codes, cur+y*stride + x, stride);
+		filter_diff_18x18_to_8x8(dct_codes, ptr, stride);
 
+		transfer16x16_copy(cur + y*stride + x, ptr, stride);
 	}
 }
 
+/* XXX: slow, inelegant... */
+static void
+interpolate18x18_switch(uint8_t * const cur,
+						const uint8_t * const refn,
+						const uint32_t x,
+						const uint32_t y,
+						const int32_t dx,
+						const int dy,
+						const int32_t stride,
+						const int32_t rounding)
+{
+	interpolate8x8_switch(cur, refn, x-1, y-1, dx, dy, stride, rounding);
+	interpolate8x8_switch(cur, refn, x+7, y-1, dx, dy, stride, rounding);
+	interpolate8x8_switch(cur, refn, x+9, y-1, dx, dy, stride, rounding);
+
+	interpolate8x8_switch(cur, refn, x-1, y+7, dx, dy, stride, rounding);
+	interpolate8x8_switch(cur, refn, x+7, y+7, dx, dy, stride, rounding);
+	interpolate8x8_switch(cur, refn, x+9, y+7, dx, dy, stride, rounding);
+
+	interpolate8x8_switch(cur, refn, x-1, y+9, dx, dy, stride, rounding);
+	interpolate8x8_switch(cur, refn, x+7, y+9, dx, dy, stride, rounding);
+	interpolate8x8_switch(cur, refn, x+9, y+9, dx, dy, stride, rounding);
+}
 
+static void
+CompensateChroma(	int dx, int dy,
+					const int i, const int j,
+					IMAGE * const Cur,
+					const IMAGE * const Ref,
+					uint8_t * const temp,
+					int16_t * const coeff,
+					const int32_t stride,
+					const int rounding,
+					const int rrv)
+{ /* uv-block-based compensation */
+
+	if (!rrv) {
+		transfer_8to16sub(coeff, Cur->u + 8 * j * stride + 8 * i,
+							interpolate8x8_switch2(temp, Ref->u, 8 * i, 8 * j,
+													dx, dy, stride, rounding),
+							stride);
+		transfer_8to16sub(coeff + 64, Cur->v + 8 * j * stride + 8 * i,
+ 							interpolate8x8_switch2(temp, Ref->v, 8 * i, 8 * j,
+													dx, dy, stride, rounding),
+							stride);
+	} else {
+		uint8_t * current, * reference;
+
+		current = Cur->u + 16*j*stride + 16*i;
+		reference = temp - 16*j*stride - 16*i;
+		interpolate18x18_switch(reference, Ref->u, 16*i, 16*j, dx, dy, stride, rounding);
+		filter_18x18_to_8x8(coeff, current, stride);
+		filter_diff_18x18_to_8x8(coeff, temp, stride);
+		transfer16x16_copy(current, temp, stride);
+
+		current = Cur->v + 16*j*stride + 16*i;
+		interpolate18x18_switch(reference, Ref->v, 16*i, 16*j, dx, dy, stride, rounding);
+		filter_18x18_to_8x8(coeff + 64, current, stride);
+		filter_diff_18x18_to_8x8(coeff + 64, temp, stride);
+		transfer16x16_copy(current, temp, stride);
+	}
+}
 
-void MBMotionCompensationBVOP(
-			MBParam * pParam,
-			MACROBLOCK * const mb,
-		    const uint32_t i,
-			const uint32_t j,
-			IMAGE * const cur,
-		    const IMAGE * const f_ref,
-			const IMAGE * const f_refh,
-		    const IMAGE * const f_refv,
-			const IMAGE * const f_refhv,
-		    const IMAGE * const b_ref,
-			const IMAGE * const b_refh,
-		    const IMAGE * const b_refv,
-			const IMAGE * const b_refhv,
-		    int16_t dct_codes[][64])
+void
+MBMotionCompensation(MACROBLOCK * const mb,
+					const uint32_t i,
+					const uint32_t j,
+					const IMAGE * const ref,
+					const IMAGE * const refh,
+					const IMAGE * const refv,
+					const IMAGE * const refhv,
+					const IMAGE * const refGMC,
+					IMAGE * const cur,
+					int16_t * dct_codes,
+					const uint32_t width,
+					const uint32_t height,
+					const uint32_t edged_width,
+					const int32_t quarterpel,
+					const int reduced_resolution,
+					const int32_t rounding)
 {
-	static const uint32_t roundtab[16] =
-		{ 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2 };
+	int32_t dx;
+	int32_t dy;
 
-	const int32_t edged_width = pParam->edged_width;
-	int32_t dx, dy;
-	int32_t b_dx, b_dy;
-	int x = i;
-	int y = j;
+	uint8_t * const tmp = refv->u;
 
+	if ( (!reduced_resolution) && (mb->mode == MODE_NOT_CODED) ) {	/* quick copy for early SKIP */
+/* early SKIP is only activated in P-VOPs, not in S-VOPs, so mcsel can never be 1 */
 
+		transfer16x16_copy(cur->y + 16 * (i + j * edged_width),
+						  ref->y + 16 * (i + j * edged_width),
+						  edged_width);
+
+		transfer8x8_copy(cur->u + 8 * (i + j * edged_width/2),
+							ref->u + 8 * (i + j * edged_width/2),
+							edged_width / 2);
+		transfer8x8_copy(cur->v + 8 * (i + j * edged_width/2),
+							ref->v + 8 * (i + j * edged_width/2),
+							edged_width / 2);
+		return;
+	}
 
-	switch(mb->mode)
-	{
-	case MODE_FORWARD :
-		dx = mb->mvs[0].x;
-		dy = mb->mvs[0].y;
-
-		transfer_8to16sub_c(
-			dct_codes[0],
-			cur->y + (j*16)*edged_width + (i*16),
-			get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y,
-							i*16, j*16, 1, dx, dy, edged_width), 
-			edged_width);
-
-		transfer_8to16sub(
-			dct_codes[1],
-			cur->y + (j*16)*edged_width + (i*16+8),
-			get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y,
-							i*16+8, j*16, 1, dx, dy, edged_width), 
-			edged_width);
-
-		transfer_8to16sub_c(
-			dct_codes[2],
-			cur->y + (j*16+8)*edged_width + (i*16),
-			get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y,
-							i*16, j*16+8, 1, dx, dy, edged_width), 
-			edged_width);
-
-		transfer_8to16sub(
-			dct_codes[3],
-			cur->y + (j*16+8)*edged_width + (i*16+8),
-			get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y,
-							i*16+8, j*16+8, 1, dx, dy, edged_width), 
-			edged_width);
-
-
-		dx = (dx & 3) ? (dx >> 1) | 1 : dx / 2;
-		dy = (dy & 3) ? (dy >> 1) | 1 : dy / 2;
-
-		/* uv-image-based compensation */
-		compensate8x8_halfpel(dct_codes[4], cur->u, f_ref->u, f_refh->u, f_refv->u, f_refhv->u,
-								8*i, 8*j, dx, dy, edged_width/2);
-		compensate8x8_halfpel(dct_codes[5], cur->v, f_ref->v, f_refh->v, f_refv->v, f_refhv->v,
-								8*i, 8*j, dx, dy, edged_width/2);		
+	if ((mb->mode == MODE_NOT_CODED || mb->mode == MODE_INTER
+				|| mb->mode == MODE_INTER_Q)) {
 
