1 files changed, 444 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/video_coding/svc/scalability_structure_full_svc.cc b/third_party/libwebrtc/modules/video_coding/svc/scalability_structure_full_svc.cc
new file mode 100644
index 0000000000..a262317597
--- /dev/null
+++ b/third_party/libwebrtc/modules/video_coding/svc/scalability_structure_full_svc.cc
@@ -0,0 +1,444 @@
+/*
+ *  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_full_svc.h"
+
+#include <utility>
+#include <vector>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+#include "api/transport/rtp/dependency_descriptor.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+constexpr int ScalabilityStructureFullSvc::kMaxNumSpatialLayers;
+constexpr int ScalabilityStructureFullSvc::kMaxNumTemporalLayers;
+constexpr absl::string_view ScalabilityStructureFullSvc::kFramePatternNames[];
+
+ScalabilityStructureFullSvc::ScalabilityStructureFullSvc(
+    int num_spatial_layers,
+    int num_temporal_layers,
+    ScalingFactor resolution_factor)
+    : num_spatial_layers_(num_spatial_layers),
+      num_temporal_layers_(num_temporal_layers),
+      resolution_factor_(resolution_factor),
+      active_decode_targets_(
+          (uint32_t{1} << (num_spatial_layers * num_temporal_layers)) - 1) {
+  RTC_DCHECK_LE(num_spatial_layers, kMaxNumSpatialLayers);
+  RTC_DCHECK_LE(num_temporal_layers, kMaxNumTemporalLayers);
+}
+
+ScalabilityStructureFullSvc::~ScalabilityStructureFullSvc() = default;
+
+ScalabilityStructureFullSvc::StreamLayersConfig
+ScalabilityStructureFullSvc::StreamConfig() const {
+  StreamLayersConfig result;
+  result.num_spatial_layers = num_spatial_layers_;
+  result.num_temporal_layers = num_temporal_layers_;
+  result.scaling_factor_num[num_spatial_layers_ - 1] = 1;
+  result.scaling_factor_den[num_spatial_layers_ - 1] = 1;
+  for (int sid = num_spatial_layers_ - 1; sid > 0; --sid) {
+    result.scaling_factor_num[sid - 1] =
+        resolution_factor_.num * result.scaling_factor_num[sid];
+    result.scaling_factor_den[sid - 1] =
+        resolution_factor_.den * result.scaling_factor_den[sid];
+  }
+  result.uses_reference_scaling = num_spatial_layers_ > 1;
+  return result;
+}
+
+bool ScalabilityStructureFullSvc::TemporalLayerIsActive(int tid) const {
+  if (tid >= num_temporal_layers_) {
+    return false;
+  }
+  for (int sid = 0; sid < num_spatial_layers_; ++sid) {
+    if (DecodeTargetIsActive(sid, tid)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+DecodeTargetIndication ScalabilityStructureFullSvc::Dti(
+    int sid,
+    int tid,
+    const LayerFrameConfig& config) {
+  if (sid < config.SpatialId() || tid < config.TemporalId()) {
+    return DecodeTargetIndication::kNotPresent;
+  }
+  if (sid == config.SpatialId()) {
+    if (tid == 0) {
+      RTC_DCHECK_EQ(config.TemporalId(), 0);
+      return DecodeTargetIndication::kSwitch;
+    }
+    if (tid == config.TemporalId()) {
+      return DecodeTargetIndication::kDiscardable;
+    }
+    if (tid > config.TemporalId()) {
+      RTC_DCHECK_GT(tid, config.TemporalId());
+      return DecodeTargetIndication::kSwitch;
+    }
+  }
+  RTC_DCHECK_GT(sid, config.SpatialId());
+  RTC_DCHECK_GE(tid, config.TemporalId());
+  if (config.IsKeyframe() || config.Id() == kKey) {
+    return DecodeTargetIndication::kSwitch;
+  }
+  return DecodeTargetIndication::kRequired;
