diff --git a/av1/common/av1_fwd_txfm1d.c b/av1/common/av1_fwd_txfm1d.c
index 7b961aa..cfe2741 100644
--- a/av1/common/av1_fwd_txfm1d.c
+++ b/av1/common/av1_fwd_txfm1d.c
@@ -10,6 +10,7 @@
  */
 
 #include <stdlib.h>
+#include "aom_dsp/inv_txfm.h"
 #include "av1/common/av1_fwd_txfm1d.h"
 #if CONFIG_COEFFICIENT_RANGE_CHECKING
 
@@ -1516,6 +1517,38 @@
   range_check(stage, input, bf1, size, stage_range[stage]);
 }
 
+#if CONFIG_EXT_TX
+void av1_fidentity4_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 4; ++i)
+    output[i] = (int32_t)dct_const_round_shift(input[i] * Sqrt2);
+  range_check(0, input, output, 4, stage_range[0]);
+}
+
+void av1_fidentity8_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 8; ++i) output[i] = input[i] * 2;
+  range_check(0, input, output, 8, stage_range[0]);
+}
+
+void av1_fidentity16_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 16; ++i)
+    output[i] = (int32_t)dct_const_round_shift(input[i] * 2 * Sqrt2);
+  range_check(0, input, output, 16, stage_range[0]);
+}
+
+void av1_fidentity32_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 32; ++i) output[i] = input[i] * 4;
+  range_check(0, input, output, 32, stage_range[0]);
+}
+#endif  // CONFIG_EXT_TX
+
 #if CONFIG_TX64X64
 void av1_fdct64_new(const int32_t *input, int32_t *output,
                     const int8_t *cos_bit, const int8_t *stage_range) {
diff --git a/av1/common/av1_fwd_txfm1d.h b/av1/common/av1_fwd_txfm1d.h
index 9f24671..f641930 100644
--- a/av1/common/av1_fwd_txfm1d.h
+++ b/av1/common/av1_fwd_txfm1d.h
@@ -37,6 +37,16 @@
                      const int8_t *cos_bit, const int8_t *stage_range);
 void av1_fadst32_new(const int32_t *input, int32_t *output,
                      const int8_t *cos_bit, const int8_t *stage_range);
+#if CONFIG_EXT_TX
+void av1_fidentity4_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range);
+void av1_fidentity8_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range);
+void av1_fidentity16_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range);
+void av1_fidentity32_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range);
+#endif  // CONFIG_EXT_TX
 
 #ifdef __cplusplus
 }
diff --git a/av1/common/av1_fwd_txfm1d_cfg.h b/av1/common/av1_fwd_txfm1d_cfg.h
index 53ef60b..c794268 100644
--- a/av1/common/av1_fwd_txfm1d_cfg.h
+++ b/av1/common/av1_fwd_txfm1d_cfg.h
@@ -13,6 +13,9 @@
 #define AV1_FWD_TXFM2D_CFG_H_
 #include "av1/common/enums.h"
 #include "av1/common/av1_fwd_txfm1d.h"
+// Identity will always use max bitdepth regardless of size
+static const int8_t fwd_stage_range_identity[1] = { 12 };
+
 //  ---------------- 4x4 1D constants -----------------------
 // shift
 static const int8_t fwd_shift_4[3] = { 2, 0, 0 };
@@ -311,4 +314,51 @@
   fwd_cos_bit_col_adst_32,      // .cos_bit
   TXFM_TYPE_ADST32,             // .txfm_type
 };
+
+#if CONFIG_EXT_TX
+// identity does not need to differentiate between row and col
+//  ---------------- row/col config fwd_identity_4 ----------
+static const TXFM_1D_CFG fwd_txfm_1d_cfg_identity_4 = {
+  4,  // .txfm_size
+  1,  // .stage_num
+  // 0,  // .log_scale
+  fwd_shift_4,               // .shift
+  fwd_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY4,       // .txfm_type
+};
+
+//  ---------------- row/col config fwd_identity_8 ----------------
+static const TXFM_1D_CFG fwd_txfm_1d_cfg_identity_8 = {
+  8,  // .txfm_size
+  1,  // .stage_num
+  // 0,  // .log_scale
+  fwd_shift_8,               // .shift
+  fwd_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY8,       // .txfm_type
+};
+
+//  ---------------- row/col config fwd_identity_16 ----------------
+static const TXFM_1D_CFG fwd_txfm_1d_cfg_identity_16 = {
+  16,  // .txfm_size
+  1,   // .stage_num
+  // 0,  // .log_scale
+  fwd_shift_16,              // .shift
+  fwd_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY16,      // .txfm_type
+};
+
+//  ---------------- row/col config fwd_identity_32 ----------------
+static const TXFM_1D_CFG fwd_txfm_1d_cfg_identity_32 = {
+  32,  // .txfm_size
+  1,   // .stage_num
+  // 1,  // .log_scale
+  fwd_shift_32,              // .shift
+  fwd_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY32,      // .txfm_type
+};
+#endif  // CONFIG_EXT_TX
 #endif  // AV1_FWD_TXFM2D_CFG_H_
diff --git a/av1/common/av1_fwd_txfm2d.c b/av1/common/av1_fwd_txfm2d.c
index 5ee4691..96443ac 100644
--- a/av1/common/av1_fwd_txfm2d.c
+++ b/av1/common/av1_fwd_txfm2d.c
@@ -27,6 +27,12 @@
     case TXFM_TYPE_ADST8: return av1_fadst8_new;
     case TXFM_TYPE_ADST16: return av1_fadst16_new;
     case TXFM_TYPE_ADST32: return av1_fadst32_new;
+#if CONFIG_EXT_TX
+    case TXFM_TYPE_IDENTITY4: return av1_fidentity4_c;
+    case TXFM_TYPE_IDENTITY8: return av1_fidentity8_c;
+    case TXFM_TYPE_IDENTITY16: return av1_fidentity16_c;
+    case TXFM_TYPE_IDENTITY32: return av1_fidentity32_c;
+#endif  // CONFIG_EXT_TX
     default: assert(0); return NULL;
   }
 }
@@ -141,13 +147,13 @@
 #endif
       &fwd_txfm_1d_col_cfg_adst_4, &fwd_txfm_1d_col_cfg_adst_8,
       &fwd_txfm_1d_col_cfg_adst_16, &fwd_txfm_1d_col_cfg_adst_32 },
-  // IDENTITY PLACEHOLDER
+  // IDENTITY
   {
 #if CONFIG_CB4X4
       NULL,
 #endif
-      &fwd_txfm_1d_col_cfg_adst_4, &fwd_txfm_1d_col_cfg_adst_8,
-      &fwd_txfm_1d_col_cfg_adst_16, &fwd_txfm_1d_col_cfg_adst_32 },
+      &fwd_txfm_1d_cfg_identity_4, &fwd_txfm_1d_cfg_identity_8,
+      &fwd_txfm_1d_cfg_identity_16, &fwd_txfm_1d_cfg_identity_32 },
 #endif  // CONFIG_EXT_TX
 };
 
