[FFmpeg-devel] [PATCH] cbs_h266: add range extension support

[Nuo Mi <nuomi2021@gmail.com>]

From: frankplow <post@frankplowman.com>

---
 libavcodec/cbs_h266.h                 | 18 ++++++
 libavcodec/cbs_h266_syntax_template.c | 79 +++++++++++++++++++++++++--
 2 files changed, 93 insertions(+), 4 deletions(-)

diff --git a/libavcodec/cbs_h266.h b/libavcodec/cbs_h266.h
index e33d08a0f5..40aba9eb13 100644
--- a/libavcodec/cbs_h266.h
+++ b/libavcodec/cbs_h266.h
@@ -120,6 +120,13 @@ typedef struct H266GeneralConstraintsInfo {
     uint8_t gci_no_virtual_boundaries_constraint_flag;
     uint8_t gci_num_reserved_bits;
     uint8_t gci_reserved_zero_bit[255];
+
+    uint8_t gci_all_rap_pictures_constraint_flag;
+    uint8_t gci_no_extended_precision_processing_constraint_flag;
+    uint8_t gci_no_ts_residual_coding_rice_constraint_flag;
+    uint8_t gci_no_rrc_rice_extension_constraint_flag;
+    uint8_t gci_no_persistent_rice_adaptation_constraint_flag;
+    uint8_t gci_no_reverse_last_sig_coeff_constraint_flag;
 } H266GeneralConstraintsInfo;
 
 typedef struct H266RawProfileTierLevel {
@@ -451,6 +458,15 @@ typedef struct H266RawSPS {
 
     uint8_t  sps_extension_flag;
 
+    uint8_t  sps_range_extension_flag;
+    uint8_t  sps_extension_7bits;
+
+    uint8_t  sps_extended_precision_flag;
+    uint8_t  sps_ts_residual_coding_rice_present_in_sh_flag;
+    uint8_t  sps_rrc_rice_extension_flag;
+    uint8_t  sps_persistent_rice_adaptation_enabled_flag;
+    uint8_t  sps_reverse_last_sig_coeff_enabled_flag;
+
     H266RawExtensionData extension_data;
 
 } H266RawSPS;
@@ -734,6 +750,8 @@ typedef struct  H266RawSliceHeader {
 
     uint8_t  sh_sign_data_hiding_used_flag;
     uint8_t  sh_ts_residual_coding_disabled_flag;
+    uint8_t  sh_ts_residual_coding_rice_idx_minus1;
+    uint8_t  sh_reverse_last_sig_coeff_flag;
     uint16_t sh_slice_header_extension_length;
     uint8_t  sh_slice_header_extension_data_byte[256];
 
diff --git a/libavcodec/cbs_h266_syntax_template.c b/libavcodec/cbs_h266_syntax_template.c
index 485c02f590..893fa55369 100644
--- a/libavcodec/cbs_h266_syntax_template.c
+++ b/libavcodec/cbs_h266_syntax_template.c
@@ -61,7 +61,7 @@ static int FUNC(general_constraints_info) (CodedBitstreamContext *ctx,
                                            RWContext *rw,
                                            H266GeneralConstraintsInfo *current)
 {
-    int err, i;
+    int err, i, num_additional_bits_used;
 
     flag(gci_present_flag);
     if (current->gci_present_flag) {
@@ -149,7 +149,25 @@ static int FUNC(general_constraints_info) (CodedBitstreamContext *ctx,
         flag(gci_no_ladf_constraint_flag);
         flag(gci_no_virtual_boundaries_constraint_flag);
         ub(8, gci_num_reserved_bits);
-        for (i = 0; i < current->gci_num_reserved_bits; i++) {
+        if (current->gci_num_reserved_bits > 5) {
+            flag(gci_all_rap_pictures_constraint_flag);
+            flag(gci_no_extended_precision_processing_constraint_flag);
+            flag(gci_no_ts_residual_coding_rice_constraint_flag);
+            flag(gci_no_rrc_rice_extension_constraint_flag);
+            flag(gci_no_persistent_rice_adaptation_constraint_flag);
+            flag(gci_no_reverse_last_sig_coeff_constraint_flag);
+            num_additional_bits_used = 6;
+        } else {
+            infer(gci_all_rap_pictures_constraint_flag, 0);
+            infer(gci_no_extended_precision_processing_constraint_flag, 0);
+            infer(gci_no_ts_residual_coding_rice_constraint_flag, 0);
+            infer(gci_no_rrc_rice_extension_constraint_flag, 0);
+            infer(gci_no_persistent_rice_adaptation_constraint_flag, 0);
+            infer(gci_no_reverse_last_sig_coeff_constraint_flag, 0);
+            num_additional_bits_used = 0;
+        }
+
+        for (i = 0; i < current->gci_num_reserved_bits - num_additional_bits_used; i++) {
             flags(gci_reserved_zero_bit[i], 1, i);
         }
     }
@@ -963,6 +981,23 @@ static int FUNC(vps) (CodedBitstreamContext *ctx, RWContext *rw,
     return 0;
 }
 
