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1 /*
2  *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 #include "modules/video_coding/codecs/av1/scalability_structure_l3t3.h"
11 
12 #include <utility>
13 #include <vector>
14 
15 #include "absl/base/macros.h"
16 #include "absl/types/optional.h"
17 #include "api/transport/rtp/dependency_descriptor.h"
18 #include "rtc_base/logging.h"
19 
20 namespace webrtc {
21 namespace {
22 
23 constexpr auto kNotPresent = DecodeTargetIndication::kNotPresent;
24 constexpr auto kDiscardable = DecodeTargetIndication::kDiscardable;
25 constexpr auto kSwitch = DecodeTargetIndication::kSwitch;
26 constexpr auto kRequired = DecodeTargetIndication::kRequired;
27 
28 constexpr DecodeTargetIndication kDtis[12][9] = {
29     // Key, S0
30     {kSwitch, kSwitch, kSwitch,   // S0
31      kSwitch, kSwitch, kSwitch,   // S1
32      kSwitch, kSwitch, kSwitch},  // S2
33     // Key, S1
34     {kNotPresent, kNotPresent, kNotPresent,  // S0
35      kSwitch, kSwitch, kSwitch,              // S1
36      kSwitch, kSwitch, kSwitch},             // S2
37     // Key, S2
38     {kNotPresent, kNotPresent, kNotPresent,  // S0
39      kNotPresent, kNotPresent, kNotPresent,  // S1
40      kSwitch, kSwitch, kSwitch},             // S2
41     // Delta, S0T2
42     {kNotPresent, kNotPresent, kDiscardable,  // S0
43      kNotPresent, kNotPresent, kRequired,     // S1
44      kNotPresent, kNotPresent, kRequired},    // S2
45     // Delta, S1T2
46     {kNotPresent, kNotPresent, kNotPresent,   // S0
47      kNotPresent, kNotPresent, kDiscardable,  // S1
48      kNotPresent, kNotPresent, kRequired},    // S2
49     // Delta, S2T2
50     {kNotPresent, kNotPresent, kNotPresent,    // S0
51      kNotPresent, kNotPresent, kNotPresent,    // S1
52      kNotPresent, kNotPresent, kDiscardable},  // S2
53     // Delta, S0T1
54     {kNotPresent, kDiscardable, kSwitch,  // S0
55      kNotPresent, kRequired, kRequired,   // S1
56      kNotPresent, kRequired, kRequired},  // S2
57     // Delta, S1T1
58     {kNotPresent, kNotPresent, kNotPresent,  // S0
59      kNotPresent, kDiscardable, kSwitch,     // S1
60      kNotPresent, kRequired, kRequired},     // S2
61     // Delta, S2T1
62     {kNotPresent, kNotPresent, kNotPresent,  // S0
63      kNotPresent, kNotPresent, kNotPresent,  // S1
64      kNotPresent, kDiscardable, kSwitch},    // S2
65     // Delta, S0T0
66     {kSwitch, kSwitch, kSwitch,         // S0
67      kRequired, kRequired, kRequired,   // S1
68      kRequired, kRequired, kRequired},  // S2
69     // Delta, S1T0
70     {kNotPresent, kNotPresent, kNotPresent,  // S0
71      kSwitch, kSwitch, kSwitch,              // S1
72      kRequired, kRequired, kRequired},       // S2
73     // Delta, S2T0
74     {kNotPresent, kNotPresent, kNotPresent,  // S0
75      kNotPresent, kNotPresent, kNotPresent,  // S1
76      kSwitch, kSwitch, kSwitch},             // S2
77 };
78 
79 }  // namespace
80 
81 ScalabilityStructureL3T3::~ScalabilityStructureL3T3() = default;
82 
83 ScalableVideoController::StreamLayersConfig
StreamConfig() const84 ScalabilityStructureL3T3::StreamConfig() const {
85   StreamLayersConfig result;
86   result.num_spatial_layers = 3;
87   result.num_temporal_layers = 3;
88   result.scaling_factor_num[0] = 1;
89   result.scaling_factor_den[0] = 4;
90   result.scaling_factor_num[1] = 1;
91   result.scaling_factor_den[1] = 2;
92   return result;
93 }
94 
DependencyStructure() const95 FrameDependencyStructure ScalabilityStructureL3T3::DependencyStructure() const {
96   FrameDependencyStructure structure;
97   structure.num_decode_targets = 9;
98   structure.num_chains = 3;
99   structure.decode_target_protected_by_chain = {0, 0, 0, 1, 1, 1, 2, 2, 2};
100   auto& t = structure.templates;
101   t.resize(15);
102   // Templates are shown in the order frames following them appear in the
103   // stream, but in `structure.templates` array templates are sorted by
104   // (`spatial_id`, `temporal_id`) since that is a dependency descriptor
105   // requirement. Indexes are written in hex for nicer alignment.
