shithub: libvpx

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Fix bug in 1st pass motion compensation

In the case where the best reference mv is not (0,0) a secondary
search is carried out centered on (0,0). However, rather than
sending tmp_err into the search function, motion_error was
inadvertently passed.

As a result tmp_err remains set at INT_MAX and the (0,0)-based
search result will never be selected, even if it is better.

Change-Id: I3c82b246c8c82ba887b9d3fb4c9e0a0f2fe5a76c

--- a/vp8/encoder/firstpass.c

+++ b/vp8/encoder/firstpass.c

@@ -639,14 +639,18 @@

                 d->bmi.mv.as_mv.row = 0;

                 d->bmi.mv.as_mv.col = 0;

-                // Test last reference frame using the previous best mv as the starting point (best reference) for the search

-                vp8_first_pass_motion_search(cpi, x, &best_ref_mv, &d->bmi.mv.as_mv, &cm->last_frame, &motion_error, recon_yoffset);

+                // Test last reference frame using the previous best mv as the

+                // starting point (best reference) for the search

+                vp8_first_pass_motion_search(cpi, x, &best_ref_mv,

+                                        &d->bmi.mv.as_mv, &cm->last_frame,

+                                        &motion_error, recon_yoffset);

                 // If the current best reference mv is not centred on 0,0 then do a 0,0 based search as well

                 if ((best_ref_mv.col != 0) || (best_ref_mv.row != 0))

                 {

                    tmp_err = INT_MAX;

-                   vp8_first_pass_motion_search(cpi, x, &zero_ref_mv, &tmp_mv, &cm->last_frame, &motion_error, recon_yoffset);

+                   vp8_first_pass_motion_search(cpi, x, &zero_ref_mv, &tmp_mv,

+                                     &cm->last_frame, &tmp_err, recon_yoffset);

                    if ( tmp_err < motion_error )

                    {