/*
* Copyright (C) 2010 Georg Martius <georg.martius@web.de>
* Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* 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.
*
* Algorithm:
* - 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
*
* TODO:
* - 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.
*/
#include "avfilter.h"
#include "libavutil/common.h"
#include "libavutil/mem.h"
#include "libavutil/pixdesc.h"
#include "libavcodec/dsputil.h"
#include "transform.h"
#define CHROMA_WIDTH(link) -((-link->w) >> av_pix_fmt_descriptors[link->format].log2_chroma_w)
#define CHROMA_HEIGHT(link) -((-link->h) >> av_pix_fmt_descriptors[link->format].log2_chroma_h)
enum SearchMethod {
EXHAUSTIVE, ///< Search all possible positions
SMART_EXHAUSTIVE, ///< Search most possible positions (faster)
SEARCH_COUNT
};
typedef struct {
double x; ///< Horizontal shift
double y; ///< Vertical shift
} MotionVector;
typedef struct {
MotionVector vector; ///< Motion vector
double angle; ///< Angle of rotation
double zoom; ///< Zoom percentage
} Transform;
typedef struct {
AVClass av_class;
AVFilterBufferRef *ref; ///< Previous frame
int rx; ///< Maximum horizontal shift
int ry; ///< Maximum vertical shift
enum FillMethod edge; ///< Edge fill method
int blocksize; ///< Size of blocks to compare
int contrast; ///< Contrast threshold
enum SearchMethod search; ///< Motion search method
AVCodecContext *avctx;
DSPContext c; ///< Context providing optimized SAD methods
Transform last; ///< Transform from last frame
int refcount; ///< Number of reference frames (defines averaging window)
FILE *fp;
Transform avg;
int cw; ///< Crop motion search to this box
int ch;
int cx;
int cy;
} DeshakeContext;
static int cmp(const double *a, const double *b)
{
return *a < *b ? -1 : ( *a > *b ? 1 : 0 );
}
/**
* Cleaned mean (cuts off 20% of values to remove outliers and then averages)
*/
static double clean_mean(double *values, int count)
{
double mean = 0;
int cut = count / 5;
int x;
qsort(values, count, sizeof(double), (void*)cmp);
for (x = cut; x < count - cut; x++) {
mean += values[x];
}
return mean / (count - cut * 2);
}
/**
* Find the most likely shift in motion between two frames for a given
* macroblock. Test each block against several shifts given by the rx
* and ry attributes. Searches using a simple matrix of those shifts and
* chooses the most likely shift by the smallest difference in blocks.
*/
static void find_block_motion(DeshakeContext *deshake, uint8_t *src1,
uint8_t *src2, int cx, int cy, int stride,
MotionVector *mv)
{
int x, y;
int diff;
int smallest = INT_MAX;
int tmp, tmp2;
#define CMP(i, j) deshake->c.sad[0](deshake, src1 + cy * stride + cx, \
src2 + (j) * stride + (i), stride, \
deshake->blocksize)
if (deshake->search == EXHAUSTIVE) {
// Compare every possible position - this is sloooow!
for (y = -deshake->ry; y <= deshake->ry; y++) {
for (x = -deshake->rx; x <= deshake->rx; x++) {
diff = CMP(cx - x, cy - y);
if (diff < smallest) {
smallest = diff;
mv->x = x;
mv->y = y;
}
}
}
} else if (deshake->search == SMART_EXHAUSTIVE) {
// Compare every other possible position and find the best match
for (y = -deshake->ry + 1; y < deshake->ry - 2; y += 2) {
for (x = -deshake->rx + 1; x < deshake->rx - 2; x += 2) {
diff = CMP(cx - x, cy - y);
if (diff < smallest) {
smallest = diff;
mv->x = x;
mv->y = y;
}
}
}
// Hone in on the specific best match around the match we found above
tmp = mv->x;
tmp2 = mv->y;
for (y = tmp2 - 1; y <= tmp2 + 1; y++) {
for (x = tmp - 1; x <= tmp + 1; x++) {
if (x == tmp && y == tmp2)
continue;
diff = CMP(cx - x, cy - y);
if (diff < smallest) {
smallest = diff;
mv->x = x;
mv->y = y;
}
}
}
}
if (smallest > 512) {
mv->x = -1;
mv->y = -1;
}
emms_c();
//av_log(NULL, AV_LOG_ERROR, "%d\n", smallest);
//av_log(NULL, AV_LOG_ERROR, "Final: (%d, %d) = %d x %d\n", cx, cy, mv->x, mv->y);
}
/**
* Find the contrast of a given block. When searching for global motion we
* really only care about the high contrast blocks, so using this method we
* can actually skip blocks we don't care much about.
