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| 1 // Copyright 2013 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 #include "media/cast/rtp_receiver/receiver_stats.h" | |
| 6 | |
| 7 #include "base/logging.h" | |
| 8 #include "media/cast/rtp_receiver/rtp_receiver_defines.h" | |
| 9 | |
| 10 namespace media { | |
| 11 namespace cast { | |
| 12 | |
| 13 static const uint32 kMaxSequenceNumber = 65536; | |
| 14 | |
| 15 ReceiverStats::ReceiverStats(base::TickClock* clock) | |
| 16 : clock_(clock), | |
| 17 min_sequence_number_(0), | |
| 18 max_sequence_number_(0), | |
| 19 total_number_packets_(0), | |
| 20 sequence_number_cycles_(0), | |
| 21 interval_min_sequence_number_(0), | |
| 22 interval_number_packets_(0), | |
| 23 interval_wrap_count_(0) {} | |
| 24 | |
| 25 ReceiverStats::~ReceiverStats() {} | |
| 26 | |
| 27 void ReceiverStats::GetStatistics(uint8* fraction_lost, | |
| 28 uint32* cumulative_lost, | |
| 29 uint32* extended_high_sequence_number, | |
| 30 uint32* jitter) { | |
| 31 // Compute losses. | |
| 32 if (interval_number_packets_ == 0) { | |
| 33 *fraction_lost = 0; | |
| 34 } else { | |
| 35 int diff = 0; | |
| 36 if (interval_wrap_count_ == 0) { | |
| 37 diff = max_sequence_number_ - interval_min_sequence_number_ + 1; | |
| 38 } else { | |
| 39 diff = kMaxSequenceNumber * (interval_wrap_count_ - 1) + | |
| 40 (max_sequence_number_ - interval_min_sequence_number_ + | |
| 41 kMaxSequenceNumber + 1); | |
| 42 } | |
| 43 | |
| 44 if (diff < 1) { | |
| 45 *fraction_lost = 0; | |
| 46 } else { | |
| 47 float tmp_ratio = | |
| 48 (1 - static_cast<float>(interval_number_packets_) / abs(diff)); | |
| 49 *fraction_lost = static_cast<uint8>(256 * tmp_ratio); | |
| 50 } | |
| 51 } | |
| 52 | |
| 53 int expected_packets_num = max_sequence_number_ - min_sequence_number_ + 1; | |
| 54 if (total_number_packets_ == 0) { | |
| 55 *cumulative_lost = 0; | |
| 56 } else if (sequence_number_cycles_ == 0) { | |
| 57 *cumulative_lost = expected_packets_num - total_number_packets_; | |
| 58 } else { | |
| 59 *cumulative_lost = | |
| 60 kMaxSequenceNumber * (sequence_number_cycles_ - 1) + | |
| 61 (expected_packets_num - total_number_packets_ + kMaxSequenceNumber); | |
| 62 } | |
| 63 | |
| 64 // Extended high sequence number consists of the highest seq number and the | |
| 65 // number of cycles (wrap). | |
| 66 *extended_high_sequence_number = | |
| 67 (sequence_number_cycles_ << 16) + max_sequence_number_; | |
| 68 | |
| 69 *jitter = static_cast<uint32>(std::abs(jitter_.InMillisecondsRoundedUp())); | |
| 70 | |
| 71 // Reset interval values. | |
| 72 interval_min_sequence_number_ = 0; | |
| 73 interval_number_packets_ = 0; | |
| 74 interval_wrap_count_ = 0; | |
| 75 } | |
| 76 | |
| 77 void ReceiverStats::UpdateStatistics(const RtpCastHeader& header) { | |
| 78 const uint16 new_seq_num = header.sequence_number; | |
| 79 | |
| 80 if (interval_number_packets_ == 0) { | |
| 81 // First packet in the interval. | |
| 82 interval_min_sequence_number_ = new_seq_num; | |
| 83 } | |
| 84 if (total_number_packets_ == 0) { | |
| 85 // First incoming packet. | |
| 86 min_sequence_number_ = new_seq_num; | |
| 87 max_sequence_number_ = new_seq_num; | |
| 88 } | |
| 89 | |
| 90 if (IsNewerSequenceNumber(new_seq_num, max_sequence_number_)) { | |
| 91 // Check wrap. | |
| 92 if (new_seq_num < max_sequence_number_) { | |
| 93 ++sequence_number_cycles_; | |
| 94 ++interval_wrap_count_; | |
| 95 } | |
| 96 max_sequence_number_ = new_seq_num; | |
| 97 } | |
| 98 | |
| 99 // Compute Jitter. | |
| 100 base::TimeTicks now = clock_->NowTicks(); | |
| 101 base::TimeDelta delta_new_timestamp = | |
| 102 base::TimeDelta::FromMilliseconds(header.rtp_timestamp); | |
| 103 if (total_number_packets_ > 0) { | |
| 104 // Update jitter. | |
| 105 base::TimeDelta delta = | |
| 106 (now - last_received_packet_time_) - | |
| 107 ((delta_new_timestamp - last_received_timestamp_) / 90); | |
| 108 jitter_ += (delta - jitter_) / 16; | |
| 109 } | |
| 110 last_received_timestamp_ = delta_new_timestamp; | |
| 111 last_received_packet_time_ = now; | |
| 112 | |
| 113 // Increment counters. | |
| 114 ++total_number_packets_; | |
| 115 ++interval_number_packets_; | |
| 116 } | |
| 117 | |
| 118 } // namespace cast | |
| 119 } // namespace media | |
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Chromium Code Reviews
Issue 388663003:
Cast: Reshuffle files under media/cast (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src