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| 1 /* |
| 2 * Copyright (c) 2016 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/rtp_rtcp/source/rtp_header_extensions.h" |
| 12 |
| 13 #include "webrtc/base/checks.h" |
| 14 #include "webrtc/base/logging.h" |
| 15 #include "webrtc/modules/rtp_rtcp/include/rtp_cvo.h" |
| 16 #include "webrtc/modules/rtp_rtcp/source/byte_io.h" |
| 17 |
| 18 namespace webrtc { |
| 19 // Absolute send time in RTP streams. |
| 20 // |
| 21 // The absolute send time is signaled to the receiver in-band using the |
| 22 // general mechanism for RTP header extensions [RFC5285]. The payload |
| 23 // of this extension (the transmitted value) is a 24-bit unsigned integer |
| 24 // containing the sender's current time in seconds as a fixed point number |
| 25 // with 18 bits fractional part. |
| 26 // |
| 27 // The form of the absolute send time extension block: |
| 28 // |
| 29 // 0 1 2 3 |
| 30 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| 31 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 32 // | ID | len=2 | absolute send time | |
| 33 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 34 const char* AbsoluteSendTime::kName = |
| 35 "http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time"; |
| 36 bool AbsoluteSendTime::IsSupportedFor(MediaType type) { |
| 37 return true; |
| 38 } |
| 39 |
| 40 bool AbsoluteSendTime::Parse(const uint8_t* data, uint32_t* value) { |
| 41 *value = ByteReader<uint32_t, 3>::ReadBigEndian(data); |
| 42 return true; |
| 43 } |
| 44 |
| 45 bool AbsoluteSendTime::Write(uint8_t* data, int64_t time_ms) { |
| 46 const uint32_t kAbsSendTimeFraction = 18; |
| 47 uint32_t time_24_bits = |
| 48 static_cast<uint32_t>(((time_ms << kAbsSendTimeFraction) + 500) / 1000) & |
| 49 0x00FFFFFF; |
| 50 |
| 51 ByteWriter<uint32_t, 3>::WriteBigEndian(data, time_24_bits); |
| 52 return true; |
| 53 } |
| 54 |
| 55 // An RTP Header Extension for Client-to-Mixer Audio Level Indication |
| 56 // |
| 57 // https://datatracker.ietf.org/doc/draft-lennox-avt-rtp-audio-level-exthdr/ |
| 58 // |
| 59 // The form of the audio level extension block: |
| 60 // |
| 61 // 0 1 |
| 62 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 |
| 63 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 64 // | ID | len=0 |V| level | |
| 65 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 66 // |
| 67 const char* AudioLevel::kName = "urn:ietf:params:rtp-hdrext:ssrc-audio-level"; |
| 68 bool AudioLevel::IsSupportedFor(MediaType type) { |
| 69 switch (type) { |
| 70 case MediaType::ANY: |
| 71 case MediaType::AUDIO: |
| 72 return true; |
| 73 case MediaType::VIDEO: |
| 74 case MediaType::DATA: |
| 75 return false; |
| 76 } |
| 77 RTC_NOTREACHED(); |
| 78 return false; |
| 79 } |
| 80 |
| 81 bool AudioLevel::Parse(const uint8_t* data, |
| 82 bool* voice_activity, |
| 83 uint8_t* audio_level) { |
| 84 *voice_activity = (data[0] & 0x80) != 0; |
| 85 *audio_level = data[0] & 0x7F; |
| 86 return true; |
| 87 } |
| 88 |
| 89 bool AudioLevel::Write(uint8_t* data, |
| 90 bool voice_activity, |
| 91 uint8_t audio_level) { |
| 92 RTC_CHECK_LE(audio_level, 0x7f); |
| 93 data[0] = (voice_activity ? 0x80 : 0x00) | audio_level; |
| 94 return true; |
| 95 } |
| 96 |
| 97 // From RFC 5450: Transmission Time Offsets in RTP Streams. |
| 98 // |
| 99 // The transmission time is signaled to the receiver in-band using the |
| 100 // general mechanism for RTP header extensions [RFC5285]. The payload |
| 101 // of this extension (the transmitted value) is a 24-bit signed integer. |
| 102 // When added to the RTP timestamp of the packet, it represents the |
| 103 // "effective" RTP transmission time of the packet, on the RTP |
