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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_fax.h"
     12 
     13 #include <assert.h>
     14 
     15 #include <algorithm>
     16 
     17 #include "webrtc/modules/audio_coding/neteq/decoder_database.h"
     18 #include "webrtc/modules/audio_coding/neteq/sync_buffer.h"
     19 
     20 namespace webrtc {
     21 
     22 Operations DecisionLogicFax::GetDecisionSpecialized(
     23     const SyncBuffer& sync_buffer,
     24     const Expand& expand,
     25     int decoder_frame_length,
     26     const RTPHeader* packet_header,
     27     Modes prev_mode,
     28     bool play_dtmf,
     29     bool* reset_decoder) {
     30   assert(playout_mode_ == kPlayoutFax || playout_mode_ == kPlayoutOff);
     31   uint32_t target_timestamp = sync_buffer.end_timestamp();
     32   uint32_t available_timestamp = 0;
     33   int is_cng_packet = 0;
     34   if (packet_header) {
     35     available_timestamp = packet_header->timestamp;
     36     is_cng_packet =
     37         decoder_database_->IsComfortNoise(packet_header->payloadType);
     38   }
     39   if (is_cng_packet) {
     40     if (static_cast<int32_t>((generated_noise_samples_ + target_timestamp)
     41         - available_timestamp) >= 0) {
     42       // Time to play this packet now.
     43       return kRfc3389Cng;
     44     } else {
     45       // Wait before playing this packet.
     46       return kRfc3389CngNoPacket;
     47     }
     48   }
     49   if (!packet_header) {
     50     // No packet. If in CNG mode, play as usual. Otherwise, use other method to
     51     // generate data.
     52     if (cng_state_ == kCngRfc3389On) {
     53       // Continue playing comfort noise.
     54       return kRfc3389CngNoPacket;
     55     } else if (cng_state_ == kCngInternalOn) {
     56       // Continue playing codec-internal comfort noise.
     57       return kCodecInternalCng;
     58     } else {
     59       // Nothing to play. Generate some data to play out.
     60       switch (playout_mode_) {
     61         case kPlayoutOff:
     62           return kAlternativePlc;
     63         case kPlayoutFax:
     64           return kAudioRepetition;
     65         default:
     66           assert(false);
     67           return kUndefined;
     68       }
     69     }
     70   } else if (target_timestamp == available_timestamp) {
     71     return kNormal;
     72   } else {
     73     if (static_cast<int32_t>((generated_noise_samples_ + target_timestamp)
     74         - available_timestamp) >= 0) {
     75       return kNormal;
     76     } else {
     77       // If currently playing comfort noise, continue with that. Do not
     78       // increase the timestamp counter since generated_noise_samples_ will
     79       // be increased.
     80       if (cng_state_ == kCngRfc3389On) {
     81         return kRfc3389CngNoPacket;
     82       } else if (cng_state_ == kCngInternalOn) {
     83         return kCodecInternalCng;
     84       } else {
     85         // Otherwise, do packet-loss concealment and increase the
     86         // timestamp while waiting for the time to play this packet.
     87         switch (playout_mode_) {
     88           case kPlayoutOff:
     89             return kAlternativePlcIncreaseTimestamp;
     90           case kPlayoutFax:
     91             return kAudioRepetitionIncreaseTimestamp;
     92           default:
     93             assert(0);
     94             return kUndefined;
     95         }
     96       }
     97     }
     98   }
     99 }
    100 
    101 
    102 }  // namespace webrtc
    103