ZLMediaKit/webrtc/RtpExt.cpp

200 lines
7.3 KiB
C++
Raw Normal View History

2021-05-07 11:19:12 +08:00
/*
2021-05-06 16:25:18 +08:00
* Copyright (c) 2016 The ZLMediaKit project authors. All Rights Reserved.
*
* This file is part of ZLMediaKit(https://github.com/xia-chu/ZLMediaKit).
*
* Use of this source code is governed by MIT license that can be found in the
* LICENSE file in the root of the source tree. All contributing project authors
* may be found in the AUTHORS file in the root of the source tree.
*/
#include "RtpExt.h"
#if defined(_WIN32)
#pragma pack(push, 1)
#endif // defined(_WIN32)
//https://tools.ietf.org/html/draft-holmer-rmcat-transport-wide-cc-extensions-01
//https://tools.ietf.org/html/rfc5285
// 0 1 2 3
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | 0xBE | 0xDE | length=3 |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L=0 | data | ID | L=1 | data...
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// ...data | 0 (pad) | 0 (pad) | ID | L=3 |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | data |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
class RtpExtOneByte {
public:
static constexpr uint16_t kMinSize = 1;
size_t getSize() const;
uint8_t getId() const;
uint8_t* getData();
private:
#if __BYTE_ORDER == __BIG_ENDIAN
uint8_t id: 4;
uint8_t len: 4;
#else
uint8_t len: 4;
uint8_t id: 4;
#endif
uint8_t data[1];
} PACKED;
//0 1 2 3
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | 0x100 |appbits| length=3 |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L=0 | ID | L=1 |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | data | 0 (pad) | ID | L=4 |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | data |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
class RtpExtTwoByte {
public:
static constexpr uint16_t kMinSize = 2;
size_t getSize() const;
uint8_t getId() const;
uint8_t* getData();
private:
uint8_t id;
uint8_t len;
uint8_t data[1];
} PACKED;
#if defined(_WIN32)
#pragma pack(pop)
#endif // defined(_WIN32)
//////////////////////////////////////////////////////////////////
size_t RtpExtOneByte::getSize() const {
return len + 1;
}
uint8_t RtpExtOneByte::getId() const {
return id;
}
uint8_t *RtpExtOneByte::getData() {
return data;
}
//////////////////////////////////////////////////////////////////
size_t RtpExtTwoByte::getSize() const {
return len;
}
uint8_t RtpExtTwoByte::getId() const {
return id;
}
uint8_t *RtpExtTwoByte::getData() {
return data;
}
//////////////////////////////////////////////////////////////////
static constexpr uint16_t kOneByteHeader = 0xBEDE;
static constexpr uint16_t kTwoByteHeader = 0x1000;
2021-05-07 12:00:26 +08:00
map<uint8_t/*id*/, RtpExt/*data*/> RtpExt::getExtValue(const RtpHeader *header, const RtcMedia &media) {
map<uint8_t, RtpExt> ret;
2021-05-06 16:25:18 +08:00
assert(header);
auto ext_size = header->getExtSize();
if (!ext_size) {
return ret;
}
auto reserved = header->getExtReserved();
auto ptr = const_cast<RtpHeader *>(header)->getExtData();
auto end = ptr + ext_size;
2021-05-07 12:00:26 +08:00
RtpExtType type;
2021-05-06 16:25:18 +08:00
if (reserved == kOneByteHeader) {
while (ptr < end) {
RtpExtOneByte *ext = reinterpret_cast<RtpExtOneByte *>(ptr);
2021-05-07 12:00:26 +08:00
