/*
  * 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 "formats.h"

 #include "internal.h"

 #include "video.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_desc_get(link->format)->log2_chroma_w)
 #define CHROMA_HEIGHT(link) -((-link->h) >> av_pix_fmt_desc_get(link->format)->log2_chroma_h)

 
 enum SearchMethod {

     EXHAUSTIVE,        ///< Search all possible positions
     SMART_EXHAUSTIVE,  ///< Search most possible positions (faster)

     SEARCH_COUNT
 };
 
 typedef struct {

     int x;             ///< Horizontal shift
     int y;             ///< Vertical shift
 } IntMotionVector;
 
 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

     int edge;                  ///< Edge fill method

     int blocksize;             ///< Size of blocks to compare
     int contrast;              ///< Contrast threshold

     int 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,

                               IntMotionVector *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, IntMotionVector *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;

     IntMotionVector 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));

     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[mv.x + deshake->rx][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;
                 }
             }
         }
     }
 

     if (pos) {
          center_x /= pos;
          center_y /= pos;
          t->angle = clean_mean(angles, pos);
          if (t->angle < 0.001)
               t->angle = 0;
     } else {
          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 / 2.0);
     p_y = (center_y - height / 2.0);

     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)

 {
     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, &deshake->edge,
                &deshake->blocksize, &deshake->contrast, &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_VERBOSE, "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)
 {

     static const enum AVPixelFormat pix_fmts[] = {

         AV_PIX_FMT_YUV420P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV440P,  AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_NONE

     };
 

     ff_set_common_formats(ctx, ff_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);

     if (deshake->avctx)
         avcodec_close(deshake->avctx);

     av_freep(&deshake->avctx);

 }
 

 static int filter_frame(AVFilterLink *link, AVFilterBufferRef *in)

 {
     DeshakeContext *deshake = link->dst->priv;

     AVFilterLink *outlink = link->dst->outputs[0];
     AVFilterBufferRef *out;

     Transform t = {{0},0}, orig = {{0},0};

     float matrix[9];

     float alpha = 2.0 / deshake->refcount;
     char tmp[256];
 

     out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
     if (!out) {
         avfilter_unref_bufferp(&in);
         return AVERROR(ENOMEM);
     }
     avfilter_copy_buffer_ref_props(out, in);
 

     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);
 

     // Cleanup the old reference frame

     avfilter_unref_buffer(deshake->ref);

     // Store the current frame as the reference frame for calculating the
     // motion of the next frame

     deshake->ref = in;
 

     return ff_filter_frame(outlink, out);

 }
 

 static const AVFilterPad deshake_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,

         .filter_frame = filter_frame,

         .config_props = config_props,
         .min_perms    = AV_PERM_READ | AV_PERM_PRESERVE,
     },
     { NULL }
 };
 
 static const AVFilterPad deshake_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 

 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        = deshake_inputs,
     .outputs       = deshake_outputs,

 };