-		break;
+	/* reduced resolution + GMC:  not possible */
 
-	case MODE_BACKWARD :
-		b_dx = mb->b_mvs[0].x;
-		b_dy = mb->b_mvs[0].y;
-
-		transfer_8to16sub_c(
-			dct_codes[0],
-			cur->y + (j*16)*edged_width + (i*16),
-			get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y,
-							i*16, j*16, 1, b_dx, b_dy, edged_width), 
-			edged_width);
-
-		transfer_8to16sub(
-			dct_codes[1],
-			cur->y + (j*16)*edged_width + (i*16+8),
-			get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y,
-							i*16+8, j*16, 1, b_dx, b_dy, edged_width), 
-			edged_width);
-
-		transfer_8to16sub_c(
-			dct_codes[2],
-			cur->y + (j*16+8)*edged_width + (i*16),
-			get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y,
-							i*16, j*16+8, 1, b_dx, b_dy, edged_width), 
-			edged_width);
-
-		transfer_8to16sub(
-			dct_codes[3],
-			cur->y + (j*16+8)*edged_width + (i*16+8),
-			get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y,
-							i*16+8, j*16+8, 1, b_dx, b_dy, edged_width), 
-			edged_width);
-
-		b_dx = (b_dx & 3) ? (b_dx >> 1) | 1 : b_dx / 2;
-		b_dy = (b_dy & 3) ? (b_dy >> 1) | 1 : b_dy / 2;
-
-		/* uv-image-based compensation */
-		compensate8x8_halfpel(dct_codes[4], cur->u, 
-					b_ref->u, b_refh->u, b_refv->u, b_refhv->u,
-					8*i, 8*j, b_dx, b_dy, edged_width/2);
-		compensate8x8_halfpel(dct_codes[5], cur->v, 
-					b_ref->v, b_refh->v, b_refv->v, b_refhv->v,
-					8*i, 8*j, b_dx, b_dy, edged_width/2);		
+		if (mb->mcsel) {
 
-		break;
+			/* call normal routine once, easier than "if (mcsel)"ing all the time */
 
