Rework 2D stabilizator

See this page for motivation and description of concepts:
https://github.com/Ichthyostega/blender/wiki

See this video for UI explanation and demonstration of usage
http://vimeo.com/blenderHack/stabilizerdemo

This proposal attempts to improve usability of Blender's image stabilization
feature for real-world footage esp. with moving and panning camera. It builds
upon the feature tracking to get a measurement of 2D image movement.

  - Use a weighted average of movement contributions (instead of a median).
  - Allow for rotation compensation and zoom (image scale) compensation.
  - Allow to pick a different set of tracks for translation and for
    rotation/zoom.
  - Treat translation / rotation / zoom contributions systematically in a
    similar way.
  - Improve handling of partial tracking data with gaps and varying
    start / end points.
  - Have a user definable anchor frame and interpolate / extrapolate data to
    avoid jumping back to "neutral" position when no tracking data is available.
  - Support for travelling and panning shots by including an //intended//
    position/rotation/zoom ("target position"). The idea is for these parameters
    to be //animated// by the user, in order to supply an smooth, intended
    camera movement. This way, we can keep the image content roughly in frame
    even when moving completely away from the initial view.

A known shortcoming is that the pivot point for rotation compensation is set to
the translation compensated image center. This can produce spurious rotation on
travelling shots, which needs to be compensated manually (by animating the
target rotation parameter). There are several possible ways to address that
problem, yet all of them are considered beyond the scope of this improvement
proposal for now.

Own modifications:

- Restrict line length, it's really handy for split-view editing
- In motion tracking we prefer fully human-readable comments, meaning we
  don't use doxygen with it's weird markup and comments are supposed to
  start with capital and end with a full stop,
- Add explicit comparison of pointer to NULL.

Reviewers: sergey

Subscribers: kusi, kdawg, forest-house, mardy, Samoth, plasmasolutions, willolis, sebastian_k, hype, enetheru, sunboy, jta, leon_cheung

Maniphest Tasks: T49036

Differential Revision: https://developer.blender.org/D583

1 files changed, 19 insertions, 8 deletions

diff --git a/source/blender/makesdna/DNA_tracking_types.h b/source/blender/makesdna/DNA_tracking_types.h
index 9888b735b8b..42b72c1ff93 100644
--- a/source/blender/makesdna/DNA_tracking_types.h
+++ b/source/blender/makesdna/DNA_tracking_types.h
@@ -158,7 +158,10 @@ typedef struct MovieTrackingTrack {
 	 * Used to prevent jumps of the camera when tracks are appearing or
 	 * disappearing.
 	 */
-	float weight, pad;
+	float weight;
+
+	/* track weight especially for 2D stabilization */
+	float weight_stab;
 } MovieTrackingTrack;
 
 typedef struct MovieTrackingPlaneMarker {
@@ -250,19 +253,24 @@ typedef struct MovieTrackingSettings {
 
 typedef struct MovieTrackingStabilization {
 	int flag;
-	int tot_track, act_track;       /* total number and index of active track in list */
+	int tot_track, act_track;       	/* total number of translation tracks and index of active track in list */
+	int tot_rot_track, act_rot_track;	/* total number of rotation tracks and index of active track in list */
 
 	/* 2d stabilization */
 	float maxscale;         /* max auto-scale factor */
-	MovieTrackingTrack *rot_track;  /* track used to stabilize rotation */
+	MovieTrackingTrack *rot_track DNA_DEPRECATED;  /* use TRACK_USE_2D_STAB_ROT on individual tracks instead */
+
+	int anchor_frame;		/* reference point to anchor stabilization offset */
+	float target_pos[2];	/* expected target position of frame after raw stabilization, will be subtracted */
+	float target_rot;       /* expected target rotation of frame after raw stabilization, will be compensated */
+	float scale;			/* zoom factor known to be present on original footage. Also used for autoscale */
 
 	float locinf, scaleinf, rotinf; /* influence on location, scale and rotation */
 
 	int filter;     /* filter used for pixel interpolation */
 
-	/* some pre-computing run-time variables */
-	int ok;                     /* are precomputed values and scaled buf relevant? */
-	float scale;                /* autoscale factor */
+	/* initialization and run-time data */
+	int ok DNA_DEPRECATED;	/* Without effect now, we initialize on every frame. Formerly used for caching of init values */
 } MovieTrackingStabilization;
 
 typedef struct MovieTrackingReconstruction {
@@ -386,7 +394,8 @@ enum {
 	TRACK_USE_2D_STAB       = (1 << 8),
 	TRACK_PREVIEW_GRAYSCALE = (1 << 9),
 	TRACK_DOPE_SEL          = (1 << 10),
-	TRACK_PREVIEW_ALPHA     = (1 << 11)
+	TRACK_PREVIEW_ALPHA     = (1 << 11),
+	TRACK_USE_2D_STAB_ROT   = (1 << 12)
 };
 
 /* MovieTrackingTrack->motion_model */
@@ -452,7 +461,9 @@ enum {
 enum {
 	TRACKING_2D_STABILIZATION   = (1 << 0),
 	TRACKING_AUTOSCALE          = (1 << 1),
-	TRACKING_STABILIZE_ROTATION = (1 << 2)
+	TRACKING_STABILIZE_ROTATION = (1 << 2),
+	TRACKING_STABILIZE_SCALE    = (1 << 3),
+	TRACKING_SHOW_STAB_TRACKS   = (1 << 5)
 };
 
 /* MovieTrackingStrabilization->filter */