tor-browser

cbs_av1_syntax_template.c (71624B)

---

/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

static int FUNC(obu_header)(CodedBitstreamContext *ctx, RWContext *rw,
                           AV1RawOBUHeader *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   int err;

   HEADER("OBU header");

   fc(1, obu_forbidden_bit, 0, 0);

   fc(4, obu_type, 0, AV1_OBU_PADDING);
   flag(obu_extension_flag);
   flag(obu_has_size_field);

   fc(1, obu_reserved_1bit, 0, 0);

   if (current->obu_extension_flag) {
       fb(3, temporal_id);
       fb(2, spatial_id);
       fc(3, extension_header_reserved_3bits, 0, 0);
   } else {
       infer(temporal_id, 0);
       infer(spatial_id, 0);
   }

   priv->temporal_id = current->temporal_id;
   priv->spatial_id  = current->spatial_id;

   return 0;
}

static int FUNC(trailing_bits)(CodedBitstreamContext *ctx, RWContext *rw, int nb_bits)
{
   int err;

   av_assert0(nb_bits > 0);

   fixed(1, trailing_one_bit, 1);
   --nb_bits;

   while (nb_bits > 0) {
       fixed(1, trailing_zero_bit, 0);
       --nb_bits;
   }

   return 0;
}

static int FUNC(byte_alignment)(CodedBitstreamContext *ctx, RWContext *rw)
{
   int err;

   while (byte_alignment(rw) != 0)
       fixed(1, zero_bit, 0);

   return 0;
}

static int FUNC(color_config)(CodedBitstreamContext *ctx, RWContext *rw,
                             AV1RawColorConfig *current, int seq_profile)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   int err;

   flag(high_bitdepth);

   if (seq_profile == AV_PROFILE_AV1_PROFESSIONAL &&
       current->high_bitdepth) {
       flag(twelve_bit);
       priv->bit_depth = current->twelve_bit ? 12 : 10;
   } else {
       priv->bit_depth = current->high_bitdepth ? 10 : 8;
   }

   if (seq_profile == AV_PROFILE_AV1_HIGH)
       infer(mono_chrome, 0);
   else
       flag(mono_chrome);
   priv->num_planes = current->mono_chrome ? 1 : 3;

   flag(color_description_present_flag);
   if (current->color_description_present_flag) {
       fb(8, color_primaries);
       fb(8, transfer_characteristics);
       fb(8, matrix_coefficients);
   } else {
       infer(color_primaries,          AVCOL_PRI_UNSPECIFIED);
       infer(transfer_characteristics, AVCOL_TRC_UNSPECIFIED);
       infer(matrix_coefficients,      AVCOL_SPC_UNSPECIFIED);
   }

   if (current->mono_chrome) {
       flag(color_range);

       infer(subsampling_x, 1);
       infer(subsampling_y, 1);
       infer(chroma_sample_position, AV1_CSP_UNKNOWN);
       infer(separate_uv_delta_q, 0);

   } else if (current->color_primaries          == AVCOL_PRI_BT709 &&
              current->transfer_characteristics == AVCOL_TRC_IEC61966_2_1 &&
              current->matrix_coefficients      == AVCOL_SPC_RGB) {
       infer(color_range,   1);
       infer(subsampling_x, 0);
       infer(subsampling_y, 0);
       flag(separate_uv_delta_q);

   } else {
       flag(color_range);

       if (seq_profile == AV_PROFILE_AV1_MAIN) {
           infer(subsampling_x, 1);
           infer(subsampling_y, 1);
       } else if (seq_profile == AV_PROFILE_AV1_HIGH) {
           infer(subsampling_x, 0);
           infer(subsampling_y, 0);
       } else {
           if (priv->bit_depth == 12) {
               fb(1, subsampling_x);
               if (current->subsampling_x)
                   fb(1, subsampling_y);
               else
                   infer(subsampling_y, 0);
           } else {
               infer(subsampling_x, 1);
               infer(subsampling_y, 0);
           }
       }
       if (current->subsampling_x && current->subsampling_y) {
           fc(2, chroma_sample_position, AV1_CSP_UNKNOWN,
                                         AV1_CSP_COLOCATED);
       }

       flag(separate_uv_delta_q);
   }

   return 0;
}

static int FUNC(timing_info)(CodedBitstreamContext *ctx, RWContext *rw,
                            AV1RawTimingInfo *current)
{
   int err;

   fc(32, num_units_in_display_tick, 1, MAX_UINT_BITS(32));
   fc(32, time_scale,                1, MAX_UINT_BITS(32));

   flag(equal_picture_interval);
   if (current->equal_picture_interval)
       uvlc(num_ticks_per_picture_minus_1, 0, MAX_UINT_BITS(32) - 1);

   return 0;
}

static int FUNC(decoder_model_info)(CodedBitstreamContext *ctx, RWContext *rw,
                                   AV1RawDecoderModelInfo *current)
{
   int err;

   fb(5, buffer_delay_length_minus_1);
   fc(32, num_units_in_decoding_tick, 1, MAX_UINT_BITS(32));
   fb(5,  buffer_removal_time_length_minus_1);
   fb(5,  frame_presentation_time_length_minus_1);

   return 0;
}

static int FUNC(sequence_header_obu)(CodedBitstreamContext *ctx, RWContext *rw,
                                    AV1RawSequenceHeader *current)
{
   int i, err;

   HEADER("Sequence Header");

   fc(3, seq_profile, AV_PROFILE_AV1_MAIN,
                      AV_PROFILE_AV1_PROFESSIONAL);
   flag(still_picture);
   flag(reduced_still_picture_header);

   if (current->reduced_still_picture_header) {
       infer(timing_info_present_flag,           0);
       infer(decoder_model_info_present_flag,    0);
       infer(initial_display_delay_present_flag, 0);
       infer(operating_points_cnt_minus_1,       0);
       infer(operating_point_idc[0],             0);

       fb(5, seq_level_idx[0]);

       infer(seq_tier[0], 0);
       infer(decoder_model_present_for_this_op[0],         0);
       infer(initial_display_delay_present_for_this_op[0], 0);

   } else {
       flag(timing_info_present_flag);
       if (current->timing_info_present_flag) {
           CHECK(FUNC(timing_info)(ctx, rw, &current->timing_info));

           flag(decoder_model_info_present_flag);
           if (current->decoder_model_info_present_flag) {
               CHECK(FUNC(decoder_model_info)
                         (ctx, rw, &current->decoder_model_info));
           }
       } else {
           infer(decoder_model_info_present_flag, 0);
       }

       flag(initial_display_delay_present_flag);

       fb(5, operating_points_cnt_minus_1);
       for (i = 0; i <= current->operating_points_cnt_minus_1; i++) {
           fbs(12, operating_point_idc[i], 1, i);
           fbs(5,  seq_level_idx[i], 1, i);

           if (current->seq_level_idx[i] > 7)
               flags(seq_tier[i], 1, i);
           else
               infer(seq_tier[i], 0);

           if (current->decoder_model_info_present_flag) {
               flags(decoder_model_present_for_this_op[i], 1, i);
               if (current->decoder_model_present_for_this_op[i]) {
                   int n = current->decoder_model_info.buffer_delay_length_minus_1 + 1;
                   fbs(n, decoder_buffer_delay[i], 1, i);
                   fbs(n, encoder_buffer_delay[i], 1, i);
                   flags(low_delay_mode_flag[i], 1, i);
               }
           } else {
               infer(decoder_model_present_for_this_op[i], 0);
           }

           if (current->initial_display_delay_present_flag) {
               flags(initial_display_delay_present_for_this_op[i], 1, i);
               if (current->initial_display_delay_present_for_this_op[i])
                   fbs(4, initial_display_delay_minus_1[i], 1, i);
           }
       }
   }

   fb(4, frame_width_bits_minus_1);
   fb(4, frame_height_bits_minus_1);

   fb(current->frame_width_bits_minus_1  + 1, max_frame_width_minus_1);
   fb(current->frame_height_bits_minus_1 + 1, max_frame_height_minus_1);

   if (current->reduced_still_picture_header)
       infer(frame_id_numbers_present_flag, 0);
   else
       flag(frame_id_numbers_present_flag);
   if (current->frame_id_numbers_present_flag) {
       fb(4, delta_frame_id_length_minus_2);
       fb(3, additional_frame_id_length_minus_1);
   }

   flag(use_128x128_superblock);
   flag(enable_filter_intra);
   flag(enable_intra_edge_filter);

   if (current->reduced_still_picture_header) {
       infer(enable_interintra_compound, 0);
       infer(enable_masked_compound,     0);
       infer(enable_warped_motion,       0);
       infer(enable_dual_filter,         0);
       infer(enable_order_hint,          0);
       infer(enable_jnt_comp,            0);
       infer(enable_ref_frame_mvs,       0);

       infer(seq_force_screen_content_tools,
             AV1_SELECT_SCREEN_CONTENT_TOOLS);
       infer(seq_force_integer_mv,
             AV1_SELECT_INTEGER_MV);
   } else {
       flag(enable_interintra_compound);
       flag(enable_masked_compound);
       flag(enable_warped_motion);
       flag(enable_dual_filter);

       flag(enable_order_hint);
       if (current->enable_order_hint) {
           flag(enable_jnt_comp);
           flag(enable_ref_frame_mvs);
       } else {
           infer(enable_jnt_comp,      0);
           infer(enable_ref_frame_mvs, 0);
       }

       flag(seq_choose_screen_content_tools);
       if (current->seq_choose_screen_content_tools)
           infer(seq_force_screen_content_tools,
                 AV1_SELECT_SCREEN_CONTENT_TOOLS);
       else
           fb(1, seq_force_screen_content_tools);
       if (current->seq_force_screen_content_tools > 0) {
           flag(seq_choose_integer_mv);
           if (current->seq_choose_integer_mv)
               infer(seq_force_integer_mv,
                     AV1_SELECT_INTEGER_MV);
           else
               fb(1, seq_force_integer_mv);
       } else {
           infer(seq_force_integer_mv, AV1_SELECT_INTEGER_MV);
       }

       if (current->enable_order_hint)
           fb(3, order_hint_bits_minus_1);
   }

   flag(enable_superres);
   flag(enable_cdef);
   flag(enable_restoration);

