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/*
* 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 "modules/rtp_rtcp/source/rtp_header_extensions.h"
#include <string.h>
#include "modules/rtp_rtcp/include/rtp_cvo.h"
#include "modules/rtp_rtcp/source/byte_io.h"
// TODO(bug:9855) Move kNoSpatialIdx from vp9_globals.h to common_constants
#include "modules/video_coding/codecs/interface/common_constants.h"
#include "rtc_base/checks.h"
namespace webrtc {
// Absolute send time in RTP streams.
//
// The absolute send time is signaled to the receiver in-band using the
// general mechanism for RTP header extensions [RFC8285]. The payload
// of this extension (the transmitted value) is a 24-bit unsigned integer
// containing the sender's current time in seconds as a fixed point number
// with 18 bits fractional part.
//
// The form of the absolute send time extension block:
//
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | len=2 | absolute send time |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType AbsoluteSendTime::kId;
constexpr uint8_t AbsoluteSendTime::kValueSizeBytes;
constexpr const char AbsoluteSendTime::kUri[];
bool AbsoluteSendTime::Parse(rtc::ArrayView<const uint8_t> data,
uint32_t* time_24bits) {
if (data.size() != 3)
return false;
*time_24bits = ByteReader<uint32_t, 3>::ReadBigEndian(data.data());
return true;
}
bool AbsoluteSendTime::Write(rtc::ArrayView<uint8_t> data,
uint32_t time_24bits) {
RTC_DCHECK_EQ(data.size(), 3);
RTC_DCHECK_LE(time_24bits, 0x00FFFFFF);
ByteWriter<uint32_t, 3>::WriteBigEndian(data.data(), time_24bits);
return true;
}
// An RTP Header Extension for Client-to-Mixer Audio Level Indication
//
// https://datatracker.ietf.org/doc/draft-lennox-avt-rtp-audio-level-exthdr/
//
// The form of the audio level extension block:
//
// 0 1
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | len=0 |V| level |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
constexpr RTPExtensionType AudioLevel::kId;
constexpr uint8_t AudioLevel::kValueSizeBytes;
constexpr const char AudioLevel::kUri[];
bool AudioLevel::Parse(rtc::ArrayView<const uint8_t> data,
bool* voice_activity,
uint8_t* audio_level) {
if (data.size() != 1)
return false;
*voice_activity = (data[0] & 0x80) != 0;
*audio_level = data[0] & 0x7F;
return true;
}
bool AudioLevel::Write(rtc::ArrayView<uint8_t> data,
bool voice_activity,
uint8_t audio_level) {
RTC_DCHECK_EQ(data.size(), 1);
RTC_CHECK_LE(audio_level, 0x7f);
data[0] = (voice_activity ? 0x80 : 0x00) | audio_level;
return true;
}
// From RFC 5450: Transmission Time Offsets in RTP Streams.
//
// The transmission time is signaled to the receiver in-band using the
// general mechanism for RTP header extensions [RFC8285]. The payload
// of this extension (the transmitted value) is a 24-bit signed integer.
// When added to the RTP timestamp of the packet, it represents the
// "effective" RTP transmission time of the packet, on the RTP
// timescale.
//
// The form of the transmission offset extension block:
//
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | len=2 | transmission offset |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType TransmissionOffset::kId;
constexpr uint8_t TransmissionOffset::kValueSizeBytes;
constexpr const char TransmissionOffset::kUri[];
bool TransmissionOffset::Parse(rtc::ArrayView<const uint8_t> data,
int32_t* rtp_time) {
if (data.size() != 3)
return false;
*rtp_time = ByteReader<int32_t, 3>::ReadBigEndian(data.data());
return true;
}
bool TransmissionOffset::Write(rtc::ArrayView<uint8_t> data, int32_t rtp_time) {
RTC_DCHECK_EQ(data.size(), 3);
RTC_DCHECK_LE(rtp_time, 0x00ffffff);
ByteWriter<int32_t, 3>::WriteBigEndian(data.data(), rtp_time);
return true;
}
// 0 1 2
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L=1 |transport wide sequence number |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType TransportSequenceNumber::kId;
constexpr uint8_t TransportSequenceNumber::kValueSizeBytes;
constexpr const char TransportSequenceNumber::kUri[];
bool TransportSequenceNumber::Parse(rtc::ArrayView<const uint8_t> data,
uint16_t* value) {
if (data.size() != 2)
return false;
*value = ByteReader<uint16_t>::ReadBigEndian(data.data());
return true;
}
bool TransportSequenceNumber::Write(rtc::ArrayView<uint8_t> data,
uint16_t value) {
RTC_DCHECK_EQ(data.size(), 2);
ByteWriter<uint16_t>::WriteBigEndian(data.data(), value);
return true;
}
// Coordination of Video Orientation in RTP streams.
