1 files changed, 4 insertions, 0 deletions
diff --git a/vp9/encoder/vp9_firstpass.c b/vp9/encoder/vp9_firstpass.c
index 557f773ac..2f1fe360d 100644
--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -843,6 +843,10 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
       xd->mi[0]->mode = DC_PRED;
       xd->mi[0]->tx_size =
           use_dc_pred ? (bsize >= BLOCK_16X16 ? TX_16X16 : TX_8X8) : TX_4X4;
+
+      // Set the 16x16 src_diff block to zero, which ensures correct this_error
+      // calculation for block sizes smaller than 16x16.
+      vp9_zero_array(x->plane[0].src_diff, 256);
       vp9_encode_intra_block_plane(x, bsize, 0, 0);
       this_error = vpx_get_mb_ss(x->plane[0].src_diff);
       this_intra_error = this_error;