   CHECK(FUNC(color_config)(ctx, rw, &current->color_config,
                            current->seq_profile));

   flag(film_grain_params_present);

   return 0;
}

static int FUNC(temporal_delimiter_obu)(CodedBitstreamContext *ctx, RWContext *rw)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;

   HEADER("Temporal Delimiter");

   priv->seen_frame_header = 0;

   return 0;
}

static int FUNC(set_frame_refs)(CodedBitstreamContext *ctx, RWContext *rw,
                               AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   static const uint8_t ref_frame_list[AV1_NUM_REF_FRAMES - 2] = {
       AV1_REF_FRAME_LAST2, AV1_REF_FRAME_LAST3, AV1_REF_FRAME_BWDREF,
       AV1_REF_FRAME_ALTREF2, AV1_REF_FRAME_ALTREF
   };
   int8_t ref_frame_idx[AV1_REFS_PER_FRAME], used_frame[AV1_NUM_REF_FRAMES];
   int16_t shifted_order_hints[AV1_NUM_REF_FRAMES];
   int cur_frame_hint, latest_order_hint, earliest_order_hint, ref;
   int i, j;

   for (i = 0; i < AV1_REFS_PER_FRAME; i++)
       ref_frame_idx[i] = AV1_REF_FRAME_NONE;
   ref_frame_idx[AV1_REF_FRAME_LAST - AV1_REF_FRAME_LAST] = current->last_frame_idx;
   ref_frame_idx[AV1_REF_FRAME_GOLDEN - AV1_REF_FRAME_LAST] = current->golden_frame_idx;

   for (i = 0; i < AV1_NUM_REF_FRAMES; i++)
       used_frame[i] = 0;
   used_frame[current->last_frame_idx] = 1;
   used_frame[current->golden_frame_idx] = 1;

   cur_frame_hint = 1 << (seq->order_hint_bits_minus_1);
   for (i = 0; i < AV1_NUM_REF_FRAMES; i++)
       shifted_order_hints[i] = cur_frame_hint +
                                cbs_av1_get_relative_dist(seq, priv->ref[i].order_hint,
                                                          priv->order_hint);

   latest_order_hint = shifted_order_hints[current->last_frame_idx];
   earliest_order_hint = shifted_order_hints[current->golden_frame_idx];

   ref = AV1_REF_FRAME_NONE;
   for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
       int hint = shifted_order_hints[i];
       if (!used_frame[i] && hint >= cur_frame_hint &&
           (ref < 0 || hint >= latest_order_hint)) {
           ref = i;
           latest_order_hint = hint;
       }
   }
   if (ref >= 0) {
       ref_frame_idx[AV1_REF_FRAME_ALTREF - AV1_REF_FRAME_LAST] = ref;
       used_frame[ref] = 1;
   }

   ref = AV1_REF_FRAME_NONE;
   for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
       int hint = shifted_order_hints[i];
       if (!used_frame[i] && hint >= cur_frame_hint &&
           (ref < 0 || hint < earliest_order_hint)) {
           ref = i;
           earliest_order_hint = hint;
       }
   }
   if (ref >= 0) {
       ref_frame_idx[AV1_REF_FRAME_BWDREF - AV1_REF_FRAME_LAST] = ref;
       used_frame[ref] = 1;
   }

   ref = AV1_REF_FRAME_NONE;
   for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
       int hint = shifted_order_hints[i];
       if (!used_frame[i] && hint >= cur_frame_hint &&
           (ref < 0 || hint < earliest_order_hint)) {
           ref = i;
           earliest_order_hint = hint;
       }
   }
   if (ref >= 0) {
       ref_frame_idx[AV1_REF_FRAME_ALTREF2 - AV1_REF_FRAME_LAST] = ref;
       used_frame[ref] = 1;
   }

   for (i = 0; i < AV1_REFS_PER_FRAME - 2; i++) {
       int ref_frame = ref_frame_list[i];
       if (ref_frame_idx[ref_frame - AV1_REF_FRAME_LAST] < 0 ) {
           ref = AV1_REF_FRAME_NONE;
           for (j = 0; j < AV1_NUM_REF_FRAMES; j++) {
               int hint = shifted_order_hints[j];
               if (!used_frame[j] && hint < cur_frame_hint &&
                   (ref < 0 || hint >= latest_order_hint)) {
                   ref = j;
                   latest_order_hint = hint;
               }
           }
           if (ref >= 0) {
               ref_frame_idx[ref_frame - AV1_REF_FRAME_LAST] = ref;
               used_frame[ref] = 1;
           }
       }
   }

   ref = AV1_REF_FRAME_NONE;
   for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
       int hint = shifted_order_hints[i];
       if (ref < 0 || hint < earliest_order_hint) {
           ref = i;
           earliest_order_hint = hint;
       }
   }
   for (i = 0; i < AV1_REFS_PER_FRAME; i++) {
       if (ref_frame_idx[i] < 0)
           ref_frame_idx[i] = ref;
       infer(ref_frame_idx[i], ref_frame_idx[i]);
   }

   return 0;
}

static int FUNC(superres_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int denom, err;

   if (seq->enable_superres)
       flag(use_superres);
   else
       infer(use_superres, 0);

   if (current->use_superres) {
       fb(3, coded_denom);
       denom = current->coded_denom + AV1_SUPERRES_DENOM_MIN;
   } else {
       denom = AV1_SUPERRES_NUM;
   }

   priv->upscaled_width = priv->frame_width;
   priv->frame_width = (priv->upscaled_width * AV1_SUPERRES_NUM +
                        denom / 2) / denom;

   return 0;
}

static int FUNC(frame_size)(CodedBitstreamContext *ctx, RWContext *rw,
                           AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int err;

   if (current->frame_size_override_flag) {
       fb(seq->frame_width_bits_minus_1 + 1,  frame_width_minus_1);
       fb(seq->frame_height_bits_minus_1 + 1, frame_height_minus_1);
   } else {
       infer(frame_width_minus_1,  seq->max_frame_width_minus_1);
       infer(frame_height_minus_1, seq->max_frame_height_minus_1);
   }

   priv->frame_width  = current->frame_width_minus_1  + 1;
   priv->frame_height = current->frame_height_minus_1 + 1;

   CHECK(FUNC(superres_params)(ctx, rw, current));

   return 0;
}

static int FUNC(render_size)(CodedBitstreamContext *ctx, RWContext *rw,
                            AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   int err;

   flag(render_and_frame_size_different);

   if (current->render_and_frame_size_different) {
       fb(16, render_width_minus_1);
       fb(16, render_height_minus_1);
   } else {
       infer(render_width_minus_1,  current->frame_width_minus_1);
       infer(render_height_minus_1, current->frame_height_minus_1);
   }

   priv->render_width  = current->render_width_minus_1  + 1;
   priv->render_height = current->render_height_minus_1 + 1;

   return 0;
}

static int FUNC(frame_size_with_refs)(CodedBitstreamContext *ctx, RWContext *rw,
                                     AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   int i, err;

   for (i = 0; i < AV1_REFS_PER_FRAME; i++) {
       flags(found_ref[i], 1, i);
       if (current->found_ref[i]) {
           AV1ReferenceFrameState *ref =
               &priv->ref[current->ref_frame_idx[i]];

           if (!ref->valid) {
               av_log(ctx->log_ctx, AV_LOG_ERROR,
                      "Missing reference frame needed for frame size "
                      "(ref = %d, ref_frame_idx = %d).\n",
                      i, current->ref_frame_idx[i]);
               return AVERROR_INVALIDDATA;
           }

           infer(frame_width_minus_1,   ref->upscaled_width - 1);
           infer(frame_height_minus_1,  ref->frame_height - 1);
           infer(render_width_minus_1,  ref->render_width - 1);
           infer(render_height_minus_1, ref->render_height - 1);

           priv->upscaled_width = ref->upscaled_width;
           priv->frame_width    = priv->upscaled_width;
           priv->frame_height   = ref->frame_height;
           priv->render_width   = ref->render_width;
           priv->render_height  = ref->render_height;
           break;
       }
   }

