Fixing multi-thread decoding mismatch

When multi-threading is used for decoding, max_scan_line needs to be set according to the correct scan order and not the max EOB.
This ensures only the respective buffers are accessed in each decoding thread.

av1/decoder/decodetxb.c

diff --git a/av1/decoder/decodetxb.c b/av1/decoder/decodetxb.c
index 37e5fe8..0a2a46b 100644
--- a/av1/decoder/decodetxb.c
+++ b/av1/decoder/decodetxb.c
@@ -299,10 +299,8 @@
   int8_t signs_buf[TX_PAD_2D];
   int8_t *const signs = set_signs(signs_buf, width);
   eob_info *eob_data = dcb->eob_data[plane] + dcb->txb_offset[plane];
-  uint16_t *const eob = &(eob_data->eob);
-  uint16_t *const max_scan_line = &(eob_data->max_scan_line);
-  *max_scan_line = 0;
-  *eob = 0;
+  eob_data->max_scan_line = 0;
+  eob_data->eob = av1_get_max_eob(tx_size);
 
   const TX_TYPE tx_type =
       av1_get_tx_type(xd, plane_type, blk_row, blk_col, tx_size,
@@ -312,23 +310,21 @@
   const SCAN_ORDER *const scan_order = get_scan(tx_size, tx_type);
   const int16_t *const scan = scan_order->scan;
 
-  *eob = av1_get_max_eob(tx_size);
-  eob_data->eob = *eob;
-  eob_data->max_scan_line = *eob;
-
-  if (*eob > 1) {
+  if (eob_data->eob > 1) {
     memset(levels_buf, 0, sizeof(*levels_buf) * TX_PAD_2D);
     memset(signs_buf, 0, sizeof(*signs_buf) * TX_PAD_2D);
     base_cdf_arr base_cdf = ec_ctx->coeff_base_cdf_idtx;
     br_cdf_arr br_cdf = ec_ctx->coeff_br_cdf_idtx;
-    read_coeffs_forward_2d(r, 0, *eob - 1, scan, bwl, levels, base_cdf, br_cdf);
+    read_coeffs_forward_2d(r, 0, eob_data->eob - 1, scan, bwl, levels, base_cdf,
+                           br_cdf);
   }
 
-  for (int c = *eob - 1; c >= 0; --c) {
+  for (int c = eob_data->eob - 1; c >= 0; --c) {
     const int pos = scan[c];
     uint8_t sign;
     tran_low_t level = levels[get_padded_idx_left(pos, bwl)];
     if (level) {
+      eob_data->max_scan_line = AOMMAX(eob_data->max_scan_line, pos);
       int idtx_sign_ctx = get_sign_ctx_skip(signs, levels, pos, bwl);
       sign =
           aom_read_symbol(r, ec_ctx->idtx_sign_cdf[idtx_sign_ctx], 2, ACCT_STR);

test/decode_multithreaded_test.cc

diff --git a/test/decode_multithreaded_test.cc b/test/decode_multithreaded_test.cc
index 2da1c3c..dfa707a 100644
--- a/test/decode_multithreaded_test.cc
+++ b/test/decode_multithreaded_test.cc
@@ -37,8 +37,8 @@
         row_mt_(GET_PARAM(5)) {
     init_flags_ = AOM_CODEC_USE_PSNR;
     aom_codec_dec_cfg_t cfg = aom_codec_dec_cfg_t();
-    cfg.w = 704;
-    cfg.h = 576;
+    cfg.w = 352;
+    cfg.h = 288;
     cfg.threads = 1;
     single_thread_dec_ = codec_->CreateDecoder(cfg, 0);
 
@@ -110,7 +110,7 @@
     cfg_.g_lag_in_frames = 12;
     cfg_.rc_end_usage = AOM_VBR;
 
-    libaom_test::I420VideoSource video("hantro_collage_w352h288.yuv", 704, 576,
+    libaom_test::I420VideoSource video("hantro_collage_w352h288.yuv", 352, 288,
                                        timebase.den, timebase.num, 0, 2);
     ASSERT_NO_FATAL_FAILURE(RunLoop(&video));
 

test/tile_independence_test.cc

diff --git a/test/tile_independence_test.cc b/test/tile_independence_test.cc
index 58e4486..aca8c8d 100644
--- a/test/tile_independence_test.cc
+++ b/test/tile_independence_test.cc
@@ -32,8 +32,8 @@
         n_tile_groups_(GET_PARAM(3)) {
     init_flags_ = AOM_CODEC_USE_PSNR;
     aom_codec_dec_cfg_t cfg = aom_codec_dec_cfg_t();
-    cfg.w = 704;
-    cfg.h = 576;
+    cfg.w = 352;
+    cfg.h = 288;
     cfg.threads = 1;
     fw_dec_ = codec_->CreateDecoder(cfg, 0);
     inv_dec_ = codec_->CreateDecoder(cfg, 0);
@@ -97,7 +97,7 @@
     cfg_.g_lag_in_frames = 12;
     cfg_.rc_end_usage = AOM_VBR;
 
-    libaom_test::I420VideoSource video("hantro_collage_w352h288.yuv", 704, 576,
+    libaom_test::I420VideoSource video("hantro_collage_w352h288.yuv", 352, 288,
                                        timebase.den, timebase.num, 0, 5);
     ASSERT_NO_FATAL_FAILURE(RunLoop(&video));