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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /third_party/libwebrtc/modules/rtp_rtcp/source/rtp_packetizer_av1.cc | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/libwebrtc/modules/rtp_rtcp/source/rtp_packetizer_av1.cc')
-rw-r--r-- | third_party/libwebrtc/modules/rtp_rtcp/source/rtp_packetizer_av1.cc | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/rtp_rtcp/source/rtp_packetizer_av1.cc b/third_party/libwebrtc/modules/rtp_rtcp/source/rtp_packetizer_av1.cc new file mode 100644 index 0000000000..95dbaf364c --- /dev/null +++ b/third_party/libwebrtc/modules/rtp_rtcp/source/rtp_packetizer_av1.cc @@ -0,0 +1,402 @@ +/* + * Copyright (c) 2019 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_packetizer_av1.h" + +#include <stddef.h> +#include <stdint.h> + +#include <algorithm> + +#include "api/array_view.h" +#include "api/video/video_frame_type.h" +#include "modules/rtp_rtcp/source/leb128.h" +#include "modules/rtp_rtcp/source/rtp_packet_to_send.h" +#include "rtc_base/byte_buffer.h" +#include "rtc_base/checks.h" +#include "rtc_base/logging.h" + +namespace webrtc { +namespace { +constexpr int kAggregationHeaderSize = 1; +// when there are 3 or less OBU (fragments) in a packet, size of the last one +// can be omited. +constexpr int kMaxNumObusToOmitSize = 3; +constexpr uint8_t kObuSizePresentBit = 0b0'0000'010; +constexpr int kObuTypeSequenceHeader = 1; +constexpr int kObuTypeTemporalDelimiter = 2; +constexpr int kObuTypeTileList = 8; +constexpr int kObuTypePadding = 15; + +bool ObuHasExtension(uint8_t obu_header) { + return obu_header & 0b0'0000'100; +} + +bool ObuHasSize(uint8_t obu_header) { + return obu_header & kObuSizePresentBit; +} + +int ObuType(uint8_t obu_header) { + return (obu_header & 0b0'1111'000) >> 3; +} + +// Given `remaining_bytes` free bytes left in a packet, returns max size of an +// OBU fragment that can fit into the packet. +// i.e. MaxFragmentSize + Leb128Size(MaxFragmentSize) <= remaining_bytes. +int MaxFragmentSize(int remaining_bytes) { + if (remaining_bytes <= 1) { + return 0; + } + for (int i = 1;; ++i) { + if (remaining_bytes < (1 << 7 * i) + i) { + return remaining_bytes - i; + } + } +} + +} // namespace + +RtpPacketizerAv1::RtpPacketizerAv1(rtc::ArrayView<const uint8_t> payload, + RtpPacketizer::PayloadSizeLimits limits, + VideoFrameType frame_type, + bool is_last_frame_in_picture) + : frame_type_(frame_type), + obus_(ParseObus(payload)), + packets_(Packetize(obus_, limits)), + is_last_frame_in_picture_(is_last_frame_in_picture) {} + +std::vector<RtpPacketizerAv1::Obu> RtpPacketizerAv1::ParseObus( + rtc::ArrayView<const uint8_t> payload) { + std::vector<Obu> result; + rtc::ByteBufferReader payload_reader( + reinterpret_cast<const char*>(payload.data()), payload.size()); + while (payload_reader.Length() > 0) { + Obu obu; + payload_reader.ReadUInt8(&obu.header); + obu.size = 1; + if (ObuHasExtension(obu.header)) { + if (payload_reader.Length() == 0) { + RTC_DLOG(LS_ERROR) << "Malformed AV1 input: expected extension_header, " + "no more bytes in the buffer. Offset: " + << (payload.size() - payload_reader.Length()); + return {}; + } + payload_reader.ReadUInt8(&obu.extension_header); + ++obu.size; + } + if (!ObuHasSize(obu.header)) { + obu.payload = rtc::MakeArrayView( + reinterpret_cast<const uint8_t*>(payload_reader.Data()), + payload_reader.Length()); + payload_reader.Consume(payload_reader.Length()); + } else { + uint64_t size = 0; + if (!payload_reader.ReadUVarint(&size) || + size > payload_reader.Length()) { + RTC_DLOG(LS_ERROR) << "Malformed AV1 input: declared size " << size + << " is larger than remaining buffer size " + << payload_reader.Length(); + return {}; + } + obu.payload = rtc::MakeArrayView( + reinterpret_cast<const uint8_t*>(payload_reader.Data()), size); + payload_reader.Consume(size); + } + obu.size += obu.payload.size(); + // Skip obus that shouldn't be transfered over rtp. + int obu_type = ObuType(obu.header); + if (obu_type != kObuTypeTemporalDelimiter && // + obu_type != kObuTypeTileList && // + obu_type != kObuTypePadding) { + result.push_back(obu); + } + } + return result; +} + +int RtpPacketizerAv1::AdditionalBytesForPreviousObuElement( + const Packet& packet) { + if (packet.packet_size == 0) { + // Packet is still empty => no last OBU element, no need to reserve space + // for it. + return 0; + } + if (packet.num_obu_elements > kMaxNumObusToOmitSize) { + // There is so many obu elements in the packet, all of them must be + // prepended with the length field. That imply space for the length of the + // last obu element is already reserved. + return 0; + } + // No space was reserved for length field of the last OBU element, but that + // element becoming non-last, so it now requires explicit length field. + // Calculate how many bytes are needed to store the length in leb128 format. + return Leb128Size(packet.last_obu_size); +} + +std::vector<RtpPacketizerAv1::Packet> RtpPacketizerAv1::Packetize( + rtc::ArrayView<const Obu> obus, + PayloadSizeLimits limits) { + std::vector<Packet> packets; + if (obus.empty()) { + return packets; + } + // Ignore certian edge cases where packets should be very small. They are + // inpractical but adds complexity to handle. + if (limits.max_payload_len - limits.last_packet_reduction_len < 3 || + limits.max_payload_len - limits.first_packet_reduction_len < 3) { + RTC_DLOG(LS_ERROR) << "Failed to packetize AV1 frame: requested packet " + "size is unreasonable small."; + return packets; + } + // Aggregation header is present in all packets. + limits.max_payload_len -= kAggregationHeaderSize; + + // Assemble packets. Push to current packet as much as it can hold before + // considering next one. That would normally cause uneven distribution across + // packets, specifically last one would be generally smaller. + packets.emplace_back(/*first_obu_index=*/0); + int packet_remaining_bytes = + limits.max_payload_len - limits.first_packet_reduction_len; + for (size_t obu_index = 0; obu_index < obus.size(); ++obu_index) { + const bool is_last_obu = obu_index == obus.size() - 1; + const Obu& obu = obus[obu_index]; + + // Putting `obu` into the last packet would make last obu element stored in + // that packet not last. All not last OBU elements must be prepend with the + // element length. AdditionalBytesForPreviousObuElement calculates how many + // bytes are needed to store that length. + int previous_obu_extra_size = + AdditionalBytesForPreviousObuElement(packets.back()); + int min_required_size = + packets.back().num_obu_elements >= kMaxNumObusToOmitSize ? 2 : 1; + if (packet_remaining_bytes < previous_obu_extra_size + min_required_size) { + // Start a new packet. + packets.emplace_back(/*first_obu_index=*/obu_index); + packet_remaining_bytes = limits.max_payload_len; + previous_obu_extra_size = 0; + } + Packet& packet = packets.back(); + // Start inserting current obu into the packet. + packet.packet_size += previous_obu_extra_size; + packet_remaining_bytes -= previous_obu_extra_size; + packet.num_obu_elements++; + + bool must_write_obu_element_size = + packet.num_obu_elements > kMaxNumObusToOmitSize; + // Can fit all of the obu into the packet? + int required_bytes = obu.size; + if (must_write_obu_element_size) { + required_bytes += Leb128Size(obu.size); + } + int available_bytes = packet_remaining_bytes; + if (is_last_obu) { + // If this packet would be the last packet, available size is smaller. + if (packets.size() == 1) { + available_bytes += limits.first_packet_reduction_len; + available_bytes -= limits.single_packet_reduction_len; + } else { + available_bytes -= limits.last_packet_reduction_len; + } + } + if (required_bytes <= available_bytes) { + // Insert the obu into the packet unfragmented. + packet.last_obu_size = obu.size; + packet.packet_size += required_bytes; + packet_remaining_bytes -= required_bytes; + continue; + } + + // Fragment the obu. + int max_first_fragment_size = must_write_obu_element_size + ? MaxFragmentSize(packet_remaining_bytes) + : packet_remaining_bytes; + // Because available_bytes might be different than + // packet_remaining_bytes it might happen that max_first_fragment_size >= + // obu.size. Also, since checks above verified `obu` should not be put + // completely into the `packet`, leave at least 1 byte for later packet. + int first_fragment_size = std::min(obu.size - 1, max_first_fragment_size); + if (first_fragment_size == 0) { + // Rather than writing 0-size element at the tail of the packet, + // 'uninsert' the `obu` from the `packet`. + packet.num_obu_elements--; + packet.packet_size -= previous_obu_extra_size; + } else { + packet.packet_size += first_fragment_size; + if (must_write_obu_element_size) { + packet.packet_size += Leb128Size(first_fragment_size); + } + packet.last_obu_size = first_fragment_size; + } + + // Add middle fragments that occupy all of the packet. + // These are easy because + // - one obu per packet imply no need to store the size of the obu. + // - this packets are nor the first nor the last packets of the frame, so + // packet capacity is always limits.max_payload_len. + int obu_offset; + for (obu_offset = first_fragment_size; + obu_offset + limits.max_payload_len < obu.size; + obu_offset += limits.max_payload_len) { + packets.emplace_back(/*first_obu_index=*/obu_index); + Packet& packet = packets.back(); + packet.num_obu_elements = 1; + packet.first_obu_offset = obu_offset; + int middle_fragment_size = limits.max_payload_len; + packet.last_obu_size = middle_fragment_size; + packet.packet_size = middle_fragment_size; + } + + // Add the last fragment of the obu. + int last_fragment_size = obu.size - obu_offset; + // Check for corner case where last fragment of the last obu is too large + // to fit into last packet, but may fully fit into semi-last packet. + if (is_last_obu && + last_fragment_size > + limits.max_payload_len - limits.last_packet_reduction_len) { + // Split last fragments into two. + RTC_DCHECK_GE(last_fragment_size, 2); + // Try to even packet sizes rather than payload sizes across the last + // two packets. + int semi_last_fragment_size = + (last_fragment_size + limits.last_packet_reduction_len) / 2; + // But leave at least one payload byte for the last packet to avoid + // weird scenarios where size of the fragment is zero and rtp payload has + // nothing except for an aggregation header. + if (semi_last_fragment_size >= last_fragment_size) { + semi_last_fragment_size = last_fragment_size - 1; + } + last_fragment_size -= semi_last_fragment_size; + + packets.emplace_back(/*first_obu_index=*/obu_index); + Packet& packet = packets.back(); + packet.num_obu_elements = 1; + packet.first_obu_offset = obu_offset; + packet.last_obu_size = semi_last_fragment_size; + packet.packet_size = semi_last_fragment_size; + obu_offset += semi_last_fragment_size; + } + packets.emplace_back(/*first_obu_index=*/obu_index); + Packet& last_packet = packets.back(); + last_packet.num_obu_elements = 1; + last_packet.first_obu_offset = obu_offset; + last_packet.last_obu_size = last_fragment_size; + last_packet.packet_size = last_fragment_size; + packet_remaining_bytes = limits.max_payload_len - last_fragment_size; + } + return packets; +} + +uint8_t RtpPacketizerAv1::AggregationHeader() const { + const Packet& packet = packets_[packet_index_]; + uint8_t aggregation_header = 0; + + // Set Z flag: first obu element is continuation of the previous OBU. + bool first_obu_element_is_fragment = packet.first_obu_offset > 0; + if (first_obu_element_is_fragment) + aggregation_header |= (1 << 7); + + // Set Y flag: last obu element will be continuated in the next packet. + int last_obu_offset = + packet.num_obu_elements == 1 ? packet.first_obu_offset : 0; + bool last_obu_is_fragment = + last_obu_offset + packet.last_obu_size < + obus_[packet.first_obu + packet.num_obu_elements - 1].size; + if (last_obu_is_fragment) + aggregation_header |= (1 << 6); + + // Set W field: number of obu elements in the packet (when not too large). + if (packet.num_obu_elements <= kMaxNumObusToOmitSize) + aggregation_header |= packet.num_obu_elements << 4; + + // Set N flag: beginning of a new coded video sequence. + // Encoder may produce key frame without a sequence header, thus double check + // incoming frame includes the sequence header. Since Temporal delimiter is + // already filtered out, sequence header should be the first obu when present. + if (frame_type_ == VideoFrameType::kVideoFrameKey && packet_index_ == 0 && + ObuType(obus_.front().header) == kObuTypeSequenceHeader) { + aggregation_header |= (1 << 3); + } + return aggregation_header; +} + +bool RtpPacketizerAv1::NextPacket(RtpPacketToSend* packet) { + if (packet_index_ >= packets_.size()) { + return false; + } + const Packet& next_packet = packets_[packet_index_]; + + RTC_DCHECK_GT(next_packet.num_obu_elements, 0); + RTC_DCHECK_LT(next_packet.first_obu_offset, + obus_[next_packet.first_obu].size); + RTC_DCHECK_LE( + next_packet.last_obu_size, + obus_[next_packet.first_obu + next_packet.num_obu_elements - 1].size); + + uint8_t* const rtp_payload = + packet->AllocatePayload(kAggregationHeaderSize + next_packet.packet_size); + uint8_t* write_at = rtp_payload; + + *write_at++ = AggregationHeader(); + + int obu_offset = next_packet.first_obu_offset; + // Store all OBU elements except the last one. + for (int i = 0; i < next_packet.num_obu_elements - 1; ++i) { + const Obu& obu = obus_[next_packet.first_obu + i]; + size_t fragment_size = obu.size - obu_offset; + write_at += WriteLeb128(fragment_size, write_at); + if (obu_offset == 0) { + *write_at++ = obu.header & ~kObuSizePresentBit; + } + if (obu_offset <= 1 && ObuHasExtension(obu.header)) { + *write_at++ = obu.extension_header; + } + int payload_offset = + std::max(0, obu_offset - (ObuHasExtension(obu.header) ? 2 : 1)); + size_t payload_size = obu.payload.size() - payload_offset; + if (!obu.payload.empty() && payload_size > 0) { + memcpy(write_at, obu.payload.data() + payload_offset, payload_size); + } + write_at += payload_size; + // All obus are stored from the beginning, except, may be, the first one. + obu_offset = 0; + } + // Store the last OBU element. + const Obu& last_obu = + obus_[next_packet.first_obu + next_packet.num_obu_elements - 1]; + int fragment_size = next_packet.last_obu_size; + RTC_DCHECK_GT(fragment_size, 0); + if (next_packet.num_obu_elements > kMaxNumObusToOmitSize) { + write_at += WriteLeb128(fragment_size, write_at); + } + if (obu_offset == 0 && fragment_size > 0) { + *write_at++ = last_obu.header & ~kObuSizePresentBit; + --fragment_size; + } + if (obu_offset <= 1 && ObuHasExtension(last_obu.header) && + fragment_size > 0) { + *write_at++ = last_obu.extension_header; + --fragment_size; + } + RTC_DCHECK_EQ(write_at - rtp_payload + fragment_size, + kAggregationHeaderSize + next_packet.packet_size); + int payload_offset = + std::max(0, obu_offset - (ObuHasExtension(last_obu.header) ? 2 : 1)); + memcpy(write_at, last_obu.payload.data() + payload_offset, fragment_size); + write_at += fragment_size; + + RTC_DCHECK_EQ(write_at - rtp_payload, + kAggregationHeaderSize + next_packet.packet_size); + + ++packet_index_; + bool is_last_packet_in_frame = packet_index_ == packets_.size(); + packet->SetMarker(is_last_packet_in_frame && is_last_frame_in_picture_); + return true; +} + +} // namespace webrtc |