   if (i >= AV1_REFS_PER_FRAME) {
       CHECK(FUNC(frame_size)(ctx, rw, current));
       CHECK(FUNC(render_size)(ctx, rw, current));
   } else {
       CHECK(FUNC(superres_params)(ctx, rw, current));
   }

   return 0;
}

static int FUNC(interpolation_filter)(CodedBitstreamContext *ctx, RWContext *rw,
                                     AV1RawFrameHeader *current)
{
   int err;

   flag(is_filter_switchable);
   if (current->is_filter_switchable)
       infer(interpolation_filter,
             AV1_INTERPOLATION_FILTER_SWITCHABLE);
   else
       fb(2, interpolation_filter);

   return 0;
}

static int FUNC(tile_info)(CodedBitstreamContext *ctx, RWContext *rw,
                          AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int mi_cols, mi_rows, sb_cols, sb_rows, sb_shift, sb_size;
   int max_tile_width_sb, max_tile_height_sb, max_tile_area_sb;
   int min_log2_tile_cols, max_log2_tile_cols, max_log2_tile_rows;
   int min_log2_tiles, min_log2_tile_rows;
   int i, err;

   mi_cols = 2 * ((priv->frame_width  + 7) >> 3);
   mi_rows = 2 * ((priv->frame_height + 7) >> 3);

   sb_cols = seq->use_128x128_superblock ? ((mi_cols + 31) >> 5)
                                         : ((mi_cols + 15) >> 4);
   sb_rows = seq->use_128x128_superblock ? ((mi_rows + 31) >> 5)
                                         : ((mi_rows + 15) >> 4);

   sb_shift = seq->use_128x128_superblock ? 5 : 4;
   sb_size  = sb_shift + 2;

   max_tile_width_sb = AV1_MAX_TILE_WIDTH >> sb_size;
   max_tile_area_sb  = AV1_MAX_TILE_AREA  >> (2 * sb_size);

   min_log2_tile_cols = cbs_av1_tile_log2(max_tile_width_sb, sb_cols);
   max_log2_tile_cols = cbs_av1_tile_log2(1, FFMIN(sb_cols, AV1_MAX_TILE_COLS));
   max_log2_tile_rows = cbs_av1_tile_log2(1, FFMIN(sb_rows, AV1_MAX_TILE_ROWS));
   min_log2_tiles = FFMAX(min_log2_tile_cols,
                          cbs_av1_tile_log2(max_tile_area_sb, sb_rows * sb_cols));

   flag(uniform_tile_spacing_flag);

   if (current->uniform_tile_spacing_flag) {
       int tile_width_sb, tile_height_sb;

       increment(tile_cols_log2, min_log2_tile_cols, max_log2_tile_cols);

       tile_width_sb = (sb_cols + (1 << current->tile_cols_log2) - 1) >>
           current->tile_cols_log2;

       for (int off = 0, i = 0; off < sb_cols; off += tile_width_sb)
           current->tile_start_col_sb[i++] = off;

       current->tile_cols = (sb_cols + tile_width_sb - 1) / tile_width_sb;

       min_log2_tile_rows = FFMAX(min_log2_tiles - current->tile_cols_log2, 0);

       increment(tile_rows_log2, min_log2_tile_rows, max_log2_tile_rows);

       tile_height_sb = (sb_rows + (1 << current->tile_rows_log2) - 1) >>
           current->tile_rows_log2;

       for (int off = 0, i = 0; off < sb_rows; off += tile_height_sb)
           current->tile_start_row_sb[i++] = off;

       current->tile_rows = (sb_rows + tile_height_sb - 1) / tile_height_sb;

       for (i = 0; i < current->tile_cols - 1; i++)
           infer(width_in_sbs_minus_1[i], tile_width_sb - 1);
       infer(width_in_sbs_minus_1[i],
             sb_cols - (current->tile_cols - 1) * tile_width_sb - 1);
       for (i = 0; i < current->tile_rows - 1; i++)
           infer(height_in_sbs_minus_1[i], tile_height_sb - 1);
       infer(height_in_sbs_minus_1[i],
             sb_rows - (current->tile_rows - 1) * tile_height_sb - 1);

   } else {
       int widest_tile_sb, start_sb, size_sb, max_width, max_height;

       widest_tile_sb = 0;

       start_sb = 0;
       for (i = 0; start_sb < sb_cols && i < AV1_MAX_TILE_COLS; i++) {
           current->tile_start_col_sb[i] = start_sb;
           max_width = FFMIN(sb_cols - start_sb, max_tile_width_sb);
           ns(max_width, width_in_sbs_minus_1[i], 1, i);
           size_sb = current->width_in_sbs_minus_1[i] + 1;
           widest_tile_sb = FFMAX(size_sb, widest_tile_sb);
           start_sb += size_sb;
       }
       current->tile_cols_log2 = cbs_av1_tile_log2(1, i);
       current->tile_cols = i;

       if (min_log2_tiles > 0)
           max_tile_area_sb = (sb_rows * sb_cols) >> (min_log2_tiles + 1);
       else
           max_tile_area_sb = sb_rows * sb_cols;
       max_tile_height_sb = FFMAX(max_tile_area_sb / widest_tile_sb, 1);

       start_sb = 0;
       for (i = 0; start_sb < sb_rows && i < AV1_MAX_TILE_ROWS; i++) {
           current->tile_start_row_sb[i] = start_sb;
           max_height = FFMIN(sb_rows - start_sb, max_tile_height_sb);
           ns(max_height, height_in_sbs_minus_1[i], 1, i);
           size_sb = current->height_in_sbs_minus_1[i] + 1;
           start_sb += size_sb;
       }
       current->tile_rows_log2 = cbs_av1_tile_log2(1, i);
       current->tile_rows = i;
   }

   if (current->tile_cols_log2 > 0 ||
       current->tile_rows_log2 > 0) {
       fb(current->tile_cols_log2 + current->tile_rows_log2,
          context_update_tile_id);
       fb(2, tile_size_bytes_minus1);
   } else {
       infer(context_update_tile_id, 0);
   }

   priv->tile_cols = current->tile_cols;
   priv->tile_rows = current->tile_rows;

   return 0;
}

static int FUNC(quantization_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                    AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int err;

   fb(8, base_q_idx);

   delta_q(delta_q_y_dc);

   if (priv->num_planes > 1) {
       if (seq->color_config.separate_uv_delta_q)
           flag(diff_uv_delta);
       else
           infer(diff_uv_delta, 0);

       delta_q(delta_q_u_dc);
       delta_q(delta_q_u_ac);

       if (current->diff_uv_delta) {
           delta_q(delta_q_v_dc);
           delta_q(delta_q_v_ac);
       } else {
           infer(delta_q_v_dc, current->delta_q_u_dc);
           infer(delta_q_v_ac, current->delta_q_u_ac);
       }
   } else {
       infer(delta_q_u_dc, 0);
       infer(delta_q_u_ac, 0);
       infer(delta_q_v_dc, 0);
       infer(delta_q_v_ac, 0);
   }

   flag(using_qmatrix);
   if (current->using_qmatrix) {
       fb(4, qm_y);
       fb(4, qm_u);
       if (seq->color_config.separate_uv_delta_q)
           fb(4, qm_v);
       else
           infer(qm_v, current->qm_u);
   }

   return 0;
}

static int FUNC(segmentation_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                    AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   static const uint8_t bits[AV1_SEG_LVL_MAX] = { 8, 6, 6, 6, 6, 3, 0, 0 };
   static const uint8_t sign[AV1_SEG_LVL_MAX] = { 1, 1, 1, 1, 1, 0, 0, 0 };
   static const uint8_t default_feature_enabled[AV1_SEG_LVL_MAX] = { 0 };
   static const int16_t default_feature_value[AV1_SEG_LVL_MAX] = { 0 };
   int i, j, err;

   flag(segmentation_enabled);

   if (current->segmentation_enabled) {
       if (current->primary_ref_frame == AV1_PRIMARY_REF_NONE) {
           infer(segmentation_update_map,      1);
           infer(segmentation_temporal_update, 0);
           infer(segmentation_update_data,     1);
       } else {
           flag(segmentation_update_map);
           if (current->segmentation_update_map)
               flag(segmentation_temporal_update);
           else
               infer(segmentation_temporal_update, 0);
           flag(segmentation_update_data);
       }

       for (i = 0; i < AV1_MAX_SEGMENTS; i++) {
           const uint8_t *ref_feature_enabled;
           const int16_t *ref_feature_value;

           if (current->primary_ref_frame == AV1_PRIMARY_REF_NONE) {
               ref_feature_enabled = default_feature_enabled;
               ref_feature_value = default_feature_value;
           } else {
               ref_feature_enabled =
                   priv->ref[current->ref_frame_idx[current->primary_ref_frame]].feature_enabled[i];
               ref_feature_value =
                   priv->ref[current->ref_frame_idx[current->primary_ref_frame]].feature_value[i];
           }

           for (j = 0; j < AV1_SEG_LVL_MAX; j++) {
               if (current->segmentation_update_data) {
                   flags(feature_enabled[i][j], 2, i, j);