+			transfer_8to16sub(&dct_codes[0*64], cur->y + 16*j*edged_width + 16*i,
+								 			refGMC->y + 16*j*edged_width + 16*i, edged_width);
+			transfer_8to16sub(&dct_codes[1*64], cur->y + 16*j*edged_width + 16*i+8,
+											refGMC->y + 16*j*edged_width + 16*i+8, edged_width);
+			transfer_8to16sub(&dct_codes[2*64], cur->y + (16*j+8)*edged_width + 16*i,
+											refGMC->y + (16*j+8)*edged_width + 16*i, edged_width);
+			transfer_8to16sub(&dct_codes[3*64], cur->y + (16*j+8)*edged_width + 16*i+8,
+											refGMC->y + (16*j+8)*edged_width + 16*i+8, edged_width);
+
+/* lumi is needed earlier for mode decision, but chroma should be done block-based, but it isn't, yet. */
+
+			transfer_8to16sub(&dct_codes[4 * 64], cur->u + 8 *j*edged_width/2 + 8*i,
+								refGMC->u + 8 *j*edged_width/2 + 8*i, edged_width/2);
+
+			transfer_8to16sub(&dct_codes[5 * 64], cur->v + 8*j* edged_width/2 + 8*i,
+								refGMC->v + 8*j* edged_width/2 + 8*i, edged_width/2);
+
+			return;
+		}
+
+		/* ordinary compensation */
+
+		dx = (quarterpel ? mb->qmvs[0].x : mb->mvs[0].x);
+		dy = (quarterpel ? mb->qmvs[0].y : mb->mvs[0].y);
+
+		if (reduced_resolution) {
+			dx = RRV_MV_SCALEUP(dx);
+			dy = RRV_MV_SCALEUP(dy);
+		}
+
+		compensate16x16_interpolate(&dct_codes[0 * 64], cur->y, ref->y, refh->y,
+							refv->y, refhv->y, tmp, 16 * i, 16 * j, dx, dy,
+							edged_width, quarterpel, reduced_resolution, rounding);
+
+		if (quarterpel) { dx /= 2; dy /= 2; }
+
+		dx = (dx >> 1) + roundtab_79[dx & 0x3];
+		dy = (dy >> 1) + roundtab_79[dy & 0x3];
+
+	} else {					// mode == MODE_INTER4V
+		int k, sumx = 0, sumy = 0;
+		const VECTOR * const mvs = (quarterpel ? mb->qmvs : mb->mvs);
+
+		for (k = 0; k < 4; k++) {
+			dx = mvs[k].x;
+			dy = mvs[k].y;
+			sumx += quarterpel ? dx/2 : dx;
+			sumy += quarterpel ? dy/2 : dy;
+
+			if (reduced_resolution){
+				dx = RRV_MV_SCALEUP(dx);
+				dy = RRV_MV_SCALEUP(dy);
+			}
+
+			compensate8x8_interpolate(&dct_codes[k * 64], cur->y, ref->y, refh->y,
+									refv->y, refhv->y, tmp, 16 * i + 8*(k&1), 16 * j + 8*(k>>1), dx,
+									dy, edged_width, quarterpel, reduced_resolution, rounding);
+		}
+		dx = (sumx >> 3) + roundtab_76[sumx & 0xf];
+		dy = (sumy >> 3) + roundtab_76[sumy & 0xf];
+	}
+
+	CompensateChroma(dx, dy, i, j, cur, ref, tmp,
+					&dct_codes[4 * 64], edged_width / 2, rounding, reduced_resolution);
+}
+
+
+void
+MBMotionCompensationBVOP(MBParam * pParam,
+						MACROBLOCK * const mb,
+						const uint32_t i,
+						const uint32_t j,
+						IMAGE * const cur,
+						const IMAGE * const f_ref,
+						const IMAGE * const f_refh,
+						const IMAGE * const f_refv,
+						const IMAGE * const f_refhv,
+						const IMAGE * const b_ref,
+						const IMAGE * const b_refh,
+						const IMAGE * const b_refv,
+						const IMAGE * const b_refhv,
+						int16_t * dct_codes)
+{
+	const uint32_t edged_width = pParam->edged_width;
+	int32_t dx, dy, b_dx, b_dy, sumx, sumy, b_sumx, b_sumy;
+	int k;
+	const int quarterpel = pParam->vol_flags & XVID_QUARTERPEL;
+	const uint8_t * ptr1, * ptr2;
+	uint8_t * const tmp = f_refv->u;
+	const VECTOR * const fmvs = (quarterpel ? mb->qmvs : mb->mvs);
+	const VECTOR * const bmvs = (quarterpel ? mb->b_qmvs : mb->b_mvs);
+
+	switch (mb->mode) {
+	case MODE_FORWARD:
+		dx = fmvs->x; dy = fmvs->y;
+
+		compensate16x16_interpolate(&dct_codes[0 * 64], cur->y, f_ref->y, f_refh->y,
+							f_refv->y, f_refhv->y, tmp, 16 * i, 16 * j, dx,
+							dy, edged_width, quarterpel, 0, 0);
+
+		if (quarterpel) { dx /= 2; dy /= 2; }
+
+		CompensateChroma(	(dx >> 1) + roundtab_79[dx & 0x3],
+							(dy >> 1) + roundtab_79[dy & 0x3],
+							i, j, cur, f_ref, tmp,
+							&dct_codes[4 * 64], edged_width / 2, 0, 0);
+
+		return;
+
+	case MODE_BACKWARD:
+		b_dx = bmvs->x; b_dy = bmvs->y;
+
+		compensate16x16_interpolate(&dct_codes[0 * 64], cur->y, b_ref->y, b_refh->y,
+										b_refv->y, b_refhv->y, tmp, 16 * i, 16 * j, b_dx,
+										b_dy, edged_width, quarterpel, 0, 0);
+
+		if (quarterpel) { b_dx /= 2; b_dy /= 2; }
+
+		CompensateChroma(	(b_dx >> 1) + roundtab_79[b_dx & 0x3],
+							(b_dy >> 1) + roundtab_79[b_dy & 0x3],
+							i, j, cur, b_ref, tmp,
+							&dct_codes[4 * 64], edged_width / 2, 0, 0);
+
+		return;
+
+	case MODE_INTERPOLATE: /* _could_ use DIRECT, but would be overkill (no 4MV there) */
+	case MODE_DIRECT_NO4V:
+		dx = fmvs->x; dy = fmvs->y;
+		b_dx = bmvs->x; b_dy = bmvs->y;
+
+		if (quarterpel) {
+
+			if ((dx&3) | (dy&3)) {
+				interpolate16x16_quarterpel(tmp - i * 16 - j * 16 * edged_width,
+					(uint8_t *) f_ref->y, tmp + 32,
+					tmp + 64, tmp + 96, 16*i, 16*j, dx, dy, edged_width, 0);
+				ptr1 = tmp;
+			} else ptr1 = f_ref->y + (16*j + dy/4)*edged_width + 16*i + dx/4; // fullpixel position
+
+			if ((b_dx&3) | (b_dy&3)) {
+				interpolate16x16_quarterpel(tmp - i * 16 - j * 16 * edged_width + 16,
+					(uint8_t *) b_ref->y, tmp + 32,
+					tmp + 64, tmp + 96, 16*i, 16*j, b_dx, b_dy, edged_width, 0);
+				ptr2 = tmp + 16;
+			} else ptr2 = b_ref->y + (16*j + b_dy/4)*edged_width + 16*i + b_dx/4; // fullpixel position
+
+			b_dx /= 2;
+			b_dy /= 2;
+			dx /= 2;
+			dy /= 2;
+
+		} else {
+			ptr1 = get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y,
+							i, j, 16, dx, dy, edged_width);
+
+			ptr2 = get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y,
+							i, j, 16, b_dx, b_dy, edged_width);
+		}
+		for (k = 0; k < 4; k++)
+				transfer_8to16sub2(&dct_codes[k * 64],
+									cur->y + (i * 16+(k&1)*8) + (j * 16+((k>>1)*8)) * edged_width,
+									ptr1 + (k&1)*8 + (k>>1)*8*edged_width,
+									ptr2 + (k&1)*8 + (k>>1)*8*edged_width, edged_width);
+
+
+		dx = (dx >> 1) + roundtab_79[dx & 0x3];
+		dy = (dy >> 1) + roundtab_79[dy & 0x3];
+
+		b_dx = (b_dx >> 1) + roundtab_79[b_dx & 0x3];
+		b_dy = (b_dy >> 1) + roundtab_79[b_dy & 0x3];
 