*/
static int block_contrast(uint8_t *src, int x, int y, int stride, int blocksize)
{
int highest = 0;
int lowest = 0;
int i, j, pos;
for (i = 0; i <= blocksize * 2; i++) {
// We use a width of 16 here to match the libavcodec sad functions
for (j = 0; i <= 15; i++) {
pos = (y - i) * stride + (x - j);
if (src[pos] < lowest)
lowest = src[pos];
else if (src[pos] > highest) {
highest = src[pos];
}
}
}
return highest - lowest;
}
/**
* Find the rotation for a given block.
*/
static double block_angle(int x, int y, int cx, int cy, MotionVector *shift)
{
double a1, a2, diff;
a1 = atan2(y - cy, x - cx);
a2 = atan2(y - cy + shift->y, x - cx + shift->x);
diff = a2 - a1;
return (diff > M_PI) ? diff - 2 * M_PI :
(diff < -M_PI) ? diff + 2 * M_PI :
diff;
}
/**
* 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).
*/
static void find_motion(DeshakeContext *deshake, uint8_t *src1, uint8_t *src2,
int width, int height, int stride, Transform *t)
{
int x, y;
MotionVector mv = {0, 0};
int counts[128][128];
int count_max_value = 0;
int contrast;
int pos;
double *angles = av_malloc(sizeof(*angles) * width * height / (16 * deshake->blocksize));
double totalangles = 0;
int center_x = 0, center_y = 0;
double p_x, p_y;
// Reset counts to zero
for (x = 0; x < deshake->rx * 2 + 1; x++) {
for (y = 0; y < deshake->ry * 2 + 1; y++) {
counts[x][y] = 0;
}
}
pos = 0;
// Find motion for every block and store the motion vector in the counts
for (y = deshake->ry; y < height - deshake->ry - (deshake->blocksize * 2); y += deshake->blocksize * 2) {
// We use a width of 16 here to match the libavcodec sad functions
for (x = deshake->rx; x < width - deshake->rx - 16; x += 16) {
// If the contrast is too low, just skip this block as it probably
// won't be very useful to us.
contrast = block_contrast(src2, x, y, stride, deshake->blocksize);
if (contrast > deshake->contrast) {
//av_log(NULL, AV_LOG_ERROR, "%d\n", contrast);
find_block_motion(deshake, src1, src2, x, y, stride, &mv);
if (mv.x != -1 && mv.y != -1) {
counts[(int)(mv.x + deshake->rx)][(int)(mv.y + deshake->ry)] += 1;
if (x > deshake->rx && y > deshake->ry)
angles[pos++] = block_angle(x, y, 0, 0, &mv);
center_x += mv.x;
center_y += mv.y;
}
}
}
}
pos = FFMAX(1, pos);
center_x /= pos;
center_y /= pos;
for (x = 0; x < pos; x++) {
totalangles += angles[x];
}
//av_log(NULL, AV_LOG_ERROR, "Angle: %lf\n", totalangles / (pos - 1));
t->angle = totalangles / (pos - 1);
t->angle = clean_mean(angles, pos);
if (t->angle < 0.001)
t->angle = 0;
// Find the most common motion vector in the frame and use it as the gmv
for (y = deshake->ry * 2; y >= 0; y--) {
for (x = 0; x < deshake->rx * 2 + 1; x++) {
//av_log(NULL, AV_LOG_ERROR, "%5d ", counts[x][y]);
if (counts[x][y] > count_max_value) {
t->vector.x = x - deshake->rx;
t->vector.y = y - deshake->ry;
count_max_value = counts[x][y];
}
}
//av_log(NULL, AV_LOG_ERROR, "\n");
}
p_x = (center_x - width / 2);
p_y = (center_y - height / 2);
t->vector.x += (cos(t->angle)-1)*p_x - sin(t->angle)*p_y;
t->vector.y += sin(t->angle)*p_x + (cos(t->angle)-1)*p_y;
// Clamp max shift & rotation?