if (ext->getId() == (uint8_t) RtpExtType::padding) {
2021-05-06 16:25:18 +08:00
//padding忽略
++ptr;
continue;
}
//15类型的rtp ext为保留
2021-05-07 12:00:26 +08:00
CHECK(ext->getId() < (uint8_t) RtpExtType::reserved);
2021-05-06 16:25:18 +08:00
CHECK(reinterpret_cast<uint8_t *>(ext) + RtpExtOneByte::kMinSize <= end);
CHECK(ext->getData() + ext->getSize() <= end);
2021-05-07 12:00:26 +08:00
ret.emplace(ext->getId(), RtpExt(type, reinterpret_cast<char *>(ext->getData()), ext->getSize()));
2021-05-06 16:25:18 +08:00
ptr += RtpExtOneByte::kMinSize + ext->getSize();
}
return ret;
}
if ((reserved & 0xFFF0) >> 4 == kTwoByteHeader) {
while (ptr < end) {
RtpExtTwoByte *ext = reinterpret_cast<RtpExtTwoByte *>(ptr);
2021-05-07 12:00:26 +08:00
if (ext->getId() == (uint8_t) RtpExtType::padding) {
2021-05-06 16:25:18 +08:00
//padding忽略
++ptr;
continue;
}
2021-05-07 12:00:26 +08:00
//15类型的rtp ext为保留
CHECK(ext->getId() < (uint8_t) RtpExtType::reserved);
2021-05-06 16:25:18 +08:00
CHECK(reinterpret_cast<uint8_t *>(ext) + RtpExtTwoByte::kMinSize <= end);
CHECK(ext->getData() + ext->getSize() <= end);
2021-05-07 12:00:26 +08:00
ret.emplace(ext->getId(), RtpExt(type, reinterpret_cast<char *>(ext->getData()), ext->getSize()));
2021-05-06 16:25:18 +08:00
ptr += RtpExtTwoByte::kMinSize + ext->getSize();
}
return ret;
}
return ret;
}
2021-05-07 12:00:26 +08:00
#define RTP_EXT_MAP(XX) \
XX(RtpExtType::ssrc_audio_level, "urn:ietf:params:rtp-hdrext:ssrc-audio-level") \
XX(RtpExtType::abs_send_time, "http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time") \
XX(RtpExtType::transport_cc, "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01") \
XX(RtpExtType::sdes_mid, "urn:ietf:params:rtp-hdrext:sdes:mid") \
XX(RtpExtType::sdes_rtp_stream_id, "urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id") \
XX(RtpExtType::sdes_repaired_rtp_stream_id, "urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id") \
XX(RtpExtType::video_timing, "http://www.webrtc.org/experiments/rtp-hdrext/video-timing") \
XX(RtpExtType::color_space, "http://www.webrtc.org/experiments/rtp-hdrext/color-space") \
XX(RtpExtType::video_content_type, "http://www.webrtc.org/experiments/rtp-hdrext/video-content-type") \
XX(RtpExtType::playout_delay, "http://www.webrtc.org/experiments/rtp-hdrext/playout-delay") \
XX(RtpExtType::video_orientation, "urn:3gpp:video-orientation") \
XX(RtpExtType::toffset, "urn:ietf:params:rtp-hdrext:toffset")
#define XX(type, url) {type , url},
static unordered_map<RtpExtType/*id*/, string/*ext*/> s_type_to_url = {RTP_EXT_MAP(XX)};
#undef XX
#define XX(type, url) {url, type},
static unordered_map<string/*ext*/, RtpExtType/*id*/> s_url_to_type = {RTP_EXT_MAP(XX)};
#undef XX
2021-05-07 14:01:24 +08:00
RtpExtType RtpExt::getExtType(const string &url) {
2021-05-07 12:00:26 +08:00
auto it = s_url_to_type.find(url);
if (it == s_url_to_type.end()) {
throw std::invalid_argument(string("未识别的rtp ext url类型:") + url);
}
return it->second;
}
2021-05-07 14:01:24 +08:00
const string &RtpExt::getExtUrl(RtpExtType type) {
2021-05-07 12:00:26 +08:00
auto it = s_type_to_url.find(type);
if (it == s_type_to_url.end()) {
throw std::invalid_argument(string("未识别的rtp ext类型:") + to_string((int) type));
}
return it->second;
}