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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_CAST_NET_RTCP_RECEIVER_RTCP_EVENT_SUBSCRIBER_H_
#define MEDIA_CAST_NET_RTCP_RECEIVER_RTCP_EVENT_SUBSCRIBER_H_
#include <stddef.h>
#include <stdint.h>
#include <vector>
#include "base/containers/circular_deque.h"
#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "media/cast/logging/logging_defines.h"
#include "media/cast/logging/raw_event_subscriber.h"
#include "media/cast/net/rtcp/rtcp_defines.h"
namespace media {
namespace cast {
static const size_t kNumResends = 3;
static const size_t kResendDelay = 10;
static const size_t kMaxEventsPerRTCP = 20;
// A RawEventSubscriber implementation with the following properties:
// - Only processes raw event types that are relevant for sending from cast
// receiver to cast sender via RTCP.
// - Captures information to be sent over to RTCP from raw event logs into the
// more compact RtcpEvent struct.
// - Orders events by RTP timestamp with a multimap.
// - Internally, the map is capped at a maximum size configurable by the caller.
// The subscriber only keeps the most recent events (determined by RTP
// timestamp) up to the size limit.
class ReceiverRtcpEventSubscriber : public RawEventSubscriber {
public:
typedef std::pair<RtpTimeTicks, RtcpEvent> RtcpEventPair;
typedef std::vector<std::pair<RtpTimeTicks, RtcpEvent>> RtcpEvents;
// |max_size_to_retain|: The object will keep up to |max_size_to_retain|
// events
// in the map. Once threshold has been reached, an event with the smallest
// RTP timestamp will be removed.
// |type|: Determines whether the subscriber will process only audio or video
// events.
ReceiverRtcpEventSubscriber(const size_t max_size_to_retain,
EventMediaType type);
~ReceiverRtcpEventSubscriber() final;
// RawEventSubscriber implementation.
void OnReceiveFrameEvent(const FrameEvent& frame_event) final;
void OnReceivePacketEvent(const PacketEvent& packet_event) final;
// Assigns events collected to |rtcp_events|. If there is space, some
// older events will be added for redundancy as well.
void GetRtcpEventsWithRedundancy(RtcpEvents* rtcp_events);
private:
// If |rtcp_events_.size()| exceeds |max_size_to_retain_|, remove an oldest
// entry (determined by RTP timestamp) so its size no greater than
// |max_size_to_retain_|.
void TruncateMapIfNeeded();
// Returns |true| if events of |event_type| and |media_type|
// should be processed.
bool ShouldProcessEvent(CastLoggingEvent event_type,
EventMediaType media_type);
const size_t max_size_to_retain_;
EventMediaType type_;
// The key should really be something more than just a RTP timestamp in order
// to differentiate between video and audio frames, but since the
// implementation doesn't mix audio and video frame events, RTP timestamp
// only as key is fine.
base::circular_deque<RtcpEventPair> rtcp_events_;
// Counts how many events have been removed from rtcp_events_.
uint64_t popped_events_;
// Events greater than send_ptrs_[0] have not been sent yet.
// Events greater than send_ptrs_[1] have been transmit once.
// Note that these counters use absolute numbers, so you need
// to subtract popped_events_ before looking up the events in
// rtcp_events_.
uint64_t send_ptrs_[kNumResends];
// For each frame, we push how many events have been added to
// rtcp_events_ so far. We use this to make sure that
// send_ptrs_[N+1] is always at least kResendDelay frames behind
// send_ptrs_[N]. Old information is removed so that information
// for (kNumResends + 1) * kResendDelay frames remain.
base::circular_deque<uint64_t> event_levels_for_past_frames_;
// Ensures methods are only called on the main thread.
base::ThreadChecker thread_checker_;
DISALLOW_COPY_AND_ASSIGN(ReceiverRtcpEventSubscriber);
};
} // namespace cast
} // namespace media
#endif // MEDIA_CAST_NET_RTCP_RECEIVER_RTCP_EVENT_SUBSCRIBER_H_