                   if (current->feature_enabled[i][j] && bits[j] > 0) {
                       if (sign[j])
                           sus(1 + bits[j], feature_value[i][j], 2, i, j);
                       else
                           fbs(bits[j], feature_value[i][j], 2, i, j);
                   } else {
                       infer(feature_value[i][j], 0);
                   }
               } else {
                   infer(feature_enabled[i][j], ref_feature_enabled[j]);
                   infer(feature_value[i][j], ref_feature_value[j]);
               }
           }
       }
   } else {
       for (i = 0; i < AV1_MAX_SEGMENTS; i++) {
           for (j = 0; j < AV1_SEG_LVL_MAX; j++) {
               infer(feature_enabled[i][j], 0);
               infer(feature_value[i][j],   0);
           }
       }
   }

   return 0;
}

static int FUNC(delta_q_params)(CodedBitstreamContext *ctx, RWContext *rw,
                               AV1RawFrameHeader *current)
{
   int err;

   if (current->base_q_idx > 0)
       flag(delta_q_present);
   else
       infer(delta_q_present, 0);

   if (current->delta_q_present)
       fb(2, delta_q_res);

   return 0;
}

static int FUNC(delta_lf_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                AV1RawFrameHeader *current)
{
   int err;

   if (current->delta_q_present) {
       if (!current->allow_intrabc)
           flag(delta_lf_present);
       else
           infer(delta_lf_present, 0);
       if (current->delta_lf_present) {
           fb(2, delta_lf_res);
           flag(delta_lf_multi);
       } else {
           infer(delta_lf_res,   0);
           infer(delta_lf_multi, 0);
       }
   } else {
       infer(delta_lf_present, 0);
       infer(delta_lf_res,     0);
       infer(delta_lf_multi,   0);
   }

   return 0;
}

static int FUNC(loop_filter_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                   AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   static const int8_t default_loop_filter_ref_deltas[AV1_TOTAL_REFS_PER_FRAME] =
       { 1, 0, 0, 0, -1, 0, -1, -1 };
   static const int8_t default_loop_filter_mode_deltas[2] = { 0, 0 };
   int i, err;

   if (priv->coded_lossless || current->allow_intrabc) {
       infer(loop_filter_level[0], 0);
       infer(loop_filter_level[1], 0);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_INTRA],    1);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_LAST],     0);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_LAST2],    0);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_LAST3],    0);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_BWDREF],   0);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_GOLDEN],  -1);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_ALTREF],  -1);
       infer(loop_filter_ref_deltas[AV1_REF_FRAME_ALTREF2], -1);
       for (i = 0; i < 2; i++)
           infer(loop_filter_mode_deltas[i], 0);
       return 0;
   }

   fb(6, loop_filter_level[0]);
   fb(6, loop_filter_level[1]);

   if (priv->num_planes > 1) {
       if (current->loop_filter_level[0] ||
           current->loop_filter_level[1]) {
           fb(6, loop_filter_level[2]);
           fb(6, loop_filter_level[3]);
       }
   }

   fb(3, loop_filter_sharpness);

   flag(loop_filter_delta_enabled);
   if (current->loop_filter_delta_enabled) {
       const int8_t *ref_loop_filter_ref_deltas, *ref_loop_filter_mode_deltas;

       if (current->primary_ref_frame == AV1_PRIMARY_REF_NONE) {
           ref_loop_filter_ref_deltas = default_loop_filter_ref_deltas;
           ref_loop_filter_mode_deltas = default_loop_filter_mode_deltas;
       } else {
           ref_loop_filter_ref_deltas =
               priv->ref[current->ref_frame_idx[current->primary_ref_frame]].loop_filter_ref_deltas;
           ref_loop_filter_mode_deltas =
               priv->ref[current->ref_frame_idx[current->primary_ref_frame]].loop_filter_mode_deltas;
       }

       flag(loop_filter_delta_update);
       for (i = 0; i < AV1_TOTAL_REFS_PER_FRAME; i++) {
           if (current->loop_filter_delta_update)
               flags(update_ref_delta[i], 1, i);
           else
               infer(update_ref_delta[i], 0);
           if (current->update_ref_delta[i])
               sus(1 + 6, loop_filter_ref_deltas[i], 1, i);
           else
               infer(loop_filter_ref_deltas[i], ref_loop_filter_ref_deltas[i]);
       }
       for (i = 0; i < 2; i++) {
           if (current->loop_filter_delta_update)
               flags(update_mode_delta[i], 1, i);
           else
               infer(update_mode_delta[i], 0);
           if (current->update_mode_delta[i])
               sus(1 + 6, loop_filter_mode_deltas[i], 1, i);
           else
               infer(loop_filter_mode_deltas[i], ref_loop_filter_mode_deltas[i]);
       }
   } else {
       for (i = 0; i < AV1_TOTAL_REFS_PER_FRAME; i++)
           infer(loop_filter_ref_deltas[i], default_loop_filter_ref_deltas[i]);
       for (i = 0; i < 2; i++)
           infer(loop_filter_mode_deltas[i], default_loop_filter_mode_deltas[i]);
   }

   return 0;
}

static int FUNC(cdef_params)(CodedBitstreamContext *ctx, RWContext *rw,
                            AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int i, err;

   if (priv->coded_lossless || current->allow_intrabc ||
       !seq->enable_cdef) {
       infer(cdef_damping_minus_3, 0);
       infer(cdef_bits, 0);
       infer(cdef_y_pri_strength[0],  0);
       infer(cdef_y_sec_strength[0],  0);
       infer(cdef_uv_pri_strength[0], 0);
       infer(cdef_uv_sec_strength[0], 0);

       return 0;
   }

   fb(2, cdef_damping_minus_3);
   fb(2, cdef_bits);

   for (i = 0; i < (1 << current->cdef_bits); i++) {
       fbs(4, cdef_y_pri_strength[i], 1, i);
       fbs(2, cdef_y_sec_strength[i], 1, i);

       if (priv->num_planes > 1) {
           fbs(4, cdef_uv_pri_strength[i], 1, i);
           fbs(2, cdef_uv_sec_strength[i], 1, i);
       }
   }

   return 0;
}

static int FUNC(lr_params)(CodedBitstreamContext *ctx, RWContext *rw,
                          AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int uses_lr,  uses_chroma_lr;
   int i, err;

   if (priv->all_lossless || current->allow_intrabc ||
       !seq->enable_restoration) {
       return 0;
   }

   uses_lr = uses_chroma_lr = 0;
   for (i = 0; i < priv->num_planes; i++) {
       fbs(2, lr_type[i], 1, i);

       if (current->lr_type[i] != AV1_RESTORE_NONE) {
           uses_lr = 1;
           if (i > 0)
               uses_chroma_lr = 1;
       }
   }

   if (uses_lr) {
       if (seq->use_128x128_superblock)
           increment(lr_unit_shift, 1, 2);
       else
           increment(lr_unit_shift, 0, 2);

       if(seq->color_config.subsampling_x &&
          seq->color_config.subsampling_y && uses_chroma_lr) {
           fb(1, lr_uv_shift);
       } else {
           infer(lr_uv_shift, 0);
       }
   }

   return 0;
}

static int FUNC(read_tx_mode)(CodedBitstreamContext *ctx, RWContext *rw,
                             AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   int err;

   if (priv->coded_lossless)
       infer(tx_mode, AV1_ONLY_4X4);
   else
       increment(tx_mode, AV1_TX_MODE_LARGEST, AV1_TX_MODE_SELECT);

   return 0;
}

static int FUNC(frame_reference_mode)(CodedBitstreamContext *ctx, RWContext *rw,
                                     AV1RawFrameHeader *current)
{
   int err;

   if (current->frame_type == AV1_FRAME_INTRA_ONLY ||
       current->frame_type == AV1_FRAME_KEY)
       infer(reference_select, 0);
   else
       flag(reference_select);

   return 0;
}

static int FUNC(skip_mode_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                 AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int skip_mode_allowed;
   int err;

   if (current->frame_type == AV1_FRAME_KEY ||
       current->frame_type == AV1_FRAME_INTRA_ONLY ||
       !current->reference_select || !seq->enable_order_hint) {
       skip_mode_allowed = 0;
   } else {
       int forward_idx,  backward_idx;
       int forward_hint, backward_hint;
       int ref_hint, dist, i;

       forward_idx  = -1;
       backward_idx = -1;
       for (i = 0; i < AV1_REFS_PER_FRAME; i++) {
           ref_hint = priv->ref[current->ref_frame_idx[i]].order_hint;
           dist = cbs_av1_get_relative_dist(seq, ref_hint,
                                            priv->order_hint);
           if (dist < 0) {
               if (forward_idx < 0 ||
                   cbs_av1_get_relative_dist(seq, ref_hint,
                                             forward_hint) > 0) {
                   forward_idx  = i;
                   forward_hint = ref_hint;
               }
           } else if (dist > 0) {
               if (backward_idx < 0 ||
                   cbs_av1_get_relative_dist(seq, ref_hint,
                                             backward_hint) < 0) {
                   backward_idx  = i;
                   backward_hint = ref_hint;
               }
           }
       }