-	case MODE_INTERPOLATE :
-		dx = mb->mvs[0].x;
-		dy = mb->mvs[0].y;
-		b_dx = mb->b_mvs[0].x;
-		b_dy = mb->b_mvs[0].y;
-
-		transfer_8to16sub2_c(
-				dct_codes[0], 
-				cur->y + (i*16) + (j*16)*edged_width, 
-				get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y, 
-							16*i, 16*j, 1, dx, dy, edged_width),
-				get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y, 
-							16*i, 16*j, 1, b_dx, b_dy, edged_width),
-				edged_width);
-		
-		transfer_8to16sub2_c(
-				dct_codes[1], 
-				cur->y + (i*16+8) + (j*16)*edged_width, 
-				get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y, 
-							16*i+8, 16*j, 1, dx, dy, edged_width),
-				get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y, 
-							16*i+8, 16*j, 1, b_dx, b_dy, edged_width),
-				edged_width);
-
-		transfer_8to16sub2_c(
-				dct_codes[2], 
-				cur->y + (i*16) + (j*16+8)*edged_width, 
-				get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y, 
-							16*i, 16*j+8, 1, dx, dy, edged_width),
-				get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y, 
-							16*i, 16*j+8, 1, b_dx, b_dy, edged_width),
-				edged_width);
-
-		transfer_8to16sub2_c(
-				dct_codes[3], 
-				cur->y + (i*16+8) + (j*16+8)*edged_width, 
-				get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y, 
-							16*i + 8, 16*j + 8, 1, dx, dy, edged_width),
-				get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y, 
-							16*i + 8, 16*j + 8, 1, b_dx, b_dy, edged_width),
-				edged_width);
-
-
-		dx = (dx & 3) ? (dx >> 1) | 1 : dx / 2;
-		dy = (dy & 3) ? (dy >> 1) | 1 : dy / 2;
-
-		b_dx = (b_dx & 3) ? (b_dx >> 1) | 1 : b_dx / 2;
-		b_dy = (b_dy & 3) ? (b_dy >> 1) | 1 : b_dy / 2;
-
-		transfer_8to16sub2_c(
-				dct_codes[4], 
-				cur->u + (y*8)*edged_width/2 + (x*8), 
-				get_ref(f_ref->u, f_refh->u, f_refv->u, f_refhv->u, 
-							8*i, 8*j, 1, dx, dy, edged_width/2),
-				get_ref(b_ref->u, b_refh->u, b_refv->u, b_refhv->u, 
-							8*i, 8*j, 1, b_dx, b_dy, edged_width/2),
-				edged_width/2);
-
-		transfer_8to16sub2_c(
-				dct_codes[5], 
-				cur->v + (y*8)*edged_width/2 + (x*8), 
-				get_ref(f_ref->v, f_refh->v, f_refv->v, f_refhv->v, 
-							8*i, 8*j, 1, dx, dy, edged_width/2),
-				get_ref(b_ref->v, b_refh->v, b_refv->v, b_refhv->v, 
-							8*i, 8*j, 1, b_dx, b_dy, edged_width/2),
-				edged_width/2);
-				
 		break;
 
