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  1. /*
  2.  * Copyright (C) 2010 Georg Martius <georg.martius@web.de>
  3.  * Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. /**
  23.  * @file
  24.  * fast deshake / depan video filter
  25.  *
  26.  * SAD block-matching motion compensation to fix small changes in
  27.  * horizontal and/or vertical shift. This filter helps remove camera shake
  28.  * from hand-holding a camera, bumping a tripod, moving on a vehicle, etc.
  29.  *
  30.  * Algorithm:
  31.  *   - For each frame with one previous reference frame
  32.  *       - For each block in the frame
  33.  *           - If contrast > threshold then find likely motion vector
  34.  *       - For all found motion vectors
  35.  *           - Find most common, store as global motion vector
  36.  *       - Find most likely rotation angle
  37.  *       - Transform image along global motion
  38.  *
  39.  * TODO:
  40.  *   - Fill frame edges based on previous/next reference frames
  41.  *   - Fill frame edges by stretching image near the edges?
  42.  *       - Can this be done quickly and look decent?
  43.  *
  44.  * Dark Shikari links to http://wiki.videolan.org/SoC_x264_2010#GPU_Motion_Estimation_2
  45.  * for an algorithm similar to what could be used here to get the gmv
  46.  * It requires only a couple diamond searches + fast downscaling
  47.  *
  48.  * Special thanks to Jason Kotenko for his help with the algorithm and my
  49.  * inability to see simple errors in C code.
  50.  */
  51.  
  52. #include "avfilter.h"
  53. #include "formats.h"
  54. #include "internal.h"
  55. #include "video.h"
  56. #include "libavutil/common.h"
  57. #include "libavutil/mem.h"
  58. #include "libavutil/opt.h"
  59. #include "libavutil/pixdesc.h"
  60. #include "libavcodec/dsputil.h"
  61.  
  62. #include "deshake.h"
  63. #include "deshake_opencl.h"
  64.  
  65. #define CHROMA_WIDTH(link)  -((-link->w) >> av_pix_fmt_desc_get(link->format)->log2_chroma_w)
  66. #define CHROMA_HEIGHT(link) -((-link->h) >> av_pix_fmt_desc_get(link->format)->log2_chroma_h)
  67.  
  68. #define OFFSET(x) offsetof(DeshakeContext, x)
  69. #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
  70.  
  71. #define MAX_R 64
  72.  
  73. static const AVOption deshake_options[] = {
  74.     { "x", "set x for the rectangular search area",      OFFSET(cx), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
  75.     { "y", "set y for the rectangular search area",      OFFSET(cy), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
  76.     { "w", "set width for the rectangular search area",  OFFSET(cw), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
  77.     { "h", "set height for the rectangular search area", OFFSET(ch), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
  78.     { "rx", "set x for the rectangular search area",     OFFSET(rx), AV_OPT_TYPE_INT, {.i64=16}, 0, MAX_R, .flags = FLAGS },
  79.     { "ry", "set y for the rectangular search area",     OFFSET(ry), AV_OPT_TYPE_INT, {.i64=16}, 0, MAX_R, .flags = FLAGS },
  80.     { "edge", "set edge mode", OFFSET(edge), AV_OPT_TYPE_INT, {.i64=FILL_MIRROR}, FILL_BLANK, FILL_COUNT-1, FLAGS, "edge"},
  81.         { "blank",    "fill zeroes at blank locations",         0, AV_OPT_TYPE_CONST, {.i64=FILL_BLANK},    INT_MIN, INT_MAX, FLAGS, "edge" },
  82.         { "original", "original image at blank locations",      0, AV_OPT_TYPE_CONST, {.i64=FILL_ORIGINAL}, INT_MIN, INT_MAX, FLAGS, "edge" },
  83.         { "clamp",    "extruded edge value at blank locations", 0, AV_OPT_TYPE_CONST, {.i64=FILL_CLAMP},    INT_MIN, INT_MAX, FLAGS, "edge" },
  84.         { "mirror",   "mirrored edge at blank locations",       0, AV_OPT_TYPE_CONST, {.i64=FILL_MIRROR},   INT_MIN, INT_MAX, FLAGS, "edge" },
  85.     { "blocksize", "set motion search blocksize",       OFFSET(blocksize), AV_OPT_TYPE_INT, {.i64=8},   4, 128, .flags = FLAGS },
  86.     { "contrast",  "set contrast threshold for blocks", OFFSET(contrast),  AV_OPT_TYPE_INT, {.i64=125}, 1, 255, .flags = FLAGS },
  87.     { "search",  "set search strategy", OFFSET(search), AV_OPT_TYPE_INT, {.i64=EXHAUSTIVE}, EXHAUSTIVE, SEARCH_COUNT-1, FLAGS, "smode" },
  88.         { "exhaustive", "exhaustive search",      0, AV_OPT_TYPE_CONST, {.i64=EXHAUSTIVE},       INT_MIN, INT_MAX, FLAGS, "smode" },
  89.         { "less",       "less exhaustive search", 0, AV_OPT_TYPE_CONST, {.i64=SMART_EXHAUSTIVE}, INT_MIN, INT_MAX, FLAGS, "smode" },
  90.     { "filename", "set motion search detailed log file name", OFFSET(filename), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
  91.     { "opencl", "use OpenCL filtering capabilities", OFFSET(opencl), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, .flags = FLAGS },
  92.     { NULL }
  93. };
  94.  