+}
+
+ScalabilityStructureFullSvc::FramePattern
+ScalabilityStructureFullSvc::NextPattern() const {
+  switch (last_pattern_) {
+    case kNone:
+      return kKey;
+    case kDeltaT2B:
+      return kDeltaT0;
+    case kDeltaT2A:
+      if (TemporalLayerIsActive(1)) {
+        return kDeltaT1;
+      }
+      return kDeltaT0;
+    case kDeltaT1:
+      if (TemporalLayerIsActive(2)) {
+        return kDeltaT2B;
+      }
+      return kDeltaT0;
+    case kKey:
+    case kDeltaT0:
+      if (TemporalLayerIsActive(2)) {
+        return kDeltaT2A;
+      }
+      if (TemporalLayerIsActive(1)) {
+        return kDeltaT1;
+      }
+      return kDeltaT0;
+  }
+  RTC_DCHECK_NOTREACHED();
+  return kNone;
+}
+
+std::vector<ScalableVideoController::LayerFrameConfig>
+ScalabilityStructureFullSvc::NextFrameConfig(bool restart) {
+  std::vector<LayerFrameConfig> configs;
+  if (active_decode_targets_.none()) {
+    last_pattern_ = kNone;
+    return configs;
+  }
+  configs.reserve(num_spatial_layers_);
+
+  if (last_pattern_ == kNone || restart) {
+    can_reference_t0_frame_for_spatial_id_.reset();
+    last_pattern_ = kNone;
+  }
+  FramePattern current_pattern = NextPattern();
+
+  absl::optional<int> spatial_dependency_buffer_id;
+  switch (current_pattern) {
+    case kDeltaT0:
+    case kKey:
+      // Disallow temporal references cross T0 on higher temporal layers.
+      can_reference_t1_frame_for_spatial_id_.reset();
+      for (int sid = 0; sid < num_spatial_layers_; ++sid) {
+        if (!DecodeTargetIsActive(sid, /*tid=*/0)) {
+          // Next frame from the spatial layer `sid` shouldn't depend on
+          // potentially old previous frame from the spatial layer `sid`.
+          can_reference_t0_frame_for_spatial_id_.reset(sid);
+          continue;
+        }
+        configs.emplace_back();
+        ScalableVideoController::LayerFrameConfig& config = configs.back();
+        config.Id(current_pattern).S(sid).T(0);
+
+        if (spatial_dependency_buffer_id) {
+          config.Reference(*spatial_dependency_buffer_id);
+        } else if (current_pattern == kKey) {
+          config.Keyframe();
+        }
+
+        if (can_reference_t0_frame_for_spatial_id_[sid]) {
+          config.ReferenceAndUpdate(BufferIndex(sid, /*tid=*/0));
+        } else {
+          // TODO(bugs.webrtc.org/11999): Propagate chain restart on delta frame
+          // to ChainDiffCalculator
+          config.Update(BufferIndex(sid, /*tid=*/0));
+        }
+
+        spatial_dependency_buffer_id = BufferIndex(sid, /*tid=*/0);
+      }
+      break;
+    case kDeltaT1:
+      for (int sid = 0; sid < num_spatial_layers_; ++sid) {
+        if (!DecodeTargetIsActive(sid, /*tid=*/1) ||
+            !can_reference_t0_frame_for_spatial_id_[sid]) {
+          continue;
+        }
+        configs.emplace_back();
+        ScalableVideoController::LayerFrameConfig& config = configs.back();
+        config.Id(current_pattern).S(sid).T(1);
+        // Temporal reference.
+        config.Reference(BufferIndex(sid, /*tid=*/0));
+        // Spatial reference unless this is the lowest active spatial layer.
+        if (spatial_dependency_buffer_id) {
+          config.Reference(*spatial_dependency_buffer_id);
+        }
+        // No frame reference top layer frame, so no need save it into a buffer.
