diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index c86ef3a..4235c49 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -40,9 +40,6 @@
 #include "av1/common/seg_common.h"
 #include "av1/common/tile_common.h"
 
-#if CONFIG_ANS
-#include "aom_dsp/buf_ans.h"
-#endif  // CONFIG_ANS
 #if CONFIG_LV_MAP
 #include "av1/encoder/encodetxb.h"
 #endif  // CONFIG_LV_MAP
@@ -3780,11 +3777,7 @@
                             unsigned int *max_tile_size,
                             unsigned int *max_tile_col_size) {
   const AV1_COMMON *const cm = &cpi->common;
-#if CONFIG_ANS
-  struct BufAnsCoder *buf_ans = &cpi->buf_ans;
-#else
   aom_writer mode_bc;
-#endif  // CONFIG_ANS
   int tile_row, tile_col;
   TOKENEXTRA *(*const tok_buffers)[MAX_TILE_COLS] = cpi->tile_tok;
   TileBufferEnc(*const tile_buffers)[MAX_TILE_COLS] = cpi->tile_buffers;
@@ -3857,19 +3850,14 @@
         cpi->td.mb.pvq_q = &this_tile->pvq_q;
         cpi->td.mb.daala_enc.state.adapt = &this_tile->tctx.pvq_context;
 #endif  // CONFIG_PVQ
-#if !CONFIG_ANS
+#if CONFIG_ANS
+        mode_bc.size = 1 << cpi->common.ans_window_size_log2;
+#endif
         aom_start_encode(&mode_bc, buf->data + data_offset);
         write_modes(cpi, &tile_info, &mode_bc, &tok, tok_end);
         assert(tok == tok_end);
         aom_stop_encode(&mode_bc);
         tile_size = mode_bc.pos;
-#else
-        buf_ans_write_init(buf_ans, buf->data + data_offset);
-        write_modes(cpi, &tile_info, buf_ans, &tok, tok_end);
-        assert(tok == tok_end);
-        aom_buf_ans_flush(buf_ans);
-        tile_size = buf_ans_write_end(buf_ans);
-#endif  // !CONFIG_ANS
 #if CONFIG_PVQ
         cpi->td.mb.pvq_q = NULL;
 #endif
@@ -4033,22 +4021,17 @@
         cpi->td.mb.daala_enc.state.adapt = &this_tile->tctx.pvq_context;
 #endif  // CONFIG_PVQ
 #if CONFIG_ANS
-        buf_ans_write_init(buf_ans, dst + total_size);
-        write_modes(cpi, &tile_info, buf_ans, &tok, tok_end);
-        assert(tok == tok_end);
-        aom_buf_ans_flush(buf_ans);
-        tile_size = buf_ans_write_end(buf_ans);
-#else
-      aom_start_encode(&mode_bc, dst + total_size);
-      write_modes(cpi, &tile_info, &mode_bc, &tok, tok_end);
+        mode_bc.size = 1 << cpi->common.ans_window_size_log2;
+#endif  // CONFIG_ANS
+        aom_start_encode(&mode_bc, dst + total_size);
+        write_modes(cpi, &tile_info, &mode_bc, &tok, tok_end);
 #if !CONFIG_LV_MAP
 #if !CONFIG_PVQ
-      assert(tok == tok_end);
+        assert(tok == tok_end);
 #endif  // !CONFIG_PVQ
 #endif  // !CONFIG_LV_MAP
-      aom_stop_encode(&mode_bc);
-      tile_size = mode_bc.pos;
-#endif  // CONFIG_ANS
+        aom_stop_encode(&mode_bc);
+        tile_size = mode_bc.pos;
 #if CONFIG_PVQ
         cpi->td.mb.pvq_q = NULL;
 #endif
@@ -4635,15 +4618,12 @@
   (void)i;
   (void)fc;
 
-#if CONFIG_ANS
-  int header_size;
-  header_bc = &cpi->buf_ans;
-  buf_ans_write_init(header_bc, data);
-#else
   aom_writer real_header_bc;
   header_bc = &real_header_bc;
-  aom_start_encode(header_bc, data);
+#if CONFIG_ANS
+  header_bc->size = 1 << cpi->common.ans_window_size_log2;
 #endif
+  aom_start_encode(header_bc, data);
 
 #if CONFIG_LOOP_RESTORATION
   encode_restoration(cm, header_bc);
@@ -4788,16 +4768,9 @@
     write_global_motion(cpi, header_bc);
 #endif  // CONFIG_GLOBAL_MOTION
   }
-#if CONFIG_ANS
-  aom_buf_ans_flush(header_bc);
-  header_size = buf_ans_write_end(header_bc);
-  assert(header_size <= 0xffff);
-  return header_size;
-#else
   aom_stop_encode(header_bc);
   assert(header_bc->pos <= 0xffff);
   return header_bc->pos;
-#endif  // CONFIG_ANS
 }
 
 static int choose_size_bytes(uint32_t size, int spare_msbs) {