Merge pull request #850 from trav90/add-av1-support

Add initial support for AV1 video.

1 files changed, 839 insertions, 0 deletions

diff --git a/third_party/aom/av1/decoder/obu.c b/third_party/aom/av1/decoder/obu.c
new file mode 100644
index 000000000..44ecf818e
--- /dev/null
+++ b/third_party/aom/av1/decoder/obu.c
@@ -0,0 +1,839 @@
+/*
+ * Copyright (c) 2017, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include <assert.h>
+
+#include "config/aom_config.h"
+
+#include "aom/aom_codec.h"
+#include "aom_dsp/bitreader_buffer.h"
+#include "aom_ports/mem_ops.h"
+
+#include "av1/common/common.h"
+#include "av1/common/obu_util.h"
+#include "av1/common/timing.h"
+#include "av1/decoder/decoder.h"
+#include "av1/decoder/decodeframe.h"
+#include "av1/decoder/obu.h"
+
+// Picture prediction structures (0-12 are predefined) in scalability metadata.
+typedef enum {
+  SCALABILITY_L1T2 = 0,
+  SCALABILITY_L1T3 = 1,
+  SCALABILITY_L2T1 = 2,
+  SCALABILITY_L2T2 = 3,
+  SCALABILITY_L2T3 = 4,
+  SCALABILITY_S2T1 = 5,
+  SCALABILITY_S2T2 = 6,
+  SCALABILITY_S2T3 = 7,
+  SCALABILITY_L2T1h = 8,
+  SCALABILITY_L2T2h = 9,
+  SCALABILITY_L2T3h = 10,
+  SCALABILITY_S2T1h = 11,
+  SCALABILITY_S2T2h = 12,
+  SCALABILITY_S2T3h = 13,
+  SCALABILITY_SS = 14
+} SCALABILITY_STRUCTURES;
+
+aom_codec_err_t aom_get_num_layers_from_operating_point_idc(
+    int operating_point_idc, unsigned int *number_spatial_layers,
+    unsigned int *number_temporal_layers) {
+  // derive number of spatial/temporal layers from operating_point_idc
+
+  if (!number_spatial_layers || !number_temporal_layers)
+    return AOM_CODEC_INVALID_PARAM;
+
+  if (operating_point_idc == 0) {
+    *number_temporal_layers = 1;
+    *number_spatial_layers = 1;
+  } else {
+    *number_spatial_layers = 0;
+    *number_temporal_layers = 0;
+    for (int j = 0; j < MAX_NUM_SPATIAL_LAYERS; j++) {
+      *number_spatial_layers +=
+          (operating_point_idc >> (j + MAX_NUM_TEMPORAL_LAYERS)) & 0x1;
+    }
+    for (int j = 0; j < MAX_NUM_TEMPORAL_LAYERS; j++) {
+      *number_temporal_layers += (operating_point_idc >> j) & 0x1;
+    }
+  }
+
+  return AOM_CODEC_OK;
+}
+
+static int is_obu_in_current_operating_point(AV1Decoder *pbi,
+                                             ObuHeader obu_header) {
+  if (!pbi->current_operating_point) {
+    return 1;
+  }
+
+  if ((pbi->current_operating_point >> obu_header.temporal_layer_id) & 0x1 &&
+      (pbi->current_operating_point >> (obu_header.spatial_layer_id + 8)) &
+          0x1) {
+    return 1;
+  }
+  return 0;
+}
+
+static int byte_alignment(AV1_COMMON *const cm,
+                          struct aom_read_bit_buffer *const rb) {
+  while (rb->bit_offset & 7) {
+    if (aom_rb_read_bit(rb)) {
+      cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+      return -1;
+    }
+  }
+  return 0;
+}
+
+static uint32_t read_temporal_delimiter_obu() { return 0; }
+
+// Returns a boolean that indicates success.
+static int read_bitstream_level(BitstreamLevel *bl,
+                                struct aom_read_bit_buffer *rb) {
+  const uint8_t seq_level_idx = aom_rb_read_literal(rb, LEVEL_BITS);
+  if (!is_valid_seq_level_idx(seq_level_idx)) return 0;
+  bl->major = (seq_level_idx >> LEVEL_MINOR_BITS) + LEVEL_MAJOR_MIN;
+  bl->minor = seq_level_idx & ((1 << LEVEL_MINOR_BITS) - 1);
+  return 1;
+}
+
+// Returns whether two sequence headers are consistent with each other.
+// TODO(huisu,wtc@google.com): make sure the code matches the spec exactly.
+static int are_seq_headers_consistent(const SequenceHeader *seq_params_old,
+                                      const SequenceHeader *seq_params_new) {
+  return !memcmp(seq_params_old, seq_params_new, sizeof(SequenceHeader));
+}
+
+// On success, sets pbi->sequence_header_ready to 1 and returns the number of
+// bytes read from 'rb'.
