Camera tracking integration

===========================

Stop SAD tracker when error becomes too high.
Maximal allowed error value is controlled in Tracking Settings panel.
I haven't been able to find value which will work for most of cases
so it's now quite stupid value of 0. Currently values of 2-6 gives
quite nice result, but it depends on footage.
Upcoming changes from libmv side related on returning normalized SAD
would help here. Until this, please set max_sad manually.

extern/libmv/libmv-capi.cpp

@@ -327,14 +327,15 @@ void libmv_SADSamplePattern(unsigned char *image, int stride,
 int libmv_SADTrackerTrack(unsigned char *pattern, unsigned char *image, int stride,
 			int width, int height, double *x, double *y)
 {
+	int result;
 	float x2, y2;
 
-	libmv::Track(pattern, image, stride, width, height, &x2, &y2);
+	result = libmv::Track(pattern, image, stride, width, height, &x2, &y2);
 
 	*x= x2;
 	*y= y2;
 
-	return 1;
+	return result;
 }
 
 /* ************ Tracks ************ */

release/scripts/startup/bl_ui/space_clip.py

@@ -519,6 +519,10 @@ class CLIP_PT_track_settings(Panel):
         settings = clip.tracking.settings
 
         layout.prop(settings, "tracker")
+
+        if settings.tracker == "SAD":
+            layout.prop(settings, "max_sad")
+
         layout.prop(settings, "speed")
         layout.prop(settings, "frames_limit")
 

source/blender/blenkernel/intern/tracking.c

@@ -156,6 +156,16 @@ MovieTrackingTrack *BKE_tracking_add_track(MovieTracking *tracking, float x, flo
 	MovieTrackingMarker marker;
 	float pat[2]= {5.5f, 5.5f}, search[2]= {80.5f, 80.5f}; /* TODO: move to default setting? */
 
+	/* XXX: not very nice to have such check here, but it will prevent
+	        complaints about bad default settings for new markers */
+	if(tracking->settings.tracker==TRACKER_SAD) {
+		pat[0]= 8.f;
+		pat[1]= 8.f;
+
+		search[0]= 32.f;
+		search[1]= 32.f;
+	}
+
 	pat[0] /= (float)width;
 	pat[1] /= (float)height;
 
@@ -466,6 +476,7 @@ typedef struct TrackContext {
 	float *patch;			/* keyframed patch */
 
 	/* ** SAD tracker ** */
+	int patsize[2];			/* size of pattern (currently only 16x16 due to libmv side) */
 	unsigned char *pattern;	/* keyframed pattern */
 #endif
 } TrackContext;
@@ -934,6 +945,7 @@ int BKE_tracking_next(MovieTrackingContext *context)
 			}
 			else if(context->settings.tracker==TRACKER_SAD) {
 				unsigned char *image_new;
+				int sad, error;
 
 				if(track_context->pattern==NULL) {
 					unsigned char *image;
@@ -948,7 +960,11 @@ int BKE_tracking_next(MovieTrackingContext *context)
 					warp[0][2]= pos[0];
 					warp[1][2]= pos[1];
 
-					track_context->pattern= MEM_callocN(sizeof(unsigned char)*16*16, "trackking pattern");
+					/* pattern size is hardcoded to 16x16px in libmv */
+					track_context->patsize[0]= 16;
+					track_context->patsize[1]= 16;
+
+					track_context->pattern= MEM_callocN(sizeof(unsigned char)*track_context->patsize[0]*track_context->patsize[1], "trackking pattern");
 					libmv_SADSamplePattern(image, width, warp, track_context->pattern);
 
 					MEM_freeN(image);
@@ -957,7 +973,10 @@ int BKE_tracking_next(MovieTrackingContext *context)
 
 				image_new= acquire_search_bytebuf(ibuf_new, track, marker, &width, &height, pos, origin);
 
-				tracked= libmv_SADTrackerTrack(track_context->pattern, image_new, width, width, height, &x2, &y2);
+				sad= libmv_SADTrackerTrack(track_context->pattern, image_new, width, width, height, &x2, &y2);
+				error= sad/(track_context->patsize[0]*track_context->patsize[1]);
+
+				tracked= error<=context->settings.maxsad;
 
 				MEM_freeN(image_new);
 			}

source/blender/makesdna/DNA_tracking_types.h

@@ -101,10 +101,15 @@ typedef struct MovieTrackingTrack {
 
 typedef struct MovieTrackingSettings {
 	short tracker;	/* tracker to use */
-	short pad;
 
+	/* ** common tracker settings ** */
 	short speed;	/* speed of tracking */
 	short frames_limit;	/* number of frames to be tarcked during single tracking session (if TRACKING_FRAMES_LIMIT is set) */
+
+	/* ** SAD tracker settings ** */
+	short maxsad;	/* max value of sad which is still treated as successful tracking */
+
+	/* ** reconstructionsettings ** */
 	int keyframe1, keyframe2;	/* two keyframes for reconstrution initialization */
 
 	/* ** tool settings ** */

source/blender/makesrna/intern/rna_tracking.c

@@ -245,6 +245,13 @@ static void rna_def_trackingSettings(BlenderRNA *brna)
 	RNA_def_property_enum_items(prop, tracker_items);
 	RNA_def_property_ui_text(prop, "tracker", "Tracking algorithm to use");
 
+	/* limit frames */
+	prop= RNA_def_property(srna, "max_sad", PROP_INT, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+	RNA_def_property_int_sdna(prop, NULL, "maxsad");
+	RNA_def_property_range(prop, 0, 255);
+	RNA_def_property_ui_text(prop, "Max SAD", "Maximum value of SAD whichis still treated as successful tracking");
+
 	/* speed */
 	prop= RNA_def_property(srna, "speed", PROP_ENUM, PROP_NONE);
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);