+static int FUNC(sps_range_extension)(CodedBitstreamContext *ctx, RWContext *rw,
+                                     H266RawSPS *current)
+{
+    int err;
+
+    flag(sps_extended_precision_flag);
+    if (current->sps_transform_skip_enabled_flag) {
+        flag(sps_ts_residual_coding_rice_present_in_sh_flag);
+    } else {
+        infer(sps_ts_residual_coding_rice_present_in_sh_flag, 0);
+    }
+    flag(sps_rrc_rice_extension_flag);
+    flag(sps_persistent_rice_adaptation_enabled_flag);
+    flag(sps_reverse_last_sig_coeff_enabled_flag);
+
+    return 0;
+}
 
 static int FUNC(sps)(CodedBitstreamContext *ctx, RWContext *rw,
                      H266RawSPS *current)
@@ -1518,9 +1553,33 @@ static int FUNC(sps)(CodedBitstreamContext *ctx, RWContext *rw,
     } else {
         CHECK(FUNC(vui_parameters_default) (ctx, rw, &current->vui));
     }
+
     flag(sps_extension_flag);
-    if (current->sps_extension_flag)
-        CHECK(FUNC(extension_data) (ctx, rw, &current->extension_data));
+    if (current->sps_extension_flag) {
+        flag(sps_range_extension_flag);
+        ub(7, sps_extension_7bits);
+
+        if (current->sps_range_extension_flag) {
+            CHECK(FUNC(sps_range_extension)(ctx, rw, current));
+        } else {
+            infer(sps_extended_precision_flag, 0);
+            infer(sps_ts_residual_coding_rice_present_in_sh_flag, 0);
+            infer(sps_rrc_rice_extension_flag, 0);
+            infer(sps_persistent_rice_adaptation_enabled_flag, 0);
+            infer(sps_reverse_last_sig_coeff_enabled_flag, 0);
+        }
+    } else {
+        infer(sps_range_extension_flag, 0);
+        infer(sps_extension_7bits, 0);
+        infer(sps_extended_precision_flag, 0);
+        infer(sps_ts_residual_coding_rice_present_in_sh_flag, 0);
+        infer(sps_rrc_rice_extension_flag, 0);
+        infer(sps_persistent_rice_adaptation_enabled_flag, 0);
+        infer(sps_reverse_last_sig_coeff_enabled_flag, 0);
+    }
+
+    if (current->sps_extension_7bits)
+        CHECK(FUNC(extension_data)(ctx, rw, &current->extension_data));
 
     CHECK(FUNC(rbsp_trailing_bits) (ctx, rw));
 
@@ -3005,6 +3064,18 @@ static int FUNC(slice_header) (CodedBitstreamContext *ctx, RWContext *rw,
         flag(sh_ts_residual_coding_disabled_flag);
     else
         infer(sh_ts_residual_coding_disabled_flag, 0);
+
+    if (!current->sh_ts_residual_coding_disabled_flag &&
+        sps->sps_ts_residual_coding_rice_present_in_sh_flag)
+        ub(3, sh_ts_residual_coding_rice_idx_minus1);
+    else
+        infer(sh_ts_residual_coding_rice_idx_minus1, 0);
+
+    if (sps->sps_reverse_last_sig_coeff_enabled_flag)
+        flag(sh_reverse_last_sig_coeff_flag);
+    else
+        infer(sh_reverse_last_sig_coeff_flag, 0);
+
     if (pps->pps_slice_header_extension_present_flag) {
         ue(sh_slice_header_extension_length, 0, 256);
         for (i = 0; i < current->sh_slice_header_extension_length; i++)
-- 
2.25.1

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