blob: 28cc2fb624c4a683a7d1a0a9a574ac0e7e46a890 [file] [log] [blame]
/*
* Copyright (c) 2014 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_format_h264.h"
#include <string.h>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <memory>
#include <utility>
#include <vector>
#include "absl/types/optional.h"
#include "absl/types/variant.h"
#include "common_video/h264/h264_common.h"
#include "common_video/h264/pps_parser.h"
#include "common_video/h264/sps_parser.h"
#include "common_video/h264/sps_vui_rewriter.h"
#include "modules/include/module_common_types.h"
#include "modules/rtp_rtcp/source/byte_io.h"
#include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/system/fallthrough.h"
namespace webrtc {
namespace {
static const size_t kNalHeaderSize = 1;
static const size_t kFuAHeaderSize = 2;
static const size_t kLengthFieldSize = 2;
static const size_t kStapAHeaderSize = kNalHeaderSize + kLengthFieldSize;
// Bit masks for FU (A and B) indicators.
enum NalDefs : uint8_t { kFBit = 0x80, kNriMask = 0x60, kTypeMask = 0x1F };
// Bit masks for FU (A and B) headers.
enum FuDefs : uint8_t { kSBit = 0x80, kEBit = 0x40, kRBit = 0x20 };
// TODO(pbos): Avoid parsing this here as well as inside the jitter buffer.
bool ParseStapAStartOffsets(const uint8_t* nalu_ptr,
size_t length_remaining,
std::vector<size_t>* offsets) {
size_t offset = 0;
while (length_remaining > 0) {
// Buffer doesn't contain room for additional nalu length.
if (length_remaining < sizeof(uint16_t))
return false;
uint16_t nalu_size = ByteReader<uint16_t>::ReadBigEndian(nalu_ptr);
nalu_ptr += sizeof(uint16_t);
length_remaining -= sizeof(uint16_t);
if (nalu_size > length_remaining)
return false;
nalu_ptr += nalu_size;
length_remaining -= nalu_size;
offsets->push_back(offset + kStapAHeaderSize);
offset += kLengthFieldSize + nalu_size;
}
return true;
}
} // namespace
RtpPacketizerH264::RtpPacketizerH264(
rtc::ArrayView<const uint8_t> payload,
PayloadSizeLimits limits,
H264PacketizationMode packetization_mode,
const RTPFragmentationHeader& fragmentation)
: limits_(limits),
num_packets_left_(0) {
// Guard against uninitialized memory in packetization_mode.
RTC_CHECK(packetization_mode == H264PacketizationMode::NonInterleaved ||
packetization_mode == H264PacketizationMode::SingleNalUnit);
for (size_t i = 0; i < fragmentation.fragmentationVectorSize; ++i) {
const uint8_t* fragment =
payload.data() + fragmentation.fragmentationOffset[i];
const size_t fragment_length = fragmentation.fragmentationLength[i];
input_fragments_.push_back(Fragment(fragment, fragment_length));
}
if (!GeneratePackets(packetization_mode)) {
// If failed to generate all the packets, discard already generated
// packets in case the caller would ignore return value and still try to
// call NextPacket().
num_packets_left_ = 0;
while (!packets_.empty()) {
packets_.pop();
}
}
}
RtpPacketizerH264::~RtpPacketizerH264() = default;
RtpPacketizerH264::Fragment::~Fragment() = default;
RtpPacketizerH264::Fragment::Fragment(const uint8_t* buffer, size_t length)
: buffer(buffer), length(length) {}
RtpPacketizerH264::Fragment::Fragment(const Fragment& fragment)
: buffer(fragment.buffer), length(fragment.length) {}
size_t RtpPacketizerH264::NumPackets() const {
return num_packets_left_;
}
bool RtpPacketizerH264::GeneratePackets(
H264PacketizationMode packetization_mode) {
for (size_t i = 0; i < input_fragments_.size();) {
switch (packetization_mode) {
case H264PacketizationMode::SingleNalUnit:
if (!PacketizeSingleNalu(i))
return false;
++i;
break;
case H264PacketizationMode::NonInterleaved:
int fragment_len = input_fragments_[i].length;
int single_packet_capacity = limits_.max_payload_len;
if (input_fragments_.size() == 1)
single_packet_capacity -= limits_.single_packet_reduction_len;
else if (i == 0)
single_packet_capacity -= limits_.first_packet_reduction_len;
else if (i + 1 == input_fragments_.size())
single_packet_capacity -= limits_.last_packet_reduction_len;
if (fragment_len > single_packet_capacity) {
if (!PacketizeFuA(i))
return false;
++i;
} else {
i = PacketizeStapA(i);
}
break;
}
}
return true;
}
bool RtpPacketizerH264::PacketizeFuA(size_t fragment_index) {
// Fragment payload into packets (FU-A).