@@ -174,13 +180,13 @@
 #endif
       &fwd_txfm_1d_row_cfg_adst_4, &fwd_txfm_1d_row_cfg_adst_8,
       &fwd_txfm_1d_row_cfg_adst_16, &fwd_txfm_1d_row_cfg_adst_32 },
-  // IDENTITY PLACEHOLDER
+  // IDENTITY
   {
 #if CONFIG_CB4X4
       NULL,
 #endif
-      &fwd_txfm_1d_row_cfg_adst_4, &fwd_txfm_1d_row_cfg_adst_8,
-      &fwd_txfm_1d_row_cfg_adst_16, &fwd_txfm_1d_row_cfg_adst_32 },
+      &fwd_txfm_1d_cfg_identity_4, &fwd_txfm_1d_cfg_identity_8,
+      &fwd_txfm_1d_cfg_identity_16, &fwd_txfm_1d_cfg_identity_32 },
 #endif  // CONFIG_EXT_TX
 };
 
diff --git a/av1/common/av1_inv_txfm1d.c b/av1/common/av1_inv_txfm1d.c
index a07d79e..e9f04d3 100644
--- a/av1/common/av1_inv_txfm1d.c
+++ b/av1/common/av1_inv_txfm1d.c
@@ -10,6 +10,7 @@
  */
 
 #include <stdlib.h>
+#include "aom_dsp/inv_txfm.h"
 #include "av1/common/av1_inv_txfm1d.h"
 #if CONFIG_COEFFICIENT_RANGE_CHECKING
 
@@ -1538,6 +1539,38 @@
   range_check(stage, input, bf1, size, stage_range[stage]);
 }
 