-	case MODE_DIRECT :
-		// todo
+	default: // MODE_DIRECT (or MODE_DIRECT_NONE_MV in case of bframes decoding)
+		sumx = sumy = b_sumx = b_sumy = 0;
+
+		for (k = 0; k < 4; k++) {
+
+			dx = fmvs[k].x; dy = fmvs[k].y;
+			b_dx = bmvs[k].x; b_dy = bmvs[k].y;
+
+			if (quarterpel) {
+				sumx += dx/2; sumy += dy/2;
+				b_sumx += b_dx/2; b_sumy += b_dy/2;
+
+				if ((dx&3) | (dy&3)) {
+					interpolate8x8_quarterpel(tmp - (i * 16+(k&1)*8) - (j * 16+((k>>1)*8)) * edged_width,
+						(uint8_t *) f_ref->y,
+						tmp + 32, tmp + 64, tmp + 96,
+						16*i + (k&1)*8, 16*j + (k>>1)*8, dx, dy, edged_width, 0);
+					ptr1 = tmp;
+				} else ptr1 = f_ref->y + (16*j + (k>>1)*8 + dy/4)*edged_width + 16*i + (k&1)*8 + dx/4;
+
+				if ((b_dx&3) | (b_dy&3)) {
+					interpolate8x8_quarterpel(tmp - (i * 16+(k&1)*8) - (j * 16+((k>>1)*8)) * edged_width + 16,
+						(uint8_t *) b_ref->y,
+						tmp + 16, tmp + 32, tmp + 48,
+						16*i + (k&1)*8, 16*j + (k>>1)*8, b_dx, b_dy, edged_width, 0);
+					ptr2 = tmp + 16;
+				} else ptr2 = b_ref->y + (16*j + (k>>1)*8 + b_dy/4)*edged_width + 16*i + (k&1)*8 + b_dx/4;
+			} else {
+				sumx += dx; sumy += dy;
+				b_sumx += b_dx; b_sumy += b_dy;
+
+				ptr1 = get_ref(f_ref->y, f_refh->y, f_refv->y, f_refhv->y,
+								2*i + (k&1), 2*j + (k>>1), 8, dx, dy, edged_width);
+				ptr2 = get_ref(b_ref->y, b_refh->y, b_refv->y, b_refhv->y,
+								2*i + (k&1), 2*j + (k>>1), 8, b_dx, b_dy,  edged_width);
+			}
+			transfer_8to16sub2(&dct_codes[k * 64],
+								cur->y + (i * 16+(k&1)*8) + (j * 16+((k>>1)*8)) * edged_width,
+								ptr1, ptr2,	edged_width);
+
+		}
+
+		dx = (sumx >> 3) + roundtab_76[sumx & 0xf];
+		dy = (sumy >> 3) + roundtab_76[sumy & 0xf];
+		b_dx = (b_sumx >> 3) + roundtab_76[b_sumx & 0xf];
+		b_dy = (b_sumy >> 3) + roundtab_76[b_sumy & 0xf];
+
 		break;
 	}
+
+	// uv block-based chroma interpolation for direct and interpolate modes
+	transfer_8to16sub2(&dct_codes[4 * 64],
+						cur->u + (j * 8) * edged_width / 2 + (i * 8),
+						interpolate8x8_switch2(tmp, b_ref->u, 8 * i, 8 * j,
+												b_dx, b_dy, edged_width / 2, 0),
+						interpolate8x8_switch2(tmp + 8, f_ref->u, 8 * i, 8 * j,
+												dx, dy, edged_width / 2, 0),
+						edged_width / 2);
+
+	transfer_8to16sub2(&dct_codes[5 * 64],
+						cur->v + (j * 8) * edged_width / 2 + (i * 8),
+						interpolate8x8_switch2(tmp, b_ref->v, 8 * i, 8 * j,
+												b_dx, b_dy, edged_width / 2, 0),
+						interpolate8x8_switch2(tmp + 8, f_ref->v, 8 * i, 8 * j,
+												dx, dy, edged_width / 2, 0),
+						edged_width / 2);
+}
+
+
+
+void generate_GMCparameters( const int num_wp, const int res,
+						const WARPPOINTS *const warp,
+						const int width, const int height,
+						GMC_DATA *const gmc)
+{
+	const int du0 = warp->duv[0].x;
+	const int dv0 = warp->duv[0].y;
+	const int du1 = warp->duv[1].x;
+	const int dv1 = warp->duv[1].y;
+	const int du2 = warp->duv[2].x;
+	const int dv2 = warp->duv[2].y;
+
+	gmc->W = width;
+	gmc->H = height;
+
+	gmc->rho = 4 - log2bin(res-1);  // = {3,2,1,0} for res={2,4,8,16}
+
+	gmc->alpha = log2bin(gmc->W-1);
+	gmc->Ws = (1 << gmc->alpha);
+
+	gmc->dxF = 16*gmc->Ws + RDIV( 8*gmc->Ws*du1, gmc->W );
+	gmc->dxG = RDIV( 8*gmc->Ws*dv1, gmc->W );
+	gmc->Fo  = (res*du0 + 1) << (gmc->alpha+gmc->rho-1);
+	gmc->Go  = (res*dv0 + 1) << (gmc->alpha+gmc->rho-1);
+
+	if (num_wp==2) {
+		gmc->dyF = -gmc->dxG;
+		gmc->dyG =  gmc->dxF;
+	} else if (num_wp==3) {
+		gmc->beta = log2bin(gmc->H-1);
+		gmc->Hs = (1 << gmc->beta);
+		gmc->dyF =			 RDIV( 8*gmc->Hs*du2, gmc->H );
+		gmc->dyG = 16*gmc->Hs + RDIV( 8*gmc->Hs*dv2, gmc->H );
+		if (gmc->beta > gmc->alpha) {
+			gmc->dxF <<= (gmc->beta - gmc->alpha);
+			gmc->dxG <<= (gmc->beta - gmc->alpha);
+			gmc->alpha = gmc->beta;
+			gmc->Ws = 1<< gmc->beta;
+		} else {
+			gmc->dyF <<= gmc->alpha - gmc->beta;
+			gmc->dyG <<= gmc->alpha - gmc->beta;
+		}
+	}
+
+	gmc->cFo = gmc->dxF + gmc->dyF + (1 << (gmc->alpha+gmc->rho+1));
+	gmc->cFo += 16*gmc->Ws*(du0-1);
+
+	gmc->cGo = gmc->dxG + gmc->dyG + (1 << (gmc->alpha+gmc->rho+1));
+	gmc->cGo += 16*gmc->Ws*(dv0-1);
+}
+
+void
+generate_GMCimage(	const GMC_DATA *const gmc_data, // [input] precalculated data
+					const IMAGE *const pRef,		// [input]
+					const int mb_width,
+					const int mb_height,
+					const int stride,
+					const int stride2,
+					const int fcode, 				// [input] some parameters...
+  					const int32_t quarterpel,		// [input] for rounding avgMV
+					const int reduced_resolution,	// [input] ignored
+					const int32_t rounding,			// [input] for rounding image data
+					MACROBLOCK *const pMBs, 		// [output] average motion vectors
+					IMAGE *const pGMC)				// [output] full warped image
+{
+
+	unsigned int mj,mi;
+	VECTOR avgMV;
+
+	for (mj = 0; mj < (unsigned int)mb_height; mj++)
+		for (mi = 0; mi < (unsigned int)mb_width; mi++) {
+
+			avgMV = generate_GMCimageMB(gmc_data, pRef, mi, mj,
+						stride, stride2, quarterpel, rounding, pGMC);
+
+			pMBs[mj*mb_width+mi].amv.x = gmc_sanitize(avgMV.x, quarterpel, fcode);
+			pMBs[mj*mb_width+mi].amv.y = gmc_sanitize(avgMV.y, quarterpel, fcode);
+			pMBs[mj*mb_width+mi].mcsel = 0; /* until mode decision */
+	}
+}
+
+
+
+#define MLT(i)  (((16-(i))<<16) + (i))
+static const uint32_t MTab[16] = {
+  MLT( 0), MLT( 1), MLT( 2), MLT( 3), MLT( 4), MLT( 5), MLT( 6), MLT(7),
+  MLT( 8), MLT( 9), MLT(10), MLT(11), MLT(12), MLT(13), MLT(14), MLT(15)
+};
+#undef MLT
+
+VECTOR generate_GMCimageMB( const GMC_DATA *const gmc_data,
+							const IMAGE *const pRef,
+							const int mi, const int mj,
+							const int stride,
+							const int stride2,
+							const int quarterpel,
+							const int rounding,
+							IMAGE *const pGMC)
+{
+	const int W = gmc_data->W;
+	const int H = gmc_data->H;
+
+	const int rho = gmc_data->rho;
+	const int alpha = gmc_data->alpha;
+
+	const int rounder = ( 128 - (rounding<<(rho+rho)) ) << 16;
+
+	const int dxF = gmc_data->dxF;
+	const int dyF = gmc_data->dyF;
+	const int dxG = gmc_data->dxG;
+	const int dyG = gmc_data->dyG;
+
+	uint8_t *dstY, *dstU, *dstV;
+
+	int I,J;
+	VECTOR avgMV = {0,0};
+
+	int32_t Fj, Gj;
+
+	dstY = &pGMC->y[(mj*16)*stride+mi*16] + 16;
+
+	Fj = gmc_data->Fo + dyF*mj*16 + dxF*mi*16;
+	Gj = gmc_data->Go + dyG*mj*16 + dxG*mi*16;
+	
+	for (J = 16; J > 0; --J) {
+		int32_t Fi, Gi;
+
+		Fi = Fj; Fj += dyF;
+		Gi = Gj; Gj += dyG;
+		for (I = -16; I < 0; ++I) {
+			int32_t F, G;
+			uint32_t ri, rj;
+
+			F = ( Fi >> (alpha+rho) ) << rho; Fi += dxF;
+			G = ( Gi >> (alpha+rho) ) << rho; Gi += dxG;
+
+			avgMV.x += F;
+			avgMV.y += G;
+
+			ri = MTab[F&15];
+			rj = MTab[G&15];
+
+			F >>= 4;
+			G >>= 4;
+
+			if (F < -1) F = -1;
+			else if (F > W) F = W;
+			if (G< -1) G=-1;
+			else if (G>H) G=H;
+
+			{	 // MMX-like bilinear...
+				const int offset = G*stride + F;
+				uint32_t f0, f1;
+				f0 = pRef->y[ offset +0 ];
+				f0 |= pRef->y[ offset +1 ] << 16;
+				f1 = pRef->y[ offset+stride +0 ];
+				f1 |= pRef->y[ offset+stride +1 ] << 16;
+				f0 = (ri*f0)>>16;
+				f1 = (ri*f1) & 0x0fff0000;
+				f0 |= f1;
+				f0 = ( rj*f0 + rounder ) >> 24;
+
+				dstY[I] = (uint8_t)f0;
+			}
+		}
+		
+		dstY += stride;
+	}
+
+	dstU = &pGMC->u[(mj*8)*stride2+mi*8] + 8;
+	dstV = &pGMC->v[(mj*8)*stride2+mi*8] + 8;
+
+	Fj = gmc_data->cFo + dyF*4 *mj*8 + dxF*4 *mi*8;
+	Gj = gmc_data->cGo + dyG*4 *mj*8 + dxG*4 *mi*8;
 	