const Fragment& fragment = input_fragments_[fragment_index];
PayloadSizeLimits limits = limits_;
// Leave room for the FU-A header.
limits.max_payload_len -= kFuAHeaderSize;
// Update single/first/last packet reductions unless it is single/first/last
// fragment.
if (input_fragments_.size() != 1) {
// if this fragment is put into a single packet, it might still be the
// first or the last packet in the whole sequence of packets.
if (fragment_index == input_fragments_.size() - 1) {
limits.single_packet_reduction_len = limits_.last_packet_reduction_len;
} else if (fragment_index == 0) {
limits.single_packet_reduction_len = limits_.first_packet_reduction_len;
} else {
limits.single_packet_reduction_len = 0;
}
}
if (fragment_index != 0)
limits.first_packet_reduction_len = 0;
if (fragment_index != input_fragments_.size() - 1)
limits.last_packet_reduction_len = 0;
// Strip out the original header.
size_t payload_left = fragment.length - kNalHeaderSize;
int offset = kNalHeaderSize;
std::vector<int> payload_sizes = SplitAboutEqually(payload_left, limits);
if (payload_sizes.empty())
return false;
for (size_t i = 0; i < payload_sizes.size(); ++i) {
int packet_length = payload_sizes[i];
RTC_CHECK_GT(packet_length, 0);
packets_.push(PacketUnit(Fragment(fragment.buffer + offset, packet_length),
/*first_fragment=*/i == 0,
/*last_fragment=*/i == payload_sizes.size() - 1,
false, fragment.buffer[0]));
offset += packet_length;
payload_left -= packet_length;
}
num_packets_left_ += payload_sizes.size();
RTC_CHECK_EQ(0, payload_left);
return true;
}
size_t RtpPacketizerH264::PacketizeStapA(size_t fragment_index) {
// Aggregate fragments into one packet (STAP-A).
size_t payload_size_left = limits_.max_payload_len;
if (input_fragments_.size() == 1)
payload_size_left -= limits_.single_packet_reduction_len;
else if (fragment_index == 0)
payload_size_left -= limits_.first_packet_reduction_len;
int aggregated_fragments = 0;
size_t fragment_headers_length = 0;
const Fragment* fragment = &input_fragments_[fragment_index];
RTC_CHECK_GE(payload_size_left, fragment->length);
++num_packets_left_;
auto payload_size_needed = [&] {
size_t fragment_size = fragment->length + fragment_headers_length;
if (input_fragments_.size() == 1) {
// Single fragment, single packet, payload_size_left already adjusted
// with limits_.single_packet_reduction_len.
return fragment_size;
}
if (fragment_index == input_fragments_.size() - 1) {
// Last fragment, so StrapA might be the last packet.
return fragment_size + limits_.last_packet_reduction_len;
}
return fragment_size;
};
while (payload_size_left >= payload_size_needed()) {
RTC_CHECK_GT(fragment->length, 0);
packets_.push(PacketUnit(*fragment, aggregated_fragments == 0, false, true,
fragment->buffer[0]));
payload_size_left -= fragment->length;
payload_size_left -= fragment_headers_length;
fragment_headers_length = kLengthFieldSize;
// If we are going to try to aggregate more fragments into this packet
// we need to add the STAP-A NALU header and a length field for the first
// NALU of this packet.
if (aggregated_fragments == 0)
fragment_headers_length += kNalHeaderSize + kLengthFieldSize;
++aggregated_fragments;
// Next fragment.
++fragment_index;
if (fragment_index == input_fragments_.size())
break;
fragment = &input_fragments_[fragment_index];
}
RTC_CHECK_GT(aggregated_fragments, 0);
packets_.back().last_fragment = true;
return fragment_index;
}
bool RtpPacketizerH264::PacketizeSingleNalu(size_t fragment_index) {
// Add a single NALU to the queue, no aggregation.
