media/cast/logging/encoding_event_subscriber.h

   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
  16 namespace media {
  17 namespace 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.
  22 static 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.
  26 static const int kMaxEventsPerProto = 16;
  27
  28 typedef std::vector<linked_ptr<media::cast::proto::AggregatedFrameEvent> >
  29     FrameEventList;
  30 typedef 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.
  40 class 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   ~EncodingEventSubscriber() final;
  53
  54   // RawReventSubscriber implementations.
  55   void OnReceiveFrameEvent(const FrameEvent& frame_event) final;
  56   void OnReceivePacketEvent(const PacketEvent& packet_event) final;
  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_