  95. AVFILTER_DEFINE_CLASS(deshake);
  96.  
  97. static int cmp(const double *a, const double *b)
  98. {
  99.     return *a < *b ? -1 : ( *a > *b ? 1 : 0 );
  100. }
  101.  
  102. /**
  103.  * Cleaned mean (cuts off 20% of values to remove outliers and then averages)
  104.  */
  105. static double clean_mean(double *values, int count)
  106. {
  107.     double mean = 0;
  108.     int cut = count / 5;
  109.     int x;
  110.  
  111.     qsort(values, count, sizeof(double), (void*)cmp);
  112.  
  113.     for (x = cut; x < count - cut; x++) {
  114.         mean += values[x];
  115.     }
  116.  
  117.     return mean / (count - cut * 2);
  118. }
  119.  
  120. /**
  121.  * Find the most likely shift in motion between two frames for a given
  122.  * macroblock. Test each block against several shifts given by the rx
  123.  * and ry attributes. Searches using a simple matrix of those shifts and
  124.  * chooses the most likely shift by the smallest difference in blocks.
  125.  */
  126. static void find_block_motion(DeshakeContext *deshake, uint8_t *src1,
  127.                               uint8_t *src2, int cx, int cy, int stride,
  128.                               IntMotionVector *mv)
  129. {
  130.     int x, y;
  131.     int diff;
  132.     int smallest = INT_MAX;
  133.     int tmp, tmp2;
  134.  
  135.     #define CMP(i, j) deshake->c.sad[0](deshake, src1 + cy * stride + cx, \
  136.                                         src2 + (j) * stride + (i), stride, \
  137.                                         deshake->blocksize)
  138.  
  139.     if (deshake->search == EXHAUSTIVE) {
  140.         // Compare every possible position - this is sloooow!
  141.         for (y = -deshake->ry; y <= deshake->ry; y++) {
  142.             for (x = -deshake->rx; x <= deshake->rx; x++) {
  143.                 diff = CMP(cx - x, cy - y);
  144.                 if (diff < smallest) {
  145.                     smallest = diff;
  146.                     mv->x = x;
  147.                     mv->y = y;
  148.                 }
  149.             }
  150.         }
  151.     } else if (deshake->search == SMART_EXHAUSTIVE) {
  152.         // Compare every other possible position and find the best match
  153.         for (y = -deshake->ry + 1; y < deshake->ry; y += 2) {
  154.             for (x = -deshake->rx + 1; x < deshake->rx; x += 2) {
  155.                 diff = CMP(cx - x, cy - y);
  156.                 if (diff < smallest) {
  157.                     smallest = diff;
  158.                     mv->x = x;
  159.                     mv->y = y;
  160.                 }
  161.             }
  162.         }
  163.  
  164.         // Hone in on the specific best match around the match we found above
  165.         tmp = mv->x;
  166.         tmp2 = mv->y;
  167.  
  168.         for (y = tmp2 - 1; y <= tmp2 + 1; y++) {
  169.             for (x = tmp - 1; x <= tmp + 1; x++) {
  170.                 if (x == tmp && y == tmp2)
  171.                     continue;
  172.  
  173.                 diff = CMP(cx - x, cy - y);
  174.                 if (diff < smallest) {
  175.                     smallest = diff;
  176.                     mv->x = x;
  177.                     mv->y = y;
  178.                 }
  179.             }
  180.         }
  181.     }
  182.  
