Fix ARF construction when scaling

The ARF frame should always be the same size as the
native resolution of the input frames.

It will be scaled to the required resolution at
encode time.

Change-Id: I0afe858129aa6ef65b1648f43476331715346896

vp9/encoder/vp9_temporal_filter.c

@@ -200,8 +200,8 @@ static void temporal_filter_iterate_c(VP9_COMP *cpi,
   int frame;
   int mb_col, mb_row;
   unsigned int filter_weight;
-  int mb_cols = cpi->common.mb_cols;
-  int mb_rows = cpi->common.mb_rows;
+  int mb_cols = (frames[alt_ref_index]->y_crop_width + 15) >> 4;
+  int mb_rows = (frames[alt_ref_index]->y_crop_height + 15) >> 4;
   int mb_y_offset = 0;
   int mb_uv_offset = 0;
   DECLARE_ALIGNED_ARRAY(16, unsigned int, accumulator, 16 * 16 * 3);
@@ -233,7 +233,7 @@ static void temporal_filter_iterate_c(VP9_COMP *cpi,
     // To keep the mv in play for both Y and UV planes the max that it
     //  can be on a border is therefore 16 - (2*VP9_INTERP_EXTEND+1).
     cpi->mb.mv_row_min = -((mb_row * 16) + (17 - 2 * VP9_INTERP_EXTEND));
-    cpi->mb.mv_row_max = ((cpi->common.mb_rows - 1 - mb_row) * 16)
+    cpi->mb.mv_row_max = ((mb_rows - 1 - mb_row) * 16)
                          + (17 - 2 * VP9_INTERP_EXTEND);
 
     for (mb_col = 0; mb_col < mb_cols; mb_col++) {
@@ -244,7 +244,7 @@ static void temporal_filter_iterate_c(VP9_COMP *cpi,
       vpx_memset(count, 0, 16 * 16 * 3 * sizeof(count[0]));
 
       cpi->mb.mv_col_min = -((mb_col * 16) + (17 - 2 * VP9_INTERP_EXTEND));
-      cpi->mb.mv_col_max = ((cpi->common.mb_cols - 1 - mb_col) * 16)
+      cpi->mb.mv_col_max = ((mb_cols - 1 - mb_col) * 16)
                            + (17 - 2 * VP9_INTERP_EXTEND);
 
       for (frame = 0; frame < frame_count; frame++) {
@@ -480,10 +480,12 @@ void vp9_temporal_filter(VP9_COMP *cpi, int distance) {
       }
     }
   } else {
+    // ARF is produced at the native frame size and resized when coded.
     vp9_setup_scale_factors_for_frame(&sf,
-                                      get_frame_new_buffer(cm)->y_crop_width,
-                                      get_frame_new_buffer(cm)->y_crop_height,
-                                      cm->width, cm->height);
+                                      frames[0]->y_crop_width,
+                                      frames[0]->y_crop_height,
+                                      frames[0]->y_crop_width,
+                                      frames[0]->y_crop_height);
   }
 
   temporal_filter_iterate_c(cpi, frames, frames_to_blur,