+// On failure, sets pbi->common.error.error_code and returns 0.
+static uint32_t read_sequence_header_obu(AV1Decoder *pbi,
+                                         struct aom_read_bit_buffer *rb) {
+  AV1_COMMON *const cm = &pbi->common;
+  const uint32_t saved_bit_offset = rb->bit_offset;
+
+  // Verify rb has been configured to report errors.
+  assert(rb->error_handler);
+
+  // Use a local variable to store the information as we decode. At the end,
+  // if no errors have occurred, cm->seq_params is updated.
+  SequenceHeader sh = cm->seq_params;
+  SequenceHeader *const seq_params = &sh;
+
+  seq_params->profile = av1_read_profile(rb);
+  if (seq_params->profile > CONFIG_MAX_DECODE_PROFILE) {
+    cm->error.error_code = AOM_CODEC_UNSUP_BITSTREAM;
+    return 0;
+  }
+
+  // Still picture or not
+  seq_params->still_picture = aom_rb_read_bit(rb);
+  seq_params->reduced_still_picture_hdr = aom_rb_read_bit(rb);
+  // Video must have reduced_still_picture_hdr = 0
+  if (!seq_params->still_picture && seq_params->reduced_still_picture_hdr) {
+    cm->error.error_code = AOM_CODEC_UNSUP_BITSTREAM;
+    return 0;
+  }
+
+  if (seq_params->reduced_still_picture_hdr) {
+    cm->timing_info_present = 0;
+    seq_params->decoder_model_info_present_flag = 0;
+    seq_params->display_model_info_present_flag = 0;
+    seq_params->operating_points_cnt_minus_1 = 0;
+    seq_params->operating_point_idc[0] = 0;
+    if (!read_bitstream_level(&seq_params->level[0], rb)) {
+      cm->error.error_code = AOM_CODEC_UNSUP_BITSTREAM;
+      return 0;
+    }
+    seq_params->tier[0] = 0;
+    cm->op_params[0].decoder_model_param_present_flag = 0;
+    cm->op_params[0].display_model_param_present_flag = 0;
+  } else {
+    cm->timing_info_present = aom_rb_read_bit(rb);  // timing_info_present_flag
+    if (cm->timing_info_present) {
+      av1_read_timing_info_header(cm, rb);
+
+      seq_params->decoder_model_info_present_flag = aom_rb_read_bit(rb);
+      if (seq_params->decoder_model_info_present_flag)
+        av1_read_decoder_model_info(cm, rb);
+    } else {
+      seq_params->decoder_model_info_present_flag = 0;
+    }
+    seq_params->display_model_info_present_flag = aom_rb_read_bit(rb);
+    seq_params->operating_points_cnt_minus_1 =
+        aom_rb_read_literal(rb, OP_POINTS_CNT_MINUS_1_BITS);
+    for (int i = 0; i < seq_params->operating_points_cnt_minus_1 + 1; i++) {
+      seq_params->operating_point_idc[i] =
+          aom_rb_read_literal(rb, OP_POINTS_IDC_BITS);
+      if (!read_bitstream_level(&seq_params->level[i], rb)) {
+        cm->error.error_code = AOM_CODEC_UNSUP_BITSTREAM;
+        return 0;
+      }
+      // This is the seq_level_idx[i] > 7 check in the spec. seq_level_idx 7
+      // is equivalent to level 3.3.
