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/*
* Copyright (c) 2012 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/video_coding/session_info.h"
#include <assert.h>
#include <string.h>
#include <vector>
#include "absl/types/variant.h"
#include "modules/include/module_common_types.h"
#include "modules/include/module_common_types_public.h"
#include "modules/video_coding/codecs/interface/common_constants.h"
#include "modules/video_coding/codecs/vp8/include/vp8_globals.h"
#include "modules/video_coding/jitter_buffer_common.h"
#include "modules/video_coding/packet.h"
#include "rtc_base/logging.h"
namespace webrtc {
namespace {
uint16_t BufferToUWord16(const uint8_t* dataBuffer) {
return (dataBuffer[0] << 8) | dataBuffer[1];
}
} // namespace
VCMSessionInfo::VCMSessionInfo()
: complete_(false),
frame_type_(VideoFrameType::kVideoFrameDelta),
packets_(),
empty_seq_num_low_(-1),
empty_seq_num_high_(-1),
first_packet_seq_num_(-1),
last_packet_seq_num_(-1) {}
VCMSessionInfo::~VCMSessionInfo() {}
void VCMSessionInfo::UpdateDataPointers(const uint8_t* old_base_ptr,
const uint8_t* new_base_ptr) {
for (PacketIterator it = packets_.begin(); it != packets_.end(); ++it)
if ((*it).dataPtr != NULL) {
assert(old_base_ptr != NULL && new_base_ptr != NULL);
(*it).dataPtr = new_base_ptr + ((*it).dataPtr - old_base_ptr);
}
}
int VCMSessionInfo::LowSequenceNumber() const {
if (packets_.empty())
return empty_seq_num_low_;
return packets_.front().seqNum;
}
int VCMSessionInfo::HighSequenceNumber() const {
if (packets_.empty())
return empty_seq_num_high_;
if (empty_seq_num_high_ == -1)
return packets_.back().seqNum;
return LatestSequenceNumber(packets_.back().seqNum, empty_seq_num_high_);
}
int VCMSessionInfo::PictureId() const {
if (packets_.empty())
return kNoPictureId;
if (packets_.front().video_header.codec == kVideoCodecVP8) {
return absl::get<RTPVideoHeaderVP8>(
packets_.front().video_header.video_type_header)
.pictureId;
} else if (packets_.front().video_header.codec == kVideoCodecVP9) {
return absl::get<RTPVideoHeaderVP9>(
packets_.front().video_header.video_type_header)
.picture_id;
} else {
return kNoPictureId;
}
}
int VCMSessionInfo::TemporalId() const {
if (packets_.empty())
return kNoTemporalIdx;
if (packets_.front().video_header.codec == kVideoCodecVP8) {
return absl::get<RTPVideoHeaderVP8>(
packets_.front().video_header.video_type_header)
.temporalIdx;
} else if (packets_.front().video_header.codec == kVideoCodecVP9) {
return absl::get<RTPVideoHeaderVP9>(
packets_.front().video_header.video_type_header)
.temporal_idx;
} else {
return kNoTemporalIdx;
}
}
bool VCMSessionInfo::LayerSync() const {
if (packets_.empty())
return false;
if (packets_.front().video_header.codec == kVideoCodecVP8) {
return absl::get<RTPVideoHeaderVP8>(
packets_.front().video_header.video_type_header)
.layerSync;
} else if (packets_.front().video_header.codec == kVideoCodecVP9) {
return absl::get<RTPVideoHeaderVP9>(
packets_.front().video_header.video_type_header)
.temporal_up_switch;
} else {
return false;
}
}
int VCMSessionInfo::Tl0PicId() const {
if (packets_.empty())
return kNoTl0PicIdx;
if (packets_.front().video_header.codec == kVideoCodecVP8) {
return absl::get<RTPVideoHeaderVP8>(
packets_.front().video_header.video_type_header)
.tl0PicIdx;
} else if (packets_.front().video_header.codec == kVideoCodecVP9) {
return absl::get<RTPVideoHeaderVP9>(
packets_.front().video_header.video_type_header)
.tl0_pic_idx;
} else {
return kNoTl0PicIdx;
}
}
std::vector<NaluInfo> VCMSessionInfo::GetNaluInfos() const {
if (packets_.empty() ||
packets_.front().video_header.codec != kVideoCodecH264)
return std::vector<NaluInfo>();
std::vector<NaluInfo> nalu_infos;
for (const VCMPacket& packet : packets_) {
const auto& h264 =
absl::get<RTPVideoHeaderH264>(packet.video_header.video_type_header);
for (size_t i = 0; i < h264.nalus_length; ++i) {
