1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef MEDIA_CAST_LOGGING_ENCODING_EVENT_SUBSCRIBER_H_
6#define MEDIA_CAST_LOGGING_ENCODING_EVENT_SUBSCRIBER_H_
7
8#include <map>
9
10#include "base/memory/linked_ptr.h"
11#include "base/threading/thread_checker.h"
12#include "media/cast/logging/logging_defines.h"
13#include "media/cast/logging/proto/raw_events.pb.h"
14#include "media/cast/logging/raw_event_subscriber.h"
15
16namespace media {
17namespace cast {
18
19// Number of packets per frame recorded by the subscriber.
20// Once the max number of packets has been reached, a new aggregated proto
21// will be created.
22static const int kMaxPacketsPerFrame = 64;
23// Number of events per proto recorded by the subscriber.
24// Once the max number of events has been reached, a new aggregated proto
25// will be created.
26static const int kMaxEventsPerProto = 16;
27
28typedef std::vector<linked_ptr<media::cast::proto::AggregatedFrameEvent> >
29    FrameEventList;
30typedef std::vector<linked_ptr<media::cast::proto::AggregatedPacketEvent> >
31    PacketEventList;
32
33// A RawEventSubscriber implementation that subscribes to events,
34// encodes them in protocol buffer format, and aggregates them into a more
35// compact structure. Aggregation is per-frame, and uses a map with RTP
36// timestamp as key. Periodically, old entries in the map will be transferred
37// to a storage vector. This helps keep the size of the map small and
38// lookup times fast. The storage itself is a circular buffer that will
39// overwrite old entries once it has reached the size configured by user.
40class EncodingEventSubscriber : public RawEventSubscriber {
41 public:
42  // |event_media_type|: The subscriber will only process events that
43  // corresponds to this type.
44  // |max_frames|: How many events to keep in the frame / packet storage.
45  // This helps keep memory usage bounded.
46  // Every time one of |OnReceive[Frame,Packet]Event()| is
47  // called, it will check if the respective map size has exceeded |max_frames|.
48  // If so, it will remove the oldest aggregated entry (ordered by RTP
49  // timestamp).
50  EncodingEventSubscriber(EventMediaType event_media_type, size_t max_frames);
51
52  virtual ~EncodingEventSubscriber();
53
54  // RawReventSubscriber implementations.
55  virtual void OnReceiveFrameEvent(const FrameEvent& frame_event) OVERRIDE;
56  virtual void OnReceivePacketEvent(const PacketEvent& packet_event) OVERRIDE;
57
58  // Assigns frame events and packet events received so far to |frame_events|
59  // and |packet_events| and resets the internal state.
60  // In addition, assign metadata associated with these events to |metadata|.
61  // The protos in |frame_events| and |packets_events| are sorted in
62  // ascending RTP timestamp order.
63  void GetEventsAndReset(media::cast::proto::LogMetadata* metadata,
64                         FrameEventList* frame_events,
65                         PacketEventList* packet_events);
66
67 private:
68  typedef std::map<RtpTimestamp,
69                   linked_ptr<media::cast::proto::AggregatedFrameEvent> >
70      FrameEventMap;
71  typedef std::map<RtpTimestamp,
72                   linked_ptr<media::cast::proto::AggregatedPacketEvent> >
73      PacketEventMap;
74
75  // Transfer up to |max_num_entries| smallest entries from |frame_event_map_|
76  // to |frame_event_storage_|. This helps keep size of |frame_event_map_| small
77  // and lookup speed fast.
78  void TransferFrameEvents(size_t max_num_entries);
79  // See above.
80  void TransferPacketEvents(size_t max_num_entries);
81
82  void AddFrameEventToStorage(
83      const linked_ptr<media::cast::proto::AggregatedFrameEvent>&
84          frame_event_proto);
85  void AddPacketEventToStorage(
86      const linked_ptr<media::cast::proto::AggregatedPacketEvent>&
87          packet_event_proto);
88
89  // Returns the difference between |rtp_timestamp| and |first_rtp_timestamp_|.
90  // Sets |first_rtp_timestamp_| if it is not already set.
91  RtpTimestamp GetRelativeRtpTimestamp(RtpTimestamp rtp_timestamp);
92
93  // Clears the maps and first RTP timestamp seen.
94  void Reset();
95
96  const EventMediaType event_media_type_;
97  const size_t max_frames_;
98
99  FrameEventMap frame_event_map_;
100  FrameEventList frame_event_storage_;
101  int frame_event_storage_index_;
102
103  PacketEventMap packet_event_map_;
104  PacketEventList packet_event_storage_;
105  int packet_event_storage_index_;
106
107  // All functions must be called on the main thread.
108  base::ThreadChecker thread_checker_;
109
110  // Set to true on first event encountered after a |Reset()|.
111  bool seen_first_rtp_timestamp_;
112
113  // Set to RTP timestamp of first event encountered after a |Reset()|.
114  RtpTimestamp first_rtp_timestamp_;
115
116  DISALLOW_COPY_AND_ASSIGN(EncodingEventSubscriber);
117};
118
119}  // namespace cast
120}  // namespace media
121
122#endif  // MEDIA_CAST_LOGGING_ENCODING_EVENT_SUBSCRIBER_H_
123