+      if (seq_params->level[i].major > 3)
+        seq_params->tier[i] = aom_rb_read_bit(rb);
+      else
+        seq_params->tier[i] = 0;
+      if (seq_params->decoder_model_info_present_flag) {
+        cm->op_params[i].decoder_model_param_present_flag = aom_rb_read_bit(rb);
+        if (cm->op_params[i].decoder_model_param_present_flag)
+          av1_read_op_parameters_info(cm, rb, i);
+      } else {
+        cm->op_params[i].decoder_model_param_present_flag = 0;
+      }
+      if (cm->timing_info_present &&
+          (cm->timing_info.equal_picture_interval ||
+           cm->op_params[i].decoder_model_param_present_flag)) {
+        cm->op_params[i].bitrate = max_level_bitrate(
+            seq_params->profile,
+            major_minor_to_seq_level_idx(seq_params->level[i]),
+            seq_params->tier[i]);
+        // Level with seq_level_idx = 31 returns a high "dummy" bitrate to pass
+        // the check
+        if (cm->op_params[i].bitrate == 0)
+          aom_internal_error(&cm->error, AOM_CODEC_UNSUP_BITSTREAM,
+                             "AV1 does not support this combination of "
+                             "profile, level, and tier.");
+        // Buffer size in bits/s is bitrate in bits/s * 1 s
+        cm->op_params[i].buffer_size = cm->op_params[i].bitrate;
+      }
+      if (cm->timing_info_present && cm->timing_info.equal_picture_interval &&
+          !cm->op_params[i].decoder_model_param_present_flag) {
+        // When the decoder_model_parameters are not sent for this op, set
+        // the default ones that can be used with the resource availability mode
+        cm->op_params[i].decoder_buffer_delay = 70000;
+        cm->op_params[i].encoder_buffer_delay = 20000;
+        cm->op_params[i].low_delay_mode_flag = 0;
+      }
+
+      if (seq_params->display_model_info_present_flag) {
+        cm->op_params[i].display_model_param_present_flag = aom_rb_read_bit(rb);
+        if (cm->op_params[i].display_model_param_present_flag) {
+          cm->op_params[i].initial_display_delay =
+              aom_rb_read_literal(rb, 4) + 1;
+          if (cm->op_params[i].initial_display_delay > 10)
+            aom_internal_error(
+                &cm->error, AOM_CODEC_UNSUP_BITSTREAM,
+                "AV1 does not support more than 10 decoded frames delay");
+        } else {
+          cm->op_params[i].initial_display_delay = 10;
+        }
+      } else {
+        cm->op_params[i].display_model_param_present_flag = 0;
+        cm->op_params[i].initial_display_delay = 10;
+      }
+    }
+  }
+  // This decoder supports all levels.  Choose operating point provided by
+  // external means
+  int operating_point = pbi->operating_point;
+  if (operating_point < 0 ||
+      operating_point > seq_params->operating_points_cnt_minus_1)
+    operating_point = 0;
+  pbi->current_operating_point =
+      seq_params->operating_point_idc[operating_point];
+  if (aom_get_num_layers_from_operating_point_idc(
+          pbi->current_operating_point, &cm->number_spatial_layers,
+          &cm->number_temporal_layers) != AOM_CODEC_OK) {
+    cm->error.error_code = AOM_CODEC_ERROR;
+    return 0;
+  }
+
+  av1_read_sequence_header(cm, rb, seq_params);
+
+  av1_read_color_config(rb, pbi->allow_lowbitdepth, seq_params, &cm->error);
+  if (!(seq_params->subsampling_x == 0 && seq_params->subsampling_y == 0) &&
+      !(seq_params->subsampling_x == 1 && seq_params->subsampling_y == 1) &&
+      !(seq_params->subsampling_x == 1 && seq_params->subsampling_y == 0)) {
+    aom_internal_error(&cm->error, AOM_CODEC_UNSUP_BITSTREAM,
+                       "Only 4:4:4, 4:2:2 and 4:2:0 are currently supported, "
+                       "%d %d subsampling is not supported.\n",
+                       seq_params->subsampling_x, seq_params->subsampling_y);
+  }
+
+  seq_params->film_grain_params_present = aom_rb_read_bit(rb);
+
+  if (av1_check_trailing_bits(pbi, rb) != 0) {
+    // cm->error.error_code is already set.
+    return 0;
+  }
+
+  // If a sequence header has been decoded before, we check if the new
+  // one is consistent with the old one.
+  if (pbi->sequence_header_ready) {
+    if (!are_seq_headers_consistent(&cm->seq_params, seq_params))
+      pbi->sequence_header_changed = 1;
+  }
+
+  cm->seq_params = *seq_params;
+  pbi->sequence_header_ready = 1;
+
+  return ((rb->bit_offset - saved_bit_offset + 7) >> 3);
+}
+
+// On success, returns the frame header size. On failure, calls
+// aom_internal_error and does not return.
