Rename neteq4 folder to neteq

Keep the old neteq4/audio_decoder_unittests.isolate while waiting for
a hard-coded reference to change.

This CL effectively reverts r6257 "Rename neteq4 folder to neteq".

BUG=2996
TBR=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/21629004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6367 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq/rtcp.cc b/webrtc/modules/audio_coding/neteq/rtcp.cc
new file mode 100644
index 0000000..cf8e028
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq/rtcp.cc
@@ -0,0 +1,96 @@
+/*
+ *  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/neteq/rtcp.h"
+
+#include <string.h>
+
+#include <algorithm>
+
+#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_sequence_number =
+      (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_sequence_number - 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 = std::min(0xFFU, (lost << 8) / expected_since_last);
+  }
+
+  stats->jitter = jitter_ >> 4;  // Scaling from Q4.
+}
+
+}  // namespace webrtc