//
// Coordination of Video Orientation consists in signaling of the current
// orientation of the image captured on the sender side to the receiver for
// appropriate rendering and displaying.
//
// 0 1
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | len=0 |0 0 0 0 C F R R|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType VideoOrientation::kId;
constexpr uint8_t VideoOrientation::kValueSizeBytes;
constexpr const char VideoOrientation::kUri[];
bool VideoOrientation::Parse(rtc::ArrayView<const uint8_t> data,
VideoRotation* rotation) {
if (data.size() != 1)
return false;
*rotation = ConvertCVOByteToVideoRotation(data[0]);
return true;
}
bool VideoOrientation::Write(rtc::ArrayView<uint8_t> data,
VideoRotation rotation) {
RTC_DCHECK_EQ(data.size(), 1);
data[0] = ConvertVideoRotationToCVOByte(rotation);
return true;
}
bool VideoOrientation::Parse(rtc::ArrayView<const uint8_t> data,
uint8_t* value) {
if (data.size() != 1)
return false;
*value = data[0];
return true;
}
bool VideoOrientation::Write(rtc::ArrayView<uint8_t> data, uint8_t value) {
RTC_DCHECK_EQ(data.size(), 1);
data[0] = value;
return true;
}
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | len=2 | MIN delay | MAX delay |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType PlayoutDelayLimits::kId;
constexpr uint8_t PlayoutDelayLimits::kValueSizeBytes;
constexpr const char PlayoutDelayLimits::kUri[];
bool PlayoutDelayLimits::Parse(rtc::ArrayView<const uint8_t> data,
PlayoutDelay* playout_delay) {
RTC_DCHECK(playout_delay);
if (data.size() != 3)
return false;
uint32_t raw = ByteReader<uint32_t, 3>::ReadBigEndian(data.data());
uint16_t min_raw = (raw >> 12);
uint16_t max_raw = (raw & 0xfff);
if (min_raw > max_raw)
return false;
playout_delay->min_ms = min_raw * kGranularityMs;
playout_delay->max_ms = max_raw * kGranularityMs;
return true;
}
bool PlayoutDelayLimits::Write(rtc::ArrayView<uint8_t> data,
const PlayoutDelay& playout_delay) {
RTC_DCHECK_EQ(data.size(), 3);
RTC_DCHECK_LE(0, playout_delay.min_ms);
RTC_DCHECK_LE(playout_delay.min_ms, playout_delay.max_ms);
RTC_DCHECK_LE(playout_delay.max_ms, kMaxMs);
// Convert MS to value to be sent on extension header.
uint32_t min_delay = playout_delay.min_ms / kGranularityMs;
uint32_t max_delay = playout_delay.max_ms / kGranularityMs;
ByteWriter<uint32_t, 3>::WriteBigEndian(data.data(),
(min_delay << 12) | max_delay);
return true;
}
// Video Content Type.
//
// E.g. default video or screenshare.
//
// 0 1
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | len=0 | Content type |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType VideoContentTypeExtension::kId;
constexpr uint8_t VideoContentTypeExtension::kValueSizeBytes;
constexpr const char VideoContentTypeExtension::kUri[];
bool VideoContentTypeExtension::Parse(rtc::ArrayView<const uint8_t> data,
VideoContentType* content_type) {
if (data.size() == 1 &&
videocontenttypehelpers::IsValidContentType(data[0])) {
*content_type = static_cast<VideoContentType>(data[0]);
return true;
}
return false;
}
bool VideoContentTypeExtension::Write(rtc::ArrayView<uint8_t> data,
VideoContentType content_type) {
RTC_DCHECK_EQ(data.size(), 1);
data[0] = static_cast<uint8_t>(content_type);
return true;
}
// Video Timing.
// 6 timestamps in milliseconds counted from capture time stored in rtp header:
// encode start/finish, packetization complete, pacer exit and reserved for
// modification by the network modification. |flags| is a bitmask and has the
// following allowed values:
// 0 = Valid data, but no flags available (backwards compatibility)
// 1 = Frame marked as timing frame due to cyclic timer.
// 2 = Frame marked as timing frame due to size being outside limit.