+static uint32_t read_frame_header_obu(AV1Decoder *pbi,
+                                      struct aom_read_bit_buffer *rb,
+                                      const uint8_t *data,
+                                      const uint8_t **p_data_end,
+                                      int trailing_bits_present) {
+  return av1_decode_frame_headers_and_setup(pbi, rb, data, p_data_end,
+                                            trailing_bits_present);
+}
+
+static int32_t read_tile_group_header(AV1Decoder *pbi,
+                                      struct aom_read_bit_buffer *rb,
+                                      int *start_tile, int *end_tile,
+                                      int tile_start_implicit) {
+  AV1_COMMON *const cm = &pbi->common;
+  uint32_t saved_bit_offset = rb->bit_offset;
+  int tile_start_and_end_present_flag = 0;
+  const int num_tiles = pbi->common.tile_rows * pbi->common.tile_cols;
+
+  if (!pbi->common.large_scale_tile && num_tiles > 1) {
+    tile_start_and_end_present_flag = aom_rb_read_bit(rb);
+  }
+  if (pbi->common.large_scale_tile || num_tiles == 1 ||
+      !tile_start_and_end_present_flag) {
+    *start_tile = 0;
+    *end_tile = num_tiles - 1;
+    return ((rb->bit_offset - saved_bit_offset + 7) >> 3);
+  }
+  if (tile_start_implicit && tile_start_and_end_present_flag) {
+    aom_internal_error(
+        &cm->error, AOM_CODEC_UNSUP_BITSTREAM,
+        "For OBU_FRAME type obu tile_start_and_end_present_flag must be 0");
+    return -1;
+  }
+  *start_tile =
+      aom_rb_read_literal(rb, cm->log2_tile_rows + cm->log2_tile_cols);
+  *end_tile = aom_rb_read_literal(rb, cm->log2_tile_rows + cm->log2_tile_cols);
+
+  return ((rb->bit_offset - saved_bit_offset + 7) >> 3);
+}
+
+static uint32_t read_one_tile_group_obu(
+    AV1Decoder *pbi, struct aom_read_bit_buffer *rb, int is_first_tg,
+    const uint8_t *data, const uint8_t *data_end, const uint8_t **p_data_end,
+    int *is_last_tg, int tile_start_implicit) {
+  AV1_COMMON *const cm = &pbi->common;
+  int start_tile, end_tile;
+  int32_t header_size, tg_payload_size;
+
+  assert((rb->bit_offset & 7) == 0);
+  assert(rb->bit_buffer + aom_rb_bytes_read(rb) == data);
+
+  header_size = read_tile_group_header(pbi, rb, &start_tile, &end_tile,
+                                       tile_start_implicit);
+  if (header_size == -1 || byte_alignment(cm, rb)) return 0;
+  if (start_tile > end_tile) return header_size;
+  data += header_size;
+  av1_decode_tg_tiles_and_wrapup(pbi, data, data_end, p_data_end, start_tile,
+                                 end_tile, is_first_tg);
+
+  tg_payload_size = (uint32_t)(*p_data_end - data);
+
+  // TODO(shan):  For now, assume all tile groups received in order
+  *is_last_tg = end_tile == cm->tile_rows * cm->tile_cols - 1;
+  return header_size + tg_payload_size;
+}
+
+static void alloc_tile_list_buffer(AV1Decoder *pbi) {
+  // TODO(yunqing): for now, copy each tile's decoded YUV data directly to the
+  // output buffer. This needs to be modified according to the application
+  // requirement.
+  AV1_COMMON *const cm = &pbi->common;
+  const int tile_width_in_pixels = cm->tile_width * MI_SIZE;
+  const int tile_height_in_pixels = cm->tile_height * MI_SIZE;
+  const int ssy = cm->seq_params.subsampling_y;
+  const int ssx = cm->seq_params.subsampling_x;
+  const int num_planes = av1_num_planes(cm);
+  const size_t yplane_tile_size = tile_height_in_pixels * tile_width_in_pixels;
+  const size_t uvplane_tile_size =
+      (num_planes > 1)
+          ? (tile_height_in_pixels >> ssy) * (tile_width_in_pixels >> ssx)
+          : 0;
+  const size_t tile_size = (cm->seq_params.use_highbitdepth ? 2 : 1) *
+                           (yplane_tile_size + 2 * uvplane_tile_size);
+  pbi->tile_list_size = tile_size * (pbi->tile_count_minus_1 + 1);
+
+  if (pbi->tile_list_size > pbi->buffer_sz) {
+    if (pbi->tile_list_output != NULL) aom_free(pbi->tile_list_output);
+    pbi->tile_list_output = NULL;
+
+    pbi->tile_list_output = (uint8_t *)aom_memalign(32, pbi->tile_list_size);
+    if (pbi->tile_list_output == NULL)
+      aom_internal_error(&cm->error, AOM_CODEC_MEM_ERROR,
+                         "Failed to allocate the tile list output buffer");
+    pbi->buffer_sz = pbi->tile_list_size;
+  }
+}
+
+static void copy_decoded_tile_to_tile_list_buffer(AV1Decoder *pbi,
+                                                  uint8_t **output) {
+  AV1_COMMON *const cm = &pbi->common;
+  const int tile_width_in_pixels = cm->tile_width * MI_SIZE;
+  const int tile_height_in_pixels = cm->tile_height * MI_SIZE;
+  const int ssy = cm->seq_params.subsampling_y;
+  const int ssx = cm->seq_params.subsampling_x;
+  const int num_planes = av1_num_planes(cm);
+
+  // Copy decoded tile to the tile list output buffer.