       if (forward_idx < 0) {
           skip_mode_allowed = 0;
       } else if (backward_idx >= 0) {
           skip_mode_allowed = 1;
           // Frames for skip mode are forward_idx and backward_idx.
       } else {
           int second_forward_idx;
           int second_forward_hint;

           second_forward_idx = -1;
           for (i = 0; i < AV1_REFS_PER_FRAME; i++) {
               ref_hint = priv->ref[current->ref_frame_idx[i]].order_hint;
               if (cbs_av1_get_relative_dist(seq, ref_hint,
                                             forward_hint) < 0) {
                   if (second_forward_idx < 0 ||
                       cbs_av1_get_relative_dist(seq, ref_hint,
                                                 second_forward_hint) > 0) {
                       second_forward_idx  = i;
                       second_forward_hint = ref_hint;
                   }
               }
           }

           if (second_forward_idx < 0) {
               skip_mode_allowed = 0;
           } else {
               skip_mode_allowed = 1;
               // Frames for skip mode are forward_idx and second_forward_idx.
           }
       }
   }

   if (skip_mode_allowed)
       flag(skip_mode_present);
   else
       infer(skip_mode_present, 0);

   return 0;
}

static int FUNC(global_motion_param)(CodedBitstreamContext *ctx, RWContext *rw,
                                    AV1RawFrameHeader *current,
                                    int type, int ref, int idx)
{
   uint32_t abs_bits, prec_bits, num_syms;
   int err;

   if (idx < 2) {
       if (type == AV1_WARP_MODEL_TRANSLATION) {
           abs_bits  = AV1_GM_ABS_TRANS_ONLY_BITS  - !current->allow_high_precision_mv;
           prec_bits = AV1_GM_TRANS_ONLY_PREC_BITS - !current->allow_high_precision_mv;
       } else {
           abs_bits  = AV1_GM_ABS_TRANS_BITS;
           prec_bits = AV1_GM_TRANS_PREC_BITS;
       }
   } else {
       abs_bits  = AV1_GM_ABS_ALPHA_BITS;
       prec_bits = AV1_GM_ALPHA_PREC_BITS;
   }

   num_syms = 2 * (1 << abs_bits) + 1;
   subexp(gm_params[ref][idx], num_syms, 2, ref, idx);

   // Actual gm_params value is not reconstructed here.
   (void)prec_bits;

   return 0;
}

static int FUNC(global_motion_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                     AV1RawFrameHeader *current)
{
   int ref, type;
   int err;

   if (current->frame_type == AV1_FRAME_KEY ||
       current->frame_type == AV1_FRAME_INTRA_ONLY)
       return 0;

   for (ref = AV1_REF_FRAME_LAST; ref <= AV1_REF_FRAME_ALTREF; ref++) {
       flags(is_global[ref], 1, ref);
       if (current->is_global[ref]) {
           flags(is_rot_zoom[ref], 1, ref);
           if (current->is_rot_zoom[ref]) {
               type = AV1_WARP_MODEL_ROTZOOM;
           } else {
               flags(is_translation[ref], 1, ref);
               type = current->is_translation[ref] ? AV1_WARP_MODEL_TRANSLATION
                                                   : AV1_WARP_MODEL_AFFINE;
           }
       } else {
           type = AV1_WARP_MODEL_IDENTITY;
       }

       if (type >= AV1_WARP_MODEL_ROTZOOM) {
           CHECK(FUNC(global_motion_param)(ctx, rw, current, type, ref, 2));
           CHECK(FUNC(global_motion_param)(ctx, rw, current, type, ref, 3));
           if (type == AV1_WARP_MODEL_AFFINE) {
               CHECK(FUNC(global_motion_param)(ctx, rw, current, type, ref, 4));
               CHECK(FUNC(global_motion_param)(ctx, rw, current, type, ref, 5));
           } else {
               // gm_params[ref][4] = -gm_params[ref][3]
               // gm_params[ref][5] =  gm_params[ref][2]
           }
       }
       if (type >= AV1_WARP_MODEL_TRANSLATION) {
           CHECK(FUNC(global_motion_param)(ctx, rw, current, type, ref, 0));
           CHECK(FUNC(global_motion_param)(ctx, rw, current, type, ref, 1));
       }
   }

   return 0;
}

static int FUNC(film_grain_params)(CodedBitstreamContext *ctx, RWContext *rw,
                                  AV1RawFilmGrainParams *current,
                                  AV1RawFrameHeader *frame_header)
{
   CodedBitstreamAV1Context  *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq = priv->sequence_header;
   int num_pos_luma, num_pos_chroma;
   int i, err;

   if (!seq->film_grain_params_present ||
       (!frame_header->show_frame && !frame_header->showable_frame))
       return 0;

   flag(apply_grain);

   if (!current->apply_grain)
       return 0;

   fb(16, grain_seed);

   if (frame_header->frame_type == AV1_FRAME_INTER)
       flag(update_grain);
   else
       infer(update_grain, 1);

   if (!current->update_grain) {
       fb(3, film_grain_params_ref_idx);
       return 0;
   }

   fc(4, num_y_points, 0, 14);
   for (i = 0; i < current->num_y_points; i++) {
       fcs(8, point_y_value[i],
           i ? current->point_y_value[i - 1] + 1 : 0,
           MAX_UINT_BITS(8) - (current->num_y_points - i - 1),
           1, i);
       fbs(8, point_y_scaling[i], 1, i);
   }

   if (seq->color_config.mono_chrome)
       infer(chroma_scaling_from_luma, 0);
   else
       flag(chroma_scaling_from_luma);

   if (seq->color_config.mono_chrome ||
       current->chroma_scaling_from_luma ||
       (seq->color_config.subsampling_x == 1 &&
        seq->color_config.subsampling_y == 1 &&
        current->num_y_points == 0)) {
       infer(num_cb_points, 0);
       infer(num_cr_points, 0);
   } else {
       fc(4, num_cb_points, 0, 10);
       for (i = 0; i < current->num_cb_points; i++) {
           fcs(8, point_cb_value[i],
               i ? current->point_cb_value[i - 1] + 1 : 0,
               MAX_UINT_BITS(8) - (current->num_cb_points - i - 1),
               1, i);
           fbs(8, point_cb_scaling[i], 1, i);
       }
       fc(4, num_cr_points, 0, 10);
       for (i = 0; i < current->num_cr_points; i++) {
           fcs(8, point_cr_value[i],
               i ? current->point_cr_value[i - 1] + 1 : 0,
               MAX_UINT_BITS(8) - (current->num_cr_points - i - 1),
               1, i);
           fbs(8, point_cr_scaling[i], 1, i);
       }
   }

   fb(2, grain_scaling_minus_8);
   fb(2, ar_coeff_lag);
   num_pos_luma = 2 * current->ar_coeff_lag * (current->ar_coeff_lag + 1);
   if (current->num_y_points) {
       num_pos_chroma = num_pos_luma + 1;
       for (i = 0; i < num_pos_luma; i++)
           fbs(8, ar_coeffs_y_plus_128[i], 1, i);
   } else {
       num_pos_chroma = num_pos_luma;
   }
   if (current->chroma_scaling_from_luma || current->num_cb_points) {
       for (i = 0; i < num_pos_chroma; i++)
           fbs(8, ar_coeffs_cb_plus_128[i], 1, i);
   }
   if (current->chroma_scaling_from_luma || current->num_cr_points) {
       for (i = 0; i < num_pos_chroma; i++)
           fbs(8, ar_coeffs_cr_plus_128[i], 1, i);
   }
   fb(2, ar_coeff_shift_minus_6);
   fb(2, grain_scale_shift);
   if (current->num_cb_points) {
       fb(8, cb_mult);
       fb(8, cb_luma_mult);
       fb(9, cb_offset);
   }
   if (current->num_cr_points) {
       fb(8, cr_mult);
       fb(8, cr_luma_mult);
       fb(9, cr_offset);
   }

   flag(overlap_flag);
   flag(clip_to_restricted_range);

   return 0;
}

static int FUNC(uncompressed_header)(CodedBitstreamContext *ctx, RWContext *rw,
                                    AV1RawFrameHeader *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq;
   int id_len, diff_len, all_frames, frame_is_intra, order_hint_bits;
   int i, err;

   if (!priv->sequence_header) {
       av_log(ctx->log_ctx, AV_LOG_ERROR, "No sequence header available: "
              "unable to decode frame header.\n");
       return AVERROR_INVALIDDATA;
   }
   seq = priv->sequence_header;

   id_len = seq->additional_frame_id_length_minus_1 +
            seq->delta_frame_id_length_minus_2 + 3;
   all_frames = (1 << AV1_NUM_REF_FRAMES) - 1;

   if (seq->reduced_still_picture_header) {
       infer(show_existing_frame, 0);
       infer(frame_type,     AV1_FRAME_KEY);
       infer(show_frame,     1);
       infer(showable_frame, 0);
       frame_is_intra = 1;