// 255 = Invalid. The whole timing frame extension should be ignored.
//
// 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 2
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | len=12| flags | encode start ms delta |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | encode finish ms delta | packetizer finish ms delta |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | pacer exit ms delta | network timestamp ms delta |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | network2 timestamp ms delta |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType VideoTimingExtension::kId;
constexpr uint8_t VideoTimingExtension::kValueSizeBytes;
constexpr const char VideoTimingExtension::kUri[];
bool VideoTimingExtension::Parse(rtc::ArrayView<const uint8_t> data,
VideoSendTiming* timing) {
RTC_DCHECK(timing);
// TODO(sprang): Deprecate support for old wire format.
ptrdiff_t off = 0;
switch (data.size()) {
case kValueSizeBytes - 1:
timing->flags = 0;
off = 1; // Old wire format without the flags field.
break;
case kValueSizeBytes:
timing->flags = ByteReader<uint8_t>::ReadBigEndian(data.data());
break;
default:
return false;
}
timing->encode_start_delta_ms = ByteReader<uint16_t>::ReadBigEndian(
data.data() + VideoSendTiming::kEncodeStartDeltaOffset - off);
timing->encode_finish_delta_ms = ByteReader<uint16_t>::ReadBigEndian(
data.data() + VideoSendTiming::kEncodeFinishDeltaOffset - off);
timing->packetization_finish_delta_ms = ByteReader<uint16_t>::ReadBigEndian(
data.data() + VideoSendTiming::kPacketizationFinishDeltaOffset - off);
timing->pacer_exit_delta_ms = ByteReader<uint16_t>::ReadBigEndian(
data.data() + VideoSendTiming::kPacerExitDeltaOffset - off);
timing->network_timestamp_delta_ms = ByteReader<uint16_t>::ReadBigEndian(
data.data() + VideoSendTiming::kNetworkTimestampDeltaOffset - off);
timing->network2_timestamp_delta_ms = ByteReader<uint16_t>::ReadBigEndian(
data.data() + VideoSendTiming::kNetwork2TimestampDeltaOffset - off);
return true;
}
bool VideoTimingExtension::Write(rtc::ArrayView<uint8_t> data,
const VideoSendTiming& timing) {
RTC_DCHECK_EQ(data.size(), 1 + 2 * 6);
ByteWriter<uint8_t>::WriteBigEndian(
data.data() + VideoSendTiming::kFlagsOffset, timing.flags);
ByteWriter<uint16_t>::WriteBigEndian(
data.data() + VideoSendTiming::kEncodeStartDeltaOffset,
timing.encode_start_delta_ms);
ByteWriter<uint16_t>::WriteBigEndian(
data.data() + VideoSendTiming::kEncodeFinishDeltaOffset,
timing.encode_finish_delta_ms);
ByteWriter<uint16_t>::WriteBigEndian(
data.data() + VideoSendTiming::kPacketizationFinishDeltaOffset,
timing.packetization_finish_delta_ms);
ByteWriter<uint16_t>::WriteBigEndian(
data.data() + VideoSendTiming::kPacerExitDeltaOffset,
timing.pacer_exit_delta_ms);
ByteWriter<uint16_t>::WriteBigEndian(
data.data() + VideoSendTiming::kNetworkTimestampDeltaOffset,
timing.network_timestamp_delta_ms);
ByteWriter<uint16_t>::WriteBigEndian(
data.data() + VideoSendTiming::kNetwork2TimestampDeltaOffset,
timing.network2_timestamp_delta_ms);
return true;
}
bool VideoTimingExtension::Write(rtc::ArrayView<uint8_t> data,
uint16_t time_delta_ms,
uint8_t offset) {
RTC_DCHECK_GE(data.size(), offset + 2);
RTC_DCHECK_LE(offset, kValueSizeBytes - sizeof(uint16_t));
ByteWriter<uint16_t>::WriteBigEndian(data.data() + offset, time_delta_ms);
return true;
}
// Frame Marking.
//
// Meta-information about an RTP stream outside the encrypted media payload,
// useful for an RTP switch to do codec-agnostic selective forwarding
// without decrypting the payload.
