diff --git a/aom/aom_encoder.h b/aom/aom_encoder.h
index 208ba01..7a7f4e4 100644
--- a/aom/aom_encoder.h
+++ b/aom/aom_encoder.h
@@ -620,6 +620,13 @@
    */
   unsigned int large_scale_tile;
 
+  /*!\brief Monochrome mode
+   *
+   * If this is nonzero, the encoder will generate a monochrome stream
+   * with no chroma planes.
+   */
+  unsigned int monochrome;
+
   /*!\brief Number of explicit tile widths specified
    *
    * This value indicates the number of tile widths specified
diff --git a/aomenc.c b/aomenc.c
index 0ed4714..0128490 100644
--- a/aomenc.c
+++ b/aomenc.c
@@ -260,6 +260,10 @@
     ARG_DEF(NULL, "large-scale-tile", 1,
             "Large scale tile coding (0: off (default), 1: on)");
 #endif  // CONFIG_EXT_TILE
+#if CONFIG_MONO_VIDEO
+static const arg_def_t monochrome =
+    ARG_DEF(NULL, "monochrome", 0, "Monochrome video (no chroma planes)");
+#endif  // MONOCHROME
 
 static const arg_def_t *global_args[] = { &use_yv12,
                                           &use_i420,
@@ -284,6 +288,9 @@
 #if CONFIG_EXT_TILE
                                           &large_scale_tile,
 #endif  // CONFIG_EXT_TILE
+#if CONFIG_MONO_VIDEO
+                                          &monochrome,
+#endif  // CONFIG_MONO_VIDEO
                                           NULL };
 
 static const arg_def_t dropframe_thresh =
@@ -1065,6 +1072,10 @@
     } else if (arg_match(&arg, &large_scale_tile, argi)) {
       config->cfg.large_scale_tile = arg_parse_uint(&arg);
 #endif  // CONFIG_EXT_TILE
+#if CONFIG_MONO_VIDEO
+    } else if (arg_match(&arg, &monochrome, argi)) {
+      config->cfg.monochrome = 1;
+#endif  // CONFIG_MONO_VIDEO
     } else if (arg_match(&arg, &dropframe_thresh, argi)) {
       config->cfg.rc_dropframe_thresh = arg_parse_uint(&arg);
     } else if (arg_match(&arg, &resize_mode, argi)) {
diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index 91e43db..925077f 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -319,6 +319,9 @@
 #if CONFIG_EXT_TILE
   }
 #endif  // CONFIG_EXT_TILE
+#if CONFIG_MONO_VIDEO
+  RANGE_CHECK_HI(cfg, monochrome, 1);
+#endif  // CONFIG_MONO_VIDEO
 
 #if CONFIG_EXT_TILE
   if (cfg->large_scale_tile && extra_cfg->aq_mode)
@@ -643,6 +646,9 @@
 #if CONFIG_EXT_TILE
   }
 #endif  // CONFIG_EXT_TILE
+#if CONFIG_MONO_VIDEO
+  oxcf->monochrome = cfg->monochrome;
+#endif  // CONFIG_MONO_VIDEO
 