   } else {
       flag(show_existing_frame);

       if (current->show_existing_frame) {
           AV1ReferenceFrameState *ref;

           fb(3, frame_to_show_map_idx);
           ref = &priv->ref[current->frame_to_show_map_idx];

           if (!ref->valid) {
               av_log(ctx->log_ctx, AV_LOG_ERROR, "Missing reference frame needed for "
                      "show_existing_frame (frame_to_show_map_idx = %d).\n",
                      current->frame_to_show_map_idx);
               return AVERROR_INVALIDDATA;
           }

           if (seq->decoder_model_info_present_flag &&
               !seq->timing_info.equal_picture_interval) {
               fb(seq->decoder_model_info.frame_presentation_time_length_minus_1 + 1,
                  frame_presentation_time);
           }

           if (seq->frame_id_numbers_present_flag)
               fb(id_len, display_frame_id);

           infer(frame_type, ref->frame_type);
           if (current->frame_type == AV1_FRAME_KEY) {
               infer(refresh_frame_flags, all_frames);

               // Section 7.21
               infer(current_frame_id, ref->frame_id);
               priv->upscaled_width  = ref->upscaled_width;
               priv->frame_width     = ref->frame_width;
               priv->frame_height    = ref->frame_height;
               priv->render_width    = ref->render_width;
               priv->render_height   = ref->render_height;
               priv->bit_depth       = ref->bit_depth;
               priv->order_hint      = ref->order_hint;

               memcpy(priv->loop_filter_ref_deltas, ref->loop_filter_ref_deltas,
                      sizeof(ref->loop_filter_ref_deltas));
               memcpy(priv->loop_filter_mode_deltas, ref->loop_filter_mode_deltas,
                      sizeof(ref->loop_filter_mode_deltas));
               memcpy(priv->feature_enabled, ref->feature_enabled,
                      sizeof(ref->feature_enabled));
               memcpy(priv->feature_value, ref->feature_value,
                      sizeof(ref->feature_value));
           } else
               infer(refresh_frame_flags, 0);

           infer(frame_width_minus_1,   ref->upscaled_width - 1);
           infer(frame_height_minus_1,  ref->frame_height - 1);
           infer(render_width_minus_1,  ref->render_width - 1);
           infer(render_height_minus_1, ref->render_height - 1);

           // Section 7.20
           goto update_refs;
       }

       fb(2, frame_type);
       frame_is_intra = (current->frame_type == AV1_FRAME_INTRA_ONLY ||
                         current->frame_type == AV1_FRAME_KEY);

       flag(show_frame);
       if (current->show_frame &&
           seq->decoder_model_info_present_flag &&
           !seq->timing_info.equal_picture_interval) {
           fb(seq->decoder_model_info.frame_presentation_time_length_minus_1 + 1,
              frame_presentation_time);
       }
       if (current->show_frame)
           infer(showable_frame, current->frame_type != AV1_FRAME_KEY);
       else
           flag(showable_frame);

       if (current->frame_type == AV1_FRAME_SWITCH ||
           (current->frame_type == AV1_FRAME_KEY && current->show_frame))
           infer(error_resilient_mode, 1);
       else
           flag(error_resilient_mode);
   }

   if (current->frame_type == AV1_FRAME_KEY && current->show_frame) {
       for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
           priv->ref[i].valid = 0;
           priv->ref[i].order_hint = 0;
       }
       for (i = 0; i < AV1_REFS_PER_FRAME; i++)
           priv->order_hints[i + AV1_REF_FRAME_LAST] = 0;
   }

   flag(disable_cdf_update);

   if (seq->seq_force_screen_content_tools ==
       AV1_SELECT_SCREEN_CONTENT_TOOLS) {
       flag(allow_screen_content_tools);
   } else {
       infer(allow_screen_content_tools,
             seq->seq_force_screen_content_tools);
   }
   if (current->allow_screen_content_tools) {
       if (seq->seq_force_integer_mv == AV1_SELECT_INTEGER_MV)
           flag(force_integer_mv);
       else
           infer(force_integer_mv, seq->seq_force_integer_mv);
   } else {
       infer(force_integer_mv, 0);
   }

   if (seq->frame_id_numbers_present_flag) {
       fb(id_len, current_frame_id);

       diff_len = seq->delta_frame_id_length_minus_2 + 2;
       for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
           if (current->current_frame_id > (1 << diff_len)) {
               if (priv->ref[i].frame_id > current->current_frame_id ||
                   priv->ref[i].frame_id < (current->current_frame_id -
                                            (1 << diff_len)))
                   priv->ref[i].valid = 0;
           } else {
               if (priv->ref[i].frame_id > current->current_frame_id &&
                   priv->ref[i].frame_id < ((1 << id_len) +
                                            current->current_frame_id -
                                            (1 << diff_len)))
                   priv->ref[i].valid = 0;
           }
       }
   } else {
       infer(current_frame_id, 0);
   }

   if (current->frame_type == AV1_FRAME_SWITCH)
       infer(frame_size_override_flag, 1);
   else if(seq->reduced_still_picture_header)
       infer(frame_size_override_flag, 0);
   else
       flag(frame_size_override_flag);

   order_hint_bits =
       seq->enable_order_hint ? seq->order_hint_bits_minus_1 + 1 : 0;
   if (order_hint_bits > 0)
       fb(order_hint_bits, order_hint);
   else
       infer(order_hint, 0);
   priv->order_hint = current->order_hint;

   if (frame_is_intra || current->error_resilient_mode)
       infer(primary_ref_frame, AV1_PRIMARY_REF_NONE);
   else
       fb(3, primary_ref_frame);

   if (seq->decoder_model_info_present_flag) {
       flag(buffer_removal_time_present_flag);
       if (current->buffer_removal_time_present_flag) {
           for (i = 0; i <= seq->operating_points_cnt_minus_1; i++) {
               if (seq->decoder_model_present_for_this_op[i]) {
                   int op_pt_idc = seq->operating_point_idc[i];
                   int in_temporal_layer = (op_pt_idc >>  priv->temporal_id    ) & 1;
                   int in_spatial_layer  = (op_pt_idc >> (priv->spatial_id + 8)) & 1;
                   if (seq->operating_point_idc[i] == 0 ||
                       (in_temporal_layer && in_spatial_layer)) {
                       fbs(seq->decoder_model_info.buffer_removal_time_length_minus_1 + 1,
                           buffer_removal_time[i], 1, i);
                   }
               }
           }
       }
   }

   if (current->frame_type == AV1_FRAME_SWITCH ||
       (current->frame_type == AV1_FRAME_KEY && current->show_frame))
       infer(refresh_frame_flags, all_frames);
   else
       fb(8, refresh_frame_flags);

   if (!frame_is_intra || current->refresh_frame_flags != all_frames) {
       if (seq->enable_order_hint) {
           for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
               if (current->error_resilient_mode)
                   fbs(order_hint_bits, ref_order_hint[i], 1, i);
               else
                   infer(ref_order_hint[i], priv->ref[i].order_hint);
               if (current->ref_order_hint[i] != priv->ref[i].order_hint)
                   priv->ref[i].valid = 0;
           }
       }
   }

   if (current->frame_type == AV1_FRAME_KEY ||
       current->frame_type == AV1_FRAME_INTRA_ONLY) {
       CHECK(FUNC(frame_size)(ctx, rw, current));
       CHECK(FUNC(render_size)(ctx, rw, current));

       if (current->allow_screen_content_tools &&
           priv->upscaled_width == priv->frame_width)
           flag(allow_intrabc);
       else
           infer(allow_intrabc, 0);

   } else {
       if (!seq->enable_order_hint) {
           infer(frame_refs_short_signaling, 0);
       } else {
           flag(frame_refs_short_signaling);
           if (current->frame_refs_short_signaling) {
               fb(3, last_frame_idx);
               fb(3, golden_frame_idx);
               CHECK(FUNC(set_frame_refs)(ctx, rw, current));
           }
       }

       for (i = 0; i < AV1_REFS_PER_FRAME; i++) {
           if (!current->frame_refs_short_signaling)
               fbs(3, ref_frame_idx[i], 1, i);
           if (seq->frame_id_numbers_present_flag) {
               fbs(seq->delta_frame_id_length_minus_2 + 2,
                   delta_frame_id_minus1[i], 1, i);
           }
       }

       if (current->frame_size_override_flag &&
           !current->error_resilient_mode) {
           CHECK(FUNC(frame_size_with_refs)(ctx, rw, current));
       } else {
           CHECK(FUNC(frame_size)(ctx, rw, current));
           CHECK(FUNC(render_size)(ctx, rw, current));
       }

       if (current->force_integer_mv)
           infer(allow_high_precision_mv, 0);
       else
           flag(allow_high_precision_mv);

       CHECK(FUNC(interpolation_filter)(ctx, rw, current));

       flag(is_motion_mode_switchable);

       if (current->error_resilient_mode ||
           !seq->enable_ref_frame_mvs)
           infer(use_ref_frame_mvs, 0);
       else
           flag(use_ref_frame_mvs);

       for (i = 0; i < AV1_REFS_PER_FRAME; i++) {
           int ref_frame = AV1_REF_FRAME_LAST + i;
           int hint = priv->ref[current->ref_frame_idx[i]].order_hint;
           priv->order_hints[ref_frame] = hint;
           if (!seq->enable_order_hint) {
               priv->ref_frame_sign_bias[ref_frame] = 0;
           } else {
               priv->ref_frame_sign_bias[ref_frame] =
                   cbs_av1_get_relative_dist(seq, hint,
                                             current->order_hint) > 0;
           }
       }

       infer(allow_intrabc, 0);
   }

   if (seq->reduced_still_picture_header || current->disable_cdf_update)
       infer(disable_frame_end_update_cdf, 1);
   else
       flag(disable_frame_end_update_cdf);

   if (current->primary_ref_frame == AV1_PRIMARY_REF_NONE) {
       // Init non-coeff CDFs.
       // Setup past independence.
   } else {
       // Load CDF tables from previous frame.
       // Load params from previous frame.
   }

   if (current->use_ref_frame_mvs) {
       // Perform motion field estimation process.
   }