+#if CONFIG_EXT_TX
+void av1_iidentity4_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 4; ++i)
+    output[i] = (int32_t)dct_const_round_shift(input[i] * Sqrt2);
+  range_check(0, input, output, 4, stage_range[0]);
+}
+
+void av1_iidentity8_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 8; ++i) output[i] = input[i] * 2;
+  range_check(0, input, output, 8, stage_range[0]);
+}
+
+void av1_iidentity16_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 16; ++i)
+    output[i] = (int32_t)dct_const_round_shift(input[i] * 2 * Sqrt2);
+  range_check(0, input, output, 16, stage_range[0]);
+}
+
+void av1_iidentity32_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range) {
+  (void)cos_bit;
+  for (int i = 0; i < 32; ++i) output[i] = input[i] * 4;
+  range_check(0, input, output, 32, stage_range[0]);
+}
+#endif  // CONFIG_EXT_TX
+
 #if CONFIG_TX64X64
 void av1_idct64_new(const int32_t *input, int32_t *output,
                     const int8_t *cos_bit, const int8_t *stage_range) {
diff --git a/av1/common/av1_inv_txfm1d.h b/av1/common/av1_inv_txfm1d.h
index 9e7a232..037a3c6 100644
--- a/av1/common/av1_inv_txfm1d.h
+++ b/av1/common/av1_inv_txfm1d.h
@@ -37,6 +37,16 @@
                      const int8_t *cos_bit, const int8_t *stage_range);
 void av1_iadst32_new(const int32_t *input, int32_t *output,
                      const int8_t *cos_bit, const int8_t *stage_range);
+#if CONFIG_EXT_TX
+void av1_iidentity4_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range);
+void av1_iidentity8_c(const int32_t *input, int32_t *output,
+                      const int8_t *cos_bit, const int8_t *stage_range);
+void av1_iidentity16_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range);
+void av1_iidentity32_c(const int32_t *input, int32_t *output,
+                       const int8_t *cos_bit, const int8_t *stage_range);
+#endif  // CONFIG_EXT_TX
 
 #ifdef __cplusplus
 }
diff --git a/av1/common/av1_inv_txfm1d_cfg.h b/av1/common/av1_inv_txfm1d_cfg.h
index bd0cc65..04d2b3b 100644
--- a/av1/common/av1_inv_txfm1d_cfg.h
+++ b/av1/common/av1_inv_txfm1d_cfg.h
@@ -12,6 +12,9 @@
 #ifndef AV1_INV_TXFM2D_CFG_H_
 #define AV1_INV_TXFM2D_CFG_H_
 #include "av1/common/av1_inv_txfm1d.h"
+// Identity will always use max bitdepth regardless of size
+static const int8_t inv_stage_range_identity[1] = { 12 };
+
 //  ---------------- 4x4 1D config -----------------------
 // shift
 static const int8_t inv_shift_4[2] = { 0, -4 };
@@ -309,4 +312,51 @@
   inv_cos_bit_col_adst_32,      // .cos_bit
   TXFM_TYPE_ADST32,             // .txfm_type
 };
+
+#if CONFIG_EXT_TX
+// identity does not need to differentiate between row and col
+//  ---------------- row/col config inv_identity_4 ----------
+static const TXFM_1D_CFG inv_txfm_1d_cfg_identity_4 = {
+  4,  // .txfm_size
+  1,  // .stage_num
+  // 0,  // .log_scale
+  inv_shift_4,               // .shift
+  inv_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY4,       // .txfm_type
+};
+
+//  ---------------- row/col config inv_identity_8 ----------------
+static const TXFM_1D_CFG inv_txfm_1d_cfg_identity_8 = {
+  8,  // .txfm_size
+  1,  // .stage_num
+  // 0,  // .log_scale
+  inv_shift_8,               // .shift
+  inv_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY8,       // .txfm_type
+};
+
+//  ---------------- row/col config inv_identity_16 ----------------
+static const TXFM_1D_CFG inv_txfm_1d_cfg_identity_16 = {
+  16,  // .txfm_size
+  1,   // .stage_num
+  // 0,  // .log_scale
+  inv_shift_16,              // .shift
+  inv_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY16,      // .txfm_type
+};
+
+//  ---------------- row/col config inv_identity_32 ----------------
+static const TXFM_1D_CFG inv_txfm_1d_cfg_identity_32 = {
+  32,  // .txfm_size
+  1,   // .stage_num
+  // 1,  // .log_scale
+  inv_shift_32,              // .shift
+  inv_stage_range_identity,  // .stage_range
+  NULL,                      // .cos_bit
+  TXFM_TYPE_IDENTITY32,      // .txfm_type
+};
+#endif  // CONFIG_EXT_TX
 #endif  // AV1_INV_TXFM2D_CFG_H_
diff --git a/av1/common/av1_inv_txfm2d.c b/av1/common/av1_inv_txfm2d.c
index 197b9d1..6191053 100644
--- a/av1/common/av1_inv_txfm2d.c
+++ b/av1/common/av1_inv_txfm2d.c
@@ -25,6 +25,12 @@
     case TXFM_TYPE_ADST8: return av1_iadst8_new;
     case TXFM_TYPE_ADST16: return av1_iadst16_new;
     case TXFM_TYPE_ADST32: return av1_iadst32_new;
+#if CONFIG_EXT_TX
+    case TXFM_TYPE_IDENTITY4: return av1_iidentity4_c;
+    case TXFM_TYPE_IDENTITY8: return av1_iidentity8_c;
+    case TXFM_TYPE_IDENTITY16: return av1_iidentity16_c;
+    case TXFM_TYPE_IDENTITY32: return av1_iidentity32_c;
+#endif  // CONFIG_EXT_TX
     default: assert(0); return NULL;
   }
 }
@@ -52,13 +58,13 @@
 #endif
       &inv_txfm_1d_col_cfg_adst_4, &inv_txfm_1d_col_cfg_adst_8,
       &inv_txfm_1d_col_cfg_adst_16, &inv_txfm_1d_col_cfg_adst_32 },
-  // IDENTITY PLACEHOLDER
+  // IDENTITY
   {
 #if CONFIG_CB4X4
       NULL,
 #endif
-      &inv_txfm_1d_col_cfg_adst_4, &inv_txfm_1d_col_cfg_adst_8,
-      &inv_txfm_1d_col_cfg_adst_16, &inv_txfm_1d_col_cfg_adst_32 },
+      &inv_txfm_1d_cfg_identity_4, &inv_txfm_1d_cfg_identity_8,
+      &inv_txfm_1d_cfg_identity_16, &inv_txfm_1d_cfg_identity_32 },
 #endif  // CONFIG_EXT_TX
 };
 
