a5eba6c98b
Cleaning/Parsing will be done in the https://codereview.webrtc.org/1552773002/ BUG=webrtc:5260 R=asapersson@webrtc.org, åsapersson Review URL: https://codereview.webrtc.org/1590883002 . Cr-Commit-Position: refs/heads/master@{#11268}
118 lines
4.3 KiB
C++
118 lines
4.3 KiB
C++
/*
|
|
* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
|
|
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/remb.h"
|
|
|
|
#include "webrtc/base/logging.h"
|
|
#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
|
|
|
|
using webrtc::RTCPUtility::PT_PSFB;
|
|
using webrtc::RTCPUtility::RTCPPacketPSFBAPP;
|
|
using webrtc::RTCPUtility::RTCPPacketPSFBREMBItem;
|
|
|
|
namespace webrtc {
|
|
namespace rtcp {
|
|
namespace {
|
|
const uint32_t kUnusedMediaSourceSsrc0 = 0;
|
|
|
|
void AssignUWord8(uint8_t* buffer, size_t* offset, uint8_t value) {
|
|
buffer[(*offset)++] = value;
|
|
}
|
|
|
|
void AssignUWord32(uint8_t* buffer, size_t* offset, uint32_t value) {
|
|
ByteWriter<uint32_t>::WriteBigEndian(buffer + *offset, value);
|
|
*offset += 4;
|
|
}
|
|
|
|
void ComputeMantissaAnd6bitBase2Exponent(uint32_t input_base10,
|
|
uint8_t bits_mantissa,
|
|
uint32_t* mantissa,
|
|
uint8_t* exp) {
|
|
// input_base10 = mantissa * 2^exp
|
|
assert(bits_mantissa <= 32);
|
|
uint32_t mantissa_max = (1 << bits_mantissa) - 1;
|
|
uint8_t exponent = 0;
|
|
for (uint32_t i = 0; i < 64; ++i) {
|
|
if (input_base10 <= (mantissa_max << i)) {
|
|
exponent = i;
|
|
break;
|
|
}
|
|
}
|
|
*exp = exponent;
|
|
*mantissa = (input_base10 >> exponent);
|
|
}
|
|
|
|
// Receiver Estimated Max Bitrate (REMB) (draft-alvestrand-rmcat-remb).
|
|
//
|
|
// 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
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// |V=2|P| FMT=15 | PT=206 | length |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | SSRC of packet sender |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | SSRC of media source |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | Unique identifier 'R' 'E' 'M' 'B' |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | Num SSRC | BR Exp | BR Mantissa |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | SSRC feedback |
|
|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
// | ... |
|
|
void CreateRemb(const RTCPPacketPSFBAPP& remb,
|
|
const RTCPPacketPSFBREMBItem& remb_item,
|
|
uint8_t* buffer,
|
|
size_t* pos) {
|
|
uint32_t mantissa = 0;
|
|
uint8_t exp = 0;
|
|
ComputeMantissaAnd6bitBase2Exponent(remb_item.BitRate, 18, &mantissa, &exp);
|
|
|
|
AssignUWord32(buffer, pos, remb.SenderSSRC);
|
|
AssignUWord32(buffer, pos, kUnusedMediaSourceSsrc0);
|
|
AssignUWord8(buffer, pos, 'R');
|
|
AssignUWord8(buffer, pos, 'E');
|
|
AssignUWord8(buffer, pos, 'M');
|
|
AssignUWord8(buffer, pos, 'B');
|
|
AssignUWord8(buffer, pos, remb_item.NumberOfSSRCs);
|
|
AssignUWord8(buffer, pos, (exp << 2) + ((mantissa >> 16) & 0x03));
|
|
AssignUWord8(buffer, pos, mantissa >> 8);
|
|
AssignUWord8(buffer, pos, mantissa);
|
|
for (uint8_t i = 0; i < remb_item.NumberOfSSRCs; ++i) {
|
|
AssignUWord32(buffer, pos, remb_item.SSRCs[i]);
|
|
}
|
|
}
|
|
} // namespace
|
|
|
|
bool Remb::Create(uint8_t* packet,
|
|
size_t* index,
|
|
size_t max_length,
|
|
RtcpPacket::PacketReadyCallback* callback) const {
|
|
while (*index + BlockLength() > max_length) {
|
|
if (!OnBufferFull(packet, index, callback))
|
|
return false;
|
|
}
|
|
const uint8_t kFmt = 15;
|
|
CreateHeader(kFmt, PT_PSFB, HeaderLength(), packet, index);
|
|
CreateRemb(remb_, remb_item_, packet, index);
|
|
return true;
|
|
}
|
|
|
|
void Remb::AppliesTo(uint32_t ssrc) {
|
|
if (remb_item_.NumberOfSSRCs >= kMaxNumberOfSsrcs) {
|
|
LOG(LS_WARNING) << "Max number of REMB feedback SSRCs reached.";
|
|
return;
|
|
}
|
|
remb_item_.SSRCs[remb_item_.NumberOfSSRCs++] = ssrc;
|
|
}
|
|
|
|
} // namespace rtcp
|
|
} // namespace webrtc
|