   CHECK(FUNC(tile_info)(ctx, rw, current));

   CHECK(FUNC(quantization_params)(ctx, rw, current));

   CHECK(FUNC(segmentation_params)(ctx, rw, current));

   CHECK(FUNC(delta_q_params)(ctx, rw, current));

   CHECK(FUNC(delta_lf_params)(ctx, rw, current));

   // Init coeff CDFs / load previous segments.

   priv->coded_lossless = 1;
   for (i = 0; i < AV1_MAX_SEGMENTS; i++) {
       int qindex;
       if (current->feature_enabled[i][AV1_SEG_LVL_ALT_Q]) {
           qindex = (current->base_q_idx +
                     current->feature_value[i][AV1_SEG_LVL_ALT_Q]);
       } else {
           qindex = current->base_q_idx;
       }
       qindex = av_clip_uintp2(qindex, 8);

       if (qindex                || current->delta_q_y_dc ||
           current->delta_q_u_ac || current->delta_q_u_dc ||
           current->delta_q_v_ac || current->delta_q_v_dc) {
           priv->coded_lossless = 0;
       }
   }
   priv->all_lossless = priv->coded_lossless &&
       priv->frame_width == priv->upscaled_width;

   CHECK(FUNC(loop_filter_params)(ctx, rw, current));

   CHECK(FUNC(cdef_params)(ctx, rw, current));

   CHECK(FUNC(lr_params)(ctx, rw, current));

   CHECK(FUNC(read_tx_mode)(ctx, rw, current));

   CHECK(FUNC(frame_reference_mode)(ctx, rw, current));

   CHECK(FUNC(skip_mode_params)(ctx, rw, current));

   if (frame_is_intra || current->error_resilient_mode ||
       !seq->enable_warped_motion)
       infer(allow_warped_motion, 0);
   else
       flag(allow_warped_motion);

   flag(reduced_tx_set);

   CHECK(FUNC(global_motion_params)(ctx, rw, current));

   CHECK(FUNC(film_grain_params)(ctx, rw, &current->film_grain, current));

   av_log(ctx->log_ctx, AV_LOG_DEBUG, "Frame %d:  size %dx%d  "
          "upscaled %d  render %dx%d  subsample %dx%d  "
          "bitdepth %d  tiles %dx%d.\n", priv->order_hint,
          priv->frame_width, priv->frame_height, priv->upscaled_width,
          priv->render_width, priv->render_height,
          seq->color_config.subsampling_x + 1,
          seq->color_config.subsampling_y + 1, priv->bit_depth,
          priv->tile_rows, priv->tile_cols);

update_refs:
   for (i = 0; i < AV1_NUM_REF_FRAMES; i++) {
       if (current->refresh_frame_flags & (1 << i)) {
           priv->ref[i] = (AV1ReferenceFrameState) {
               .valid          = 1,
               .frame_id       = current->current_frame_id,
               .upscaled_width = priv->upscaled_width,
               .frame_width    = priv->frame_width,
               .frame_height   = priv->frame_height,
               .render_width   = priv->render_width,
               .render_height  = priv->render_height,
               .frame_type     = current->frame_type,
               .subsampling_x  = seq->color_config.subsampling_x,
               .subsampling_y  = seq->color_config.subsampling_y,
               .bit_depth      = priv->bit_depth,
               .order_hint     = priv->order_hint,
           };

           for (int j = 0; j < AV1_REFS_PER_FRAME; j++) {
               priv->ref[i].saved_order_hints[j + AV1_REF_FRAME_LAST] =
                   priv->order_hints[j + AV1_REF_FRAME_LAST];
           }

           if (current->show_existing_frame) {
               memcpy(priv->ref[i].loop_filter_ref_deltas, priv->loop_filter_ref_deltas,
                      sizeof(priv->loop_filter_ref_deltas));
               memcpy(priv->ref[i].loop_filter_mode_deltas, priv->loop_filter_mode_deltas,
                      sizeof(priv->loop_filter_mode_deltas));
               memcpy(priv->ref[i].feature_enabled, priv->feature_enabled,
                      sizeof(priv->feature_enabled));
               memcpy(priv->ref[i].feature_value, priv->feature_value,
                      sizeof(priv->feature_value));
           } else {
               memcpy(priv->ref[i].loop_filter_ref_deltas, current->loop_filter_ref_deltas,
                      sizeof(current->loop_filter_ref_deltas));
               memcpy(priv->ref[i].loop_filter_mode_deltas, current->loop_filter_mode_deltas,
                      sizeof(current->loop_filter_mode_deltas));
               memcpy(priv->ref[i].feature_enabled, current->feature_enabled,
                      sizeof(current->feature_enabled));
               memcpy(priv->ref[i].feature_value, current->feature_value,
                      sizeof(current->feature_value));
           }
       }
   }

   return 0;
}

static int FUNC(frame_header_obu)(CodedBitstreamContext *ctx, RWContext *rw,
                                 AV1RawFrameHeader *current, int redundant,
                                 AVBufferRef *rw_buffer_ref)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   int start_pos, fh_bits, fh_bytes, err;
   uint8_t *fh_start;

   if (priv->seen_frame_header) {
       if (!redundant) {
           av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid repeated "
                  "frame header OBU.\n");
           return AVERROR_INVALIDDATA;
       } else {
           GetBitContext fh;
           size_t i, b;
           uint32_t val;

           HEADER("Redundant Frame Header");

           av_assert0(priv->frame_header_ref && priv->frame_header);

           init_get_bits(&fh, priv->frame_header,
                         priv->frame_header_size);
           for (i = 0; i < priv->frame_header_size; i += 8) {
               b = FFMIN(priv->frame_header_size - i, 8);
               val = get_bits(&fh, b);
               xf(b, frame_header_copy[i],
                  val, val, val, 1, i / 8);
           }
       }
   } else {
       if (redundant)
           HEADER("Redundant Frame Header (used as Frame Header)");
       else
           HEADER("Frame Header");

#ifdef READ
       start_pos = get_bits_count(rw);
#else
       start_pos = put_bits_count(rw);
#endif

       CHECK(FUNC(uncompressed_header)(ctx, rw, current));

       priv->tile_num = 0;

       if (current->show_existing_frame) {
           priv->seen_frame_header = 0;
       } else {
           priv->seen_frame_header = 1;

           av_buffer_unref(&priv->frame_header_ref);

#ifdef READ
           fh_bits  = get_bits_count(rw) - start_pos;
           fh_start = (uint8_t*)rw->buffer + start_pos / 8;
#else
           // Need to flush the bitwriter so that we can copy its output,
           // but use a copy so we don't affect the caller's structure.
           {
               PutBitContext tmp = *rw;
               flush_put_bits(&tmp);
           }

           fh_bits  = put_bits_count(rw) - start_pos;
           fh_start = rw->buf + start_pos / 8;
#endif
           fh_bytes = (fh_bits + 7) / 8;

           priv->frame_header_size = fh_bits;

           if (rw_buffer_ref) {
               priv->frame_header_ref = av_buffer_ref(rw_buffer_ref);
               if (!priv->frame_header_ref)
                   return AVERROR(ENOMEM);
               priv->frame_header = fh_start;
           } else {
               priv->frame_header_ref =
                   av_buffer_alloc(fh_bytes + AV_INPUT_BUFFER_PADDING_SIZE);
               if (!priv->frame_header_ref)
                   return AVERROR(ENOMEM);
               priv->frame_header = priv->frame_header_ref->data;
               memcpy(priv->frame_header, fh_start, fh_bytes);
           }
       }
   }

   return 0;
}

static int FUNC(tile_group_obu)(CodedBitstreamContext *ctx, RWContext *rw,
                               AV1RawTileGroup *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   int num_tiles, tile_bits;
   int err;

   HEADER("Tile Group");

   num_tiles = priv->tile_cols * priv->tile_rows;
   if (num_tiles > 1)
       flag(tile_start_and_end_present_flag);
   else
       infer(tile_start_and_end_present_flag, 0);

   if (num_tiles == 1 || !current->tile_start_and_end_present_flag) {
       infer(tg_start, 0);
       infer(tg_end, num_tiles - 1);
   } else {
       tile_bits = cbs_av1_tile_log2(1, priv->tile_cols) +
                   cbs_av1_tile_log2(1, priv->tile_rows);
       fc(tile_bits, tg_start, priv->tile_num, num_tiles - 1);
       fc(tile_bits, tg_end, current->tg_start, num_tiles - 1);
   }

   priv->tile_num = current->tg_end + 1;

   CHECK(FUNC(byte_alignment)(ctx, rw));

