text: /*
   *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  #include "modules/video_coding/svc/scalability_structure_l3t3.h"
  
  #include <vector>
  
  #include "api/transport/rtp/dependency_descriptor.h"
  
  namespace webrtc {
  
  ScalabilityStructureL3T3::~ScalabilityStructureL3T3() = default;
  
  FrameDependencyStructure ScalabilityStructureL3T3::DependencyStructure() const {
    FrameDependencyStructure structure;
    structure.num_decode_targets = 9;
    structure.num_chains = 3;
    structure.decode_target_protected_by_chain = {0, 0, 0, 1, 1, 1, 2, 2, 2};
    auto& t = structure.templates;
    t.resize(15);
    // Templates are shown in the order frames following them appear in the
    // stream, but in `structure.templates` array templates are sorted by
    // (`spatial_id`, `temporal_id`) since that is a dependency descriptor
    // requirement. Indexes are written in hex for nicer alignment.
    t[0x1].S(0).T(0).Dtis("SSSSSSSSS").ChainDiffs({0, 0, 0});
    t[0x6].S(1).T(0).Dtis("---SSSSSS").ChainDiffs({1, 1, 1}).FrameDiffs({1});
    t[0xB].S(2).T(0).Dtis("------SSS").ChainDiffs({2, 1, 1}).FrameDiffs({1});
    t[0x3].S(0).T(2).Dtis("--D--R--R").ChainDiffs({3, 2, 1}).FrameDiffs({3});
    t[0x8].S(1).T(2).Dtis("-----D--R").ChainDiffs({4, 3, 2}).FrameDiffs({3, 1});
    t[0xD].S(2).T(2).Dtis("--------D").ChainDiffs({5, 4, 3}).FrameDiffs({3, 1});
    t[0x2].S(0).T(1).Dtis("-DS-RR-RR").ChainDiffs({6, 5, 4}).FrameDiffs({6});
    t[0x7].S(1).T(1).Dtis("----DS-RR").ChainDiffs({7, 6, 5}).FrameDiffs({6, 1});
    t[0xC].S(2).T(1).Dtis("-------DS").ChainDiffs({8, 7, 6}).FrameDiffs({6, 1});
    t[0x4].S(0).T(2).Dtis("--D--R--R").ChainDiffs({9, 8, 7}).FrameDiffs({3});
    t[0x9].S(1).T(2).Dtis("-----D--R").ChainDiffs({10, 9, 8}).FrameDiffs({3, 1});
    t[0xE].S(2).T(2).Dtis("--------D").ChainDiffs({11, 10, 9}).FrameDiffs({3, 1});
    t[0x0].S(0).T(0).Dtis("SSSRRRRRR").ChainDiffs({12, 11, 10}).FrameDiffs({12});
    t[0x5].S(1).T(0).Dtis("---SSSRRR").ChainDiffs({1, 1, 1}).FrameDiffs({12, 1});
    t[0xA].S(2).T(0).Dtis("------SSS").ChainDiffs({2, 1, 1}).FrameDiffs({12, 1});
    return structure;
  }
  
  }  // namespace webrtc
  