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Small ELBG optimization: use last pixel as a initial guess for the co…

…debook

entry.


git-svn-id: svn://svn.ffmpeg.org/ffmpeg/trunk/libavcodec@21001 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b
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1 parent e9277e7 commit 57bf40005f8a13b2b0b18cdee955f969dbaf5cfc vitor committed Jan 2, 2010
Showing with 8 additions and 5 deletions.
  1. +8 −5 elbg.c
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13 elbg.c
@@ -355,6 +355,7 @@ void ff_do_elbg(int *points, int dim, int numpoints, int *codebook,
int *size_part = av_malloc(numCB*sizeof(int));
cell *list_buffer = av_malloc(numpoints*sizeof(cell));
cell *free_cells;
+ int best_dist, best_idx = 0;
elbg->error = INT_MAX;
elbg->dim = dim;
@@ -380,14 +381,16 @@ void ff_do_elbg(int *points, int dim, int numpoints, int *codebook,
/* This loop evaluate the actual Voronoi partition. It is the most
costly part of the algorithm. */
for (i=0; i < numpoints; i++) {
- dist_cb[i] = INT_MAX;
+ best_dist = distance_limited(elbg->points + i*elbg->dim, elbg->codebook + best_idx*elbg->dim, dim, INT_MAX);
for (k=0; k < elbg->numCB; k++) {
- dist = distance_limited(elbg->points + i*elbg->dim, elbg->codebook + k*elbg->dim, dim, dist_cb[i]);
- if (dist < dist_cb[i]) {
- dist_cb[i] = dist;
- elbg->nearest_cb[i] = k;
+ dist = distance_limited(elbg->points + i*elbg->dim, elbg->codebook + k*elbg->dim, dim, best_dist);
+ if (dist < best_dist) {
+ best_dist = dist;
+ best_idx = k;
}
}
+ elbg->nearest_cb[i] = best_idx;
+ dist_cb[i] = best_dist;
elbg->error += dist_cb[i];
elbg->utility[elbg->nearest_cb[i]] += dist_cb[i];
free_cells->index = i;

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