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      1 /*
      2  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include "webrtc/modules/audio_coding/neteq/decision_logic.h"
     12 
     13 #include <algorithm>
     14 
     15 #include "webrtc/modules/audio_coding/neteq/buffer_level_filter.h"
     16 #include "webrtc/modules/audio_coding/neteq/decision_logic_fax.h"
     17 #include "webrtc/modules/audio_coding/neteq/decision_logic_normal.h"
     18 #include "webrtc/modules/audio_coding/neteq/delay_manager.h"
     19 #include "webrtc/modules/audio_coding/neteq/expand.h"
     20 #include "webrtc/modules/audio_coding/neteq/packet_buffer.h"
     21 #include "webrtc/modules/audio_coding/neteq/sync_buffer.h"
     22 #include "webrtc/system_wrappers/interface/logging.h"
     23 
     24 namespace webrtc {
     25 
     26 DecisionLogic* DecisionLogic::Create(int fs_hz,
     27                                      int output_size_samples,
     28                                      NetEqPlayoutMode playout_mode,
     29                                      DecoderDatabase* decoder_database,
     30                                      const PacketBuffer& packet_buffer,
     31                                      DelayManager* delay_manager,
     32                                      BufferLevelFilter* buffer_level_filter) {
     33   switch (playout_mode) {
     34     case kPlayoutOn:
     35     case kPlayoutStreaming:
     36       return new DecisionLogicNormal(fs_hz,
     37                                      output_size_samples,
     38                                      playout_mode,
     39                                      decoder_database,
     40                                      packet_buffer,
     41                                      delay_manager,
     42                                      buffer_level_filter);
     43     case kPlayoutFax:
     44     case kPlayoutOff:
     45       return new DecisionLogicFax(fs_hz,
     46                                   output_size_samples,
     47                                   playout_mode,
     48                                   decoder_database,
     49                                   packet_buffer,
     50                                   delay_manager,
     51                                   buffer_level_filter);
     52   }
     53   // This line cannot be reached, but must be here to avoid compiler errors.
     54   assert(false);
     55   return NULL;
     56 }
     57 
     58 DecisionLogic::DecisionLogic(int fs_hz,
     59                              int output_size_samples,
     60                              NetEqPlayoutMode playout_mode,
     61                              DecoderDatabase* decoder_database,
     62                              const PacketBuffer& packet_buffer,
     63                              DelayManager* delay_manager,
     64                              BufferLevelFilter* buffer_level_filter)
     65     : decoder_database_(decoder_database),
     66       packet_buffer_(packet_buffer),
     67       delay_manager_(delay_manager),
     68       buffer_level_filter_(buffer_level_filter),
     69       cng_state_(kCngOff),
     70       generated_noise_samples_(0),
     71       packet_length_samples_(0),
     72       sample_memory_(0),
     73       prev_time_scale_(false),
     74       timescale_hold_off_(kMinTimescaleInterval),
     75       num_consecutive_expands_(0),
     76       playout_mode_(playout_mode) {
     77   delay_manager_->set_streaming_mode(playout_mode_ == kPlayoutStreaming);
     78   SetSampleRate(fs_hz, output_size_samples);
     79 }
     80 
     81 void DecisionLogic::Reset() {
     82   cng_state_ = kCngOff;
     83   generated_noise_samples_ = 0;
     84   packet_length_samples_ = 0;
     85   sample_memory_ = 0;
     86   prev_time_scale_ = false;
     87   timescale_hold_off_ = 0;
     88   num_consecutive_expands_ = 0;
     89 }
     90 
     91 void DecisionLogic::SoftReset() {
     92   packet_length_samples_ = 0;
     93   sample_memory_ = 0;
     94   prev_time_scale_ = false;
     95   timescale_hold_off_ = kMinTimescaleInterval;
     96 }
     97 
     98 void DecisionLogic::SetSampleRate(int fs_hz, int output_size_samples) {
     99   // TODO(hlundin): Change to an enumerator and skip assert.