  183.     if (smallest > 512) {
  184.         mv->x = -1;
  185.         mv->y = -1;
  186.     }
  187.     emms_c();
  188.     //av_log(NULL, AV_LOG_ERROR, "%d\n", smallest);
  189.     //av_log(NULL, AV_LOG_ERROR, "Final: (%d, %d) = %d x %d\n", cx, cy, mv->x, mv->y);
  190. }
  191.  
  192. /**
  193.  * Find the contrast of a given block. When searching for global motion we
  194.  * really only care about the high contrast blocks, so using this method we
  195.  * can actually skip blocks we don't care much about.
  196.  */
  197. static int block_contrast(uint8_t *src, int x, int y, int stride, int blocksize)
  198. {
  199.     int highest = 0;
  200.     int lowest = 255;
  201.     int i, j, pos;
  202.  
  203.     for (i = 0; i <= blocksize * 2; i++) {
  204.         // We use a width of 16 here to match the libavcodec sad functions
  205.         for (j = 0; j <= 15; j++) {
  206.             pos = (y - i) * stride + (x - j);
  207.             if (src[pos] < lowest)
  208.                 lowest = src[pos];
  209.             else if (src[pos] > highest) {
  210.                 highest = src[pos];
  211.             }
  212.         }
  213.     }
  214.  
  215.     return highest - lowest;
  216. }
  217.  
  218. /**
  219.  * Find the rotation for a given block.
  220.  */
  221. static double block_angle(int x, int y, int cx, int cy, IntMotionVector *shift)
  222. {
  223.     double a1, a2, diff;
  224.  
  225.     a1 = atan2(y - cy, x - cx);
  226.     a2 = atan2(y - cy + shift->y, x - cx + shift->x);
  227.  
  228.     diff = a2 - a1;
  229.  
  230.     return (diff > M_PI)  ? diff - 2 * M_PI :
  231.            (diff < -M_PI) ? diff + 2 * M_PI :
  232.            diff;
  233. }
  234.  
  235. /**
  236.  * Find the estimated global motion for a scene given the most likely shift
  237.  * for each block in the frame. The global motion is estimated to be the
  238.  * same as the motion from most blocks in the frame, so if most blocks
  239.  * move one pixel to the right and two pixels down, this would yield a
  240.  * motion vector (1, -2).
  241.  */
  242. static void find_motion(DeshakeContext *deshake, uint8_t *src1, uint8_t *src2,
  243.                         int width, int height, int stride, Transform *t)
  244. {
  245.     int x, y;
  246.     IntMotionVector mv = {0, 0};
  247.     int counts[2*MAX_R+1][2*MAX_R+1];
  248.     int count_max_value = 0;
  249.     int contrast;
  250.  
  251.     int pos;
  252.     double *angles = av_malloc(sizeof(*angles) * width * height / (16 * deshake->blocksize));
  253.     int center_x = 0, center_y = 0;
  254.     double p_x, p_y;
  255.  
  256.     // Reset counts to zero
  257.     for (x = 0; x < deshake->rx * 2 + 1; x++) {
  258.         for (y = 0; y < deshake->ry * 2 + 1; y++) {
  259.             counts[x][y] = 0;
  260.         }
  261.     }
  262.  
  263.     pos = 0;
  264.     // Find motion for every block and store the motion vector in the counts
  265.     for (y = deshake->ry; y < height - deshake->ry - (deshake->blocksize * 2); y += deshake->blocksize * 2) {
  266.         // We use a width of 16 here to match the libavcodec sad functions
  267.         for (x = deshake->rx; x < width - deshake->rx - 16; x += 16) {
  268.             // If the contrast is too low, just skip this block as it probably
  269.             // won't be very useful to us.
  270.             contrast = block_contrast(src2, x, y, stride, deshake->blocksize);
  271.             if (contrast > deshake->contrast) {
  272.                 //av_log(NULL, AV_LOG_ERROR, "%d\n", contrast);
  273.                 find_block_motion(deshake, src1, src2, x, y, stride, &mv);
  274.                 if (mv.x != -1 && mv.y != -1) {
  275.                     counts[mv.x + deshake->rx][mv.y + deshake->ry] += 1;
  276.                     if (x > deshake->rx && y > deshake->ry)
  277.                         angles[pos++] = block_angle(x, y, 0, 0, &mv);
  278.  
  279.                     center_x += mv.x;
  280.                     center_y += mv.y;
  281.                 }
  282.             }
  283.         }
  284.     }
  285.  