+  YV12_BUFFER_CONFIG *cur_frame = get_frame_new_buffer(cm);
+  const int mi_row = pbi->dec_tile_row * cm->tile_height;
+  const int mi_col = pbi->dec_tile_col * cm->tile_width;
+  const int is_hbd = (cur_frame->flags & YV12_FLAG_HIGHBITDEPTH) ? 1 : 0;
+  uint8_t *bufs[MAX_MB_PLANE] = { NULL, NULL, NULL };
+  int strides[MAX_MB_PLANE] = { 0, 0, 0 };
+  int plane;
+
+  for (plane = 0; plane < num_planes; ++plane) {
+    int shift_x = plane > 0 ? ssx : 0;
+    int shift_y = plane > 0 ? ssy : 0;
+
+    bufs[plane] = cur_frame->buffers[plane];
+    strides[plane] =
+        (plane > 0) ? cur_frame->strides[1] : cur_frame->strides[0];
+
+    bufs[plane] += mi_row * (MI_SIZE >> shift_y) * strides[plane] +
+                   mi_col * (MI_SIZE >> shift_x);
+
+    if (is_hbd) {
+      bufs[plane] = (uint8_t *)CONVERT_TO_SHORTPTR(bufs[plane]);
+      strides[plane] *= 2;
+    }
+
+    int w, h;
+    w = (plane > 0 && shift_x > 0) ? ((tile_width_in_pixels + 1) >> shift_x)
+                                   : tile_width_in_pixels;
+    w *= (1 + is_hbd);
+    h = (plane > 0 && shift_y > 0) ? ((tile_height_in_pixels + 1) >> shift_y)
+                                   : tile_height_in_pixels;
+    int j;
+
+    for (j = 0; j < h; ++j) {
+      memcpy(*output, bufs[plane], w);
+      bufs[plane] += strides[plane];
+      *output += w;
+    }
+  }
+}
+
+// Only called while large_scale_tile = 1.
+static uint32_t read_and_decode_one_tile_list(AV1Decoder *pbi,
+                                              struct aom_read_bit_buffer *rb,
+                                              const uint8_t *data,
+                                              const uint8_t *data_end,
+                                              const uint8_t **p_data_end,
+                                              int *frame_decoding_finished) {
+  AV1_COMMON *const cm = &pbi->common;
+  uint32_t tile_list_payload_size = 0;
+  const int num_tiles = cm->tile_cols * cm->tile_rows;
+  const int start_tile = 0;
+  const int end_tile = num_tiles - 1;
+  int i = 0;
+
+  // Process the tile list info.
+  pbi->output_frame_width_in_tiles_minus_1 = aom_rb_read_literal(rb, 8);
+  pbi->output_frame_height_in_tiles_minus_1 = aom_rb_read_literal(rb, 8);
+  pbi->tile_count_minus_1 = aom_rb_read_literal(rb, 16);
+  if (pbi->tile_count_minus_1 > MAX_TILES - 1) {
+    cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+    return 0;
+  }
+
+  // Allocate output frame buffer for the tile list.
+  alloc_tile_list_buffer(pbi);
+
+  uint32_t tile_list_info_bytes = 4;
+  tile_list_payload_size += tile_list_info_bytes;
+  data += tile_list_info_bytes;
+  uint8_t *output = pbi->tile_list_output;
+
+  for (i = 0; i <= pbi->tile_count_minus_1; i++) {
+    // Process 1 tile.
+    // Reset the bit reader.
+    rb->bit_offset = 0;
+    rb->bit_buffer = data;
+
+    // Read out the tile info.
+    uint32_t tile_info_bytes = 5;
+    // Set reference for each tile.
+    int ref_idx = aom_rb_read_literal(rb, 8);
+    if (ref_idx >= MAX_EXTERNAL_REFERENCES) {
+      cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+      return 0;
+    }
+    av1_set_reference_dec(cm, 0, 1, &pbi->ext_refs.refs[ref_idx]);
+
+    pbi->dec_tile_row = aom_rb_read_literal(rb, 8);
+    pbi->dec_tile_col = aom_rb_read_literal(rb, 8);
+    if (pbi->dec_tile_row < 0 || pbi->dec_tile_col < 0 ||
+        pbi->dec_tile_row >= cm->tile_rows ||
+        pbi->dec_tile_col >= cm->tile_cols) {
+      cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+      return 0;
+    }
+
+    pbi->coded_tile_data_size = aom_rb_read_literal(rb, 16) + 1;
+    data += tile_info_bytes;
+    if ((size_t)(data_end - data) < pbi->coded_tile_data_size) {
+      cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+      return 0;
+    }
+
+    av1_decode_tg_tiles_and_wrapup(pbi, data, data + pbi->coded_tile_data_size,
+                                   p_data_end, start_tile, end_tile, 0);
+    uint32_t tile_payload_size = (uint32_t)(*p_data_end - data);
+
+    tile_list_payload_size += tile_info_bytes + tile_payload_size;
+
+    // Update data ptr for next tile decoding.
