Revert "skip un-neccessary motion search in the first pass"

This patch appears to have introduced non-determinism and/or
mismatch from debug vs release.

This reverts commit 5daef90efc.

Change-Id: I80081e55cfeaaa821b510b58a4e6e6328003c7da

vp9/encoder/vp9_firstpass.c

@@ -596,26 +596,10 @@ void vp9_first_pass(VP9_COMP *cpi) {
       if (cm->current_video_frame > 0) {
         int tmp_err, motion_error;
         int_mv mv, tmp_mv;
-        int raw_motion_error;
-        struct buf_2d unscaled_last_source_buf_2d;
 
         xd->plane[0].pre[0].buf = first_ref_buf->y_buffer + recon_yoffset;
         motion_error = get_prediction_error(bsize, &x->plane[0].src,
                                             &xd->plane[0].pre[0]);
-
-        // compute the motion error of the zero motion vector using the last
-        // source frame as the reference
-        // skip the further motion search on reconstructed frame
-        // if this error is small
-        unscaled_last_source_buf_2d.buf = cpi->unscaled_last_source->y_buffer
-                                  + recon_yoffset;
-        unscaled_last_source_buf_2d.stride =
-                                          cpi->unscaled_last_source->y_stride;
-        raw_motion_error = get_prediction_error(bsize, &x->plane[0].src,
-                                                &unscaled_last_source_buf_2d);
-
-        // TODO(pengchong): Replace the hard-coded threshold
-        if (raw_motion_error > 25) {
         // Assume 0,0 motion with no mv overhead.
         mv.as_int = tmp_mv.as_int = 0;
 
@@ -628,8 +612,7 @@ void vp9_first_pass(VP9_COMP *cpi) {
           motion_error = (int)(motion_error * error_weight);
         }
 
-          // If the current best reference mv is not centered on 0,0
-          // then do a 0,0
+        // If the current best reference mv is not centered on 0,0 then do a 0,0
         // based search as well.
         if (best_ref_mv.as_int) {
           tmp_err = INT_MAX;
@@ -681,7 +664,6 @@ void vp9_first_pass(VP9_COMP *cpi) {
         } else {
           sr_coded_error += motion_error;
         }
-        }
         // Start by assuming that intra mode is best.
         best_ref_mv.as_int = 0;