--- mbtransquant.c	2002/08/19 19:19:40	1.10
+++ mbtransquant.c	2002/11/12 16:05:27	1.11.2.5
@@ -65,12 +65,12 @@
 #include "../quant/quant_h263.h"
 #include "../encoder.h"
 
+MBFIELDTEST_PTR MBFieldTest;
+
 #define MIN(X, Y) ((X)<(Y)?(X):(Y))
 #define MAX(X, Y) ((X)>(Y)?(X):(Y))
 
-#define TOOSMALL_LIMIT 3		/* skip blocks having a coefficient sum below this value */
-
-/* this isnt pretty, but its better than 20 ifdefs */
+#define TOOSMALL_LIMIT 	1	/* skip blocks having a coefficient sum below this value */
 
 void
 MBTransQuantIntra(const MBParam * pParam,
@@ -105,7 +105,9 @@
 
 	start_timer();
 	pMB->field_dct = 0;
-	if ((frame->global_flags & XVID_INTERLACING)) {
+	if ((frame->global_flags & XVID_INTERLACING) &&
+		(x_pos>0) && (x_pos<pParam->mb_width-1) &&
+		(y_pos>0) && (y_pos<pParam->mb_height-1)) {
 		pMB->field_dct = MBDecideFieldDCT(data);
 	}
 	stop_interlacing_timer();
@@ -183,12 +185,16 @@
 
 	start_timer();
 	pMB->field_dct = 0;
-	if ((frame->global_flags & XVID_INTERLACING)) {
+	if ((frame->global_flags & XVID_INTERLACING) &&
+		(x_pos>0) && (x_pos<pParam->mb_width-1) &&
+		(y_pos>0) && (y_pos<pParam->mb_height-1)) {
 		pMB->field_dct = MBDecideFieldDCT(data);
 	}
 	stop_interlacing_timer();
 
 	for (i = 0; i < 6; i++) {
+		uint32_t increase_limit = (iQuant == 1) ? 1 : 0;
+
 		/* 
 		 *  no need to transfer 8->16-bit
 		 * (this is performed already in motion compensation) 
@@ -207,7 +213,7 @@
 			stop_quant_timer();
 		}
 
-		if ((sum >= TOOSMALL_LIMIT) || (qcoeff[i*64] != 0) ||
+		if ((sum >= TOOSMALL_LIMIT + increase_limit) || (qcoeff[i*64] != 0) ||
 			(qcoeff[i*64+1] != 0) || (qcoeff[i*64+8] != 0)) {
 
 			if (pParam->m_quant_type == H263_QUANT) {
@@ -572,13 +578,27 @@
 
 
 
-/* if sum(diff between field lines) < sum(diff between frame lines), use field dct */
+/* permute block and return field dct choice */
 
 
 uint32_t
 MBDecideFieldDCT(int16_t data[6 * 64])
 {
+	uint32_t field = MBFieldTest(data);
 
+	if (field) {
+		MBFrameToField(data);
+	}
+
+	return field;
+}
+
+
+/* if sum(diff between field lines) < sum(diff between frame lines), use field dct */
+
+uint32_t
+MBFieldTest_c(int16_t data[6 * 64])
+{
 	const uint8_t blocks[] =
 		{ 0 * 64, 0 * 64, 0 * 64, 0 * 64, 2 * 64, 2 * 64, 2 * 64, 2 * 64 };
 	const uint8_t lines[] = { 0, 16, 32, 48, 0, 16, 32, 48 };
@@ -612,11 +632,7 @@
 		}
 	}
 
-	if (frame > field) {
-		MBFrameToField(data);
-	}
-
-	return (frame > field);
+	return (frame >= (field + 350));
 }