[FFmpeg-cvslog] libavfilter: add deshake filter

danielgtaylor git at videolan.org
Tue Oct 4 02:29:51 CEST 2011


ffmpeg | branch: master | danielgtaylor <dan at programmer-art.org> | Tue Oct  4 01:31:18 2011 +0200| [0cc2ed4a206551d3c1def87e6b40c67bc1caf294] | committer: Michael Niedermayer

libavfilter: add deshake filter

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0cc2ed4a206551d3c1def87e6b40c67bc1caf294
---

 libavfilter/Makefile     |    4 +-
 libavfilter/allfilters.c |    1 +
 libavfilter/vf_deshake.c |  521 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 525 insertions(+), 1 deletions(-)

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 5fc0e48..d35020f 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -18,7 +18,8 @@ OBJS = allfilters.o                                                     \
        defaults.o                                                       \
        drawutils.o                                                      \
        formats.o                                                        \
-       graphparser.o                                                    \
+       graphparser.o							\
+       transform.o                                                      \
 
 OBJS-$(CONFIG_AVCODEC)                       += avcodec.o
 
@@ -41,6 +42,7 @@ OBJS-$(CONFIG_COPY_FILTER)                   += vf_copy.o
 OBJS-$(CONFIG_CROP_FILTER)                   += vf_crop.o
 OBJS-$(CONFIG_CROPDETECT_FILTER)             += vf_cropdetect.o
 OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o
+OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o
 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o
 OBJS-$(CONFIG_DRAWTEXT_FILTER)               += vf_drawtext.o
 OBJS-$(CONFIG_FADE_FILTER)                   += vf_fade.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index dcabb68..2bb42a1 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -53,6 +53,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER (CROP,        crop,        vf);
     REGISTER_FILTER (CROPDETECT,  cropdetect,  vf);
     REGISTER_FILTER (DELOGO,      delogo,      vf);
+    REGISTER_FILTER (DESHAKE,     deshake,     vf);
     REGISTER_FILTER (DRAWBOX,     drawbox,     vf);
     REGISTER_FILTER (DRAWTEXT,    drawtext,    vf);
     REGISTER_FILTER (FADE,        fade,        vf);
diff --git a/libavfilter/vf_deshake.c b/libavfilter/vf_deshake.c
new file mode 100644
index 0000000..838a28a
--- /dev/null
+++ b/libavfilter/vf_deshake.c
@@ -0,0 +1,521 @@
+/*
+ * Copyright (C) 2010 Georg Martius <georg.martius at web.de>
+ * Copyright (C) 2010 Daniel G. Taylor <dan at 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 libavfilter/vf_deshake.c
+ * 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 {
+    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;
+} DeshakeContext;
+
+static int cmp(void const *ca, void const *cb)
+{
+    double *a = (double *) ca;
+    double *b = (double *) cb;
+    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), 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[1200];
+    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);
+}
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+    DeshakeContext *deshake = ctx->priv;
+
+    deshake->rx = 16;
+    deshake->ry = 16;
+    deshake->edge = FILL_BLANK;
+    deshake->blocksize = 8;
+    deshake->contrast = 125;
+    deshake->search = EXHAUSTIVE;
+    deshake->refcount = 20;
+    deshake->fp = fopen("stats.txt", "w");
+    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);
+
+    if (args) {
+        sscanf(args, "%d:%d:%d:%d:%d:%d", &deshake->rx, &deshake->ry, (int *)&deshake->edge,
+               &deshake->blocksize, &deshake->contrast, (int *)&deshake->search);
+
+        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);
+    }
+
+    av_log(ctx, AV_LOG_INFO, "rx: %d, ry: %d, edge: %d blocksize: %d contrast: %d search: %d\n",
+           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);
+    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;
+    static float matrix[9];
+    static Transform avg = {
+        .vector = {
+            .x = 0,
+            .y = 0
+        },
+        .angle = 0,
+        .zoom = 0.0f
+    };
+    float alpha = 2.0 / deshake->refcount;
+    char tmp[256];
+    Transform orig;
+
+    // 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);
+
+    // 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
+    avg.vector.x = alpha * t.vector.x + (1.0 - alpha) * avg.vector.x;
+    avg.vector.y = alpha * t.vector.y + (1.0 - alpha) * avg.vector.y;
+    avg.angle = alpha * t.angle + (1.0 - alpha) * avg.angle;
+    avg.zoom = alpha * t.zoom + (1.0 - alpha) * 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 -= avg.vector.x;
+    t.vector.y -= avg.vector.y;
+    t.angle -= avg.angle;
+    t.zoom -= avg.zoom;
+
+    // Invert the motion to undo it
+    t.vector.x *= -1;
+    t.vector.y *= -1;
+    t.angle *= -1;
+
+    // Write statistics to file
+    snprintf(tmp, 256, "%f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f, %f\n", orig.vector.x, avg.vector.x, t.vector.x, orig.vector.y, avg.vector.y, t.vector.y, orig.angle, avg.angle, t.angle, orig.zoom, 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    = (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   = (AVFilterPad[]) {{ .name             = "default",
+                                    .type             = AVMEDIA_TYPE_VIDEO, },
+                                  { .name = NULL}},
+};



More information about the ffmpeg-cvslog mailing list