+    data = *p_data_end;
+    assert(data <= data_end);
+
+    // Copy the decoded tile to the tile list output buffer.
+    copy_decoded_tile_to_tile_list_buffer(pbi, &output);
+  }
+
+  *frame_decoding_finished = 1;
+  return tile_list_payload_size;
+}
+
+static void read_metadata_itut_t35(const uint8_t *data, size_t sz) {
+  struct aom_read_bit_buffer rb = { data, data + sz, 0, NULL, NULL };
+  for (size_t i = 0; i < sz; i++) {
+    aom_rb_read_literal(&rb, 8);
+  }
+}
+
+static void read_metadata_hdr_cll(const uint8_t *data, size_t sz) {
+  struct aom_read_bit_buffer rb = { data, data + sz, 0, NULL, NULL };
+  aom_rb_read_literal(&rb, 16);  // max_cll
+  aom_rb_read_literal(&rb, 16);  // max_fall
+}
+
+static void read_metadata_hdr_mdcv(const uint8_t *data, size_t sz) {
+  struct aom_read_bit_buffer rb = { data, data + sz, 0, NULL, NULL };
+  for (int i = 0; i < 3; i++) {
+    aom_rb_read_literal(&rb, 16);  // primary_i_chromaticity_x
+    aom_rb_read_literal(&rb, 16);  // primary_i_chromaticity_y
+  }
+
+  aom_rb_read_literal(&rb, 16);  // white_point_chromaticity_x
+  aom_rb_read_literal(&rb, 16);  // white_point_chromaticity_y
+
+  aom_rb_read_unsigned_literal(&rb, 32);  // luminance_max
+  aom_rb_read_unsigned_literal(&rb, 32);  // luminance_min
+}
+
+static void scalability_structure(struct aom_read_bit_buffer *rb) {
+  int spatial_layers_cnt = aom_rb_read_literal(rb, 2);
+  int spatial_layer_dimensions_present_flag = aom_rb_read_bit(rb);
+  int spatial_layer_description_present_flag = aom_rb_read_bit(rb);
+  int temporal_group_description_present_flag = aom_rb_read_bit(rb);
+  aom_rb_read_literal(rb, 3);  // reserved
+
+  if (spatial_layer_dimensions_present_flag) {
+    int i;
+    for (i = 0; i < spatial_layers_cnt + 1; i++) {
+      aom_rb_read_literal(rb, 16);
+      aom_rb_read_literal(rb, 16);
+    }
+  }
+  if (spatial_layer_description_present_flag) {
+    int i;
+    for (i = 0; i < spatial_layers_cnt + 1; i++) {
+      aom_rb_read_literal(rb, 8);
+    }
+  }
+  if (temporal_group_description_present_flag) {
+    int i, j, temporal_group_size;
+    temporal_group_size = aom_rb_read_literal(rb, 8);
+    for (i = 0; i < temporal_group_size; i++) {
+      aom_rb_read_literal(rb, 3);
+      aom_rb_read_bit(rb);
+      aom_rb_read_bit(rb);
+      int temporal_group_ref_cnt = aom_rb_read_literal(rb, 3);
+      for (j = 0; j < temporal_group_ref_cnt; j++) {
+        aom_rb_read_literal(rb, 8);
+      }
+    }
+  }
+}
+
+static void read_metadata_scalability(const uint8_t *data, size_t sz) {
+  struct aom_read_bit_buffer rb = { data, data + sz, 0, NULL, NULL };
+  int scalability_mode_idc = aom_rb_read_literal(&rb, 8);
+  if (scalability_mode_idc == SCALABILITY_SS) {
+    scalability_structure(&rb);
+  }
+}
+
+static void read_metadata_timecode(const uint8_t *data, size_t sz) {
+  struct aom_read_bit_buffer rb = { data, data + sz, 0, NULL, NULL };
+  aom_rb_read_literal(&rb, 5);                     // counting_type f(5)
+  int full_timestamp_flag = aom_rb_read_bit(&rb);  // full_timestamp_flag f(1)
+  aom_rb_read_bit(&rb);                            // discontinuity_flag (f1)
+  aom_rb_read_bit(&rb);                            // cnt_dropped_flag f(1)
+  aom_rb_read_literal(&rb, 9);                     // n_frames f(9)
+  if (full_timestamp_flag) {
+    aom_rb_read_literal(&rb, 6);  // seconds_value f(6)
+    aom_rb_read_literal(&rb, 6);  // minutes_value f(6)
+    aom_rb_read_literal(&rb, 5);  // hours_value f(5)
+  } else {
+    int seconds_flag = aom_rb_read_bit(&rb);  // seconds_flag f(1)
