1 /** |
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2 * Java RTP Library (jlibrtp) |
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3 * Copyright (C) 2006 Arne Kepp |
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4 * |
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5 * This library is free software; you can redistribute it and/or |
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6 * modify it under the terms of the GNU Lesser General Public |
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7 * License as published by the Free Software Foundation; either |
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8 * version 2.1 of the License, or (at your option) any later version. |
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9 * |
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10 * This library is distributed in the hope that it will be useful, |
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11 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 * Lesser General Public License for more details. |
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14 * |
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15 * You should have received a copy of the GNU Lesser General Public |
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16 * License along with this library; if not, write to the Free Software |
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17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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18 */ |
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19 package jlibrtp; |
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20 |
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21 /** |
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22 * RTCP packets for RTP Feedback Messages |
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23 * |
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24 * In line with RFC 4585, this packet currently only supports NACKs |
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25 * |
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26 * @author Arne Kepp |
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27 */ |
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28 public class RtcpPktRTPFB extends RtcpPkt { |
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29 /** If this packet was for a different SSRC */ |
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30 protected boolean notRelevant = false; |
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31 /** SSRC we are sending feeback to */ |
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32 protected long ssrcMediaSource = -1; |
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33 /** RTP sequence numbers of lost packets */ |
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34 protected int PID[]; |
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35 /** bitmask of following lost packets, shared index with PID */ |
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36 protected int BLP[]; |
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37 |
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38 /** |
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39 * Constructor for RTP Feedback Message |
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40 * |
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41 * @param ssrcPacketSender |
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42 * SSRC of sender, taken from RTPSession |
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43 * @param ssrcMediaSource |
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44 * SSRC of recipient of this message |
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45 * @param FMT |
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46 * the Feedback Message Subtype |
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47 * @param PID |
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48 * RTP sequence numbers of lost packets |
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49 * @param BLP |
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50 * bitmask of following lost packets, shared index with PID |
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51 */ |
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52 protected RtcpPktRTPFB(long ssrcPacketSender, long ssrcMediaSource, |
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53 int FMT, int[] PID, int[] BLP) { |
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54 super.packetType = 205; // RTPFB |
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55 super.itemCount = FMT; |
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56 this.PID = PID; |
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57 this.BLP = BLP; |
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58 } |
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59 |
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60 /** |
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61 * Constructor that parses a raw packet to retrieve information |
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62 * |
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63 * @param aRawPkt |
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64 * the raw packet to be parsed |
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65 * @param start |
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66 * the start of the packet, in bytes |
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67 * @param rtpSession |
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68 * the session on which the callback interface resides |
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69 */ |
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70 protected RtcpPktRTPFB(byte[] aRawPkt, int start, RTPSession rtpSession) { |
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71 if (RTPSession.rtpDebugLevel > 8) { |
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72 System.out.println(" -> RtcpPktRTPFB(byte[], int start)"); |
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73 } |
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74 |
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75 rawPkt = aRawPkt; |
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76 |
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77 if (!super.parseHeaders(start) || packetType != 205 || super.length < 2) { |
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78 if (RTPSession.rtpDebugLevel > 2) { |
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79 System.out |
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80 .println(" <-> RtcpPktRTPFB.parseHeaders() etc. problem"); |
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81 } |
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82 super.problem = -205; |
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83 } else { |
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84 // FMT = super.itemCount; |
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85 |
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86 ssrcMediaSource = StaticProcs.bytesToUIntLong(aRawPkt, 8 + start); |
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87 |
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88 if (ssrcMediaSource == rtpSession.ssrc) { |
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89 super.ssrc = StaticProcs.bytesToUIntLong(aRawPkt, 4 + start); |
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90 int loopStop = super.length - 2; |
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91 PID = new int[loopStop]; |
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92 BLP = new int[loopStop]; |
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93 int curStart = 12; |
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94 |
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95 // Loop over Feedback Control Information (FCI) fields |
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96 for (int i = 0; i < loopStop; i++) { |
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97 PID[i] = StaticProcs.bytesToUIntInt(aRawPkt, curStart); |
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98 BLP[i] = StaticProcs.bytesToUIntInt(aRawPkt, curStart + 2); |
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99 curStart += 4; |
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100 } |
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101 |
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102 rtpSession.rtcpAVPFIntf.RTPFBPktReceived(super.ssrc, |
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103 super.itemCount, PID, BLP); |
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104 } |
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105 } |
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106 |
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107 if (RTPSession.rtpDebugLevel > 8) { |
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108 System.out.println(" <- RtcpPktRTPFB()"); |
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109 } |
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110 } |
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111 |
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112 /** |
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113 * Encode the packet into a byte[], saved in .rawPkt |
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114 * |
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115 * CompRtcpPkt will call this automatically |
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116 */ |
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117 protected void encode() { |
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118 super.rawPkt = new byte[12 + this.PID.length * 4]; |
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119 |
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120 byte[] someBytes = StaticProcs.uIntLongToByteWord(super.ssrc); |
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121 System.arraycopy(someBytes, 0, super.rawPkt, 4, 4); |
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122 someBytes = StaticProcs.uIntLongToByteWord(this.ssrcMediaSource); |
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123 System.arraycopy(someBytes, 0, super.rawPkt, 8, 4); |
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124 |
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125 // Loop over Feedback Control Information (FCI) fields |
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126 int curStart = 12; |
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127 for (int i = 0; i < this.PID.length; i++) { |
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128 someBytes = StaticProcs.uIntIntToByteWord(PID[i]); |
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129 super.rawPkt[curStart++] = someBytes[0]; |
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130 super.rawPkt[curStart++] = someBytes[1]; |
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131 someBytes = StaticProcs.uIntIntToByteWord(BLP[i]); |
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132 super.rawPkt[curStart++] = someBytes[0]; |
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133 super.rawPkt[curStart++] = someBytes[1]; |
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134 } |
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135 writeHeaders(); |
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136 } |
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137 |
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138 /** |
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139 * Get the FMT (Feedback Message Type) |
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140 * |
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141 * @return value stored in .itemcount, same field |
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142 */ |
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143 protected int getFMT() { |
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144 return this.itemCount; |
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145 } |
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146 |
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147 /** |
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148 * Debug purposes only |
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149 */ |
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150 protected void debugPrint() { |
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151 System.out.println("->RtcpPktRTPFB.debugPrint() "); |
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152 System.out.println(" ssrcPacketSender: " + super.ssrc |
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153 + " ssrcMediaSource: " + ssrcMediaSource); |
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154 |
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155 if (this.PID != null && this.PID.length < 1) { |
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156 System.out |
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157 .println(" No Feedback Control Information (FCI) fields"); |
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158 } |
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159 |
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160 for (int i = 0; i < this.PID.length; i++) { |
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161 System.out.println(" FCI -> PID: " + PID[i] + " BLP: " + BLP[i]); |
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162 } |
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163 System.out.println("<-RtcpPktRTPFB.debugPrint() "); |
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164 } |
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165 } |
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