106   t[0x1].S(0).T(0).Dtis("SSSSSSSSS").ChainDiffs({0, 0, 0});
107   t[0x6].S(1).T(0).Dtis("---SSSSSS").ChainDiffs({1, 1, 1}).FrameDiffs({1});
108   t[0xB].S(2).T(0).Dtis("------SSS").ChainDiffs({2, 1, 1}).FrameDiffs({1});
109   t[0x3].S(0).T(2).Dtis("--D--R--R").ChainDiffs({3, 2, 1}).FrameDiffs({3});
110   t[0x8].S(1).T(2).Dtis("-----D--R").ChainDiffs({4, 3, 2}).FrameDiffs({3, 1});
111   t[0xD].S(2).T(2).Dtis("--------D").ChainDiffs({5, 4, 3}).FrameDiffs({3, 1});
112   t[0x2].S(0).T(1).Dtis("-DS-RR-RR").ChainDiffs({6, 5, 4}).FrameDiffs({6});
113   t[0x7].S(1).T(1).Dtis("----DS-RR").ChainDiffs({7, 6, 5}).FrameDiffs({6, 1});
114   t[0xC].S(2).T(1).Dtis("-------DS").ChainDiffs({8, 7, 6}).FrameDiffs({6, 1});
115   t[0x4].S(0).T(2).Dtis("--D--R--R").ChainDiffs({9, 8, 7}).FrameDiffs({3});
116   t[0x9].S(1).T(2).Dtis("-----D--R").ChainDiffs({10, 9, 8}).FrameDiffs({3, 1});
117   t[0xE].S(2).T(2).Dtis("--------D").ChainDiffs({11, 10, 9}).FrameDiffs({3, 1});
118   t[0x0].S(0).T(0).Dtis("SSSRRRRRR").ChainDiffs({12, 11, 10}).FrameDiffs({12});
119   t[0x5].S(1).T(0).Dtis("---SSSRRR").ChainDiffs({1, 1, 1}).FrameDiffs({12, 1});
120   t[0xA].S(2).T(0).Dtis("------SSS").ChainDiffs({2, 1, 1}).FrameDiffs({12, 1});
121   return structure;
122 }
123 
124 ScalableVideoController::LayerFrameConfig
KeyFrameConfig() const125 ScalabilityStructureL3T3::KeyFrameConfig() const {
126   return LayerFrameConfig().Id(0).S(0).T(0).Keyframe().Update(0);
127 }
128 
129 std::vector<ScalableVideoController::LayerFrameConfig>
NextFrameConfig(bool restart)130 ScalabilityStructureL3T3::NextFrameConfig(bool restart) {
131   if (restart) {
132     next_pattern_ = kKeyFrame;
133   }
134   std::vector<LayerFrameConfig> config(3);
135 
136   // For this structure name each of 8 buffers after the layer of the frame that
137   // buffer keeps.