+        if (num_temporal_layers_ > 2 || sid < num_spatial_layers_ - 1) {
+          config.Update(BufferIndex(sid, /*tid=*/1));
+        }
+        spatial_dependency_buffer_id = BufferIndex(sid, /*tid=*/1);
+      }
+      break;
+    case kDeltaT2A:
+    case kDeltaT2B:
+      for (int sid = 0; sid < num_spatial_layers_; ++sid) {
+        if (!DecodeTargetIsActive(sid, /*tid=*/2) ||
+            !can_reference_t0_frame_for_spatial_id_[sid]) {
+          continue;
+        }
+        configs.emplace_back();
+        ScalableVideoController::LayerFrameConfig& config = configs.back();
+        config.Id(current_pattern).S(sid).T(2);
+        // Temporal reference.
+        if (current_pattern == kDeltaT2B &&
+            can_reference_t1_frame_for_spatial_id_[sid]) {
+          config.Reference(BufferIndex(sid, /*tid=*/1));
+        } else {
+          config.Reference(BufferIndex(sid, /*tid=*/0));
+        }
+        // Spatial reference unless this is the lowest active spatial layer.
+        if (spatial_dependency_buffer_id) {
+          config.Reference(*spatial_dependency_buffer_id);
+        }
+        // No frame reference top layer frame, so no need save it into a buffer.
+        if (sid < num_spatial_layers_ - 1) {
+          config.Update(BufferIndex(sid, /*tid=*/2));
+        }
+        spatial_dependency_buffer_id = BufferIndex(sid, /*tid=*/2);
+      }
+      break;
+    case kNone:
+      RTC_DCHECK_NOTREACHED();
+      break;
+  }
+
+  if (configs.empty() && !restart) {
+    RTC_LOG(LS_WARNING) << "Failed to generate configuration for L"
+                        << num_spatial_layers_ << "T" << num_temporal_layers_
+                        << " with active decode targets "
+                        << active_decode_targets_.to_string('-').substr(
+                               active_decode_targets_.size() -
+                               num_spatial_layers_ * num_temporal_layers_)
+                        << " and transition from "
+                        << kFramePatternNames[last_pattern_] << " to "
+                        << kFramePatternNames[current_pattern]
+                        << ". Resetting.";
+    return NextFrameConfig(/*restart=*/true);
+  }
+
+  return configs;
+}
+
+GenericFrameInfo ScalabilityStructureFullSvc::OnEncodeDone(
+    const LayerFrameConfig& config) {
+  // When encoder drops all frames for a temporal unit, it is better to reuse
+  // old temporal pattern rather than switch to next one, thus switch to next
+  // pattern defered here from the `NextFrameConfig`.
+  // In particular creating VP9 references rely on this behavior.
+  last_pattern_ = static_cast<FramePattern>(config.Id());
+  if (config.TemporalId() == 0) {
+    can_reference_t0_frame_for_spatial_id_.set(config.SpatialId());
+  }
+  if (config.TemporalId() == 1) {
+    can_reference_t1_frame_for_spatial_id_.set(config.SpatialId());
+  }
+
+  GenericFrameInfo frame_info;
+  frame_info.spatial_id = config.SpatialId();
+  frame_info.temporal_id = config.TemporalId();
+  frame_info.encoder_buffers = config.Buffers();
+  frame_info.decode_target_indications.reserve(num_spatial_layers_ *
+                                               num_temporal_layers_);
+  for (int sid = 0; sid < num_spatial_layers_; ++sid) {
+    for (int tid = 0; tid < num_temporal_layers_; ++tid) {
+      frame_info.decode_target_indications.push_back(Dti(sid, tid, config));
+    }
+  }
+  if (config.TemporalId() == 0) {
+    frame_info.part_of_chain.resize(num_spatial_layers_);
+    for (int sid = 0; sid < num_spatial_layers_; ++sid) {
+      frame_info.part_of_chain[sid] = config.SpatialId() <= sid;
+    }
+  } else {
+    frame_info.part_of_chain.assign(num_spatial_layers_, false);
+  }
+  frame_info.active_decode_targets = active_decode_targets_;
+  return frame_info;
+}
+
+void ScalabilityStructureFullSvc::OnRatesUpdated(
+    const VideoBitrateAllocation& bitrates) {
+  for (int sid = 0; sid < num_spatial_layers_; ++sid) {
+    // Enable/disable spatial layers independetely.
