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/delay_manager.h b/webrtc/modules/audio_coding/neteq/delay_manager.h
new file mode 100644
index 0000000..96b5e19
--- /dev/null
+++ b/webrtc/modules/audio_coding/neteq/delay_manager.h
@@ -0,0 +1,164 @@
+/*
+ *  Copyright (c) 2012 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.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ_DELAY_MANAGER_H_
+#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_DELAY_MANAGER_H_
+
+#include <string.h>  // Provide access to size_t.
+
+#include <vector>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/modules/audio_coding/neteq/interface/audio_decoder.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Forward declaration.
+class DelayPeakDetector;
+
+class DelayManager {
+ public:
+  typedef std::vector<int> IATVector;
+
+  // Create a DelayManager object. Notify the delay manager that the packet
+  // buffer can hold no more than |max_packets_in_buffer| packets (i.e., this
+  // is the number of packet slots in the buffer). Supply a PeakDetector
+  // object to the DelayManager.
+  DelayManager(int max_packets_in_buffer, DelayPeakDetector* peak_detector);
+
+  virtual ~DelayManager();
+
+  // Read the inter-arrival time histogram. Mainly for testing purposes.
+  virtual const IATVector& iat_vector() const;
+
+  // Updates the delay manager with a new incoming packet, with
+  // |sequence_number| and |timestamp| from the RTP header. This updates the
+  // inter-arrival time histogram and other statistics, as well as the
+  // associated DelayPeakDetector. A new target buffer level is calculated.
+  // Returns 0 on success, -1 on failure (invalid sample rate).
+  virtual int Update(uint16_t sequence_number,
+                     uint32_t timestamp,
+                     int sample_rate_hz);
+
+  // Calculates a new target buffer level. Called from the Update() method.
+  // Sets target_level_ (in Q8) and returns the same value. Also calculates
+  // and updates base_target_level_, which is the target buffer level before
+  // taking delay peaks into account.
+  virtual int CalculateTargetLevel(int iat_packets);
+
+  // Notifies the DelayManager of how much audio data is carried in each packet.
+  // The method updates the DelayPeakDetector too, and resets the inter-arrival
+  // time counter. Returns 0 on success, -1 on failure.
+  virtual int SetPacketAudioLength(int length_ms);
+
+  // Resets the DelayManager and the associated DelayPeakDetector.
+  virtual void Reset();
+
+  // Calculates the average inter-arrival time deviation from the histogram.
+  // The result is returned as parts-per-million deviation from the nominal
+  // inter-arrival time. That is, if the average inter-arrival time is equal to
+  // the nominal frame time, the return value is zero. A positive value
+  // corresponds to packet spacing being too large, while a negative value means
+  // that the packets arrive with less spacing than expected.
+  virtual int AverageIAT() const;
+
+  // Returns true if peak-mode is active. That is, delay peaks were observed
+  // recently. This method simply asks for the same information from the
+  // DelayPeakDetector object.
+  virtual bool PeakFound() const;
+
+  // Notifies the counters in DelayManager and DelayPeakDetector that
+  // |elapsed_time_ms| have elapsed.
+  virtual void UpdateCounters(int elapsed_time_ms);
+
+  // Reset the inter-arrival time counter to 0.
+  virtual void ResetPacketIatCount();
+
+  // Writes the lower and higher limits which the buffer level should stay
+  // within to the corresponding pointers. The values are in (fractions of)
+  // packets in Q8.
+  virtual void BufferLimits(int* lower_limit, int* higher_limit) const;
+
+  // Gets the target buffer level, in (fractions of) packets in Q8. This value
+  // includes any extra delay set through the set_extra_delay_ms() method.
+  virtual int TargetLevel() const;
+
+  virtual void LastDecoderType(NetEqDecoder decoder_type);
+
+  // Accessors and mutators.
+  // Assuming |delay| is in valid range.
+  virtual bool SetMinimumDelay(int delay_ms);
+  virtual bool SetMaximumDelay(int delay_ms);
+  virtual int least_required_delay_ms() const;
+  virtual int base_target_level() const;
+  virtual void set_streaming_mode(bool value);
+  virtual int last_pack_cng_or_dtmf() const;
+  virtual void set_last_pack_cng_or_dtmf(int value);
+
+ private:
+  static const int kLimitProbability = 53687091;  // 1/20 in Q30.
+  static const int kLimitProbabilityStreaming = 536871;  // 1/2000 in Q30.
+  static const int kMaxStreamingPeakPeriodMs = 600000;  // 10 minutes in ms.
+  static const int kCumulativeSumDrift = 2;  // Drift term for cumulative sum
+                                             // |iat_cumulative_sum_|.
+  // Steady-state forgetting factor for |iat_vector_|, 0.9993 in Q15.
+  static const int kIatFactor_ = 32745;
+  static const int kMaxIat = 64;  // Max inter-arrival time to register.
+
+  // Sets |iat_vector_| to the default start distribution and sets the
+  // |base_target_level_| and |target_level_| to the corresponding values.
+  void ResetHistogram();
+
+  // Updates |iat_cumulative_sum_| and |max_iat_cumulative_sum_|. (These are
+  // used by the streaming mode.) This method is called by Update().
+  void UpdateCumulativeSums(int packet_len_ms, uint16_t sequence_number);
+
+  // Updates the histogram |iat_vector_|. The probability for inter-arrival time
+  // equal to |iat_packets| (in integer packets) is increased slightly, while
+  // all other entries are decreased. This method is called by Update().
+  void UpdateHistogram(size_t iat_packets);
+
+  // Makes sure that |target_level_| is not too large, taking
+  // |max_packets_in_buffer_| and |extra_delay_ms_| into account. This method is
+  // called by Update().
+  void LimitTargetLevel();
+
+  bool first_packet_received_;
+  const int max_packets_in_buffer_;  // Capacity of the packet buffer.
+  IATVector iat_vector_;  // Histogram of inter-arrival times.
+  int iat_factor_;  // Forgetting factor for updating the IAT histogram (Q15).
+  int packet_iat_count_ms_;  // Milliseconds elapsed since last packet.
+  int base_target_level_;   // Currently preferred buffer level before peak
+                            // detection and streaming mode (Q0).
+  // TODO(turajs) change the comment according to the implementation of
+  // minimum-delay.
+  int target_level_;  // Currently preferred buffer level in (fractions)
+                      // of packets (Q8), before adding any extra delay.
+  int packet_len_ms_;  // Length of audio in each incoming packet [ms].
+  bool streaming_mode_;
+  uint16_t last_seq_no_;  // Sequence number for last received packet.
+  uint32_t last_timestamp_;  // Timestamp for the last received packet.
+  int minimum_delay_ms_;  // Externally set minimum delay.
+  int least_required_delay_ms_;  // Smallest preferred buffer level (same unit
+                              // as |target_level_|), before applying
+                              // |minimum_delay_ms_| and/or |maximum_delay_ms_|.
+  int maximum_delay_ms_;  // Externally set maximum allowed delay.
+  int iat_cumulative_sum_;  // Cumulative sum of delta inter-arrival times.
+  int max_iat_cumulative_sum_;  // Max of |iat_cumulative_sum_|.
+  int max_timer_ms_;  // Time elapsed since maximum was observed.
+  DelayPeakDetector& peak_detector_;
+  int last_pack_cng_or_dtmf_;
+
+  DISALLOW_COPY_AND_ASSIGN(DelayManager);
+};
+
+}  // namespace webrtc
+#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DELAY_MANAGER_H_