Add doxy comments, based on Loren's explanations posted here:

Date: Mar 30, 2007 9:00 PM
Subject: Re: [Ffmpeg-devel] Motion Estimation in snow.c for Waevelet encoded frames (DWT)

Originally committed as revision 8579 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 13 insertions, 2 deletions

diff --git a/libavcodec/motion_est_template.c b/libavcodec/motion_est_template.c
index 897c08e3df..e014250269 100644
--- a/libavcodec/motion_est_template.c
+++ b/libavcodec/motion_est_template.c
@@ -991,13 +991,24 @@ static av_always_inline int diamond_search(MpegEncContext * s, int *best, int dm
         return   var_diamond_search(s, best, dmin, src_index, ref_index, penalty_factor, size, h, flags);
 }
 
+/*!
+   \param P[10][2] a list of candidate mvs to check before starting the
+   iterative search. If one of the candidates is close to the optimal mv, then
+   it takes fewer iterations. And it increases the chance that we find the
+   optimal mv.
+ */
 static av_always_inline int epzs_motion_search_internal(MpegEncContext * s, int *mx_ptr, int *my_ptr,
                              int P[10][2], int src_index, int ref_index, int16_t (*last_mv)[2],
                              int ref_mv_scale, int flags, int size, int h)
 {
     MotionEstContext * const c= &s->me;
-    int best[2]={0, 0};
-    int d, dmin;
+    int best[2]={0, 0};      /*!< x and y coordinates of the best motion vector.
+                               i.e. the difference between the position of the
+                               block current being encoded and the position of
+                               the block chosen to predict it from. */
+    int d;                   ///< the score (cmp + penalty) of any given mv
+    int dmin;                /*!< the best value of d, i.e. the score
+                               corresponding to the mv stored in best[]. */
     int map_generation;
     int penalty_factor;
     const int ref_mv_stride= s->mb_stride; //pass as arg  FIXME