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| 1 // Copyright 2013 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "media/cast/transport/rtp_sender/rtp_packetizer/rtp_packetizer.h" | |
| 6 | |
| 7 #include "base/big_endian.h" | |
| 8 #include "base/logging.h" | |
| 9 #include "media/cast/transport/pacing/paced_sender.h" | |
| 10 | |
| 11 namespace media { | |
| 12 namespace cast { | |
| 13 namespace transport { | |
| 14 | |
| 15 static const uint16 kCommonRtpHeaderLength = 12; | |
| 16 static const uint16 kCastRtpHeaderLength = 7; | |
| 17 static const uint8 kCastKeyFrameBitMask = 0x80; | |
| 18 static const uint8 kCastReferenceFrameIdBitMask = 0x40; | |
| 19 static const uint8 kRtpMarkerBitMask = 0x80; | |
| 20 | |
| 21 RtpPacketizerConfig::RtpPacketizerConfig() | |
| 22 : payload_type(-1), | |
| 23 max_payload_length(kMaxIpPacketSize - 28), // Default is IP-v4/UDP. | |
| 24 sequence_number(0), | |
| 25 ssrc(0) {} | |
| 26 | |
| 27 RtpPacketizerConfig::~RtpPacketizerConfig() {} | |
| 28 | |
| 29 RtpPacketizer::RtpPacketizer(PacedSender* const transport, | |
| 30 PacketStorage* packet_storage, | |
| 31 RtpPacketizerConfig rtp_packetizer_config) | |
| 32 : config_(rtp_packetizer_config), | |
| 33 transport_(transport), | |
| 34 packet_storage_(packet_storage), | |
| 35 sequence_number_(config_.sequence_number), | |
| 36 rtp_timestamp_(0), | |
| 37 packet_id_(0), | |
| 38 send_packet_count_(0), | |
| 39 send_octet_count_(0) { | |
| 40 DCHECK(transport) << "Invalid argument"; | |
| 41 } | |
| 42 | |
| 43 RtpPacketizer::~RtpPacketizer() {} | |
| 44 | |
| 45 uint16 RtpPacketizer::NextSequenceNumber() { | |
| 46 ++sequence_number_; | |
| 47 return sequence_number_ - 1; | |
| 48 } | |
| 49 | |
| 50 void RtpPacketizer::SendFrameAsPackets(const EncodedFrame& frame) { | |
| 51 uint16 rtp_header_length = kCommonRtpHeaderLength + kCastRtpHeaderLength; | |
| 52 uint16 max_length = config_.max_payload_length - rtp_header_length - 1; | |
| 53 rtp_timestamp_ = frame.rtp_timestamp; | |
| 54 | |
| 55 // Split the payload evenly (round number up). | |
| 56 size_t num_packets = (frame.data.size() + max_length) / max_length; | |
| 57 size_t payload_length = (frame.data.size() + num_packets) / num_packets; | |
| 58 DCHECK_LE(payload_length, max_length) << "Invalid argument"; | |
| 59 | |
| 60 SendPacketVector packets; | |
| 61 | |
| 62 size_t remaining_size = frame.data.size(); | |
| 63 std::string::const_iterator data_iter = frame.data.begin(); | |
| 64 while (remaining_size > 0) { | |
| 65 PacketRef packet(new base::RefCountedData<Packet>); | |
| 66 | |
| 67 if (remaining_size < payload_length) { | |
| 68 payload_length = remaining_size; | |
| 69 } | |
| 70 remaining_size -= payload_length; | |
| 71 BuildCommonRTPheader( | |
| 72 &packet->data, remaining_size == 0, frame.rtp_timestamp); | |
| 73 | |
| 74 // Build Cast header. | |
| 75 // TODO(miu): Should we always set the ref frame bit and the ref_frame_id? | |
| 76 DCHECK_NE(frame.dependency, EncodedFrame::UNKNOWN_DEPENDENCY); | |
| 77 packet->data.push_back( | |
| 78 ((frame.dependency == EncodedFrame::KEY) ? kCastKeyFrameBitMask : 0) | | |
| 79 kCastReferenceFrameIdBitMask); | |
| 80 packet->data.push_back(static_cast<uint8>(frame.frame_id)); | |
| 81 size_t start_size = packet->data.size(); | |
| 82 packet->data.resize(start_size + 4); | |
| 83 base::BigEndianWriter big_endian_writer( | |
| 84 reinterpret_cast<char*>(&(packet->data[start_size])), 4); | |
| 85 big_endian_writer.WriteU16(packet_id_); | |
| 86 big_endian_writer.WriteU16(static_cast<uint16>(num_packets - 1)); | |
| 87 packet->data.push_back(static_cast<uint8>(frame.referenced_frame_id)); | |
| 88 | |
| 89 // Copy payload data. | |
| 90 packet->data.insert(packet->data.end(), | |
| 91 data_iter, | |
| 92 data_iter + payload_length); | |
| 93 data_iter += payload_length; | |
| 94 | |
| 95 const PacketKey key = | |
| 96 PacedPacketSender::MakePacketKey(frame.reference_time, | |
| 97 config_.ssrc, | |
| 98 packet_id_++); | |
| 99 packets.push_back(make_pair(key, packet)); | |
| 100 | |
| 101 // Update stats. | |
| 102 ++send_packet_count_; | |
| 103 send_octet_count_ += payload_length; | |
| 104 } | |
| 105 DCHECK(packet_id_ == num_packets) << "Invalid state"; | |
| 106 | |
| 107 packet_storage_->StoreFrame(frame.frame_id, packets); | |
| 108 | |
| 109 // Send to network. | |
| 110 transport_->SendPackets(packets); | |
| 111 | |
| 112 // Prepare for next frame. | |
| 113 packet_id_ = 0; | |
| 114 } | |
| 115 | |
| 116 void RtpPacketizer::BuildCommonRTPheader(Packet* packet, | |
| 117 bool marker_bit, | |
| 118 uint32 time_stamp) { | |
| 119 packet->push_back(0x80); | |
| 120 packet->push_back(static_cast<uint8>(config_.payload_type) | | |
| 121 (marker_bit ? kRtpMarkerBitMask : 0)); | |
| 122 size_t start_size = packet->size(); | |
| 123 packet->resize(start_size + 10); | |
| 124 base::BigEndianWriter big_endian_writer( | |
| 125 reinterpret_cast<char*>(&((*packet)[start_size])), 10); | |
| 126 big_endian_writer.WriteU16(sequence_number_); | |
| 127 big_endian_writer.WriteU32(time_stamp); | |
| 128 big_endian_writer.WriteU32(config_.ssrc); | |
| 129 ++sequence_number_; | |
| 130 } | |
| 131 | |
| 132 } // namespace transport | |
| 133 } // namespace cast | |
| 134 } // namespace media | |
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Chromium Code Reviews
Issue 388663003:
Cast: Reshuffle files under media/cast (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src