+	for (J = 8; J > 0; --J) {
+		int32_t Fi, Gi;
+		Fi = Fj; Fj += 4*dyF;
+		Gi = Gj; Gj += 4*dyG;
+
+		for (I = -8; I < 0; ++I) {
+			int32_t F, G;
+			uint32_t ri, rj;
+
+			F = ( Fi >> (alpha+rho+2) ) << rho; Fi += 4*dxF;
+			G = ( Gi >> (alpha+rho+2) ) << rho; Gi += 4*dxG;
+
+			ri = MTab[F&15];
+			rj = MTab[G&15];
+
+			F >>= 4;
+			G >>= 4;
+
+			if (F < -1) F=-1;
+			else if (F >= W/2) F = W/2;
+			if (G < -1) G = -1;
+			else if (G >= H/2) G = H/2;
+
+			{
+				const int offset = G*stride2 + F;
+				uint32_t f0, f1;
+
+				f0	= pRef->u[ offset		 +0 ];
+				f0 |= pRef->u[ offset		 +1 ] << 16;
+				f1	= pRef->u[ offset+stride2 +0 ];
+				f1 |= pRef->u[ offset+stride2 +1 ] << 16;
+				f0 = (ri*f0)>>16;
+				f1 = (ri*f1) & 0x0fff0000;
+				f0 |= f1;
+				f0 = ( rj*f0 + rounder ) >> 24;
+
+				dstU[I] = (uint8_t)f0;
+
+
+				f0	= pRef->v[ offset		 +0 ];
+				f0 |= pRef->v[ offset		 +1 ] << 16;
+				f1	= pRef->v[ offset+stride2 +0 ];
+				f1 |= pRef->v[ offset+stride2 +1 ] << 16;
+				f0 = (ri*f0)>>16;
+				f1 = (ri*f1) & 0x0fff0000;
+				f0 |= f1;
+				f0 = ( rj*f0 + rounder ) >> 24;
+
+				dstV[I] = (uint8_t)f0;
+			}
+		}
+		dstU += stride2;
+		dstV += stride2;
+	}
+
+
+	avgMV.x -= 16*((256*mi+120)<<4);	// 120 = 15*16/2
+	avgMV.y -= 16*((256*mj+120)<<4);
+
+	avgMV.x = RSHIFT( avgMV.x, (4+7-quarterpel) );
+	avgMV.y = RSHIFT( avgMV.y, (4+7-quarterpel) );
+
+	return avgMV;
+}
+
+
+
+#ifdef OLD_GRUEL_GMC
+void
+generate_GMCparameters(	const int num_wp,			// [input]: number of warppoints
+						const int res, 			// [input]: resolution
+						const WARPPOINTS *const warp, // [input]: warp points
+						const int width, const int height,
+						GMC_DATA *const gmc) 	// [output] precalculated parameters
+{
+
+/* We follow mainly two sources: The original standard, which is ugly, and the
+   thesis from Andreas Dehnhardt, which is much nicer.
+
+	Notation is: indices are written next to the variable,
+				 primes in the standard are denoted by a suffix 'p'.
+	types are   "c"=constant, "i"=input parameter, "f"=calculated, then fixed,
+				"o"=output data, " "=other, "u" = unused, "p"=calc for every pixel
+
+type | variable name  |   ISO name (TeX-style) |  value or range  |  usage
+-------------------------------------------------------------------------------------
+ c   | H			  |   H 				   |  [16 , ?]  	  |  image width (w/o edges)
+ c   | W			  |   W 				   |  [16 , ?]  	  |  image height (w/o edges)
+
+ c   | i0			  |   i_0				   |  0 			  |  ref. point #1, X
+ c   | j0			  |   j_0				   |  0 			  |  ref. point #1, Y
+ c   | i1			  |   i_1				   |  W 			  |  ref. point #2, X
+ c   | j1			  |   j_1				   |  0 			  |  ref. point #2, Y
+ cu  | i2			  |   i_2				   |  0 			  |  ref. point #3, X
+ cu  | i2			  |   j_2				   |  H 			  |  ref. point #3, Y
+
+ i   | du0  		  |   du[0] 			   |  [-16863,16863]  |  warp vector #1, Y
+ i   | dv0  		  |   dv[0] 			   |  [-16863,16863]  |  warp vector #1, Y
+ i   | du1  		  |   du[1] 			   |  [-16863,16863]  |  warp vector #2, Y
+ i   | dv1  		  |   dv[1] 			   |  [-16863,16863]  |  warp vector #2, Y
+ iu  | du2  		  |   du[2] 			   |  [-16863,16863]  |  warp vector #3, Y	
+ iu  | dv2  		  |   dv[2] 			   |  [-16863,16863]  |  warp vector #3, Y
+
+ i   | s			  |   s					|  {2,4,8,16}	  |  interpol. resolution
+ f   | sigma		  |		-			   |  log2(s)		 |  X / s == X >> sigma
+ f   | r			  |   r					|  =16/s		   |  complementary res.
+ f   | rho			|   \rho				 |  log2(r)		 |  X / r == X >> rho
+
+ f   | i0s			|   i'_0				 |				  |
+ f   | j0s			|   j'_0				 |				  |
+ f	 | i1s			|   i'_1				 |				  |
+ f	 | j1s			|   j'_1				 |				  |
+ f	 | i2s			|   i'_2				 |				  |
+ f	 | j2s			|   j'_2				 |				  |
+
+ f   | alpha		  |   \alpha			   |				  |  2^{alpha-1} < W <= 2^alpha
+ f   | beta		   |   \beta				|				  |  2^{beta-1} < H <= 2^beta
+
+ f   | Ws			 |   W'				   | W = 2^{alpha}	|  scaled width
+ f   | Hs			 |   H'				   | W = 2^{beta}	 |  scaled height
+
+ f   | i1ss		   |   i''_1				|  "virtual sprite stuff"
+ f   | j1ss		   |   j''_1				|  "virtual sprite stuff"
+ f   | i2ss		   |   i''_2				|  "virtual sprite stuff"
+ f   | j2ss		   |   j''_2				|  "virtual sprite stuff"
+*/
+
+/* Some calculations are disabled because we only use 2 warppoints at the moment */
+
+	int du0 = warp->duv[0].x;