  286.     if (pos) {
  287.          center_x /= pos;
  288.          center_y /= pos;
  289.          t->angle = clean_mean(angles, pos);
  290.          if (t->angle < 0.001)
  291.               t->angle = 0;
  292.     } else {
  293.          t->angle = 0;
  294.     }
  295.  
  296.     // Find the most common motion vector in the frame and use it as the gmv
  297.     for (y = deshake->ry * 2; y >= 0; y--) {
  298.         for (x = 0; x < deshake->rx * 2 + 1; x++) {
  299.             //av_log(NULL, AV_LOG_ERROR, "%5d ", counts[x][y]);
  300.             if (counts[x][y] > count_max_value) {
  301.                 t->vector.x = x - deshake->rx;
  302.                 t->vector.y = y - deshake->ry;
  303.                 count_max_value = counts[x][y];
  304.             }
  305.         }
  306.         //av_log(NULL, AV_LOG_ERROR, "\n");
  307.     }
  308.  
  309.     p_x = (center_x - width / 2);
  310.     p_y = (center_y - height / 2);
  311.     t->vector.x += (cos(t->angle)-1)*p_x  - sin(t->angle)*p_y;
  312.     t->vector.y += sin(t->angle)*p_x  + (cos(t->angle)-1)*p_y;
  313.  
  314.     // Clamp max shift & rotation?
  315.     t->vector.x = av_clipf(t->vector.x, -deshake->rx * 2, deshake->rx * 2);
  316.     t->vector.y = av_clipf(t->vector.y, -deshake->ry * 2, deshake->ry * 2);
  317.     t->angle = av_clipf(t->angle, -0.1, 0.1);
  318.  
  319.     //av_log(NULL, AV_LOG_ERROR, "%d x %d\n", avg->x, avg->y);
  320.     av_free(angles);
  321. }
  322.  
  323. static int deshake_transform_c(AVFilterContext *ctx,
  324.                                     int width, int height, int cw, int ch,
  325.                                     const float *matrix_y, const float *matrix_uv,
  326.                                     enum InterpolateMethod interpolate,
  327.                                     enum FillMethod fill, AVFrame *in, AVFrame *out)
  328. {
  329.     int i = 0, ret = 0;
  330.     const float *matrixs[3];
  331.     int plane_w[3], plane_h[3];
  332.     matrixs[0] = matrix_y;
  333.     matrixs[1] =  matrixs[2] = matrix_uv;
  334.     plane_w[0] = width;
  335.     plane_w[1] = plane_w[2] = cw;
  336.     plane_h[0] = height;
  337.     plane_h[1] = plane_h[2] = ch;
  338.  
  339.     for (i = 0; i < 3; i++) {
  340.         // Transform the luma and chroma planes
  341.         ret = avfilter_transform(in->data[i], out->data[i], in->linesize[i], out->linesize[i],
  342.                                  plane_w[i], plane_h[i], matrixs[i], interpolate, fill);
  343.         if (ret < 0)
  344.             return ret;
  345.     }
  346.     return ret;
  347. }
  348.  
  349. static av_cold int init(AVFilterContext *ctx)
  350. {
  351.     int ret;
  352.     DeshakeContext *deshake = ctx->priv;
  353.  
  354.     deshake->refcount = 20; // XXX: add to options?
  355.     deshake->blocksize /= 2;
  356.     deshake->blocksize = av_clip(deshake->blocksize, 4, 128);
  357.  
  358.     if (deshake->rx % 16) {
  359.         av_log(ctx, AV_LOG_ERROR, "rx must be a multiple of 16\n");
  360.         return AVERROR_PATCHWELCOME;
  361.     }
  362.  
  363.     if (deshake->filename)
  364.         deshake->fp = fopen(deshake->filename, "w");
  365.     if (deshake->fp)
  366.         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);
  367.  
  368.     // Quadword align left edge of box for MMX code, adjust width if necessary
  369.     // to keep right margin
  370.     if (deshake->cx > 0) {
  371.         deshake->cw += deshake->cx - (deshake->cx & ~15);
  372.         deshake->cx &= ~15;
  373.     }
  374.     deshake->transform = deshake_transform_c;
  375.     if (!CONFIG_OPENCL && deshake->opencl) {
  376.         av_log(ctx, AV_LOG_ERROR, "OpenCL support was not enabled in this build, cannot be selected\n");
  377.         return AVERROR(EINVAL);
  378.     }
  379.  