138   static constexpr int kS0T0 = 0;
139   static constexpr int kS1T0 = 1;
140   static constexpr int kS2T0 = 2;
141   static constexpr int kS0T1 = 3;
142   static constexpr int kS1T1 = 4;
143   static constexpr int kS2T1 = 5;
144   static constexpr int kS0T2 = 6;
145   static constexpr int kS1T2 = 7;
146   switch (next_pattern_) {
147     case kKeyFrame:
148       config[0].Id(0).S(0).T(0).Keyframe().Update(kS0T0);
149       config[1].Id(1).S(1).T(0).Update(kS1T0).Reference(kS0T0);
150       config[2].Id(2).S(2).T(0).Update(kS2T0).Reference(kS1T0);
151       next_pattern_ = kDeltaFrameT2A;
152       break;
153     case kDeltaFrameT2A:
154       config[0].Id(3).S(0).T(2).Reference(kS0T0).Update(kS0T2);
155       config[1].Id(4).S(1).T(2).Reference(kS1T0).Reference(kS0T2).Update(kS1T2);
156       config[2].Id(5).S(2).T(2).Reference(kS2T0).Reference(kS1T2);
157       next_pattern_ = kDeltaFrameT1;
158       break;
159     case kDeltaFrameT1:
160       config[0].Id(6).S(0).T(1).Reference(kS0T0).Update(kS0T1);
161       config[1].Id(7).S(1).T(1).Reference(kS1T0).Reference(kS0T1).Update(kS1T1);
162       config[2].Id(8).S(2).T(1).Reference(kS2T0).Reference(kS1T1).Update(kS2T1);
163       next_pattern_ = kDeltaFrameT2B;
164       break;
165     case kDeltaFrameT2B:
166       config[0].Id(3).S(0).T(2).Reference(kS0T1).Update(kS0T2);
167       config[1].Id(4).S(1).T(2).Reference(kS1T1).Reference(kS0T2).Update(kS1T2);
168       config[2].Id(5).S(2).T(2).Reference(kS2T1).Reference(kS1T2);
169       next_pattern_ = kDeltaFrameT0;
170       break;
171     case kDeltaFrameT0:
172       config[0].Id(9).S(0).T(0).ReferenceAndUpdate(kS0T0);
173       config[1].Id(10).S(1).T(0).ReferenceAndUpdate(kS1T0).Reference(kS0T0);
174       config[2].Id(11).S(2).T(0).ReferenceAndUpdate(kS2T0).Reference(kS1T0);
175       next_pattern_ = kDeltaFrameT2A;
176       break;
177   }
178   return config;
179 }
180 
OnEncodeDone(LayerFrameConfig config)181 absl::optional<GenericFrameInfo> ScalabilityStructureL3T3::OnEncodeDone(
182     LayerFrameConfig config) {
183   if (config.IsKeyframe() && config.Id() != 0) {
184     // Encoder generated a key frame without asking to.
185     if (config.SpatialId() > 0) {
186       RTC_LOG(LS_WARNING) << "Unexpected spatial id " << config.SpatialId()
187                           << " for key frame.";
188     }
189     config = LayerFrameConfig()
190                  .Keyframe()
191                  .Id(0)
192                  .S(0)
193                  .T(0)
194                  .Update(0)
195                  .Update(1)
196                  .Update(2)
197                  .Update(3)
198                  .Update(4)
199                  .Update(5)
200                  .Update(6)
201                  .Update(7);
202   }
203 
204   absl::optional<GenericFrameInfo> frame_info;
205   if (config.Id() < 0 || config.Id() >= int{ABSL_ARRAYSIZE(kDtis)}) {
206     RTC_LOG(LS_ERROR) << "Unexpected config id " << config.Id();
207     return frame_info;
208   }
209   frame_info.emplace();
210   frame_info->spatial_id = config.SpatialId();
211   frame_info->temporal_id = config.TemporalId();
212   frame_info->encoder_buffers = config.Buffers();
213   frame_info->decode_target_indications.assign(std::begin(kDtis[config.Id()]),
214                                                std::end(kDtis[config.Id()]));
215   if (config.TemporalId() == 0) {
216     frame_info->part_of_chain = {config.SpatialId() == 0,
217                                  config.SpatialId() <= 1, true};
218   } else {
219     frame_info->part_of_chain = {false, false, false};
220   }
221   return frame_info;
222 }
223 
224 }  // namespace webrtc
225