nalu_infos.push_back(h264.nalus[i]);
}
}
return nalu_infos;
}
void VCMSessionInfo::SetGofInfo(const GofInfoVP9& gof_info, size_t idx) {
if (packets_.empty())
return;
auto* vp9_header = absl::get_if<RTPVideoHeaderVP9>(
&packets_.front().video_header.video_type_header);
if (!vp9_header || vp9_header->flexible_mode)
return;
vp9_header->temporal_idx = gof_info.temporal_idx[idx];
vp9_header->temporal_up_switch = gof_info.temporal_up_switch[idx];
vp9_header->num_ref_pics = gof_info.num_ref_pics[idx];
for (uint8_t i = 0; i < gof_info.num_ref_pics[idx]; ++i) {
vp9_header->pid_diff[i] = gof_info.pid_diff[idx][i];
}
}
void VCMSessionInfo::Reset() {
complete_ = false;
frame_type_ = VideoFrameType::kVideoFrameDelta;
packets_.clear();
empty_seq_num_low_ = -1;
empty_seq_num_high_ = -1;
first_packet_seq_num_ = -1;
last_packet_seq_num_ = -1;
}
size_t VCMSessionInfo::SessionLength() const {
size_t length = 0;
for (PacketIteratorConst it = packets_.begin(); it != packets_.end(); ++it)
length += (*it).sizeBytes;
return length;
}
int VCMSessionInfo::NumPackets() const {
return packets_.size();
}
size_t VCMSessionInfo::InsertBuffer(uint8_t* frame_buffer,
PacketIterator packet_it) {
VCMPacket& packet = *packet_it;
PacketIterator it;
// Calculate the offset into the frame buffer for this packet.
size_t offset = 0;
for (it = packets_.begin(); it != packet_it; ++it)
offset += (*it).sizeBytes;
// Set the data pointer to pointing to the start of this packet in the
// frame buffer.
const uint8_t* packet_buffer = packet.dataPtr;
packet.dataPtr = frame_buffer + offset;
// We handle H.264 STAP-A packets in a special way as we need to remove the
// two length bytes between each NAL unit, and potentially add start codes.
// TODO(pbos): Remove H264 parsing from this step and use a fragmentation
// header supplied by the H264 depacketizer.
const size_t kH264NALHeaderLengthInBytes = 1;
const size_t kLengthFieldLength = 2;
const auto* h264 =
absl::get_if<RTPVideoHeaderH264>(&packet.video_header.video_type_header);
if (h264 && h264->packetization_type == kH264StapA) {
size_t required_length = 0;
const uint8_t* nalu_ptr = packet_buffer + kH264NALHeaderLengthInBytes;
while (nalu_ptr < packet_buffer + packet.sizeBytes) {
size_t length = BufferToUWord16(nalu_ptr);
required_length +=
length + (packet.insertStartCode ? kH264StartCodeLengthBytes : 0);
nalu_ptr += kLengthFieldLength + length;
}
ShiftSubsequentPackets(packet_it, required_length);
nalu_ptr = packet_buffer + kH264NALHeaderLengthInBytes;
uint8_t* frame_buffer_ptr = frame_buffer + offset;
while (nalu_ptr < packet_buffer + packet.sizeBytes) {
size_t length = BufferToUWord16(nalu_ptr);
nalu_ptr += kLengthFieldLength;
frame_buffer_ptr += Insert(nalu_ptr, length, packet.insertStartCode,
const_cast<uint8_t*>(frame_buffer_ptr));
nalu_ptr += length;
}
packet.sizeBytes = required_length;
return packet.sizeBytes;
}
ShiftSubsequentPackets(
packet_it, packet.sizeBytes +
(packet.insertStartCode ? kH264StartCodeLengthBytes : 0));
packet.sizeBytes =
Insert(packet_buffer, packet.sizeBytes, packet.insertStartCode,
const_cast<uint8_t*>(packet.dataPtr));
return packet.sizeBytes;
}
size_t VCMSessionInfo::Insert(const uint8_t* buffer,
size_t length,
bool insert_start_code,
uint8_t* frame_buffer) {
if (insert_start_code) {
const unsigned char startCode[] = {0, 0, 0, 1};
memcpy(frame_buffer, startCode, kH264StartCodeLengthBytes);
}
memcpy(frame_buffer + (insert_start_code ? kH264StartCodeLengthBytes : 0),
buffer, length);
length += (insert_start_code ? kH264StartCodeLengthBytes : 0);
return length;
}
void VCMSessionInfo::ShiftSubsequentPackets(PacketIterator it,
int steps_to_shift) {
++it;
if (it == packets_.end())
return;
uint8_t* first_packet_ptr = const_cast<uint8_t*>((*it).dataPtr);
int shift_length = 0;
// Calculate the total move length and move the data pointers in advance.