  380.     if (CONFIG_OPENCL && deshake->opencl) {
  381.         deshake->transform = ff_opencl_transform;
  382.         ret = ff_opencl_deshake_init(ctx);
  383.         if (ret < 0)
  384.             return ret;
  385.     }
  386.     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",
  387.            deshake->cx, deshake->cy, deshake->cw, deshake->ch,
  388.            deshake->rx, deshake->ry, deshake->edge, deshake->blocksize * 2, deshake->contrast, deshake->search);
  389.  
  390.     return 0;
  391. }
  392.  
  393. static int query_formats(AVFilterContext *ctx)
  394. {
  395.     static const enum AVPixelFormat pix_fmts[] = {
  396.         AV_PIX_FMT_YUV420P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV410P,
  397.         AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV440P,  AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
  398.         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_NONE
  399.     };
  400.  
  401.     ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
  402.  
  403.     return 0;
  404. }
  405.  
  406. static int config_props(AVFilterLink *link)
  407. {
  408.     DeshakeContext *deshake = link->dst->priv;
  409.  
  410.     deshake->ref = NULL;
  411.     deshake->last.vector.x = 0;
  412.     deshake->last.vector.y = 0;
  413.     deshake->last.angle = 0;
  414.     deshake->last.zoom = 0;
  415.  
  416.     deshake->avctx = avcodec_alloc_context3(NULL);
  417.     avpriv_dsputil_init(&deshake->c, deshake->avctx);
  418.  
  419.     return 0;
  420. }
  421.  
  422. static av_cold void uninit(AVFilterContext *ctx)
  423. {
  424.     DeshakeContext *deshake = ctx->priv;
  425.     if (CONFIG_OPENCL && deshake->opencl) {
  426.         ff_opencl_deshake_uninit(ctx);
  427.     }
  428.     av_frame_free(&deshake->ref);
  429.     if (deshake->fp)
  430.         fclose(deshake->fp);
  431.     if (deshake->avctx)
  432.         avcodec_close(deshake->avctx);
  433.     av_freep(&deshake->avctx);
  434. }
  435.  
  436. static int filter_frame(AVFilterLink *link, AVFrame *in)
  437. {
  438.     DeshakeContext *deshake = link->dst->priv;
  439.     AVFilterLink *outlink = link->dst->outputs[0];
  440.     AVFrame *out;
  441.     Transform t = {{0},0}, orig = {{0},0};
  442.     float matrix_y[9], matrix_uv[9];
  443.     float alpha = 2.0 / deshake->refcount;
  444.     char tmp[256];
  445.     int ret = 0;
  446.  
  447.     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
  448.     if (!out) {
  449.         av_frame_free(&in);
  450.         return AVERROR(ENOMEM);
  451.     }
  452.     av_frame_copy_props(out, in);
  453.  
  454.     if (CONFIG_OPENCL && deshake->opencl) {
  455.         ret = ff_opencl_deshake_process_inout_buf(link->dst,in, out);
  456.         if (ret < 0)
  457.             return ret;
  458.     }
  459.  
  460.     if (deshake->cx < 0 || deshake->cy < 0 || deshake->cw < 0 || deshake->ch < 0) {
  461.         // Find the most likely global motion for the current frame
  462.         find_motion(deshake, (deshake->ref == NULL) ? in->data[0] : deshake->ref->data[0], in->data[0], link->w, link->h, in->linesize[0], &t);
  463.     } else {
  464.         uint8_t *src1 = (deshake->ref == NULL) ? in->data[0] : deshake->ref->data[0];
  465.         uint8_t *src2 = in->data[0];
  466.  
  467.         deshake->cx = FFMIN(deshake->cx, link->w);
  468.         deshake->cy = FFMIN(deshake->cy, link->h);
  469.  
  470.         if ((unsigned)deshake->cx + (unsigned)deshake->cw > link->w) deshake->cw = link->w - deshake->cx;
  471.         if ((unsigned)deshake->cy + (unsigned)deshake->ch > link->h) deshake->ch = link->h - deshake->cy;
  472.  
  473.         // Quadword align right margin
  474.         deshake->cw &= ~15;
  475.  
  476.         src1 += deshake->cy * in->linesize[0] + deshake->cx;
  477.         src2 += deshake->cy * in->linesize[0] + deshake->cx;
  478.  
  479.         find_motion(deshake, src1, src2, deshake->cw, deshake->ch, in->linesize[0], &t);
  480.     }
  481.  