size_t payload_size_left = limits_.max_payload_len;
if (input_fragments_.size() == 1)
payload_size_left -= limits_.single_packet_reduction_len;
else if (fragment_index == 0)
payload_size_left -= limits_.first_packet_reduction_len;
else if (fragment_index + 1 == input_fragments_.size())
payload_size_left -= limits_.last_packet_reduction_len;
const Fragment* fragment = &input_fragments_[fragment_index];
if (payload_size_left < fragment->length) {
RTC_LOG(LS_ERROR) << "Failed to fit a fragment to packet in SingleNalu "
"packetization mode. Payload size left "
<< payload_size_left << ", fragment length "
<< fragment->length << ", packet capacity "
<< limits_.max_payload_len;
return false;
}
RTC_CHECK_GT(fragment->length, 0u);
packets_.push(PacketUnit(*fragment, true /* first */, true /* last */,
false /* aggregated */, fragment->buffer[0]));
++num_packets_left_;
return true;
}
bool RtpPacketizerH264::NextPacket(RtpPacketToSend* rtp_packet) {
RTC_DCHECK(rtp_packet);
if (packets_.empty()) {
return false;
}
PacketUnit packet = packets_.front();
if (packet.first_fragment && packet.last_fragment) {
// Single NAL unit packet.
size_t bytes_to_send = packet.source_fragment.length;
uint8_t* buffer = rtp_packet->AllocatePayload(bytes_to_send);
memcpy(buffer, packet.source_fragment.buffer, bytes_to_send);
packets_.pop();
input_fragments_.pop_front();
} else if (packet.aggregated) {
NextAggregatePacket(rtp_packet);
} else {
NextFragmentPacket(rtp_packet);
}
rtp_packet->SetMarker(packets_.empty());
--num_packets_left_;
return true;
}
void RtpPacketizerH264::NextAggregatePacket(RtpPacketToSend* rtp_packet) {
// Reserve maximum available payload, set actual payload size later.
size_t payload_capacity = rtp_packet->FreeCapacity();
RTC_CHECK_GE(payload_capacity, kNalHeaderSize);
uint8_t* buffer = rtp_packet->AllocatePayload(payload_capacity);
RTC_DCHECK(buffer);
PacketUnit* packet = &packets_.front();
RTC_CHECK(packet->first_fragment);
// STAP-A NALU header.
buffer[0] = (packet->header & (kFBit | kNriMask)) | H264::NaluType::kStapA;
size_t index = kNalHeaderSize;
bool is_last_fragment = packet->last_fragment;
while (packet->aggregated) {
const Fragment& fragment = packet->source_fragment;
RTC_CHECK_LE(index + kLengthFieldSize + fragment.length, payload_capacity);
// Add NAL unit length field.
ByteWriter<uint16_t>::WriteBigEndian(&buffer[index], fragment.length);
index += kLengthFieldSize;
// Add NAL unit.
memcpy(&buffer[index], fragment.buffer, fragment.length);
index += fragment.length;
packets_.pop();
input_fragments_.pop_front();
if (is_last_fragment)
break;
packet = &packets_.front();
is_last_fragment = packet->last_fragment;
}
RTC_CHECK(is_last_fragment);
rtp_packet->SetPayloadSize(index);
}
void RtpPacketizerH264::NextFragmentPacket(RtpPacketToSend* rtp_packet) {
PacketUnit* packet = &packets_.front();
// NAL unit fragmented over multiple packets (FU-A).
// We do not send original NALU header, so it will be replaced by the
// FU indicator header of the first packet.
uint8_t fu_indicator =
(packet->header & (kFBit | kNriMask)) | H264::NaluType::kFuA;
uint8_t fu_header = 0;
// S | E | R | 5 bit type.
fu_header |= (packet->first_fragment ? kSBit : 0);
fu_header |= (packet->last_fragment ? kEBit : 0);
uint8_t type = packet->header & kTypeMask;
fu_header |= type;
const Fragment& fragment = packet->source_fragment;
uint8_t* buffer =
rtp_packet->AllocatePayload(kFuAHeaderSize + fragment.length);
buffer[0] = fu_indicator;
buffer[1] = fu_header;
memcpy(buffer + kFuAHeaderSize, fragment.buffer, fragment.length);
if (packet->last_fragment)
input_fragments_.pop_front();
packets_.pop();
}
RtpDepacketizerH264::RtpDepacketizerH264() : offset_(0), length_(0) {}
RtpDepacketizerH264::~RtpDepacketizerH264() {}
bool RtpDepacketizerH264::Parse(ParsedPayload* parsed_payload,
const uint8_t* payload_data,
size_t payload_data_length) {
RTC_CHECK(parsed_payload != nullptr);
if (payload_data_length == 0) {
RTC_LOG(LS_ERROR) << "Empty payload.";
return false;
}
offset_ = 0;
length_ = payload_data_length;
modified_buffer_.reset();
uint8_t nal_type = payload_data[0] & kTypeMask;
parsed_payload->video_header()
.video_type_header.emplace<RTPVideoHeaderH264>();
if (nal_type == H264::NaluType::kFuA) {
// Fragmented NAL units (FU-A).
if (!ParseFuaNalu(parsed_payload, payload_data))
return false;
} else {
// We handle STAP-A and single NALU's the same way here. The jitter buffer
// will depacketize the STAP-A into NAL units later.
