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platform-external-webrtc/webrtc/modules/audio_coding/neteq4/rtcp.cc
henrik.lundin@webrtc.org d94659dc27 Initial upload of NetEq4
This is the first public upload of the new NetEq, version 4.

It has been through extensive internal review during the course of
the project.

TEST=trybots

Review URL: https://webrtc-codereview.appspot.com/1073005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@3425 4adac7df-926f-26a2-2b94-8c16560cd09d
2013-01-29 12:09:21 +00:00

96 lines
3.3 KiB
C++

/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "webrtc/modules/audio_coding/neteq4/rtcp.h"
#include <string.h>
#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
#include "webrtc/modules/interface/module_common_types.h"
namespace webrtc {
void Rtcp::Init(uint16_t start_sequence_number) {
cycles_ = 0;
max_seq_no_ = start_sequence_number;
base_seq_no_ = start_sequence_number;
received_packets_ = 0;
received_packets_prior_ = 0;
expected_prior_ = 0;
jitter_ = 0;
transit_ = 0;
}
void Rtcp::Update(const RTPHeader& rtp_header, uint32_t receive_timestamp) {
// Update number of received packets, and largest packet number received.
received_packets_++;
int16_t sn_diff = rtp_header.sequenceNumber - max_seq_no_;
if (sn_diff >= 0) {
if (rtp_header.sequenceNumber < max_seq_no_) {
// Wrap-around detected.
cycles_++;
}
max_seq_no_ = rtp_header.sequenceNumber;
}
// Calculate jitter according to RFC 3550, and update previous timestamps.
// Note that the value in |jitter_| is in Q4.
if (received_packets_ > 1) {
int32_t ts_diff = receive_timestamp - (rtp_header.timestamp - transit_);
ts_diff = WEBRTC_SPL_ABS_W32(ts_diff);
int32_t jitter_diff = (ts_diff << 4) - jitter_;
// Calculate 15 * jitter_ / 16 + jitter_diff / 16 (with proper rounding).
jitter_ = jitter_ + ((jitter_diff + 8) >> 4);
}
transit_ = rtp_header.timestamp - receive_timestamp;
}
void Rtcp::GetStatistics(bool no_reset, RtcpStatistics* stats) {
// Extended highest sequence number received.
stats->extended_max = (static_cast<int>(cycles_) << 16) + max_seq_no_;
// Calculate expected number of packets and compare it with the number of
// packets that were actually received. The cumulative number of lost packets
// can be extracted.
uint32_t expected_packets = stats->extended_max - base_seq_no_ + 1;
if (received_packets_ == 0) {
// No packets received, assume none lost.
stats->cumulative_lost = 0;
} else if (expected_packets > received_packets_) {
stats->cumulative_lost = expected_packets - received_packets_;
if (stats->cumulative_lost > 0xFFFFFF) {
stats->cumulative_lost = 0xFFFFFF;
}
} else {
stats->cumulative_lost = 0;
}
// Fraction lost since last report.
uint32_t expected_since_last = expected_packets - expected_prior_;
uint32_t received_since_last = received_packets_ - received_packets_prior_;
if (!no_reset) {
expected_prior_ = expected_packets;
received_packets_prior_ = received_packets_;
}
int32_t lost = expected_since_last - received_since_last;
if (expected_since_last == 0 || lost <= 0 || received_packets_ == 0) {
stats->fraction_lost = 0;
} else {
stats->fraction_lost = (lost << 8) / expected_since_last;
}
if (stats->fraction_lost > 0xFF) {
stats->fraction_lost = 0xFF;
}
stats->jitter = jitter_ >> 4; // Scaling from Q4.
}
} // namespace webrtc