--- mbprediction.c	2004/03/22 22:36:24	1.14
+++ mbprediction.c	2004/06/12 13:02:12	1.16
@@ -20,7 +20,7 @@
  *  along with this program ; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  *
- * $Id: mbprediction.c,v 1.14 2004/03/22 22:36:24 edgomez Exp $
+ * $Id: mbprediction.c,v 1.16 2004/06/12 13:02:12 edgomez Exp $
  *
  ****************************************************************************/
 
@@ -67,7 +67,7 @@
 			 uint32_t current_quant,
 			 int32_t iDcScaler,
 			 int16_t predictors[8],
-			const int bound)
+			 const int bound)
 
 {
 	const int mbpos = (y * mb_width) + x;
@@ -184,11 +184,8 @@
 		break;
 	}
 
-	/*
-	 * determine ac prediction direction & ac/dc predictor place rescaled ac/dc
-	 * predictions into predictors[] for later use
-	 */
-
+	/* determine ac prediction direction & ac/dc predictor place rescaled ac/dc
+	 * predictions into predictors[] for later use */
 	if (abs(pLeft[0] - pDiag[0]) < abs(pDiag[0] - pTop[0])) {
 		*acpred_direction = 1;	/* vertical */
 		predictors[0] = DIV_DIV(pTop[0], iDcScaler);
@@ -209,13 +206,17 @@
    store current coeffs to pred_values[] for future prediction
 */
 
+/* Up to this version, no DC clipping was performed, so we try to be backward
+ * compatible to avoid artifacts */
+#define BS_VERSION_BUGGY_DC_CLIPPING 34
 
 void
 add_acdc(MACROBLOCK * pMB,
 		 uint32_t block,
 		 int16_t dct_codes[64],
 		 uint32_t iDcScaler,
-		 int16_t predictors[8])
+		 int16_t predictors[8],
+		 const int bsversion)
 {
 	uint8_t acpred_direction = pMB->acpred_directions[block];
 	int16_t *pCurrent = pMB->pred_values[block];
@@ -224,7 +225,10 @@
 	DPRINTF(XVID_DEBUG_COEFF,"predictor[0] %i\n", predictors[0]);
 
 	dct_codes[0] += predictors[0];	/* dc prediction */
-	pCurrent[0] = dct_codes[0] * iDcScaler;
+	pCurrent[0] = dct_codes[0]*iDcScaler;
+	if (!bsversion || bsversion > BS_VERSION_BUGGY_DC_CLIPPING) {
+		pCurrent[0] = CLIP(pCurrent[0], -2048, 2047);
+	}
 
 	if (acpred_direction == 1) {
 		for (i = 1; i < 8; i++) {
@@ -281,6 +285,7 @@
 	/* store current coeffs to pred_values[] for future prediction */
 
 	pCurrent[0] = qcoeff[0] * iDcScaler;
+	pCurrent[0] = CLIP(pCurrent[0], -2048, 2047);
 	for (i = 1; i < 8; i++) {
 		pCurrent[i] = qcoeff[i];
 		pCurrent[i + 7] = qcoeff[i * 8];
@@ -337,6 +342,7 @@
 
 	/* store current coeffs to pred_values[] for future prediction */
 	pCurrent[0] = qcoeff[0] * iDcScaler;
+	pCurrent[0] = CLIP(pCurrent[0], -2048, 2047);
 	for (i = 1; i < 8; i++) {
 		pCurrent[i] = qcoeff[i];
 		pCurrent[i + 7] = qcoeff[i * 8];