for (; it != packets_.end(); ++it) {
shift_length += (*it).sizeBytes;
if ((*it).dataPtr != NULL)
(*it).dataPtr += steps_to_shift;
}
memmove(first_packet_ptr + steps_to_shift, first_packet_ptr, shift_length);
}
void VCMSessionInfo::UpdateCompleteSession() {
if (HaveFirstPacket() && HaveLastPacket()) {
// Do we have all the packets in this session?
bool complete_session = true;
PacketIterator it = packets_.begin();
PacketIterator prev_it = it;
++it;
for (; it != packets_.end(); ++it) {
if (!InSequence(it, prev_it)) {
complete_session = false;
break;
}
prev_it = it;
}
complete_ = complete_session;
}
}
bool VCMSessionInfo::complete() const {
return complete_;
}
// Find the end of the NAL unit which the packet pointed to by |packet_it|
// belongs to. Returns an iterator to the last packet of the frame if the end
// of the NAL unit wasn't found.
VCMSessionInfo::PacketIterator VCMSessionInfo::FindNaluEnd(
PacketIterator packet_it) const {
if ((*packet_it).completeNALU == kNaluEnd ||
(*packet_it).completeNALU == kNaluComplete) {
return packet_it;
}
// Find the end of the NAL unit.
for (; packet_it != packets_.end(); ++packet_it) {
if (((*packet_it).completeNALU == kNaluComplete &&
(*packet_it).sizeBytes > 0) ||
// Found next NALU.
(*packet_it).completeNALU == kNaluStart)
return --packet_it;
if ((*packet_it).completeNALU == kNaluEnd)
return packet_it;
}
// The end wasn't found.
return --packet_it;
}
size_t VCMSessionInfo::DeletePacketData(PacketIterator start,
PacketIterator end) {
size_t bytes_to_delete = 0; // The number of bytes to delete.
PacketIterator packet_after_end = end;
++packet_after_end;
// Get the number of bytes to delete.
// Clear the size of these packets.
for (PacketIterator it = start; it != packet_after_end; ++it) {
bytes_to_delete += (*it).sizeBytes;
(*it).sizeBytes = 0;
(*it).dataPtr = NULL;
}
if (bytes_to_delete > 0)
ShiftSubsequentPackets(end, -static_cast<int>(bytes_to_delete));
return bytes_to_delete;
}
VCMSessionInfo::PacketIterator VCMSessionInfo::FindNextPartitionBeginning(
PacketIterator it) const {
while (it != packets_.end()) {
if (absl::get<RTPVideoHeaderVP8>((*it).video_header.video_type_header)
.beginningOfPartition) {
return it;
}
++it;
}
return it;
}
VCMSessionInfo::PacketIterator VCMSessionInfo::FindPartitionEnd(
PacketIterator it) const {
assert((*it).codec() == kVideoCodecVP8);
PacketIterator prev_it = it;
const int partition_id =
absl::get<RTPVideoHeaderVP8>((*it).video_header.video_type_header)
.partitionId;
while (it != packets_.end()) {
bool beginning =
absl::get<RTPVideoHeaderVP8>((*it).video_header.video_type_header)
.beginningOfPartition;
int current_partition_id =
absl::get<RTPVideoHeaderVP8>((*it).video_header.video_type_header)
.partitionId;
bool packet_loss_found = (!beginning && !InSequence(it, prev_it));
if (packet_loss_found ||
(beginning && current_partition_id != partition_id)) {
// Missing packet, the previous packet was the last in sequence.
return prev_it;
}
prev_it = it;
++it;
}
return prev_it;
}
bool VCMSessionInfo::InSequence(const PacketIterator& packet_it,
const PacketIterator& prev_packet_it) {
// If the two iterators are pointing to the same packet they are considered
// to be in sequence.
return (packet_it == prev_packet_it ||
(static_cast<uint16_t>((*prev_packet_it).seqNum + 1) ==
(*packet_it).seqNum));
}
size_t VCMSessionInfo::MakeDecodable() {
size_t return_length = 0;
if (packets_.empty()) {
return 0;
}
PacketIterator it = packets_.begin();
// Make sure we remove the first NAL unit if it's not decodable.
if ((*it).completeNALU == kNaluIncomplete || (*it).completeNALU == kNaluEnd) {
PacketIterator nalu_end = FindNaluEnd(it);
return_length += DeletePacketData(it, nalu_end);
it = nalu_end;
}
PacketIterator prev_it = it;
// Take care of the rest of the NAL units.
for (; it != packets_.end(); ++it) {
bool start_of_nalu = ((*it).completeNALU == kNaluStart ||
(*it).completeNALU == kNaluComplete);
if (!start_of_nalu && !InSequence(it, prev_it)) {
// Found a sequence number gap due to packet loss.