+    bool active = true;
+    for (int tid = 0; tid < num_temporal_layers_; ++tid) {
+      // To enable temporal layer, require bitrates for lower temporal layers.
+      active = active && bitrates.GetBitrate(sid, tid) > 0;
+      SetDecodeTargetIsActive(sid, tid, active);
+    }
+  }
+}
+
+FrameDependencyStructure ScalabilityStructureL1T2::DependencyStructure() const {
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = 2;
+  structure.num_chains = 1;
+  structure.decode_target_protected_by_chain = {0, 0};
+  structure.templates.resize(3);
+  structure.templates[0].T(0).Dtis("SS").ChainDiffs({0});
+  structure.templates[1].T(0).Dtis("SS").ChainDiffs({2}).FrameDiffs({2});
+  structure.templates[2].T(1).Dtis("-D").ChainDiffs({1}).FrameDiffs({1});
+  return structure;
+}
+
+FrameDependencyStructure ScalabilityStructureL1T3::DependencyStructure() const {
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = 3;
+  structure.num_chains = 1;
+  structure.decode_target_protected_by_chain = {0, 0, 0};
+  structure.templates.resize(5);
+  structure.templates[0].T(0).Dtis("SSS").ChainDiffs({0});
+  structure.templates[1].T(0).Dtis("SSS").ChainDiffs({4}).FrameDiffs({4});
+  structure.templates[2].T(1).Dtis("-DS").ChainDiffs({2}).FrameDiffs({2});
+  structure.templates[3].T(2).Dtis("--D").ChainDiffs({1}).FrameDiffs({1});
+  structure.templates[4].T(2).Dtis("--D").ChainDiffs({3}).FrameDiffs({1});
+  return structure;
+}
+
+FrameDependencyStructure ScalabilityStructureL2T1::DependencyStructure() const {
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = 2;
+  structure.num_chains = 2;
+  structure.decode_target_protected_by_chain = {0, 1};
+  structure.templates.resize(4);
+  structure.templates[0].S(0).Dtis("SR").ChainDiffs({2, 1}).FrameDiffs({2});
+  structure.templates[1].S(0).Dtis("SS").ChainDiffs({0, 0});
+  structure.templates[2].S(1).Dtis("-S").ChainDiffs({1, 1}).FrameDiffs({2, 1});
+  structure.templates[3].S(1).Dtis("-S").ChainDiffs({1, 1}).FrameDiffs({1});
+  return structure;
+}
+
+FrameDependencyStructure ScalabilityStructureL2T2::DependencyStructure() const {
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = 4;
+  structure.num_chains = 2;
+  structure.decode_target_protected_by_chain = {0, 0, 1, 1};
+  structure.templates.resize(6);
+  auto& templates = structure.templates;
+  templates[0].S(0).T(0).Dtis("SSSS").ChainDiffs({0, 0});
+  templates[1].S(0).T(0).Dtis("SSRR").ChainDiffs({4, 3}).FrameDiffs({4});
+  templates[2].S(0).T(1).Dtis("-D-R").ChainDiffs({2, 1}).FrameDiffs({2});
+  templates[3].S(1).T(0).Dtis("--SS").ChainDiffs({1, 1}).FrameDiffs({1});
+  templates[4].S(1).T(0).Dtis("--SS").ChainDiffs({1, 1}).FrameDiffs({4, 1});
+  templates[5].S(1).T(1).Dtis("---D").ChainDiffs({3, 2}).FrameDiffs({2, 1});
+  return structure;
+}
+
