| ||AVFILTER_DEFINE_CLASS (deshake)|
|static int ||cmp (const double *a, const double *b)|
|static double ||clean_mean (double *values, int count)|
| ||Cleaned mean (cuts off 20% of values to remove outliers and then averages) |
|static void ||find_block_motion (DeshakeContext *deshake, uint8_t *src1, uint8_t *src2, int cx, int cy, int stride, IntMotionVector *mv)|
| ||Find the most likely shift in motion between two frames for a given macroblock. |
|static int ||block_contrast (uint8_t *src, int x, int y, int stride, int blocksize)|
| ||Find the contrast of a given block. |
|static double ||block_angle (int x, int y, int cx, int cy, IntMotionVector *shift)|
| ||Find the rotation for a given block. |
|static void ||find_motion (DeshakeContext *deshake, uint8_t *src1, uint8_t *src2, int width, int height, int stride, Transform *t)|
| ||Find the estimated global motion for a scene given the most likely shift for each block in the frame. |
|static int ||deshake_transform_c (AVFilterContext *ctx, int width, int height, int cw, int ch, const float *matrix_y, const float *matrix_uv, enum InterpolateMethod interpolate, enum FillMethod fill, AVFrame *in, AVFrame *out)|
|static av_cold int ||init (AVFilterContext *ctx)|
|static int ||query_formats (AVFilterContext *ctx)|
|static int ||config_props (AVFilterLink *link)|
|static av_cold void ||uninit (AVFilterContext *ctx)|
|static int ||filter_frame (AVFilterLink *link, AVFrame *in)|
fast deshake / depan video filter
SAD block-matching motion compensation to fix small changes in horizontal and/or vertical shift. This filter helps remove camera shake from hand-holding a camera, bumping a tripod, moving on a vehicle, etc.
- For each frame with one previous reference frame
- For each block in the frame
- If contrast > threshold then find likely motion vector
- For all found motion vectors
- Find most common, store as global motion vector
- Find most likely rotation angle
- Transform image along global motion
- Fill frame edges based on previous/next reference frames
- Fill frame edges by stretching image near the edges?
- Can this be done quickly and look decent?
Dark Shikari links to http://wiki.videolan.org/SoC_x264_2010#GPU_Motion_Estimation_2 for an algorithm similar to what could be used here to get the gmv It requires only a couple diamond searches + fast downscaling
Special thanks to Jason Kotenko for his help with the algorithm and my inability to see simple errors in C code.
Definition in file vf_deshake.c.
Find the estimated global motion for a scene given the most likely shift for each block in the frame.
The global motion is estimated to be the same as the motion from most blocks in the frame, so if most blocks move one pixel to the right and two pixels down, this would yield a motion vector (1, -2).
Definition at line 240 of file vf_deshake.c.
Referenced by filter_frame().