t->vector.x = av_clipf(t->vector.x, -deshake->rx * 2, deshake->rx * 2);
t->vector.y = av_clipf(t->vector.y, -deshake->ry * 2, deshake->ry * 2);
t->angle = av_clipf(t->angle, -0.1, 0.1);
//av_log(NULL, AV_LOG_ERROR, "%d x %d\n", avg->x, avg->y);
av_free(angles);
}
static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
{
DeshakeContext *deshake = ctx->priv;
char filename[256] = {0};
deshake->rx = 16;
deshake->ry = 16;
deshake->edge = FILL_MIRROR;
deshake->blocksize = 8;
deshake->contrast = 125;
deshake->search = EXHAUSTIVE;
deshake->refcount = 20;
deshake->cw = -1;
deshake->ch = -1;
deshake->cx = -1;
deshake->cy = -1;
if (args) {
sscanf(args, "%d:%d:%d:%d:%d:%d:%d:%d:%d:%d:%255s",
&deshake->cx, &deshake->cy, &deshake->cw, &deshake->ch,
&deshake->rx, &deshake->ry, (int *)&deshake->edge,
&deshake->blocksize, &deshake->contrast, (int *)&deshake->search, filename);
deshake->blocksize /= 2;
deshake->rx = av_clip(deshake->rx, 0, 64);
deshake->ry = av_clip(deshake->ry, 0, 64);
deshake->edge = av_clip(deshake->edge, FILL_BLANK, FILL_COUNT - 1);
deshake->blocksize = av_clip(deshake->blocksize, 4, 128);
deshake->contrast = av_clip(deshake->contrast, 1, 255);
deshake->search = av_clip(deshake->search, EXHAUSTIVE, SEARCH_COUNT - 1);
}
if (*filename)
deshake->fp = fopen(filename, "w");
if (deshake->fp)
fwrite("Ori x, Avg x, Fin x, Ori y, Avg y, Fin y, Ori angle, Avg angle, Fin angle, Ori zoom, Avg zoom, Fin zoom\n", sizeof(char), 104, deshake->fp);
// Quadword align left edge of box for MMX code, adjust width if necessary
// to keep right margin
if (deshake->cx > 0) {
deshake->cw += deshake->cx - (deshake->cx & ~15);
deshake->cx &= ~15;
}
av_log(ctx, AV_LOG_INFO, "cx: %d, cy: %d, cw: %d, ch: %d, rx: %d, ry: %d, edge: %d blocksize: %d contrast: %d search: %d\n",
deshake->cx, deshake->cy, deshake->cw, deshake->ch,
deshake->rx, deshake->ry, deshake->edge, deshake->blocksize * 2, deshake->contrast, deshake->search);
return 0;
}
static int query_formats(AVFilterContext *ctx)
{
enum PixelFormat pix_fmts[] = {
PIX_FMT_YUV420P, PIX_FMT_YUV422P, PIX_FMT_YUV444P, PIX_FMT_YUV410P,
PIX_FMT_YUV411P, PIX_FMT_YUV440P, PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P,
PIX_FMT_YUVJ444P, PIX_FMT_YUVJ440P, PIX_FMT_NONE
};
avfilter_set_common_pixel_formats(ctx, avfilter_make_format_list(pix_fmts));
return 0;
}
static int config_props(AVFilterLink *link)
{
DeshakeContext *deshake = link->dst->priv;
deshake->ref = NULL;
deshake->last.vector.x = 0;
deshake->last.vector.y = 0;
deshake->last.angle = 0;
deshake->last.zoom = 0;
deshake->avctx = avcodec_alloc_context3(NULL);
dsputil_init(&deshake->c, deshake->avctx);
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
DeshakeContext *deshake = ctx->priv;
avfilter_unref_buffer(deshake->ref);
if (deshake->fp)
fclose(deshake->fp);
}
static void end_frame(AVFilterLink *link)
{
DeshakeContext *deshake = link->dst->priv;
AVFilterBufferRef *in = link->cur_buf;
AVFilterBufferRef *out = link->dst->outputs[0]->out_buf;
Transform t;
float matrix[9];
float alpha = 2.0 / deshake->refcount;
char tmp[256];
Transform orig;
if (deshake->cx < 0 || deshake->cy < 0 || deshake->cw < 0 || deshake->ch < 0) {
// Find the most likely global motion for the current frame
find_motion(deshake, (deshake->ref == NULL) ? in->data[0] : deshake->ref->data[0], in->data[0], link->w, link->h, in->linesize[0], &t);
} else {
uint8_t *src1 = (deshake->ref == NULL) ? in->data[0] : deshake->ref->data[0];
uint8_t *src2 = in->data[0];
deshake->cx = FFMIN(deshake->cx, link->w);
deshake->cy = FFMIN(deshake->cy, link->h);
if ((unsigned)deshake->cx + (unsigned)deshake->cw > link->w) deshake->cw = link->w - deshake->cx;
if ((unsigned)deshake->cy + (unsigned)deshake->ch > link->h) deshake->ch = link->h - deshake->cy;
// Quadword align right margin
deshake->cw &= ~15;
