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_l2t2.h"
11
12 #include <utility>
13 #include <vector>
14
15 #include "absl/base/macros.h"
16 #include "api/transport/rtp/dependency_descriptor.h"
17 #include "rtc_base/checks.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 // decode targets: S0T0, S0T1, S1T0, S1T1
29 constexpr DecodeTargetIndication kDtis[6][4] = {
30 {kSwitch, kSwitch, kSwitch, kSwitch}, // kKey, S0
31 {kNotPresent, kNotPresent, kSwitch, kSwitch}, // kKey, S1
32 {kNotPresent, kDiscardable, kNotPresent, kRequired}, // kDeltaT1, S0
33 {kNotPresent, kNotPresent, kNotPresent, kDiscardable}, // kDeltaT1, S1
34 {kSwitch, kSwitch, kRequired, kRequired}, // kDeltaT0, S0
35 {kNotPresent, kNotPresent, kSwitch, kSwitch}, // kDeltaT0, S1
36 };
37
38 } // namespace
39
40 ScalabilityStructureL2T2::~ScalabilityStructureL2T2() = default;
41
42 ScalableVideoController::StreamLayersConfig
StreamConfig() const43 ScalabilityStructureL2T2::StreamConfig() const {
44 StreamLayersConfig result;
45 result.num_spatial_layers = 2;
46 result.num_temporal_layers = 2;
47 result.scaling_factor_num[0] = 1;
48 result.scaling_factor_den[0] = 2;
49 return result;
50 }
51
DependencyStructure() const52 FrameDependencyStructure ScalabilityStructureL2T2::DependencyStructure() const {
53 FrameDependencyStructure structure;
54 structure.num_decode_targets = 4;
55 structure.num_chains = 2;
56 structure.decode_target_protected_by_chain = {0, 0, 1, 1};
57 structure.templates.resize(6);
58 auto& templates = structure.templates;
59 templates[0].S(0).T(0).Dtis("SSSS").ChainDiffs({0, 0});
60 templates[1].S(0).T(0).Dtis("SSRR").ChainDiffs({4, 3}).FrameDiffs({4});
61 templates[2].S(0).T(1).Dtis("-D-R").ChainDiffs({2, 1}).FrameDiffs({2});
62 templates[3].S(1).T(0).Dtis("--SS").ChainDiffs({1, 1}).FrameDiffs({1});
63 templates[4].S(1).T(0).Dtis("--SS").ChainDiffs({1, 1}).FrameDiffs({4, 1});
64 templates[5].S(1).T(1).Dtis("---D").ChainDiffs({3, 2}).FrameDiffs({2, 1});
65 return structure;
66 }
67
68 ScalableVideoController::LayerFrameConfig
KeyFrameConfig() const69 ScalabilityStructureL2T2::KeyFrameConfig() const {
70 return LayerFrameConfig().Id(0).Keyframe().S(0).T(0).Update(0);
71 }
72
73 std::vector<ScalableVideoController::LayerFrameConfig>
NextFrameConfig(bool restart)74 ScalabilityStructureL2T2::NextFrameConfig(bool restart) {
75 if (restart) {
76 next_pattern_ = kKey;
77 }
78 std::vector<LayerFrameConfig> result(2);
79
80 // Buffer0 keeps latest S0T0 frame,
81 // Buffer1 keeps latest S1T0 frame.
82 // Buffer2 keeps latest S0T1 frame.
83 switch (next_pattern_) {
84 case kKey:
85 result[0] = KeyFrameConfig();
86 result[1].Id(1).S(1).T(0).Reference(0).Update(1);
87 next_pattern_ = kDeltaT1;
88 break;
89 case kDeltaT1:
90 result[0].Id(2).S(0).T(1).Reference(0).Update(2);
91 result[1].Id(3).S(1).T(1).Reference(2).Reference(1);
92 next_pattern_ = kDeltaT0;
93 break;
94 case kDeltaT0:
95 result[0].Id(4).S(0).T(0).ReferenceAndUpdate(0);
96 result[1].Id(5).S(1).T(0).Reference(0).ReferenceAndUpdate(1);
97 next_pattern_ = kDeltaT1;
98 break;
99 }
100 return result;
101 }
102
OnEncodeDone(LayerFrameConfig config)103 absl::optional<GenericFrameInfo> ScalabilityStructureL2T2::OnEncodeDone(
104 LayerFrameConfig config) {
105 if (config.IsKeyframe()) {
106 config = KeyFrameConfig();
107 }
108
109 absl::optional<GenericFrameInfo> frame_info;
110 if (config.Id() < 0 || config.Id() >= int{ABSL_ARRAYSIZE(kDtis)}) {
111 RTC_LOG(LS_ERROR) << "Unexpected config id " << config.Id();
112 return frame_info;
113 }
114 frame_info.emplace();
115 frame_info->spatial_id = config.SpatialId();
116 frame_info->temporal_id = config.TemporalId();
117 frame_info->encoder_buffers = config.Buffers();
118 frame_info->decode_target_indications.assign(std::begin(kDtis[config.Id()]),
119 std::end(kDtis[config.Id()]));
120 if (config.TemporalId() == 0) {
121 frame_info->part_of_chain = {config.SpatialId() == 0, true};
122 } else {
123 frame_info->part_of_chain = {false, false};
124 }
125 return frame_info;
126 }
127
128 } // namespace webrtc
129