+	int dv0 = warp->duv[0].y;
+	int du1 = warp->duv[1].x;
+	int dv1 = warp->duv[1].y;
+//	int du2 = warp->duv[2].x;
+//	int dv2 = warp->duv[2].y;
+
+	gmc->num_wp = num_wp;
+
+	gmc->s = res;						/* scaling parameters 2,4,8 or 16 */
+	gmc->sigma = log2bin(res-1);	/* log2bin(15)=4, log2bin(16)=5, log2bin(17)=5  */
+	gmc->r = 16/res;
+	gmc->rho = 4 - gmc->sigma; 		/* = log2bin(r-1) */
+
+	gmc->W = width;
+	gmc->H = height;			/* fixed reference coordinates */
+
+	gmc->alpha = log2bin(gmc->W-1);
+	gmc->Ws= 1<<gmc->alpha;
+
+//	gmc->beta = log2bin(gmc->H-1);
+//	gmc->Hs= 1<<gmc->beta;
+
+//	printf("du0=%d dv0=%d du1=%d dv1=%d s=%d sigma=%d W=%d alpha=%d, Ws=%d, rho=%d\n",du0,dv0,du1,dv1,gmc->s,gmc->sigma,gmc->W,gmc->alpha,gmc->Ws,gmc->rho);
+
+	/* i2s is only needed for num_wp >= 3, etc.  */
+	/* the 's' values are in 1/s pel resolution */
+	gmc->i0s = res/2 * ( du0 );
+	gmc->j0s = res/2 * ( dv0 );
+	gmc->i1s = res/2 * (2*width + du1 + du0 );
+	gmc->j1s = res/2 * ( dv1 + dv0 );
+//	gmc->i2s = res/2 * ( du2 + du0 );
+//	gmc->j2s = res/2 * (2*height + dv2 + dv0 );
+
+	/* i2s and i2ss are only needed for num_wp == 3, etc.  */
+
+	/* the 'ss' values are in 1/16 pel resolution */
+	gmc->i1ss = 16*gmc->Ws + ROUNDED_DIV(((gmc->W-gmc->Ws)*(gmc->r*gmc->i0s) + gmc->Ws*(gmc->r*gmc->i1s - 16*gmc->W)),gmc->W);
+	gmc->j1ss = ROUNDED_DIV( ((gmc->W - gmc->Ws)*(gmc->r*gmc->j0s) + gmc->Ws*gmc->r*gmc->j1s) ,gmc->W );
+
+//	gmc->i2ss = ROUNDED_DIV( ((gmc->H - gmc->Hs)*(gmc->r*gmc->i0s) + gmc->Hs*(gmc->r*gmc->i2s)), gmc->H);
+//	gmc->j2ss = 16*gmc->Hs + ROUNDED_DIV( ((gmc->H-gmc->Hs)*(gmc->r*gmc->j0s) + gmc->Ws*(gmc->r*gmc->j2s - 16*gmc->H)), gmc->H);
+
+	return;
+}
+
+void
+generate_GMCimage(	const GMC_DATA *const gmc_data, 	// [input] precalculated data
+					const IMAGE *const pRef,			// [input]
+					const int mb_width,
+					const int mb_height,
+					const int stride,
+					const int stride2,
+					const int fcode, 					// [input] some parameters...
+  					const int32_t quarterpel,			// [input] for rounding avgMV
+					const int reduced_resolution,		// [input] ignored
+					const int32_t rounding,			// [input] for rounding image data
+					MACROBLOCK *const pMBs, 	// [output] average motion vectors
+					IMAGE *const pGMC)			// [output] full warped image
+{
+
+	unsigned int mj,mi;
+	VECTOR avgMV;
+
+	for (mj = 0;mj < mb_height; mj++)
+	for (mi = 0;mi < mb_width; mi++) {
+		
+		avgMV = generate_GMCimageMB(gmc_data, pRef, mi, mj,
+					stride, stride2, quarterpel, rounding, pGMC);
+
+		pMBs[mj*mb_width+mi].amv.x = gmc_sanitize(avgMV.x, quarterpel, fcode);
+		pMBs[mj*mb_width+mi].amv.y = gmc_sanitize(avgMV.y, quarterpel, fcode);
+		pMBs[mj*mb_width+mi].mcsel = 0; /* until mode decision */
+	}
+}
+
+
+VECTOR generate_GMCimageMB(	const GMC_DATA *const gmc_data, /* [input] all precalc data */
+							const IMAGE *const pRef,		/* [input] */
+							const int mi, const int mj, 	/* [input] MB position  */
+							const int stride,				/* [input] Lumi stride */
+							const int stride2,				/* [input] chroma stride */
+							const int quarterpel, 			/* [input] for rounding of avgMV */
+							const int rounding, 			/* [input] for rounding of imgae data */
+							IMAGE *const pGMC)				/* [outut] generate image */
+
+/*
+type | variable name  |   ISO name (TeX-style) |  value or range  |  usage
+-------------------------------------------------------------------------------------
+ p   | F			  |   F(i,j)			   |				  | pelwise motion vector X in s-th pel
+ p   | G			  |   G(i,j)			   |				  | pelwise motion vector Y in s-th pel
+ p   | Fc			 |   F_c(i,j)			 |				  |
+ p   | Gc			 |   G_c(i,j)			 |				  | same for chroma
+
+ p   | Y00			|   Y_{00}			   |  [0,255*s*s]	 | first: 4 neighbouring Y-values
+ p   | Y01			|   Y_{01}			   |  [0,255]		 | at fullpel position, around the
+ p   | Y10			|   Y_{10}			   |  [0,255*s]	   | position where pelweise MV points to
+ p   | Y11			|   Y_{11}			   |  [0,255]		 | later: bilinear interpol Y-values in Y00
+
+ p   | C00			|   C_{00}			   |  [0,255*s*s]	 | same for chroma Cb and Cr
+ p   | C01			|   C_{01}			   |  [0,255]		 |
+ p   | C10			|   C_{10}			   |  [0,255*s]	   |
+ p   | C11			|   C_{11}			   |  [0,255]		 |
+
+*/
+{
+	const int W = gmc_data->W;
+	const int H = gmc_data->H;
+
+	const int s = gmc_data->s;
