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Update rtp_utils to support two-byte RTP header extensions

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Bug: webrtc:11691
Change-Id: Icdd3eeed0fe0c6e1dee387cc03740628ee24e5c3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/177343
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Johannes Kron <kron@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31537}
This commit is contained in:
Johannes Kron
2020-06-16 16:35:28 +02:00
committed by Commit Bot
parent 2a70703eb8
commit a46fce2194
2 changed files with 114 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files

57
media/base/rtp_utils.cc
View File

@ -34,6 +34,7 @@ static const size_t kRtcpPayloadTypeOffset = 1;
static const size_t kRtpExtensionHeaderLen = 4;
static const size_t kAbsSendTimeExtensionLen = 3;
static const size_t kOneByteExtensionHeaderLen = 1;
static const size_t kTwoByteExtensionHeaderLen = 2;
namespace {
@ -424,10 +425,13 @@ bool UpdateRtpAbsSendTimeExtension(uint8_t* rtp,
rtp += kRtpExtensionHeaderLen; // Moving past extension header.
constexpr uint16_t kOneByteExtensionProfileId = 0xBEDE;
constexpr uint16_t kTwoByteExtensionProfileId = 0x1000;
bool found = false;
// WebRTC is using one byte header extension.
// TODO(mallinath) - Handle two byte header extension.
if (profile_id == 0xBEDE) { // OneByte extension header
if (profile_id == kOneByteExtensionProfileId ||
profile_id == kTwoByteExtensionProfileId) {
// OneByte extension header
// 0
// 0 1 2 3 4 5 6 7
// +-+-+-+-+-+-+-+-+
@ -445,24 +449,53 @@ bool UpdateRtpAbsSendTimeExtension(uint8_t* rtp,
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | data |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// TwoByte extension header
// 0
// 0 1 2 3 4 5 6 7
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | length |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | 0x10 | 0x00 | length=3 |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L=1 | data | ID |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | L=2 | data | 0 (pad) |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L=2 | data |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
size_t extension_header_length = profile_id == kOneByteExtensionProfileId
? kOneByteExtensionHeaderLen
: kTwoByteExtensionHeaderLen;
const uint8_t* extension_start = rtp;
const uint8_t* extension_end = extension_start + extension_length;
while (rtp < extension_end) {
const int id = (*rtp & 0xF0) >> 4;
const size_t length = (*rtp & 0x0F) + 1;
if (rtp + kOneByteExtensionHeaderLen + length > extension_end) {
// rtp + 1 since the minimum size per header extension is two bytes for both
// one- and two-byte header extensions.
while (rtp + 1 < extension_end) {
// See RFC8285 Section 4.2-4.3 for more information about one- and
// two-byte header extensions.
const int id =
profile_id == kOneByteExtensionProfileId ? (*rtp & 0xF0) >> 4 : *rtp;
const size_t length = profile_id == kOneByteExtensionProfileId
? (*rtp & 0x0F) + 1
: *(rtp + 1);
if (rtp + extension_header_length + length > extension_end) {
return false;
}
// The 4-bit length is the number minus one of data bytes of this header
// extension element following the one-byte header.
if (id == extension_id) {
UpdateAbsSendTimeExtensionValue(rtp + kOneByteExtensionHeaderLen,
length, time_us);
UpdateAbsSendTimeExtensionValue(rtp + extension_header_length, length,
time_us);
found = true;
break;
}
rtp += kOneByteExtensionHeaderLen + length;
rtp += extension_header_length + length;
// Counting padding bytes.
while ((rtp < extension_end) && (*rtp == 0)) {
++rtp;