+    if (seconds_flag) {
+      aom_rb_read_literal(&rb, 6);              // seconds_value f(6)
+      int minutes_flag = aom_rb_read_bit(&rb);  // minutes_flag f(1)
+      if (minutes_flag) {
+        aom_rb_read_literal(&rb, 6);            // minutes_value f(6)
+        int hours_flag = aom_rb_read_bit(&rb);  // hours_flag f(1)
+        if (hours_flag) {
+          aom_rb_read_literal(&rb, 5);  // hours_value f(5)
+        }
+      }
+    }
+  }
+  // time_offset_length f(5)
+  int time_offset_length = aom_rb_read_literal(&rb, 5);
+  if (time_offset_length) {
+    aom_rb_read_literal(&rb, time_offset_length);  // f(time_offset_length)
+  }
+}
+
+static size_t read_metadata(const uint8_t *data, size_t sz) {
+  size_t type_length;
+  uint64_t type_value;
+  OBU_METADATA_TYPE metadata_type;
+  if (aom_uleb_decode(data, sz, &type_value, &type_length) < 0) {
+    return sz;
+  }
+  metadata_type = (OBU_METADATA_TYPE)type_value;
+  if (metadata_type == OBU_METADATA_TYPE_ITUT_T35) {
+    read_metadata_itut_t35(data + type_length, sz - type_length);
+  } else if (metadata_type == OBU_METADATA_TYPE_HDR_CLL) {
+    read_metadata_hdr_cll(data + type_length, sz - type_length);
+  } else if (metadata_type == OBU_METADATA_TYPE_HDR_MDCV) {
+    read_metadata_hdr_mdcv(data + type_length, sz - type_length);
+  } else if (metadata_type == OBU_METADATA_TYPE_SCALABILITY) {
+    read_metadata_scalability(data + type_length, sz - type_length);
+  } else if (metadata_type == OBU_METADATA_TYPE_TIMECODE) {
+    read_metadata_timecode(data + type_length, sz - type_length);
+  }
+
+  return sz;
+}
+
+// On success, returns a boolean that indicates whether the decoding of the
+// current frame is finished. On failure, sets cm->error.error_code and
+// returns -1.
+int aom_decode_frame_from_obus(struct AV1Decoder *pbi, const uint8_t *data,
+                               const uint8_t *data_end,
+                               const uint8_t **p_data_end) {
+  AV1_COMMON *const cm = &pbi->common;
+  int frame_decoding_finished = 0;
+  int is_first_tg_obu_received = 1;
+  uint32_t frame_header_size = 0;
+  ObuHeader obu_header;
+  memset(&obu_header, 0, sizeof(obu_header));
+  pbi->seen_frame_header = 0;
+
+  if (data_end < data) {
+    cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+    return -1;
+  }
+
+  // Reset pbi->camera_frame_header_ready to 0 if cm->large_scale_tile = 0.
+  if (!cm->large_scale_tile) pbi->camera_frame_header_ready = 0;
+
+  // decode frame as a series of OBUs
+  while (!frame_decoding_finished && !cm->error.error_code) {
+    struct aom_read_bit_buffer rb;
+    size_t payload_size = 0;
+    size_t decoded_payload_size = 0;
+    size_t obu_payload_offset = 0;
+    size_t bytes_read = 0;
+    const size_t bytes_available = data_end - data;
+
+    if (bytes_available == 0 && !pbi->seen_frame_header) {
+      *p_data_end = data;
+      cm->error.error_code = AOM_CODEC_OK;
+      break;
+    }
+
+    aom_codec_err_t status =
+        aom_read_obu_header_and_size(data, bytes_available, cm->is_annexb,
+                                     &obu_header, &payload_size, &bytes_read);
+
+    if (status != AOM_CODEC_OK) {
+      cm->error.error_code = status;
+      return -1;
+    }
+
+    // Record obu size header information.
+    pbi->obu_size_hdr.data = data + obu_header.size;
+    pbi->obu_size_hdr.size = bytes_read - obu_header.size;
+
+    // Note: aom_read_obu_header_and_size() takes care of checking that this
+    // doesn't cause 'data' to advance past 'data_end'.