+	const int sigma = gmc_data->sigma;
+
+	const int r = gmc_data->r;
+	const int rho = gmc_data->rho;
+
+	const int i0s = gmc_data->i0s;
+	const int j0s = gmc_data->j0s;
+
+	const int i1ss = gmc_data->i1ss;
+	const int j1ss = gmc_data->j1ss;
+//	const int i2ss = gmc_data->i2ss;
+//	const int j2ss = gmc_data->j2ss;
+
+	const int alpha = gmc_data->alpha;
+	const int Ws	= gmc_data->Ws;
+
+//	const int beta  = gmc_data->beta;
+//	const int Hs	= gmc_data->Hs;
+
+	int I,J;
+	VECTOR avgMV = {0,0};
+
+	for (J=16*mj;J<16*(mj+1);J++)
+	for (I=16*mi;I<16*(mi+1);I++)
+	{
+		int F= i0s + ( ((-r*i0s+i1ss)*I + (r*j0s-j1ss)*J + (1<<(alpha+rho-1))) >>  (alpha+rho) );
+		int G= j0s + ( ((-r*j0s+j1ss)*I + (-r*i0s+i1ss)*J + (1<<(alpha+rho-1))) >> (alpha+rho) );
+
+/* this naive implementation (with lots of multiplications) isn't slower (rather faster) than
+   working incremental. Don't ask me why... maybe the whole this is memory bound? */
+
+		const int ri= F & (s-1); // fractional part of pelwise MV X
+		const int rj= G & (s-1); // fractional part of pelwise MV Y
+
+		int Y00,Y01,Y10,Y11;
+
+/* unclipped values are used for avgMV */
+		avgMV.x += F-(I<<sigma);		/* shift position to 1/s-pel, as the MV is */
+		avgMV.y += G-(J<<sigma);		/* TODO: don't do this (of course) */
+
+		F >>= sigma;
+		G >>= sigma;
+
+/* clip values to be in range. Since we have edges, clip to 1 less than lower boundary
+   this way positions F+1/G+1 are still right */
+
+		if (F< -1)
+			F=-1;
+		else if (F>W)
+			F=W;	/* W or W-1 doesn't matter, so save 1 subtract ;-) */
+		if (G< -1)
+			G=-1;
+		else if (G>H)
+			G=H;		/* dito */
+
+		Y00 = pRef->y[ G*stride + F ];				// Lumi values
+		Y01 = pRef->y[ G*stride + F+1 ];
+		Y10 = pRef->y[ G*stride + F+stride ];
+		Y11 = pRef->y[ G*stride + F+stride+1 ];
+
+		/* bilinear interpolation */
+		Y00 = ((s-ri)*Y00 + ri*Y01);
+		Y10 = ((s-ri)*Y10 + ri*Y11);
+		Y00 = ((s-rj)*Y00 + rj*Y10 + s*s/2 - rounding ) >> (sigma+sigma);
+
+		pGMC->y[J*stride+I] = (uint8_t)Y00;										/* output 1 Y-pixel */
+	}
+
+
+/* doing chroma _here_ is even more stupid and slow, because won't be used until Compensation and
+	most likely not even then (only if the block really _is_ GMC)
+*/
+
+	for (J=8*mj;J<8*(mj+1);J++)		/* this plays the role of j_c,i_c in the standard */
+	for (I=8*mi;I<8*(mi+1);I++)		/* For I_c we have to use I_c = 4*i_c+1 ! */
+	{
+		/* same positions for both chroma components, U=Cb and V=Cr */
+		int Fc=((-r*i0s+i1ss)*(4*I+1) + (r*j0s-j1ss)*(4*J+1) +2*Ws*r*i0s
+						-16*Ws +(1<<(alpha+rho+1)))>>(alpha+rho+2);
+	 	int Gc=((-r*j0s+j1ss)*(4*I+1) +(-r*i0s+i1ss)*(4*J+1) +2*Ws*r*j0s
+						-16*Ws +(1<<(alpha+rho+1))) >>(alpha+rho+2);
+
+		const int ri= Fc & (s-1); // fractional part of pelwise MV X
+		const int rj= Gc & (s-1); // fractional part of pelwise MV Y
+
+		int C00,C01,C10,C11;
+
+		Fc >>= sigma;
+		Gc >>= sigma;
+
+		if (Fc< -1)
+			Fc=-1;
+		else if (Fc>=W/2)
+			Fc=W/2;		/* W or W-1 doesn't matter, so save 1 subtraction ;-) */
+		if (Gc< -1)
+			Gc=-1;
+		else if (Gc>=H/2)
+			Gc=H/2;		/* dito */
+
+/* now calculate U data */
+		C00 = pRef->u[ Gc*stride2 + Fc ];				// chroma-value Cb
+		C01 = pRef->u[ Gc*stride2 + Fc+1 ];
+		C10 = pRef->u[ (Gc+1)*stride2 + Fc ];
+		C11 = pRef->u[ (Gc+1)*stride2 + Fc+1 ];
+
+		/* bilinear interpolation */
+		C00 = ((s-ri)*C00 + ri*C01);
+		C10 = ((s-ri)*C10 + ri*C11);
+		C00 = ((s-rj)*C00 + rj*C10 + s*s/2 - rounding ) >> (sigma+sigma);
+
+		pGMC->u[J*stride2+I] = (uint8_t)C00;										/* output 1 U-pixel */
+
+/* now calculate V data */
+		C00 = pRef->v[ Gc*stride2 + Fc ];				// chroma-value Cr
+		C01 = pRef->v[ Gc*stride2 + Fc+1 ];
+		C10 = pRef->v[ (Gc+1)*stride2 + Fc ];
+		C11 = pRef->v[ (Gc+1)*stride2 + Fc+1 ];
+
+		/* bilinear interpolation */
+		C00 = ((s-ri)*C00 + ri*C01);
+		C10 = ((s-ri)*C10 + ri*C11);
+		C00 = ((s-rj)*C00 + rj*C10 + s*s/2 - rounding ) >> (sigma+sigma);
+
+		pGMC->v[J*stride2+I] = (uint8_t)C00;										/* output 1 V-pixel */
+	}
+
+/* The average vector is rounded from 1/s-pel to 1/2 or 1/4 using the '//' operator*/
+
+	avgMV.x = RSHIFT( avgMV.x, (sigma+7-quarterpel) );
+	avgMV.y = RSHIFT( avgMV.y, (sigma+7-quarterpel) );
+
+	/* ^^^^ this is the way MS Reference Software does it */
+
+	return avgMV;	/* clipping to fcode area is done outside! */
 }
 
+#endif