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
11 #ifndef API_TRANSPORT_RTP_DEPENDENCY_DESCRIPTOR_H_
12 #define API_TRANSPORT_RTP_DEPENDENCY_DESCRIPTOR_H_
13
14 #include <stdint.h>
15
16 #include <initializer_list>
17 #include <memory>
18 #include <vector>
19
20 #include "absl/container/inlined_vector.h"
21 #include "absl/strings/string_view.h"
22 #include "absl/types/optional.h"
23 #include "api/video/render_resolution.h"
24
25 namespace webrtc {
26 // Structures to build and parse dependency descriptor as described in
27 // https://aomediacodec.github.io/av1-rtp-spec/#dependency-descriptor-rtp-header-extension
28
29 // Relationship of a frame to a Decode target.
30 enum class DecodeTargetIndication {
31 kNotPresent = 0, // DecodeTargetInfo symbol '-'
32 kDiscardable = 1, // DecodeTargetInfo symbol 'D'
33 kSwitch = 2, // DecodeTargetInfo symbol 'S'
34 kRequired = 3 // DecodeTargetInfo symbol 'R'
35 };
36
37 struct FrameDependencyTemplate {
38 // Setters are named briefly to chain them when building the template.
39 FrameDependencyTemplate& S(int spatial_layer);
40 FrameDependencyTemplate& T(int temporal_layer);
41 FrameDependencyTemplate& Dtis(absl::string_view dtis);
42 FrameDependencyTemplate& FrameDiffs(std::initializer_list<int> diffs);
43 FrameDependencyTemplate& ChainDiffs(std::initializer_list<int> diffs);
44
45 friend bool operator==(const FrameDependencyTemplate& lhs,
46 const FrameDependencyTemplate& rhs) {
47 return lhs.spatial_id == rhs.spatial_id &&
48 lhs.temporal_id == rhs.temporal_id &&
49 lhs.decode_target_indications == rhs.decode_target_indications &&
50 lhs.frame_diffs == rhs.frame_diffs &&
51 lhs.chain_diffs == rhs.chain_diffs;
52 }
53
54 int spatial_id = 0;
55 int temporal_id = 0;
56 absl::InlinedVector<DecodeTargetIndication, 10> decode_target_indications;
57 absl::InlinedVector<int, 4> frame_diffs;
58 absl::InlinedVector<int, 4> chain_diffs;
59 };
60
61 struct FrameDependencyStructure {
62 friend bool operator==(const FrameDependencyStructure& lhs,
63 const FrameDependencyStructure& rhs) {
64 return lhs.num_decode_targets == rhs.num_decode_targets &&
65 lhs.num_chains == rhs.num_chains &&
66 lhs.decode_target_protected_by_chain ==
67 rhs.decode_target_protected_by_chain &&
68 lhs.resolutions == rhs.resolutions && lhs.templates == rhs.templates;
69 }
70
71 int structure_id = 0;
72 int num_decode_targets = 0;
73 int num_chains = 0;
74 // If chains are used (num_chains > 0), maps decode target index into index of
75 // the chain protecting that target.
76 absl::InlinedVector<int, 10> decode_target_protected_by_chain;
77 absl::InlinedVector<RenderResolution, 4> resolutions;
78 std::vector<FrameDependencyTemplate> templates;
79 };
80
81 struct DependencyDescriptor {
82 static constexpr int kMaxSpatialIds = 4;
83 static constexpr int kMaxTemporalIds = 8;
84 static constexpr int kMaxDecodeTargets = 32;
85 static constexpr int kMaxTemplates = 64;
86
87 bool first_packet_in_frame = true;
88 bool last_packet_in_frame = true;
89 int frame_number = 0;
90 FrameDependencyTemplate frame_dependencies;
91 absl::optional<RenderResolution> resolution;
92 absl::optional<uint32_t> active_decode_targets_bitmask;
93 std::unique_ptr<FrameDependencyStructure> attached_structure;
94 };
95
96 // Below are implementation details.
97 namespace webrtc_impl {
98 absl::InlinedVector<DecodeTargetIndication, 10> StringToDecodeTargetIndications(
99 absl::string_view indication_symbols);
100 } // namespace webrtc_impl
101
S(int spatial_layer)102 inline FrameDependencyTemplate& FrameDependencyTemplate::S(int spatial_layer) {
103 this->spatial_id = spatial_layer;
104 return *this;
105 }
T(int temporal_layer)106 inline FrameDependencyTemplate& FrameDependencyTemplate::T(int temporal_layer) {
107 this->temporal_id = temporal_layer;
108 return *this;
109 }
Dtis(absl::string_view dtis)110 inline FrameDependencyTemplate& FrameDependencyTemplate::Dtis(
111 absl::string_view dtis) {
112 this->decode_target_indications =
113 webrtc_impl::StringToDecodeTargetIndications(dtis);
114 return *this;
115 }
FrameDiffs(std::initializer_list<int> diffs)116 inline FrameDependencyTemplate& FrameDependencyTemplate::FrameDiffs(
117 std::initializer_list<int> diffs) {
118 this->frame_diffs.assign(diffs.begin(), diffs.end());
119 return *this;
120 }
ChainDiffs(std::initializer_list<int> diffs)121 inline FrameDependencyTemplate& FrameDependencyTemplate::ChainDiffs(
122 std::initializer_list<int> diffs) {
123 this->chain_diffs.assign(diffs.begin(), diffs.end());
124 return *this;
125 }
126
127 } // namespace webrtc
128
129 #endif // API_TRANSPORT_RTP_DEPENDENCY_DESCRIPTOR_H_
130