PacketIterator nalu_end = FindNaluEnd(it);
return_length += DeletePacketData(it, nalu_end);
it = nalu_end;
}
prev_it = it;
}
return return_length;
}
bool VCMSessionInfo::HaveFirstPacket() const {
return !packets_.empty() && (first_packet_seq_num_ != -1);
}
bool VCMSessionInfo::HaveLastPacket() const {
return !packets_.empty() && (last_packet_seq_num_ != -1);
}
int VCMSessionInfo::InsertPacket(const VCMPacket& packet,
uint8_t* frame_buffer,
const FrameData& frame_data) {
if (packet.video_header.frame_type == VideoFrameType::kEmptyFrame) {
// Update sequence number of an empty packet.
// Only media packets are inserted into the packet list.
InformOfEmptyPacket(packet.seqNum);
return 0;
}
if (packets_.size() == kMaxPacketsInSession) {
RTC_LOG(LS_ERROR) << "Max number of packets per frame has been reached.";
return -1;
}
// Find the position of this packet in the packet list in sequence number
// order and insert it. Loop over the list in reverse order.
ReversePacketIterator rit = packets_.rbegin();
for (; rit != packets_.rend(); ++rit)
if (LatestSequenceNumber(packet.seqNum, (*rit).seqNum) == packet.seqNum)
break;
// Check for duplicate packets.
if (rit != packets_.rend() && (*rit).seqNum == packet.seqNum &&
(*rit).sizeBytes > 0)
return -2;
if (packet.codec() == kVideoCodecH264) {
frame_type_ = packet.video_header.frame_type;
if (packet.is_first_packet_in_frame() &&
(first_packet_seq_num_ == -1 ||
IsNewerSequenceNumber(first_packet_seq_num_, packet.seqNum))) {
first_packet_seq_num_ = packet.seqNum;
}
if (packet.markerBit &&
(last_packet_seq_num_ == -1 ||
IsNewerSequenceNumber(packet.seqNum, last_packet_seq_num_))) {
last_packet_seq_num_ = packet.seqNum;
}
} else {
// Only insert media packets between first and last packets (when
// available).
// Placing check here, as to properly account for duplicate packets.
// Check if this is first packet (only valid for some codecs)
// Should only be set for one packet per session.
if (packet.is_first_packet_in_frame() && first_packet_seq_num_ == -1) {
// The first packet in a frame signals the frame type.
frame_type_ = packet.video_header.frame_type;
// Store the sequence number for the first packet.
first_packet_seq_num_ = static_cast<int>(packet.seqNum);
} else if (first_packet_seq_num_ != -1 &&
IsNewerSequenceNumber(first_packet_seq_num_, packet.seqNum)) {
RTC_LOG(LS_WARNING)
<< "Received packet with a sequence number which is out "
"of frame boundaries";
return -3;
} else if (frame_type_ == VideoFrameType::kEmptyFrame &&
packet.video_header.frame_type != VideoFrameType::kEmptyFrame) {
// Update the frame type with the type of the first media packet.
// TODO(mikhal): Can this trigger?
frame_type_ = packet.video_header.frame_type;
}
// Track the marker bit, should only be set for one packet per session.
if (packet.markerBit && last_packet_seq_num_ == -1) {
last_packet_seq_num_ = static_cast<int>(packet.seqNum);
} else if (last_packet_seq_num_ != -1 &&
IsNewerSequenceNumber(packet.seqNum, last_packet_seq_num_)) {
RTC_LOG(LS_WARNING)
<< "Received packet with a sequence number which is out "
"of frame boundaries";
return -3;
}
}
// The insert operation invalidates the iterator |rit|.
PacketIterator packet_list_it = packets_.insert(rit.base(), packet);
size_t returnLength = InsertBuffer(frame_buffer, packet_list_it);
UpdateCompleteSession();
return static_cast<int>(returnLength);
}
void VCMSessionInfo::InformOfEmptyPacket(uint16_t seq_num) {
// Empty packets may be FEC or filler packets. They are sequential and
// follow the data packets, therefore, we should only keep track of the high
// and low sequence numbers and may assume that the packets in between are
// empty packets belonging to the same frame (timestamp).
if (empty_seq_num_high_ == -1)
empty_seq_num_high_ = seq_num;
else
empty_seq_num_high_ = LatestSequenceNumber(seq_num, empty_seq_num_high_);
if (empty_seq_num_low_ == -1 ||
IsNewerSequenceNumber(empty_seq_num_low_, seq_num))
empty_seq_num_low_ = seq_num;
}
} // namespace webrtc