//
// For non-scalable streams:
// 0 1
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L = 0 |S|E|I|D|0 0 0 0|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// For scalable streams:
// 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
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L = 2 |S|E|I|D|B| TID | LID | TL0PICIDX |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
constexpr RTPExtensionType FrameMarkingExtension::kId;
constexpr const char FrameMarkingExtension::kUri[];
bool FrameMarkingExtension::IsScalable(uint8_t temporal_id, uint8_t layer_id) {
return temporal_id != kNoTemporalIdx || layer_id != kNoSpatialIdx;
}
bool FrameMarkingExtension::Parse(rtc::ArrayView<const uint8_t> data,
FrameMarking* frame_marking) {
RTC_DCHECK(frame_marking);
if (data.size() != 1 && data.size() != 3)
return false;
frame_marking->start_of_frame = (data[0] & 0x80) != 0;
frame_marking->end_of_frame = (data[0] & 0x40) != 0;
frame_marking->independent_frame = (data[0] & 0x20) != 0;
frame_marking->discardable_frame = (data[0] & 0x10) != 0;
if (data.size() == 3) {
frame_marking->base_layer_sync = (data[0] & 0x08) != 0;
frame_marking->temporal_id = data[0] & 0x7;
frame_marking->layer_id = data[1];
frame_marking->tl0_pic_idx = data[2];
} else {
// non-scalable
frame_marking->base_layer_sync = false;
frame_marking->temporal_id = kNoTemporalIdx;
frame_marking->layer_id = kNoSpatialIdx;
frame_marking->tl0_pic_idx = 0;
}
return true;
}
size_t FrameMarkingExtension::ValueSize(const FrameMarking& frame_marking) {
if (IsScalable(frame_marking.temporal_id, frame_marking.layer_id))
return 3;
else
return 1;
}
bool FrameMarkingExtension::Write(rtc::ArrayView<uint8_t> data,
const FrameMarking& frame_marking) {
RTC_DCHECK_GE(data.size(), 1);
RTC_CHECK_LE(frame_marking.temporal_id, 0x07);
data[0] = frame_marking.start_of_frame ? 0x80 : 0x00;
data[0] |= frame_marking.end_of_frame ? 0x40 : 0x00;
data[0] |= frame_marking.independent_frame ? 0x20 : 0x00;
data[0] |= frame_marking.discardable_frame ? 0x10 : 0x00;
if (IsScalable(frame_marking.temporal_id, frame_marking.layer_id)) {
RTC_DCHECK_EQ(data.size(), 3);
data[0] |= frame_marking.base_layer_sync ? 0x08 : 0x00;
data[0] |= frame_marking.temporal_id & 0x07;
data[1] = frame_marking.layer_id;
data[2] = frame_marking.tl0_pic_idx;
}
return true;
}
bool BaseRtpStringExtension::Parse(rtc::ArrayView<const uint8_t> data,
StringRtpHeaderExtension* str) {
if (data.empty() || data[0] == 0) // Valid string extension can't be empty.
return false;
str->Set(data);
RTC_DCHECK(!str->empty());
return true;
}
bool BaseRtpStringExtension::Write(rtc::ArrayView<uint8_t> data,
const StringRtpHeaderExtension& str) {
RTC_DCHECK_EQ(data.size(), str.size());
RTC_DCHECK_GE(str.size(), 1);
RTC_DCHECK_LE(str.size(), StringRtpHeaderExtension::kMaxSize);
memcpy(data.data(), str.data(), str.size());
return true;
}
bool BaseRtpStringExtension::Parse(rtc::ArrayView<const uint8_t> data,
std::string* str) {
if (data.empty() || data[0] == 0) // Valid string extension can't be empty.
return false;
const char* cstr = reinterpret_cast<const char*>(data.data());
// If there is a \0 character in the middle of the |data|, treat it as end
// of the string. Well-formed string extensions shouldn't contain it.
str->assign(cstr, strnlen(cstr, data.size()));
RTC_DCHECK(!str->empty());
return true;
}
bool BaseRtpStringExtension::Write(rtc::ArrayView<uint8_t> data,
const std::string& str) {
if (str.size() > StringRtpHeaderExtension::kMaxSize) {
return false;
}
RTC_DCHECK_EQ(data.size(), str.size());
RTC_DCHECK_GE(str.size(), 1);
memcpy(data.data(), str.data(), str.size());
return true;
}
// Constant declarations for string RTP header extension types.
constexpr RTPExtensionType RtpStreamId::kId;
constexpr const char RtpStreamId::kUri[];
constexpr RTPExtensionType RepairedRtpStreamId::kId;
constexpr const char RepairedRtpStreamId::kUri[];
constexpr RTPExtensionType RtpMid::kId;
constexpr const char RtpMid::kUri[];
} // namespace webrtc