media/cast/net/rtp/frame_buffer.cc

// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "media/cast/net/rtp/frame_buffer.h"

#include "base/logging.h"

namespace media {
namespace cast {

FrameBuffer::FrameBuffer()
    : max_packet_id_(0),
      num_packets_received_(0),
      max_seen_packet_id_(0),
      new_playout_delay_ms_(0),
      is_key_frame_(false),
      total_data_size_(0),
      packets_() {}

FrameBuffer::~FrameBuffer() = default;

bool FrameBuffer::InsertPacket(const uint8_t* payload_data,
                               size_t payload_size,
                               const RtpCastHeader& rtp_header) {
  // Is this the first packet in the frame?
  if (packets_.empty()) {
    frame_id_ = rtp_header.frame_id;
    max_packet_id_ = rtp_header.max_packet_id;
    is_key_frame_ = rtp_header.is_key_frame;
    new_playout_delay_ms_ = rtp_header.new_playout_delay_ms;
    if (is_key_frame_)
      DCHECK_EQ(rtp_header.frame_id, rtp_header.reference_frame_id);
    last_referenced_frame_id_ = rtp_header.reference_frame_id;
    rtp_timestamp_ = rtp_header.rtp_timestamp;
  }
  // Is this the correct frame?
  if (rtp_header.frame_id != frame_id_)
    return false;

  // Insert every packet only once.
  if (packets_.find(rtp_header.packet_id) != packets_.end()) {
    return false;
  }

  std::vector<uint8_t> data;
  std::pair<PacketMap::iterator, bool> retval =
      packets_.insert(make_pair(rtp_header.packet_id, data));

  // Insert the packet.
  retval.first->second.resize(payload_size);
  std::copy(
      payload_data, payload_data + payload_size, retval.first->second.begin());

  ++num_packets_received_;
  max_seen_packet_id_ = std::max(max_seen_packet_id_, rtp_header.packet_id);
  total_data_size_ += payload_size;
  return true;
}

bool FrameBuffer::Complete() const {
  return num_packets_received_ - 1 == max_packet_id_;
}

bool FrameBuffer::AssembleEncodedFrame(EncodedFrame* frame) const {
  if (!Complete())
    return false;

  // Frame is complete -> construct.
  if (is_key_frame_)
    frame->dependency = EncodedFrame::KEY;
  else if (frame_id_ == last_referenced_frame_id_)
    frame->dependency = EncodedFrame::INDEPENDENT;
  else
    frame->dependency = EncodedFrame::DEPENDENT;
  frame->frame_id = frame_id_;
  frame->referenced_frame_id = last_referenced_frame_id_;
  frame->rtp_timestamp = rtp_timestamp_;
  frame->new_playout_delay_ms = new_playout_delay_ms_;

  // Build the data vector.
  frame->data.clear();
  frame->data.reserve(total_data_size_);
  PacketMap::const_iterator it;
  for (it = packets_.begin(); it != packets_.end(); ++it)
    frame->data.insert(frame->data.end(), it->second.begin(), it->second.end());
  return true;
}

void FrameBuffer::GetMissingPackets(bool newest_frame,
                                    PacketIdSet* missing_packets) const {
  // Missing packets capped by max_seen_packet_id_.
  // (Iff it's the latest frame)
  int maximum = newest_frame ? max_seen_packet_id_ : max_packet_id_;
  int packet = 0;
  for (auto i = packets_.begin(); i != packets_.end() && packet <= maximum;
       ++i) {
    int end = std::min<int>(i->first, maximum + 1);
    while (packet < end) {
      missing_packets->insert(packet);
      packet++;
    }
    packet++;
  }
  while (packet <= maximum) {
    missing_packets->insert(packet);
    packet++;
  }
}


}  // namespace cast
}  // namespace media