 #if CONFIG_MAX_TILE
   oxcf->tile_width_count = AOMMIN(cfg->tile_width_count, MAX_TILE_COLS);
@@ -1711,6 +1717,7 @@
         0,            // kf_min_dist
         9999,         // kf_max_dist
         0,            // large_scale_tile
+        0,            // monochrome
         0,            // tile_width_count
         0,            // tile_height_count
         { 0 },        // tile_widths
diff --git a/av1/av1_dx_iface.c b/av1/av1_dx_iface.c
index ec896c2..3a02a8b 100644
--- a/av1/av1_dx_iface.c
+++ b/av1/av1_dx_iface.c
@@ -281,11 +281,8 @@
     }
     error_resilient = aom_rb_read_bit(&rb);
 #if CONFIG_REFERENCE_BUFFER
-#if CONFIG_FRAME_SIZE
-    SequenceHeader seq_params = { 0, 0, 0, 0, 0, 0, 0 };
-#else
-    SequenceHeader seq_params = { 0, 0, 0 };
-#endif
+    SequenceHeader seq_params;
+    memset(&seq_params, 0, sizeof(seq_params));
     if (si->is_kf) {
       /* TODO: Move outside frame loop or inside key-frame branch */
       read_sequence_header(&seq_params, &rb);
diff --git a/av1/common/onyxc_int.h b/av1/common/onyxc_int.h
index 1666ffc..3f4c4d3 100644
--- a/av1/common/onyxc_int.h
+++ b/av1/common/onyxc_int.h
@@ -216,6 +216,9 @@
   int frame_id_numbers_present_flag;
   int frame_id_length;
   int delta_frame_id_length;
+#if CONFIG_MONO_VIDEO
+  int monochrome;
+#endif  // CONFIG_MONO_VIDEO
 } SequenceHeader;
 #endif  // CONFIG_REFERENCE_BUFFER
 
@@ -480,6 +483,10 @@
   unsigned int single_tile_decoding;
 #endif  // CONFIG_EXT_TILE
 
+#if CONFIG_MONO_VIDEO
+  int monochrome;
+#endif  // CONFIG_MONO_VIDEO
+
 #if CONFIG_DEPENDENT_HORZTILES
   int dependent_horz_tiles;
   int tile_group_start_row[MAX_TILE_ROWS][MAX_TILE_COLS];
diff --git a/av1/decoder/decodeframe.c b/av1/decoder/decodeframe.c
index d523cff..ecc0baf 100644
--- a/av1/decoder/decodeframe.c
+++ b/av1/decoder/decodeframe.c
@@ -2573,6 +2573,10 @@
     seq_params->frame_id_length =
         aom_rb_read_literal(rb, 3) + seq_params->delta_frame_id_length + 1;
   }
+
+#if CONFIG_MONO_VIDEO
+  seq_params->monochrome = aom_rb_read_bit(rb);
+#endif  // CONFIG_MONO_VIDEO
 }
 #endif  // CONFIG_REFERENCE_BUFFER || CONFIG_OBU
 
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 04cb6e5..0798cfb 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -3658,6 +3658,11 @@
         wb, seq_params->frame_id_length - seq_params->delta_frame_id_length - 1,
         3);
   }
+
+#if CONFIG_MONO_VIDEO
+  seq_params->monochrome = cm->monochrome;
+  aom_wb_write_bit(wb, seq_params->monochrome);
+#endif  // CONFIG_MONO_VIDEO
 }
 #endif  // CONFIG_REFERENCE_BUFFER || CONFIG_OBU
 
diff --git a/av1/encoder/encoder.c b/av1/encoder/encoder.c
index e3630b0..5b0e6ff 100644
--- a/av1/encoder/encoder.c
+++ b/av1/encoder/encoder.c
@@ -5516,6 +5516,10 @@
   cm->single_tile_decoding = cpi->oxcf.single_tile_decoding;
 #endif  // CONFIG_EXT_TILE
 
+#if CONFIG_MONO_VIDEO
+  cm->monochrome = oxcf->monochrome;
+#endif  // CONFIG_MONO_VIDEO
+
 #if CONFIG_XIPHRC
   if (drop_this_frame) {
     av1_rc_postencode_update_drop_frame(cpi);
diff --git a/av1/encoder/encoder.h b/av1/encoder/encoder.h
index 3584098..d288701 100644
--- a/av1/encoder/encoder.h
+++ b/av1/encoder/encoder.h
@@ -304,6 +304,9 @@
   unsigned int large_scale_tile;
   unsigned int single_tile_decoding;
 #endif  // CONFIG_EXT_TILE
+#if CONFIG_MONO_VIDEO
+  int monochrome;
+#endif  // CONFIG_MONO_VIDEO
 
   unsigned int motion_vector_unit_test;
 } AV1EncoderConfig;