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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 
11 #ifndef MODULES_VIDEO_CODING_RTP_VP9_REF_FINDER_H_
12 #define MODULES_VIDEO_CODING_RTP_VP9_REF_FINDER_H_
13 
14 #include <deque>
15 #include <map>
16 #include <memory>
17 #include <set>
18 
19 #include "absl/container/inlined_vector.h"
20 #include "modules/video_coding/frame_object.h"
21 #include "modules/video_coding/rtp_frame_reference_finder.h"
22 #include "rtc_base/numerics/sequence_number_util.h"
23 
24 namespace webrtc {
25 
26 class RtpVp9RefFinder {
27  public:
28   RtpVp9RefFinder() = default;
29 
30   RtpFrameReferenceFinder::ReturnVector ManageFrame(
31       std::unique_ptr<RtpFrameObject> frame);
32   void ClearTo(uint16_t seq_num);
33 
34  private:
35   static constexpr int kFrameIdLength = 1 << 15;
36   static constexpr int kMaxGofSaved = 50;
37   static constexpr int kMaxLayerInfo = 50;
38   static constexpr int kMaxNotYetReceivedFrames = 100;
39   static constexpr int kMaxStashedFrames = 100;
40   static constexpr int kMaxTemporalLayers = 5;
41 
42   enum FrameDecision { kStash, kHandOff, kDrop };
43 
44   struct GofInfo {
GofInfoGofInfo45     GofInfo(GofInfoVP9* gof, uint16_t last_picture_id)
46         : gof(gof), last_picture_id(last_picture_id) {}
47     GofInfoVP9* gof;
48     uint16_t last_picture_id;
49   };
50 
51   struct UnwrappedTl0Frame {
52     int64_t unwrapped_tl0;
53     std::unique_ptr<RtpFrameObject> frame;
54   };
55 
56   FrameDecision ManageFrameFlexible(RtpFrameObject* frame,
57                                     const RTPVideoHeaderVP9& vp9_header);
58   FrameDecision ManageFrameGof(RtpFrameObject* frame,
59                                const RTPVideoHeaderVP9& vp9_header,
60                                int64_t unwrapped_tl0);
61   void RetryStashedFrames(RtpFrameReferenceFinder::ReturnVector& res);
62 
63   bool MissingRequiredFrameVp9(uint16_t picture_id, const GofInfo& info);
64 
65   void FrameReceivedVp9(uint16_t picture_id, GofInfo* info);
66   bool UpSwitchInIntervalVp9(uint16_t picture_id,
67                              uint8_t temporal_idx,
68                              uint16_t pid_ref);
69 
70   void FlattenFrameIdAndRefs(RtpFrameObject* frame, bool inter_layer_predicted);
71 
72   // Frames that have been fully received but didn't have all the information
73   // needed to determine their references.
74   std::deque<UnwrappedTl0Frame> stashed_frames_;
75 
76   // Where the current scalability structure is in the
77   // `scalability_structures_` array.
78   uint8_t current_ss_idx_ = 0;
79 
80   // Holds received scalability structures.
81   std::array<GofInfoVP9, kMaxGofSaved> scalability_structures_;
82 
83   // Holds the the Gof information for a given unwrapped TL0 picture index.
84   std::map<int64_t, GofInfo> gof_info_;
85 
86   // Keep track of which picture id and which temporal layer that had the
87   // up switch flag set.
88   std::map<uint16_t, uint8_t, DescendingSeqNumComp<uint16_t, kFrameIdLength>>
89       up_switch_;
90 
91   // For every temporal layer, keep a set of which frames that are missing.
92   std::array<std::set<uint16_t, DescendingSeqNumComp<uint16_t, kFrameIdLength>>,
93              kMaxTemporalLayers>
94       missing_frames_for_layer_;
95 
96   // Unwrapper used to unwrap VP8/VP9 streams which have their picture id
97   // specified.
98   SeqNumUnwrapper<uint16_t, kFrameIdLength> unwrapper_;
99 
100   SeqNumUnwrapper<uint8_t> tl0_unwrapper_;
101 };
102 
103 }  // namespace webrtc
104 
105 #endif  // MODULES_VIDEO_CODING_RTP_VP9_REF_FINDER_H_
106