| 104 // timescale. |
| 105 // |
| 106 // The form of the transmission offset extension block: |
| 107 // |
| 108 // 0 1 2 3 |
| 109 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| 110 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 111 // | ID | len=2 | transmission offset | |
| 112 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 113 const char* TransmissionOffset::kName = "urn:ietf:params:rtp-hdrext:toffset"; |
| 114 bool TransmissionOffset::IsSupportedFor(MediaType type) { |
| 115 switch (type) { |
| 116 case MediaType::ANY: |
| 117 case MediaType::VIDEO: |
| 118 return true; |
| 119 case MediaType::AUDIO: |
| 120 case MediaType::DATA: |
| 121 return false; |
| 122 } |
| 123 RTC_NOTREACHED(); |
| 124 return false; |
| 125 } |
| 126 |
| 127 bool TransmissionOffset::Parse(const uint8_t* data, int32_t* value) { |
| 128 *value = ByteReader<int32_t, 3>::ReadBigEndian(data); |
| 129 return true; |
| 130 } |
| 131 |
| 132 bool TransmissionOffset::Write(uint8_t* data, int64_t value) { |
| 133 RTC_CHECK_LE(value, 0x00ffffff); |
| 134 ByteWriter<int32_t, 3>::WriteBigEndian(data, value); |
| 135 return true; |
| 136 } |
| 137 |
| 138 // 0 1 2 |
| 139 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 |
| 140 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 141 // | ID | L=1 |transport wide sequence number | |
| 142 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 143 const char* TransportSequenceNumber::kName = |
| 144 "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions"; |
| 145 bool TransportSequenceNumber::IsSupportedFor(MediaType type) { |
| 146 return true; |
| 147 } |
| 148 |
| 149 bool TransportSequenceNumber::Parse(const uint8_t* data, uint16_t* value) { |
| 150 *value = ByteReader<uint16_t>::ReadBigEndian(data); |
| 151 return true; |
| 152 } |
| 153 |
| 154 bool TransportSequenceNumber::Write(uint8_t* data, uint16_t value) { |
| 155 ByteWriter<uint16_t>::WriteBigEndian(data, value); |
| 156 return true; |
| 157 } |
| 158 |
| 159 // Coordination of Video Orientation in RTP streams. |
| 160 // |
| 161 // Coordination of Video Orientation consists in signaling of the current |
| 162 // orientation of the image captured on the sender side to the receiver for |
| 163 // appropriate rendering and displaying. |
| 164 // |
| 165 // 0 1 |
| 166 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 |
| 167 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 168 // | ID | len=0 |0 0 0 0 C F R R| |
| 169 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| 170 const char* VideoOrientation::kName = "urn:3gpp:video-orientation"; |
| 171 bool VideoOrientation::IsSupportedFor(MediaType type) { |
| 172 switch (type) { |
| 173 case MediaType::ANY: |
| 174 case MediaType::VIDEO: |
| 175 return true; |
| 176 case MediaType::AUDIO: |
| 177 case MediaType::DATA: |
| 178 return false; |
| 179 } |
| 180 RTC_NOTREACHED(); |
| 181 return false; |
| 182 } |
| 183 |
| 184 bool VideoOrientation::Parse(const uint8_t* data, VideoRotation* rotation) { |
| 185 *rotation = ConvertCVOByteToVideoRotation(data[0] & 0x03); |
| 186 return true; |
| 187 } |
| 188 |
| 189 bool VideoOrientation::Write(uint8_t* data, VideoRotation rotation) { |
| 190 data[0] = ConvertVideoRotationToCVOByte(rotation); |
| 191 return true; |
| 192 } |
| 193 |
| 194 bool VideoOrientation::Parse(const uint8_t* data, uint8_t* value) { |
| 195 *value = data[0]; |
| 196 return true; |
| 197 } |
| 198 |
| 199 bool VideoOrientation::Write(uint8_t* data, uint8_t value) { |
| 200 data[0] = value; |
| 201 return true; |
| 202 } |
| 203 } // namespace webrtc |
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