text: ﻿/*
   *  Copyright (c) 2014 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 "modules/audio_coding/neteq/tools/constant_pcm_packet_source.h"
  
  #include <algorithm>
  
  #include "modules/audio_coding/codecs/pcm16b/pcm16b.h"
  #include "modules/audio_coding/neteq/tools/packet.h"
  #include "rtc_base/checks.h"
  
  namespace webrtc {
  namespace test {
  
  ConstantPcmPacketSource::ConstantPcmPacketSource(size_t payload_len_samples,
                                                   int16_t sample_value,
                                                   int sample_rate_hz,
                                                   int payload_type)
      : payload_len_samples_(payload_len_samples),
        packet_len_bytes_(2 * payload_len_samples_ + kHeaderLenBytes),
        samples_per_ms_(sample_rate_hz / 1000),
        next_arrival_time_ms_(0.0),
        payload_type_(payload_type),
        seq_number_(0),
        timestamp_(0),
        payload_ssrc_(0xABCD1234) {
    size_t encoded_len = WebRtcPcm16b_Encode(&sample_value, 1, encoded_sample_);
    RTC_CHECK_EQ(2U, encoded_len);
  }
  
  std::unique_ptr<Packet> ConstantPcmPacketSource::NextPacket() {
    RTC_CHECK_GT(packet_len_bytes_, kHeaderLenBytes);
    uint8_t* packet_memory = new uint8_t[packet_len_bytes_];
    // Fill the payload part of the packet memory with the pre-encoded value.
    for (unsigned i = 0; i < 2 * payload_len_samples_; ++i)
      packet_memory[kHeaderLenBytes + i] = encoded_sample_[i % 2];
    WriteHeader(packet_memory);
    // |packet| assumes ownership of |packet_memory|.
    std::unique_ptr<Packet> packet(
        new Packet(packet_memory, packet_len_bytes_, next_arrival_time_ms_));
    next_arrival_time_ms_ += payload_len_samples_ / samples_per_ms_;
    return packet;
  }
  
  void ConstantPcmPacketSource::WriteHeader(uint8_t* packet_memory) {
    packet_memory[0] = 0x80;
    packet_memory[1] = static_cast<uint8_t>(payload_type_);
    packet_memory[2] = seq_number_ >> 8;
    packet_memory[3] = seq_number_ & 0xFF;
    packet_memory[4] = timestamp_ >> 24;
    packet_memory[5] = (timestamp_ >> 16) & 0xFF;
    packet_memory[6] = (timestamp_ >> 8) & 0xFF;
    packet_memory[7] = timestamp_ & 0xFF;
    packet_memory[8] = payload_ssrc_ >> 24;
    packet_memory[9] = (payload_ssrc_ >> 16) & 0xFF;
    packet_memory[10] = (payload_ssrc_ >> 8) & 0xFF;
    packet_memory[11] = payload_ssrc_ & 0xFF;
    ++seq_number_;
    timestamp_ += static_cast<uint32_t>(payload_len_samples_);
  }
  
  }  // namespace test
  }  // namespace webrtc
  