    100   assert(fs_hz == 8000 || fs_hz == 16000 || fs_hz ==  32000 || fs_hz == 48000);
    101   fs_mult_ = fs_hz / 8000;
    102   output_size_samples_ = output_size_samples;
    103 }
    104 
    105 Operations DecisionLogic::GetDecision(const SyncBuffer& sync_buffer,
    106                                       const Expand& expand,
    107                                       int decoder_frame_length,
    108                                       const RTPHeader* packet_header,
    109                                       Modes prev_mode,
    110                                       bool play_dtmf, bool* reset_decoder) {
    111   if (prev_mode == kModeRfc3389Cng ||
    112       prev_mode == kModeCodecInternalCng ||
    113       prev_mode == kModeExpand) {
    114     // If last mode was CNG (or Expand, since this could be covering up for
    115     // a lost CNG packet), increase the |generated_noise_samples_| counter.
    116     generated_noise_samples_ += output_size_samples_;
    117     // Remember that CNG is on. This is needed if comfort noise is interrupted
    118     // by DTMF.
    119     if (prev_mode == kModeRfc3389Cng) {
    120       cng_state_ = kCngRfc3389On;
    121     } else if (prev_mode == kModeCodecInternalCng) {
    122       cng_state_ = kCngInternalOn;
    123     }
    124   }
    125 
    126   const int samples_left = static_cast<int>(
    127       sync_buffer.FutureLength() - expand.overlap_length());
    128   const int cur_size_samples =
    129       samples_left + packet_buffer_.NumSamplesInBuffer(decoder_database_,
    130                                                        decoder_frame_length);
    131   LOG(LS_VERBOSE) << "Buffers: " << packet_buffer_.NumPacketsInBuffer() <<
    132       " packets * " << decoder_frame_length << " samples/packet + " <<
    133       samples_left << " samples in sync buffer = " << cur_size_samples;
    134 
    135   prev_time_scale_ = prev_time_scale_ &&
    136       (prev_mode == kModeAccelerateSuccess ||
    137           prev_mode == kModeAccelerateLowEnergy ||
    138           prev_mode == kModePreemptiveExpandSuccess ||
    139           prev_mode == kModePreemptiveExpandLowEnergy);
    140 
    141   FilterBufferLevel(cur_size_samples, prev_mode);
    142 
    143   return GetDecisionSpecialized(sync_buffer, expand, decoder_frame_length,
    144                                 packet_header, prev_mode, play_dtmf,
    145                                 reset_decoder);
    146 }
    147 
    148 void DecisionLogic::ExpandDecision(Operations operation) {
    149   if (operation == kExpand) {
    150     num_consecutive_expands_++;
    151   } else {
    152     num_consecutive_expands_ = 0;
    153   }
    154 }
    155 
    156 void DecisionLogic::FilterBufferLevel(int buffer_size_samples,
    157                                       Modes prev_mode) {
    158   const int elapsed_time_ms = output_size_samples_ / (8 * fs_mult_);
    159   delay_manager_->UpdateCounters(elapsed_time_ms);
    160 
    161   // Do not update buffer history if currently playing CNG since it will bias
    162   // the filtered buffer level.
    163   if ((prev_mode != kModeRfc3389Cng) && (prev_mode != kModeCodecInternalCng)) {
    164     buffer_level_filter_->SetTargetBufferLevel(
    165         delay_manager_->base_target_level());
    166 
    167     int buffer_size_packets = 0;
    168     if (packet_length_samples_ > 0) {
    169       // Calculate size in packets.
    170       buffer_size_packets = buffer_size_samples / packet_length_samples_;
    171     }
    172     int sample_memory_local = 0;
    173     if (prev_time_scale_) {
    174       sample_memory_local = sample_memory_;
    175       timescale_hold_off_ = kMinTimescaleInterval;
    176     }
    177     buffer_level_filter_->Update(buffer_size_packets, sample_memory_local,
    178                                  packet_length_samples_);
    179     prev_time_scale_ = false;
    180   }
    181 
    182   timescale_hold_off_ = std::max(timescale_hold_off_ - 1, 0);
    183 }
    184 
    185 }  // namespace webrtc
    186