// TODO(sprang): Parse STAP-A offsets here and store in fragmentation vec.
if (!ProcessStapAOrSingleNalu(parsed_payload, payload_data))
return false;
}
const uint8_t* payload =
modified_buffer_ ? modified_buffer_->data() : payload_data;
parsed_payload->payload = payload + offset_;
parsed_payload->payload_length = length_;
return true;
}
bool RtpDepacketizerH264::ProcessStapAOrSingleNalu(
ParsedPayload* parsed_payload,
const uint8_t* payload_data) {
parsed_payload->video_header().width = 0;
parsed_payload->video_header().height = 0;
parsed_payload->video_header().codec = kVideoCodecH264;
parsed_payload->video_header().simulcastIdx = 0;
parsed_payload->video_header().is_first_packet_in_frame = true;
auto& h264_header = absl::get<RTPVideoHeaderH264>(
parsed_payload->video_header().video_type_header);
const uint8_t* nalu_start = payload_data + kNalHeaderSize;
const size_t nalu_length = length_ - kNalHeaderSize;
uint8_t nal_type = payload_data[0] & kTypeMask;
std::vector<size_t> nalu_start_offsets;
if (nal_type == H264::NaluType::kStapA) {
// Skip the StapA header (StapA NAL type + length).
if (length_ <= kStapAHeaderSize) {
RTC_LOG(LS_ERROR) << "StapA header truncated.";
return false;
}
if (!ParseStapAStartOffsets(nalu_start, nalu_length, &nalu_start_offsets)) {
RTC_LOG(LS_ERROR) << "StapA packet with incorrect NALU packet lengths.";
return false;
}
h264_header.packetization_type = kH264StapA;
nal_type = payload_data[kStapAHeaderSize] & kTypeMask;
} else {
h264_header.packetization_type = kH264SingleNalu;
nalu_start_offsets.push_back(0);
}
h264_header.nalu_type = nal_type;
parsed_payload->video_header().frame_type = VideoFrameType::kVideoFrameDelta;
nalu_start_offsets.push_back(length_ + kLengthFieldSize); // End offset.
for (size_t i = 0; i < nalu_start_offsets.size() - 1; ++i) {
size_t start_offset = nalu_start_offsets[i];
// End offset is actually start offset for next unit, excluding length field
// so remove that from this units length.
size_t end_offset = nalu_start_offsets[i + 1] - kLengthFieldSize;
if (end_offset - start_offset < H264::kNaluTypeSize) {
RTC_LOG(LS_ERROR) << "STAP-A packet too short";
return false;
}
NaluInfo nalu;
nalu.type = payload_data[start_offset] & kTypeMask;
nalu.sps_id = -1;
nalu.pps_id = -1;
start_offset += H264::kNaluTypeSize;
switch (nalu.type) {
case H264::NaluType::kSps: {
// Check if VUI is present in SPS and if it needs to be modified to
// avoid
// excessive decoder latency.
// Copy any previous data first (likely just the first header).
std::unique_ptr<rtc::Buffer> output_buffer(new rtc::Buffer());
if (start_offset)
output_buffer->AppendData(payload_data, start_offset);
absl::optional<SpsParser::SpsState> sps;
SpsVuiRewriter::ParseResult result = SpsVuiRewriter::ParseAndRewriteSps(
&payload_data[start_offset], end_offset - start_offset, &sps,
nullptr, output_buffer.get(), SpsVuiRewriter::Direction::kIncoming);
if (result == SpsVuiRewriter::ParseResult::kVuiRewritten) {
if (modified_buffer_) {
RTC_LOG(LS_WARNING)
<< "More than one H264 SPS NAL units needing "
"rewriting found within a single STAP-A packet. "
"Keeping the first and rewriting the last.";
}
// Rewrite length field to new SPS size.
if (h264_header.packetization_type == kH264StapA) {
size_t length_field_offset =
start_offset - (H264::kNaluTypeSize + kLengthFieldSize);
// Stap-A Length includes payload data and type header.
size_t rewritten_size =
output_buffer->size() - start_offset + H264::kNaluTypeSize;
ByteWriter<uint16_t>::WriteBigEndian(
&(*output_buffer)[length_field_offset], rewritten_size);
}
// Append rest of packet.