src1 += deshake->cy * in->linesize[0] + deshake->cx;
src2 += deshake->cy * in->linesize[0] + deshake->cx;
find_motion(deshake, src1, src2, deshake->cw, deshake->ch, in->linesize[0], &t);
}
// Copy transform so we can output it later to compare to the smoothed value
orig.vector.x = t.vector.x;
orig.vector.y = t.vector.y;
orig.angle = t.angle;
orig.zoom = t.zoom;
// Generate a one-sided moving exponential average
deshake->avg.vector.x = alpha * t.vector.x + (1.0 - alpha) * deshake->avg.vector.x;
deshake->avg.vector.y = alpha * t.vector.y + (1.0 - alpha) * deshake->avg.vector.y;
deshake->avg.angle = alpha * t.angle + (1.0 - alpha) * deshake->avg.angle;
deshake->avg.zoom = alpha * t.zoom + (1.0 - alpha) * deshake->avg.zoom;
// Remove the average from the current motion to detect the motion that
// is not on purpose, just as jitter from bumping the camera
t.vector.x -= deshake->avg.vector.x;
t.vector.y -= deshake->avg.vector.y;
t.angle -= deshake->avg.angle;
t.zoom -= deshake->avg.zoom;
// Invert the motion to undo it
t.vector.x *= -1;
t.vector.y *= -1;
t.angle *= -1;
// Write statistics to file
if (deshake->fp) {
snprintf(tmp, 256, "%f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f\n", orig.vector.x, deshake->avg.vector.x, t.vector.x, orig.vector.y, deshake->avg.vector.y, t.vector.y, orig.angle, deshake->avg.angle, t.angle, orig.zoom, deshake->avg.zoom, t.zoom);
fwrite(tmp, sizeof(char), strlen(tmp), deshake->fp);
}
// Turn relative current frame motion into absolute by adding it to the
// last absolute motion
t.vector.x += deshake->last.vector.x;
t.vector.y += deshake->last.vector.y;
t.angle += deshake->last.angle;
t.zoom += deshake->last.zoom;
// Shrink motion by 10% to keep things centered in the camera frame
t.vector.x *= 0.9;
t.vector.y *= 0.9;
t.angle *= 0.9;
// Store the last absolute motion information
deshake->last.vector.x = t.vector.x;
deshake->last.vector.y = t.vector.y;
deshake->last.angle = t.angle;
deshake->last.zoom = t.zoom;
// Generate a luma transformation matrix
avfilter_get_matrix(t.vector.x, t.vector.y, t.angle, 1.0 + t.zoom / 100.0, matrix);
// Transform the luma plane
avfilter_transform(in->data[0], out->data[0], in->linesize[0], out->linesize[0], link->w, link->h, matrix, INTERPOLATE_BILINEAR, deshake->edge);
// Generate a chroma transformation matrix
avfilter_get_matrix(t.vector.x / (link->w / CHROMA_WIDTH(link)), t.vector.y / (link->h / CHROMA_HEIGHT(link)), t.angle, 1.0 + t.zoom / 100.0, matrix);
// Transform the chroma planes
avfilter_transform(in->data[1], out->data[1], in->linesize[1], out->linesize[1], CHROMA_WIDTH(link), CHROMA_HEIGHT(link), matrix, INTERPOLATE_BILINEAR, deshake->edge);
avfilter_transform(in->data[2], out->data[2], in->linesize[2], out->linesize[2], CHROMA_WIDTH(link), CHROMA_HEIGHT(link), matrix, INTERPOLATE_BILINEAR, deshake->edge);
// Store the current frame as the reference frame for calculating the
// motion of the next frame
if (deshake->ref != NULL)
avfilter_unref_buffer(deshake->ref);
// Cleanup the old reference frame
deshake->ref = in;
// Draw the transformed frame information
avfilter_draw_slice(link->dst->outputs[0], 0, link->h, 1);
avfilter_end_frame(link->dst->outputs[0]);
avfilter_unref_buffer(out);
}
static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
{
}
AVFilter avfilter_vf_deshake = {
.name = "deshake",
.description = NULL_IF_CONFIG_SMALL("Stabilize shaky video."),
.priv_size = sizeof(DeshakeContext),
.init = init,
.uninit = uninit,
.query_formats = query_formats,
.inputs = (const AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.draw_slice = draw_slice,
.end_frame = end_frame,
.config_props = config_props,
.min_perms = AV_PERM_READ, },
{ .name = NULL}},
.outputs = (const AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO, },
{ .name = NULL}},
};