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Refactor FEC code to use COW buffers

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This refactoring helps to reduce unnecessary memcpy calls on the receive
side.

This CL is the first stage of refactoring: it only replaces
|uint8 data[IP_PACKET_SIZE]| with |rtc::CopyOnWriteBuffer data| and does
necessary changes.

A follow-up CL will remove length field of the Packet class.


Bug: webrtc:10750
Change-Id: Ie233da83ff33f6370f511955e4c65d59522389a7
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/144881
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28539}
This commit is contained in:
Ilya Nikolaevskiy
2019-07-10 11:28:04 +02:00
committed by Commit Bot
parent 1300ce12e8
commit 7325bc3917
24 changed files with 199 additions and 159 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
modules/rtp_rtcp/source/ulpfec_receiver_impl.cc
View File

@ -130,26 +130,28 @@ int32_t UlpfecReceiverImpl::AddReceivedRedPacket(
++packet_counter_.num_fec_packets;
// everything behind the RED header
memcpy(received_packet->pkt->data,
incoming_rtp_packet + header.headerLength + red_header_length,
payload_data_length - red_header_length);
received_packet->pkt->data.SetData(
incoming_rtp_packet + header.headerLength + red_header_length,
payload_data_length - red_header_length);
received_packet->pkt->length = payload_data_length - red_header_length;
received_packet->ssrc =
ByteReader<uint32_t>::ReadBigEndian(&incoming_rtp_packet[8]);
} else {
received_packet->pkt->data.SetSize(header.headerLength +
payload_data_length - red_header_length);
// Copy RTP header.
memcpy(received_packet->pkt->data, incoming_rtp_packet,
memcpy(received_packet->pkt->data.data(), incoming_rtp_packet,
header.headerLength);
// Set payload type.
received_packet->pkt->data[1] &= 0x80; // Reset RED payload type.
received_packet->pkt->data[1] += payload_type; // Set media payload type.
// Copy payload data.
memcpy(received_packet->pkt->data + header.headerLength,
incoming_rtp_packet + header.headerLength + red_header_length,
payload_data_length - red_header_length);
if (payload_data_length > red_header_length) {
memcpy(received_packet->pkt->data.data() + header.headerLength,
incoming_rtp_packet + header.headerLength + red_header_length,
payload_data_length - red_header_length);
}
received_packet->pkt->length =
header.headerLength + payload_data_length - red_header_length;
}
@ -182,16 +184,18 @@ int32_t UlpfecReceiverImpl::ProcessReceivedFec() {
if (!received_packet->is_fec) {
ForwardErrorCorrection::Packet* packet = received_packet->pkt;
crit_sect_.Leave();
recovered_packet_callback_->OnRecoveredPacket(packet->data,
recovered_packet_callback_->OnRecoveredPacket(packet->data.data(),
packet->length);
crit_sect_.Enter();
// Create a packet with the buffer to modify it.
RtpPacketReceived rtp_packet;
// TODO(ilnik): move extension nullifying out of RtpPacket, so there's no
// need to create one here, and avoid two memcpy calls below.
rtp_packet.Parse(packet->data, packet->length); // Does memcopy.
rtp_packet.Parse(packet->data);
rtp_packet.IdentifyExtensions(extensions_);
rtp_packet.CopyAndZeroMutableExtensions( // Does memcopy.
rtc::MakeArrayView(packet->data, packet->length));
// Reset buffer reference, so zeroing would work on a buffer with a
// single reference.
packet->data = rtc::CopyOnWriteBuffer(0);
rtp_packet.ZeroMutableExtensions();
packet->data = rtp_packet.Buffer();
}
fec_->DecodeFec(*received_packet, &recovered_packets_);
}
@ -208,7 +212,8 @@ int32_t UlpfecReceiverImpl::ProcessReceivedFec() {
// header, OnRecoveredPacket will recurse back here.
recovered_packet->returned = true;
crit_sect_.Leave();
recovered_packet_callback_->OnRecoveredPacket(packet->data, packet->length);
recovered_packet_callback_->OnRecoveredPacket(packet->data.data(),
packet->length);
crit_sect_.Enter();
}