output_buffer->AppendData(&payload_data[end_offset],
nalu_length + kNalHeaderSize - end_offset);
modified_buffer_ = std::move(output_buffer);
length_ = modified_buffer_->size();
}
if (sps) {
parsed_payload->video_header().width = sps->width;
parsed_payload->video_header().height = sps->height;
nalu.sps_id = sps->id;
} else {
RTC_LOG(LS_WARNING) << "Failed to parse SPS id from SPS slice.";
}
parsed_payload->video_header().frame_type =
VideoFrameType::kVideoFrameKey;
break;
}
case H264::NaluType::kPps: {
uint32_t pps_id;
uint32_t sps_id;
if (PpsParser::ParsePpsIds(&payload_data[start_offset],
end_offset - start_offset, &pps_id,
&sps_id)) {
nalu.pps_id = pps_id;
nalu.sps_id = sps_id;
} else {
RTC_LOG(LS_WARNING)
<< "Failed to parse PPS id and SPS id from PPS slice.";
}
break;
}
case H264::NaluType::kIdr:
parsed_payload->video_header().frame_type =
VideoFrameType::kVideoFrameKey;
RTC_FALLTHROUGH();
case H264::NaluType::kSlice: {
absl::optional<uint32_t> pps_id = PpsParser::ParsePpsIdFromSlice(
&payload_data[start_offset], end_offset - start_offset);
if (pps_id) {
nalu.pps_id = *pps_id;
} else {
RTC_LOG(LS_WARNING) << "Failed to parse PPS id from slice of type: "
<< static_cast<int>(nalu.type);
}
break;
}
// Slices below don't contain SPS or PPS ids.
case H264::NaluType::kAud:
case H264::NaluType::kEndOfSequence:
case H264::NaluType::kEndOfStream:
case H264::NaluType::kFiller:
case H264::NaluType::kSei:
break;
case H264::NaluType::kStapA:
case H264::NaluType::kFuA:
RTC_LOG(LS_WARNING) << "Unexpected STAP-A or FU-A received.";
return false;
}
if (h264_header.nalus_length == kMaxNalusPerPacket) {
RTC_LOG(LS_WARNING)
<< "Received packet containing more than " << kMaxNalusPerPacket
<< " NAL units. Will not keep track sps and pps ids for all of them.";
} else {
h264_header.nalus[h264_header.nalus_length++] = nalu;
}
}
return true;
}
bool RtpDepacketizerH264::ParseFuaNalu(
RtpDepacketizer::ParsedPayload* parsed_payload,
const uint8_t* payload_data) {
if (length_ < kFuAHeaderSize) {
RTC_LOG(LS_ERROR) << "FU-A NAL units truncated.";
return false;
}
uint8_t fnri = payload_data[0] & (kFBit | kNriMask);
uint8_t original_nal_type = payload_data[1] & kTypeMask;
bool first_fragment = (payload_data[1] & kSBit) > 0;
NaluInfo nalu;
nalu.type = original_nal_type;
nalu.sps_id = -1;
nalu.pps_id = -1;
if (first_fragment) {
offset_ = 0;
length_ -= kNalHeaderSize;
absl::optional<uint32_t> pps_id = PpsParser::ParsePpsIdFromSlice(
payload_data + 2 * kNalHeaderSize, length_ - kNalHeaderSize);
if (pps_id) {
nalu.pps_id = *pps_id;
} else {
RTC_LOG(LS_WARNING)
<< "Failed to parse PPS from first fragment of FU-A NAL "
"unit with original type: "
<< static_cast<int>(nalu.type);
}
uint8_t original_nal_header = fnri | original_nal_type;
modified_buffer_.reset(new rtc::Buffer());
modified_buffer_->AppendData(payload_data + kNalHeaderSize, length_);
(*modified_buffer_)[0] = original_nal_header;
} else {
offset_ = kFuAHeaderSize;
length_ -= kFuAHeaderSize;
}
if (original_nal_type == H264::NaluType::kIdr) {
parsed_payload->video_header().frame_type = VideoFrameType::kVideoFrameKey;
} else {
parsed_payload->video_header().frame_type =
VideoFrameType::kVideoFrameDelta;
}
parsed_payload->video_header().width = 0;
parsed_payload->video_header().height = 0;
parsed_payload->video_header().codec = kVideoCodecH264;
parsed_payload->video_header().simulcastIdx = 0;
parsed_payload->video_header().is_first_packet_in_frame = first_fragment;
auto& h264_header = absl::get<RTPVideoHeaderH264>(
parsed_payload->video_header().video_type_header);
h264_header.packetization_type = kH264FuA;
h264_header.nalu_type = original_nal_type;
if (first_fragment) {
h264_header.nalus[h264_header.nalus_length] = nalu;
h264_header.nalus_length = 1;
}
return true;
}
} // namespace webrtc