blob: 3dcfc48213383da607daf9902b78c21da7e118f7 [file] [log] [blame]
/*
* 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/video_coding/packet_buffer.h"
#include <string.h>
#include <algorithm>
#include <cstdint>
#include <limits>
#include <utility>
#include <vector>
#include "absl/types/variant.h"
#include "api/array_view.h"
#include "api/rtp_packet_info.h"
#include "api/video/video_frame_type.h"
#include "common_video/h264/h264_common.h"
#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
#include "modules/rtp_rtcp/source/rtp_packet_received.h"
#include "modules/rtp_rtcp/source/rtp_video_header.h"
#include "modules/video_coding/codecs/h264/include/h264_globals.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/mod_ops.h"
namespace webrtc {
namespace video_coding {
PacketBuffer::Packet::Packet(const RtpPacketReceived& rtp_packet,
const RTPVideoHeader& video_header)
: marker_bit(rtp_packet.Marker()),
payload_type(rtp_packet.PayloadType()),
seq_num(rtp_packet.SequenceNumber()),
timestamp(rtp_packet.Timestamp()),
times_nacked(-1),
video_header(video_header) {}
PacketBuffer::PacketBuffer(size_t start_buffer_size, size_t max_buffer_size)
: max_size_(max_buffer_size),
first_seq_num_(0),
first_packet_received_(false),
is_cleared_to_first_seq_num_(false),
buffer_(start_buffer_size),
sps_pps_idr_is_h264_keyframe_(false) {
RTC_DCHECK_LE(start_buffer_size, max_buffer_size);
// Buffer size must always be a power of 2.
RTC_DCHECK((start_buffer_size & (start_buffer_size - 1)) == 0);
RTC_DCHECK((max_buffer_size & (max_buffer_size - 1)) == 0);
}
PacketBuffer::~PacketBuffer() {
Clear();
}
PacketBuffer::InsertResult PacketBuffer::InsertPacket(
std::unique_ptr<PacketBuffer::Packet> packet) {
PacketBuffer::InsertResult result;
uint16_t seq_num = packet->seq_num;
size_t index = seq_num % buffer_.size();
if (!first_packet_received_) {
first_seq_num_ = seq_num;
first_packet_received_ = true;
} else if (AheadOf(first_seq_num_, seq_num)) {
// If we have explicitly cleared past this packet then it's old,
// don't insert it, just silently ignore it.
if (is_cleared_to_first_seq_num_) {
return result;
}
first_seq_num_ = seq_num;
}
if (buffer_[index] != nullptr) {
// Duplicate packet, just delete the payload.
if (buffer_[index]->seq_num == packet->seq_num) {
return result;
}
// The packet buffer is full, try to expand the buffer.
while (ExpandBufferSize() && buffer_[seq_num % buffer_.size()] != nullptr) {
}
index = seq_num % buffer_.size();
// Packet buffer is still full since we were unable to expand the buffer.
if (buffer_[index] != nullptr) {
// Clear the buffer, delete payload, and return false to signal that a
// new keyframe is needed.
RTC_LOG(LS_WARNING) << "Clear PacketBuffer and request key frame.";
ClearInternal();
result.buffer_cleared = true;
return result;
}
}
packet->continuous = false;
buffer_[index] = std::move(packet);
UpdateMissingPackets(seq_num);
received_padding_.erase(
received_padding_.begin(),
received_padding_.lower_bound(seq_num - (buffer_.size() / 4)));
result.packets = FindFrames(seq_num);
return result;
}
void PacketBuffer::ClearTo(uint16_t seq_num) {
// We have already cleared past this sequence number, no need to do anything.
if (is_cleared_to_first_seq_num_ &&
AheadOf<uint16_t>(first_seq_num_, seq_num)) {
return;
}
// If the packet buffer was cleared between a frame was created and returned.
if (!first_packet_received_)
return;
// Avoid iterating over the buffer more than once by capping the number of
// iterations to the `size_` of the buffer.
++seq_num;
size_t diff = ForwardDiff<uint16_t>(first_seq_num_, seq_num);
size_t iterations = std::min(diff, buffer_.size());
for (size_t i = 0; i < iterations; ++i) {
auto& stored = buffer_[first_seq_num_ % buffer_.size()];
if (stored != nullptr && AheadOf<uint16_t>(seq_num, stored->seq_num)) {
stored = nullptr;
}
++first_seq_num_;
}
// If `diff` is larger than `iterations` it means that we don't increment
// `first_seq_num_` until we reach `seq_num`, so we set it here.