  482.  
  483.     // Copy transform so we can output it later to compare to the smoothed value
  484.     orig.vector.x = t.vector.x;
  485.     orig.vector.y = t.vector.y;
  486.     orig.angle = t.angle;
  487.     orig.zoom = t.zoom;
  488.  
  489.     // Generate a one-sided moving exponential average
  490.     deshake->avg.vector.x = alpha * t.vector.x + (1.0 - alpha) * deshake->avg.vector.x;
  491.     deshake->avg.vector.y = alpha * t.vector.y + (1.0 - alpha) * deshake->avg.vector.y;
  492.     deshake->avg.angle = alpha * t.angle + (1.0 - alpha) * deshake->avg.angle;
  493.     deshake->avg.zoom = alpha * t.zoom + (1.0 - alpha) * deshake->avg.zoom;
  494.  
  495.     // Remove the average from the current motion to detect the motion that
  496.     // is not on purpose, just as jitter from bumping the camera
  497.     t.vector.x -= deshake->avg.vector.x;
  498.     t.vector.y -= deshake->avg.vector.y;
  499.     t.angle -= deshake->avg.angle;
  500.     t.zoom -= deshake->avg.zoom;
  501.  
  502.     // Invert the motion to undo it
  503.     t.vector.x *= -1;
  504.     t.vector.y *= -1;
  505.     t.angle *= -1;
  506.  
  507.     // Write statistics to file
  508.     if (deshake->fp) {
  509.         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);
  510.         fwrite(tmp, sizeof(char), strlen(tmp), deshake->fp);
  511.     }
  512.  
  513.     // Turn relative current frame motion into absolute by adding it to the
  514.     // last absolute motion
  515.     t.vector.x += deshake->last.vector.x;
  516.     t.vector.y += deshake->last.vector.y;
  517.     t.angle += deshake->last.angle;
  518.     t.zoom += deshake->last.zoom;
  519.  
  520.     // Shrink motion by 10% to keep things centered in the camera frame
  521.     t.vector.x *= 0.9;
  522.     t.vector.y *= 0.9;
  523.     t.angle *= 0.9;
  524.  
  525.     // Store the last absolute motion information
  526.     deshake->last.vector.x = t.vector.x;
  527.     deshake->last.vector.y = t.vector.y;
  528.     deshake->last.angle = t.angle;
  529.     deshake->last.zoom = t.zoom;
  530.  
  531.     // Generate a luma transformation matrix
  532.     avfilter_get_matrix(t.vector.x, t.vector.y, t.angle, 1.0 + t.zoom / 100.0, matrix_y);
  533.     // Generate a chroma transformation matrix
  534.     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_uv);
  535.     // Transform the luma and chroma planes
  536.     ret = deshake->transform(link->dst, link->w, link->h, CHROMA_WIDTH(link), CHROMA_HEIGHT(link),
  537.                              matrix_y, matrix_uv, INTERPOLATE_BILINEAR, deshake->edge, in, out);
  538.  
  539.     // Cleanup the old reference frame
  540.     av_frame_free(&deshake->ref);
  541.  
  542.     if (ret < 0)
  543.         return ret;
  544.  
  545.     // Store the current frame as the reference frame for calculating the
  546.     // motion of the next frame
  547.     deshake->ref = in;
  548.  
  549.     return ff_filter_frame(outlink, out);
  550. }
  551.  
  552. static const AVFilterPad deshake_inputs[] = {
  553.     {
  554.         .name         = "default",
  555.         .type         = AVMEDIA_TYPE_VIDEO,
  556.         .filter_frame = filter_frame,
  557.         .config_props = config_props,
  558.     },
  559.     { NULL }
  560. };
  561.  
  562. static const AVFilterPad deshake_outputs[] = {
  563.     {
  564.         .name = "default",
  565.         .type = AVMEDIA_TYPE_VIDEO,
  566.     },
  567.     { NULL }
  568. };
  569.  
  570. AVFilter avfilter_vf_deshake = {
  571.     .name          = "deshake",
  572.     .description   = NULL_IF_CONFIG_SMALL("Stabilize shaky video."),
  573.     .priv_size     = sizeof(DeshakeContext),
  574.     .init          = init,
  575.     .uninit        = uninit,
  576.     .query_formats = query_formats,
  577.     .inputs        = deshake_inputs,
  578.     .outputs       = deshake_outputs,
  579.     .priv_class    = &deshake_class,
  580. };
  581.