+    data += bytes_read;
+
+    if ((size_t)(data_end - data) < payload_size) {
+      cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+      return -1;
+    }
+
+    cm->temporal_layer_id = obu_header.temporal_layer_id;
+    cm->spatial_layer_id = obu_header.spatial_layer_id;
+
+    if (obu_header.type != OBU_TEMPORAL_DELIMITER &&
+        obu_header.type != OBU_SEQUENCE_HEADER &&
+        obu_header.type != OBU_PADDING) {
+      // don't decode obu if it's not in current operating mode
+      if (!is_obu_in_current_operating_point(pbi, obu_header)) {
+        data += payload_size;
+        continue;
+      }
+    }
+
+    av1_init_read_bit_buffer(pbi, &rb, data, data + payload_size);
+
+    switch (obu_header.type) {
+      case OBU_TEMPORAL_DELIMITER:
+        decoded_payload_size = read_temporal_delimiter_obu();
+        pbi->seen_frame_header = 0;
+        break;
+      case OBU_SEQUENCE_HEADER:
+        decoded_payload_size = read_sequence_header_obu(pbi, &rb);
+        if (cm->error.error_code != AOM_CODEC_OK) return -1;
+        break;
+      case OBU_FRAME_HEADER:
+      case OBU_REDUNDANT_FRAME_HEADER:
+      case OBU_FRAME:
+        // Only decode first frame header received
+        if (!pbi->seen_frame_header ||
+            (cm->large_scale_tile && !pbi->camera_frame_header_ready)) {
+          frame_header_size = read_frame_header_obu(
+              pbi, &rb, data, p_data_end, obu_header.type != OBU_FRAME);
+          pbi->seen_frame_header = 1;
+          if (!pbi->ext_tile_debug && cm->large_scale_tile)
+            pbi->camera_frame_header_ready = 1;
+        } else {
+          // TODO(wtc): Verify that the frame_header_obu is identical to the
+          // original frame_header_obu. For now just skip frame_header_size
+          // bytes in the bit buffer.
+          if (frame_header_size > payload_size) {
+            cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+            return -1;
+          }
+          assert(rb.bit_offset == 0);
+          rb.bit_offset = 8 * frame_header_size;
+        }
+
+        decoded_payload_size = frame_header_size;
+        pbi->frame_header_size = frame_header_size;
+
+        if (cm->show_existing_frame) {
+          if (obu_header.type == OBU_FRAME) {
+            cm->error.error_code = AOM_CODEC_UNSUP_BITSTREAM;
+            return -1;
+          }
+          frame_decoding_finished = 1;
+          pbi->seen_frame_header = 0;
+          break;
+        }
+
+        // In large scale tile coding, decode the common camera frame header
+        // before any tile list OBU.
+        if (!pbi->ext_tile_debug && pbi->camera_frame_header_ready) {
+          frame_decoding_finished = 1;
+          // Skip the rest of the frame data.
+          decoded_payload_size = payload_size;
+          // Update data_end.
+          *p_data_end = data_end;
+          break;
+        }
+
+        if (obu_header.type != OBU_FRAME) break;
+        obu_payload_offset = frame_header_size;
+        // Byte align the reader before reading the tile group.
+        if (byte_alignment(cm, &rb)) return -1;
+        AOM_FALLTHROUGH_INTENDED;  // fall through to read tile group.
+      case OBU_TILE_GROUP:
+        if (!pbi->seen_frame_header) {
+          cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+          return -1;
+        }
+        if (obu_payload_offset > payload_size) {
+          cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+          return -1;
+        }
+        decoded_payload_size += read_one_tile_group_obu(
+            pbi, &rb, is_first_tg_obu_received, data + obu_payload_offset,
+            data + payload_size, p_data_end, &frame_decoding_finished,
+            obu_header.type == OBU_FRAME);
+        is_first_tg_obu_received = 0;
+        if (frame_decoding_finished) pbi->seen_frame_header = 0;
+        break;
+      case OBU_METADATA:
+        decoded_payload_size = read_metadata(data, payload_size);
+        break;
+      case OBU_TILE_LIST:
+        if (CONFIG_NORMAL_TILE_MODE) {
+          cm->error.error_code = AOM_CODEC_UNSUP_BITSTREAM;
+          return -1;
+        }
+
+        // This OBU type is purely for the large scale tile coding mode.
+        // The common camera frame header has to be already decoded.
+        if (!pbi->camera_frame_header_ready) {
+          cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+          return -1;
+        }
+
+        cm->large_scale_tile = 1;
+        av1_set_single_tile_decoding_mode(cm);
+        decoded_payload_size =
+            read_and_decode_one_tile_list(pbi, &rb, data, data + payload_size,
+                                          p_data_end, &frame_decoding_finished);
+        if (cm->error.error_code != AOM_CODEC_OK) return -1;
+        break;
+      case OBU_PADDING:
+      default:
+        // Skip unrecognized OBUs
+        decoded_payload_size = payload_size;
+        break;
+    }
+
+    // Check that the signalled OBU size matches the actual amount of data read
+    if (decoded_payload_size > payload_size) {
+      cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+      return -1;
+    }
+
+    // If there are extra padding bytes, they should all be zero
+    while (decoded_payload_size < payload_size) {
+      uint8_t padding_byte = data[decoded_payload_size++];
+      if (padding_byte != 0) {
+        cm->error.error_code = AOM_CODEC_CORRUPT_FRAME;
+        return -1;
+      }
+    }
+
+    data += payload_size;
+  }
+
+  return frame_decoding_finished;
+}