+FrameDependencyStructure ScalabilityStructureL2T3::DependencyStructure() const {
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = 6;
+  structure.num_chains = 2;
+  structure.decode_target_protected_by_chain = {0, 0, 0, 1, 1, 1};
+  auto& t = structure.templates;
+  t.resize(10);
+  t[1].S(0).T(0).Dtis("SSSSSS").ChainDiffs({0, 0});
+  t[6].S(1).T(0).Dtis("---SSS").ChainDiffs({1, 1}).FrameDiffs({1});
+  t[3].S(0).T(2).Dtis("--D--R").ChainDiffs({2, 1}).FrameDiffs({2});
+  t[8].S(1).T(2).Dtis("-----D").ChainDiffs({3, 2}).FrameDiffs({2, 1});
+  t[2].S(0).T(1).Dtis("-DS-RR").ChainDiffs({4, 3}).FrameDiffs({4});
+  t[7].S(1).T(1).Dtis("----DS").ChainDiffs({5, 4}).FrameDiffs({4, 1});
+  t[4].S(0).T(2).Dtis("--D--R").ChainDiffs({6, 5}).FrameDiffs({2});
+  t[9].S(1).T(2).Dtis("-----D").ChainDiffs({7, 6}).FrameDiffs({2, 1});
+  t[0].S(0).T(0).Dtis("SSSRRR").ChainDiffs({8, 7}).FrameDiffs({8});
+  t[5].S(1).T(0).Dtis("---SSS").ChainDiffs({1, 1}).FrameDiffs({8, 1});
+  return structure;
+}
+
+FrameDependencyStructure ScalabilityStructureL3T1::DependencyStructure() const {
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = 3;
+  structure.num_chains = 3;
+  structure.decode_target_protected_by_chain = {0, 1, 2};
+  auto& templates = structure.templates;
+  templates.resize(6);
+  templates[0].S(0).Dtis("SRR").ChainDiffs({3, 2, 1}).FrameDiffs({3});
+  templates[1].S(0).Dtis("SSS").ChainDiffs({0, 0, 0});
+  templates[2].S(1).Dtis("-SR").ChainDiffs({1, 1, 1}).FrameDiffs({3, 1});
+  templates[3].S(1).Dtis("-SS").ChainDiffs({1, 1, 1}).FrameDiffs({1});
+  templates[4].S(2).Dtis("--S").ChainDiffs({2, 1, 1}).FrameDiffs({3, 1});
+  templates[5].S(2).Dtis("--S").ChainDiffs({2, 1, 1}).FrameDiffs({1});
+  return structure;
+}
+
+FrameDependencyStructure ScalabilityStructureL3T2::DependencyStructure() const {
+  FrameDependencyStructure structure;
+  structure.num_decode_targets = 6;
+  structure.num_chains = 3;
+  structure.decode_target_protected_by_chain = {0, 0, 1, 1, 2, 2};
+  auto& t = structure.templates;
+  t.resize(9);
+  // 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.
+  t[1].S(0).T(0).Dtis("SSSSSS").ChainDiffs({0, 0, 0});
+  t[4].S(1).T(0).Dtis("--SSSS").ChainDiffs({1, 1, 1}).FrameDiffs({1});
+  t[7].S(2).T(0).Dtis("----SS").ChainDiffs({2, 1, 1}).FrameDiffs({1});
+  t[2].S(0).T(1).Dtis("-D-R-R").ChainDiffs({3, 2, 1}).FrameDiffs({3});
+  t[5].S(1).T(1).Dtis("---D-R").ChainDiffs({4, 3, 2}).FrameDiffs({3, 1});
+  t[8].S(2).T(1).Dtis("-----D").ChainDiffs({5, 4, 3}).FrameDiffs({3, 1});
+  t[0].S(0).T(0).Dtis("SSRRRR").ChainDiffs({6, 5, 4}).FrameDiffs({6});
+  t[3].S(1).T(0).Dtis("--SSRR").ChainDiffs({1, 1, 1}).FrameDiffs({6, 1});
+  t[6].S(2).T(0).Dtis("----SS").ChainDiffs({2, 1, 1}).FrameDiffs({6, 1});
+  return structure;
+}
+
+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