@@ -85,13 +91,13 @@
 #endif
       &inv_txfm_1d_row_cfg_adst_4, &inv_txfm_1d_row_cfg_adst_8,
       &inv_txfm_1d_row_cfg_adst_16, &inv_txfm_1d_row_cfg_adst_32 },
-  // IDENTITY PLACEHOLDER
+  // IDENTITY
   {
 #if CONFIG_CB4X4
       NULL,
 #endif
-      &inv_txfm_1d_row_cfg_adst_4, &inv_txfm_1d_row_cfg_adst_8,
-      &inv_txfm_1d_row_cfg_adst_16, &inv_txfm_1d_row_cfg_adst_32 },
+      &inv_txfm_1d_cfg_identity_4, &inv_txfm_1d_cfg_identity_8,
+      &inv_txfm_1d_cfg_identity_16, &inv_txfm_1d_cfg_identity_32 },
 #endif  // CONFIG_EXT_TX
 };
 
diff --git a/av1/common/av1_txfm.h b/av1/common/av1_txfm.h
index 0666769..b341cb7 100644
--- a/av1/common/av1_txfm.h
+++ b/av1/common/av1_txfm.h
@@ -143,6 +143,10 @@
   TXFM_TYPE_ADST8,
   TXFM_TYPE_ADST16,
   TXFM_TYPE_ADST32,
+  TXFM_TYPE_IDENTITY4,
+  TXFM_TYPE_IDENTITY8,
+  TXFM_TYPE_IDENTITY16,
+  TXFM_TYPE_IDENTITY32,
 } TXFM_TYPE;
 
 typedef struct TXFM_1D_CFG {
@@ -172,13 +176,23 @@
       cfg->lr_flip = 0;
       break;
 #if CONFIG_EXT_TX
+    case IDTX:
+    case V_DCT:
+    case H_DCT:
+    case V_ADST:
+    case H_ADST:
+      cfg->ud_flip = 0;
+      cfg->lr_flip = 0;
+      break;
     case FLIPADST_DCT:
     case FLIPADST_ADST:
+    case V_FLIPADST:
       cfg->ud_flip = 1;
       cfg->lr_flip = 0;
       break;
     case DCT_FLIPADST:
     case ADST_FLIPADST:
+    case H_FLIPADST:
       cfg->ud_flip = 0;
       cfg->lr_flip = 1;
       break;
diff --git a/av1/common/idct.c b/av1/common/idct.c
index 5275df5..e3aad5a 100644
--- a/av1/common/idct.c
+++ b/av1/common/idct.c
@@ -115,6 +115,10 @@
 
 #if CONFIG_HIGHBITDEPTH
 #if CONFIG_EXT_TX
+// TODO(sarahparker) these functions will be removed once the highbitdepth
+// codepath works properly for rectangular transforms. They have almost
+// identical versions in av1_inv_txfm1d.c, but those are currently only
+// being used for square transforms.
 static void highbd_iidtx4_c(const tran_low_t *input, tran_low_t *output,
                             int bd) {
   int i;
diff --git a/av1/encoder/dct.c b/av1/encoder/dct.c
index 412363e..049cc2b 100644
--- a/av1/encoder/dct.c
+++ b/av1/encoder/dct.c
@@ -1022,6 +1022,10 @@
 }
 
 #if CONFIG_EXT_TX
+// TODO(sarahparker) these functions will be removed once the highbitdepth
+// codepath works properly for rectangular transforms. They have almost
+// identical versions in av1_fwd_txfm1d.c, but those are currently only
+// being used for square transforms.
 static void fidtx4(const tran_low_t *input, tran_low_t *output) {
   int i;
   for (i = 0; i < 4; ++i)