first_seq_num_ = seq_num;
is_cleared_to_first_seq_num_ = true;
missing_packets_.erase(missing_packets_.begin(),
missing_packets_.lower_bound(seq_num));
received_padding_.erase(received_padding_.begin(),
received_padding_.lower_bound(seq_num));
}
void PacketBuffer::Clear() {
ClearInternal();
}
PacketBuffer::InsertResult PacketBuffer::InsertPadding(uint16_t seq_num) {
PacketBuffer::InsertResult result;
UpdateMissingPackets(seq_num);
received_padding_.insert(seq_num);
result.packets = FindFrames(static_cast<uint16_t>(seq_num + 1));
return result;
}
void PacketBuffer::ForceSpsPpsIdrIsH264Keyframe() {
sps_pps_idr_is_h264_keyframe_ = true;
}
void PacketBuffer::ResetSpsPpsIdrIsH264Keyframe() {
sps_pps_idr_is_h264_keyframe_ = false;
}
void PacketBuffer::ClearInternal() {
for (auto& entry : buffer_) {
entry = nullptr;
}
first_packet_received_ = false;
is_cleared_to_first_seq_num_ = false;
newest_inserted_seq_num_.reset();
missing_packets_.clear();
received_padding_.clear();
}
bool PacketBuffer::ExpandBufferSize() {
if (buffer_.size() == max_size_) {
RTC_LOG(LS_WARNING) << "PacketBuffer is already at max size (" << max_size_
<< "), failed to increase size.";
return false;
}
size_t new_size = std::min(max_size_, 2 * buffer_.size());
std::vector<std::unique_ptr<Packet>> new_buffer(new_size);
for (std::unique_ptr<Packet>& entry : buffer_) {
if (entry != nullptr) {
new_buffer[entry->seq_num % new_size] = std::move(entry);
}
}
buffer_ = std::move(new_buffer);
RTC_LOG(LS_INFO) << "PacketBuffer size expanded to " << new_size;
return true;
}
bool PacketBuffer::PotentialNewFrame(uint16_t seq_num) const {
size_t index = seq_num % buffer_.size();
int prev_index = index > 0 ? index - 1 : buffer_.size() - 1;
const auto& entry = buffer_[index];
const auto& prev_entry = buffer_[prev_index];
if (entry == nullptr)
return false;
if (entry->seq_num != seq_num)
return false;
if (entry->is_first_packet_in_frame())
return true;
if (prev_entry == nullptr)
return false;
if (prev_entry->seq_num != static_cast<uint16_t>(entry->seq_num - 1))
return false;
if (prev_entry->timestamp != entry->timestamp)
return false;
if (prev_entry->continuous)
return true;
return false;
}
std::vector<std::unique_ptr<PacketBuffer::Packet>> PacketBuffer::FindFrames(
uint16_t seq_num) {
std::vector<std::unique_ptr<PacketBuffer::Packet>> found_frames;
auto start = seq_num;
for (size_t i = 0; i < buffer_.size(); ++i) {
if (received_padding_.find(seq_num) != received_padding_.end()) {
seq_num += 1;
continue;
}
if (!PotentialNewFrame(seq_num)) {
break;
}
size_t index = seq_num % buffer_.size();
buffer_[index]->continuous = true;
// If all packets of the frame is continuous, find the first packet of the
// frame and add all packets of the frame to the returned packets.
if (buffer_[index]->is_last_packet_in_frame()) {
uint16_t start_seq_num = seq_num;
// Find the start index by searching backward until the packet with
// the `frame_begin` flag is set.
int start_index = index;
size_t tested_packets = 0;
int64_t frame_timestamp = buffer_[start_index]->timestamp;
// Identify H.264 keyframes by means of SPS, PPS, and IDR.
bool is_h264 = buffer_[start_index]->codec() == kVideoCodecH264;
bool has_h264_sps = false;
bool has_h264_pps = false;
bool has_h264_idr = false;
bool is_h264_keyframe = false;
int idr_width = -1;
int idr_height = -1;
bool full_frame_found = false;
while (true) {
++tested_packets;
if (!is_h264) {
if (buffer_[start_index] == nullptr ||
buffer_[start_index]->is_first_packet_in_frame()) {
full_frame_found = buffer_[start_index] != nullptr;
break;
}
}
if (is_h264) {
const auto* h264_header = absl::get_if<RTPVideoHeaderH264>(
&buffer_[start_index]->video_header.video_type_header);
if (!h264_header || h264_header->nalus_length >= kMaxNalusPerPacket)
return found_frames;
for (size_t j = 0; j < h264_header->nalus_length; ++j) {
if (h264_header->nalus[j].type == H264::NaluType::kSps) {
has_h264_sps = true;
} else if (h264_header->nalus[j].type == H264::NaluType::kPps) {
has_h264_pps = true;
} else if (h264_header->nalus[j].type == H264::NaluType::kIdr) {
has_h264_idr = true;
}
}
if ((sps_pps_idr_is_h264_keyframe_ && has_h264_idr && has_h264_sps &&
has_h264_pps) ||
(!sps_pps_idr_is_h264_keyframe_ && has_h264_idr)) {
is_h264_keyframe = true;
// Store the resolution of key frame which is the packet with
// smallest index and valid resolution; typically its IDR or SPS
// packet; there may be packet preceeding this packet, IDR's
// resolution will be applied to them.