   // Reset header for next frame.
   if (current->tg_end == num_tiles - 1)
       priv->seen_frame_header = 0;

   // Tile data follows.

   return 0;
}

static int FUNC(frame_obu)(CodedBitstreamContext *ctx, RWContext *rw,
                          AV1RawFrame *current,
                          AVBufferRef *rw_buffer_ref)
{
   int err;

   CHECK(FUNC(frame_header_obu)(ctx, rw, &current->header,
                                0, rw_buffer_ref));

   CHECK(FUNC(byte_alignment)(ctx, rw));

   CHECK(FUNC(tile_group_obu)(ctx, rw, &current->tile_group));

   return 0;
}

static int FUNC(tile_list_obu)(CodedBitstreamContext *ctx, RWContext *rw,
                              AV1RawTileList *current)
{
   int err;

   fb(8, output_frame_width_in_tiles_minus_1);
   fb(8, output_frame_height_in_tiles_minus_1);

   fb(16, tile_count_minus_1);

   // Tile data follows.

   return 0;
}

static int FUNC(metadata_hdr_cll)(CodedBitstreamContext *ctx, RWContext *rw,
                                 AV1RawMetadataHDRCLL *current)
{
   int err;

   HEADER("HDR CLL Metadata");

   fb(16, max_cll);
   fb(16, max_fall);

   return 0;
}

static int FUNC(metadata_hdr_mdcv)(CodedBitstreamContext *ctx, RWContext *rw,
                                  AV1RawMetadataHDRMDCV *current)
{
   int err, i;

   HEADER("HDR MDCV Metadata");

   for (i = 0; i < 3; i++) {
       fbs(16, primary_chromaticity_x[i], 1, i);
       fbs(16, primary_chromaticity_y[i], 1, i);
   }

   fb(16, white_point_chromaticity_x);
   fb(16, white_point_chromaticity_y);

   fb(32, luminance_max);
   fb(32, luminance_min);

   return 0;
}

static int FUNC(scalability_structure)(CodedBitstreamContext *ctx, RWContext *rw,
                                      AV1RawMetadataScalability *current)
{
   CodedBitstreamAV1Context *priv = ctx->priv_data;
   const AV1RawSequenceHeader *seq;
   int err, i, j;

   if (!priv->sequence_header) {
       av_log(ctx->log_ctx, AV_LOG_ERROR, "No sequence header available: "
              "unable to parse scalability metadata.\n");
       return AVERROR_INVALIDDATA;
   }
   seq = priv->sequence_header;

   fb(2, spatial_layers_cnt_minus_1);
   flag(spatial_layer_dimensions_present_flag);
   flag(spatial_layer_description_present_flag);
   flag(temporal_group_description_present_flag);
   fc(3, scalability_structure_reserved_3bits, 0, 0);
   if (current->spatial_layer_dimensions_present_flag) {
       for (i = 0; i <= current->spatial_layers_cnt_minus_1; i++) {
           fcs(16, spatial_layer_max_width[i],
               0, seq->max_frame_width_minus_1 + 1, 1, i);
           fcs(16, spatial_layer_max_height[i],
               0, seq->max_frame_height_minus_1 + 1, 1, i);
       }
   }
   if (current->spatial_layer_description_present_flag) {
       for (i = 0; i <= current->spatial_layers_cnt_minus_1; i++)
           fbs(8, spatial_layer_ref_id[i], 1, i);
   }
   if (current->temporal_group_description_present_flag) {
       fb(8, temporal_group_size);
       for (i = 0; i < current->temporal_group_size; i++) {
           fbs(3, temporal_group_temporal_id[i], 1, i);
           flags(temporal_group_temporal_switching_up_point_flag[i], 1, i);
           flags(temporal_group_spatial_switching_up_point_flag[i], 1, i);
           fbs(3, temporal_group_ref_cnt[i], 1, i);
           for (j = 0; j < current->temporal_group_ref_cnt[i]; j++) {
               fbs(8, temporal_group_ref_pic_diff[i][j], 2, i, j);
           }
       }
   }

   return 0;
}

static int FUNC(metadata_scalability)(CodedBitstreamContext *ctx, RWContext *rw,
                                     AV1RawMetadataScalability *current)
{
   int err;

   HEADER("Scalability Metadata");

   fb(8, scalability_mode_idc);

   if (current->scalability_mode_idc == AV1_SCALABILITY_SS)
       CHECK(FUNC(scalability_structure)(ctx, rw, current));

   return 0;
}

static int FUNC(metadata_itut_t35)(CodedBitstreamContext *ctx, RWContext *rw,
                                  AV1RawMetadataITUTT35 *current)
{
   int err;
   size_t i;

   HEADER("ITU-T T.35 Metadata");

   fb(8, itu_t_t35_country_code);
   if (current->itu_t_t35_country_code == 0xff)
       fb(8, itu_t_t35_country_code_extension_byte);

#ifdef READ
   // The payload runs up to the start of the trailing bits, but there might
   // be arbitrarily many trailing zeroes so we need to read through twice.
   current->payload_size = cbs_av1_get_payload_bytes_left(rw);

   current->payload_ref = av_buffer_alloc(current->payload_size);
   if (!current->payload_ref)
       return AVERROR(ENOMEM);
   current->payload = current->payload_ref->data;
#endif

   for (i = 0; i < current->payload_size; i++)
       xf(8, itu_t_t35_payload_bytes[i], current->payload[i],
          0x00, 0xff, 1, i);

   return 0;
}

static int FUNC(metadata_timecode)(CodedBitstreamContext *ctx, RWContext *rw,
                                  AV1RawMetadataTimecode *current)
{
   int err;

   HEADER("Timecode Metadata");

   fb(5, counting_type);
   flag(full_timestamp_flag);
   flag(discontinuity_flag);
   flag(cnt_dropped_flag);
   fb(9, n_frames);

   if (current->full_timestamp_flag) {
       fc(6, seconds_value, 0, 59);
       fc(6, minutes_value, 0, 59);
       fc(5, hours_value,   0, 23);
   } else {
       flag(seconds_flag);
       if (current->seconds_flag) {
           fc(6, seconds_value, 0, 59);
           flag(minutes_flag);
           if (current->minutes_flag) {
               fc(6, minutes_value, 0, 59);
               flag(hours_flag);
               if (current->hours_flag)
                   fc(5, hours_value, 0, 23);
           }
       }
   }

   fb(5, time_offset_length);
   if (current->time_offset_length > 0)
       fb(current->time_offset_length, time_offset_value);
   else
       infer(time_offset_length, 0);

   return 0;
}

static int FUNC(metadata_unknown)(CodedBitstreamContext *ctx, RWContext *rw,
                                 AV1RawMetadataUnknown *current)
{
   int err;
   size_t i;

   HEADER("Unknown Metadata");

#ifdef READ
   current->payload_size = cbs_av1_get_payload_bytes_left(rw);

   current->payload_ref = av_buffer_alloc(current->payload_size);
   if (!current->payload_ref)
       return AVERROR(ENOMEM);
   current->payload = current->payload_ref->data;
#endif

   for (i = 0; i < current->payload_size; i++)
       fbs(8, payload[i], 1, i);

   return 0;
}

static int FUNC(metadata_obu)(CodedBitstreamContext *ctx, RWContext *rw,
                             AV1RawMetadata *current)
{
   int err;

   leb128(metadata_type);

   switch (current->metadata_type) {
   case AV1_METADATA_TYPE_HDR_CLL:
       CHECK(FUNC(metadata_hdr_cll)(ctx, rw, &current->metadata.hdr_cll));
       break;
   case AV1_METADATA_TYPE_HDR_MDCV:
       CHECK(FUNC(metadata_hdr_mdcv)(ctx, rw, &current->metadata.hdr_mdcv));
       break;
   case AV1_METADATA_TYPE_SCALABILITY:
       CHECK(FUNC(metadata_scalability)(ctx, rw, &current->metadata.scalability));
       break;
   case AV1_METADATA_TYPE_ITUT_T35:
       CHECK(FUNC(metadata_itut_t35)(ctx, rw, &current->metadata.itut_t35));
       break;
   case AV1_METADATA_TYPE_TIMECODE:
       CHECK(FUNC(metadata_timecode)(ctx, rw, &current->metadata.timecode));
       break;
   default:
       CHECK(FUNC(metadata_unknown)(ctx, rw, &current->metadata.unknown));
   }

   return 0;
}

static int FUNC(padding_obu)(CodedBitstreamContext *ctx, RWContext *rw,
                            AV1RawPadding *current)
{
   int i, err;

   HEADER("Padding");

#ifdef READ
   // The payload runs up to the start of the trailing bits, but there might
   // be arbitrarily many trailing zeroes so we need to read through twice.
   current->payload_size = cbs_av1_get_payload_bytes_left(rw);

   current->payload_ref = av_buffer_alloc(current->payload_size);
   if (!current->payload_ref)
       return AVERROR(ENOMEM);
   current->payload = current->payload_ref->data;
#endif

   for (i = 0; i < current->payload_size; i++)
       xf(8, obu_padding_byte[i], current->payload[i], 0x00, 0xff, 1, i);

   return 0;
}