[XviD-devel] [PATCH proposal] Feedback required

[Edouard Gomez]

I propose this patch. As it touches to time code, i'd prefer
everyone test it before it goes to CVS.

What does it fix:
* Code in bitstream.c did assume like reference frames could
  not be distant from each other more than from 1s (all maths
  were done modulo the 1s time increments).
* bframe direct mode was a bit strange, mvs weren't
  interpolated right, formulas fixed, all seems to work as it
  should have been.

Please test.

NB: the code for time in bitstream was enclosed in #if 0
#endif blocks, so i guess it's not the first time someone
plays with this part of the code.

-- 
Edouard Gomez
-------------- next part --------------
* looking for ed.gomez at free.fr--2004-1/xvidcore--stable--1.0--patch-36 to compare with
* comparing to ed.gomez at free.fr--2004-1/xvidcore--stable--1.0--patch-36
M  src/decoder.c
M  src/decoder.h
M  src/bitstream/bitstream.c

* modified files

--- orig/src/bitstream/bitstream.c
+++ mod/src/bitstream/bitstream.c
@@ -814,23 +814,12 @@
 			if (coding_type != B_VOP) {
 				dec->last_time_base = dec->time_base;
 				dec->time_base += time_incr;
-				dec->time = time_increment;
-
-#if 0
-					dec->time_base * dec->time_inc_resolution +
-					time_increment;
-#endif
-					dec->time_pp = (uint32_t)
-						(dec->time_inc_resolution + dec->time - dec->last_non_b_time)%dec->time_inc_resolution;
+				dec->time = dec->time_base*dec->time_inc_resolution + time_increment;
+				dec->time_pp = (int32_t)(dec->time - dec->last_non_b_time);
 				dec->last_non_b_time = dec->time;
 			} else {
-				dec->time = time_increment;
-#if 0
-					(dec->last_time_base +
-					 time_incr) * dec->time_inc_resolution + time_increment;
-#endif
-				dec->time_bp = (uint32_t)
-					(dec->time_inc_resolution + dec->last_non_b_time - dec->time)%dec->time_inc_resolution;
+				dec->time = (dec->last_time_base + time_incr)*dec->time_inc_resolution + time_increment;
+				dec->time_bp = dec->time_pp - (int32_t)(dec->last_non_b_time - dec->time);
 			}
 			DPRINTF(XVID_DEBUG_HEADER,"time_pp=%i\n", dec->time_pp);
 			DPRINTF(XVID_DEBUG_HEADER,"time_bp=%i\n", dec->time_bp);
@@ -1023,7 +1012,7 @@
 				else
 					sscanf(tmp, "XviD%d", &dec->bs_version);
 
-				DPRINTF(XVID_DEBUG_HEADER, "xvid bitstream version=%i", dec->bs_version);
+				DPRINTF(XVID_DEBUG_HEADER, "xvid bitstream version=%i\n", dec->bs_version);
 			}
 
 		    /* divx detection */


--- orig/src/decoder.c
+++ mod/src/decoder.c
@@ -1215,7 +1215,6 @@
 	uint32_t x, y;
 	VECTOR mv;
 	const VECTOR zeromv = {0,0};
-	const int64_t TRB = dec->time_pp - dec->time_bp, TRD = dec->time_pp;
 	int i;
 
 	start_timer();
@@ -1310,14 +1309,15 @@
 
 			case MODE_DIRECT_NONE_MV:
 				for (i = 0; i < 4; i++) {
-					mb->mvs[i].x = (int32_t) ((TRB * last_mb->mvs[i].x) / TRD + mv.x);
-					mb->b_mvs[i].x = (int32_t) ((mv.x == 0)
-									? ((TRB - TRD) * last_mb->mvs[i].x) / TRD
-									: mb->mvs[i].x - last_mb->mvs[i].x);
-					mb->mvs[i].y = (int32_t) ((TRB * last_mb->mvs[i].y) / TRD + mv.y);
-					mb->b_mvs[i].y = (int32_t) ((mv.y == 0)
-									? ((TRB - TRD) * last_mb->mvs[i].y) / TRD
-									: mb->mvs[i].y - last_mb->mvs[i].y);
+					mb->mvs[i].x = last_mb->mvs[i].x*dec->time_bp/dec->time_pp + mv.x;
+					mb->mvs[i].y = last_mb->mvs[i].y*dec->time_bp/dec->time_pp + mv.y;
+					
+					mb->b_mvs[i].x = (mv.x)
+						?  mb->mvs[i].x - last_mb->mvs[i].x
+						: last_mb->mvs[i].x*(dec->time_bp - dec->time_pp)/dec->time_pp;
+					mb->b_mvs[i].y = (mv.y)
+						? mb->mvs[i].y - last_mb->mvs[i].y
+						: last_mb->mvs[i].y*(dec->time_bp - dec->time_pp)/dec->time_pp;
 				}
 
 				decoder_bf_interpolate_mbinter(dec, dec->refn[1], dec->refn[0],


--- orig/src/decoder.h
+++ mod/src/decoder.h
@@ -145,8 +145,8 @@
 	int64_t time_base;
 	int64_t last_time_base;
 	int64_t last_non_b_time;
-	uint32_t time_pp;
-	uint32_t time_bp;
+	int32_t time_pp;
+	int32_t time_bp;
 	uint32_t low_delay;			/* low_delay flage (1 means no B_VOP) */
 	uint32_t low_delay_default;	/* default value for low_delay flag */