if (buffer_[start_index]->width() > 0 &&
buffer_[start_index]->height() > 0) {
idr_width = buffer_[start_index]->width();
idr_height = buffer_[start_index]->height();
}
}
}
if (tested_packets == buffer_.size())
break;
start_index = start_index > 0 ? start_index - 1 : buffer_.size() - 1;
// In the case of H264 we don't have a frame_begin bit (yes,
// `frame_begin` might be set to true but that is a lie). So instead
// we traverese backwards as long as we have a previous packet and
// the timestamp of that packet is the same as this one. This may cause
// the PacketBuffer to hand out incomplete frames.
// See: https://bugs.chromium.org/p/webrtc/issues/detail?id=7106
if (is_h264 && (buffer_[start_index] == nullptr ||
buffer_[start_index]->timestamp != frame_timestamp)) {
break;
}
--start_seq_num;
}
if (is_h264) {
// Warn if this is an unsafe frame.
if (has_h264_idr && (!has_h264_sps || !has_h264_pps)) {
RTC_LOG(LS_WARNING)
<< "Received H.264-IDR frame "
"(SPS: "
<< has_h264_sps << ", PPS: " << has_h264_pps << "). Treating as "
<< (sps_pps_idr_is_h264_keyframe_ ? "delta" : "key")
<< " frame since WebRTC-SpsPpsIdrIsH264Keyframe is "
<< (sps_pps_idr_is_h264_keyframe_ ? "enabled." : "disabled");
}
// Now that we have decided whether to treat this frame as a key frame
// or delta frame in the frame buffer, we update the field that
// determines if the RtpFrameObject is a key frame or delta frame.
const size_t first_packet_index = start_seq_num % buffer_.size();
if (is_h264_keyframe) {
buffer_[first_packet_index]->video_header.frame_type =
VideoFrameType::kVideoFrameKey;
if (idr_width > 0 && idr_height > 0) {
// IDR frame was finalized and we have the correct resolution for
// IDR; update first packet to have same resolution as IDR.
buffer_[first_packet_index]->video_header.width = idr_width;
buffer_[first_packet_index]->video_header.height = idr_height;
}
} else {
buffer_[first_packet_index]->video_header.frame_type =
VideoFrameType::kVideoFrameDelta;
}
// If this is not a keyframe, make sure there are no gaps in the packet
// sequence numbers up until this point.
if (!is_h264_keyframe && missing_packets_.upper_bound(start_seq_num) !=
missing_packets_.begin()) {
return found_frames;
}
}
if (is_h264 || full_frame_found) {
const uint16_t end_seq_num = seq_num + 1;
// Use uint16_t type to handle sequence number wrap around case.
uint16_t num_packets = end_seq_num - start_seq_num;
found_frames.reserve(found_frames.size() + num_packets);
for (uint16_t i = start_seq_num; i != end_seq_num; ++i) {
std::unique_ptr<Packet>& packet = buffer_[i % buffer_.size()];
RTC_DCHECK(packet);
RTC_DCHECK_EQ(i, packet->seq_num);
// Ensure frame boundary flags are properly set.
packet->video_header.is_first_packet_in_frame = (i == start_seq_num);
packet->video_header.is_last_packet_in_frame = (i == seq_num);
found_frames.push_back(std::move(packet));
}
missing_packets_.erase(missing_packets_.begin(),
missing_packets_.upper_bound(seq_num));
received_padding_.erase(received_padding_.lower_bound(start),
received_padding_.upper_bound(seq_num));
}
}
++seq_num;
}
return found_frames;
}
void PacketBuffer::UpdateMissingPackets(uint16_t seq_num) {
if (!newest_inserted_seq_num_)
newest_inserted_seq_num_ = seq_num;
const int kMaxPaddingAge = 1000;
if (AheadOf(seq_num, *newest_inserted_seq_num_)) {
uint16_t old_seq_num = seq_num - kMaxPaddingAge;
auto erase_to = missing_packets_.lower_bound(old_seq_num);
missing_packets_.erase(missing_packets_.begin(), erase_to);
// Guard against inserting a large amount of missing packets if there is a
// jump in the sequence number.
if (AheadOf(old_seq_num, *newest_inserted_seq_num_))
*newest_inserted_seq_num_ = old_seq_num;
++*newest_inserted_seq_num_;
while (AheadOf(seq_num, *newest_inserted_seq_num_)) {
missing_packets_.insert(*newest_inserted_seq_num_);
++*newest_inserted_seq_num_;
}
} else {
missing_packets_.erase(seq_num);
}
}
} // namespace video_coding
} // namespace webrtc