fec: Skip traversal the list of recovered packets if possible
Do not traverse the list of recovered media packets
if none of them was recovered through FEC recovery procedure.
Bug: None
Change-Id: Ib3aa59c946919fab08f0e20fcf279b1b8032d0e3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/315320
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Auto-Submit: Andrei Volykhin <andrey.volykhin@lge.com>
Cr-Commit-Position: refs/heads/main@{#40546}
diff --git a/modules/rtp_rtcp/source/flexfec_receiver.cc b/modules/rtp_rtcp/source/flexfec_receiver.cc
index 9f30a72..7f2cc0c 100644
--- a/modules/rtp_rtcp/source/flexfec_receiver.cc
+++ b/modules/rtp_rtcp/source/flexfec_receiver.cc
@@ -149,7 +149,12 @@
RTC_DCHECK_RUN_ON(&sequence_checker_);
// Decode.
- erasure_code_->DecodeFec(received_packet, &recovered_packets_);
+ ForwardErrorCorrection::DecodeFecResult decode_result =
+ erasure_code_->DecodeFec(received_packet, &recovered_packets_);
+
+ if (decode_result.num_recovered_packets == 0) {
+ return;
+ }
// Return recovered packets through callback.
for (const auto& recovered_packet : recovered_packets_) {
diff --git a/modules/rtp_rtcp/source/forward_error_correction.cc b/modules/rtp_rtcp/source/forward_error_correction.cc
index ee99bb9..15a0801 100644
--- a/modules/rtp_rtcp/source/forward_error_correction.cc
+++ b/modules/rtp_rtcp/source/forward_error_correction.cc
@@ -665,8 +665,10 @@
return true;
}
-void ForwardErrorCorrection::AttemptRecovery(
+size_t ForwardErrorCorrection::AttemptRecovery(
RecoveredPacketList* recovered_packets) {
+ size_t num_recovered_packets = 0;
+
auto fec_packet_it = received_fec_packets_.begin();
while (fec_packet_it != received_fec_packets_.end()) {
// Search for each FEC packet's protected media packets.
@@ -683,6 +685,8 @@
continue;
}
+ ++num_recovered_packets;
+
auto* recovered_packet_ptr = recovered_packet.get();
// Add recovered packet to the list of recovered packets and update any
// FEC packets covering this packet with a pointer to the data.
@@ -708,6 +712,8 @@
fec_packet_it++;
}
}
+
+ return num_recovered_packets;
}
int ForwardErrorCorrection::NumCoveredPacketsMissing(
@@ -758,8 +764,9 @@
return (packet[8] << 24) + (packet[9] << 16) + (packet[10] << 8) + packet[11];
}
-void ForwardErrorCorrection::DecodeFec(const ReceivedPacket& received_packet,
- RecoveredPacketList* recovered_packets) {
+ForwardErrorCorrection::DecodeFecResult ForwardErrorCorrection::DecodeFec(
+ const ReceivedPacket& received_packet,
+ RecoveredPacketList* recovered_packets) {
RTC_DCHECK(recovered_packets);
const size_t max_media_packets = fec_header_reader_->MaxMediaPackets();
@@ -782,7 +789,10 @@
}
InsertPacket(received_packet, recovered_packets);
- AttemptRecovery(recovered_packets);
+
+ DecodeFecResult decode_result;
+ decode_result.num_recovered_packets = AttemptRecovery(recovered_packets);
+ return decode_result;
}
size_t ForwardErrorCorrection::MaxPacketOverhead() const {
diff --git a/modules/rtp_rtcp/source/forward_error_correction.h b/modules/rtp_rtcp/source/forward_error_correction.h
index ff6c459..84278a8 100644
--- a/modules/rtp_rtcp/source/forward_error_correction.h
+++ b/modules/rtp_rtcp/source/forward_error_correction.h
@@ -229,8 +229,13 @@
// list will be valid until the next call to
// DecodeFec().
//
- void DecodeFec(const ReceivedPacket& received_packet,
- RecoveredPacketList* recovered_packets);
+ struct DecodeFecResult {
+ // Number of recovered media packets using FEC.
+ size_t num_recovered_packets = 0;
+ };
+
+ DecodeFecResult DecodeFec(const ReceivedPacket& received_packet,
+ RecoveredPacketList* recovered_packets);
// Get the number of generated FEC packets, given the number of media packets
// and the protection factor.
@@ -302,7 +307,7 @@
// Attempt to recover missing packets, using the internally stored
// received FEC packets.
- void AttemptRecovery(RecoveredPacketList* recovered_packets);
+ size_t AttemptRecovery(RecoveredPacketList* recovered_packets);
// Initializes headers and payload before the XOR operation
// that recovers a packet.
diff --git a/modules/rtp_rtcp/source/ulpfec_receiver.cc b/modules/rtp_rtcp/source/ulpfec_receiver.cc
index 4452bdb..7f74a18 100644
--- a/modules/rtp_rtcp/source/ulpfec_receiver.cc
+++ b/modules/rtp_rtcp/source/ulpfec_receiver.cc
@@ -192,6 +192,7 @@
received_packets;
received_packets.swap(received_packets_);
RtpHeaderExtensionMap* last_recovered_extension_map = nullptr;
+ size_t num_recovered_packets = 0;
for (const auto& received_packet : received_packets) {
// Send received media packet to VCM.
@@ -217,11 +218,17 @@
// different set of the RTP header extensions and thus different byte
// representation than the original packet, That will corrupt
// FEC calculation.
- fec_->DecodeFec(*received_packet, &recovered_packets_);
+ ForwardErrorCorrection::DecodeFecResult decode_result =
+ fec_->DecodeFec(*received_packet, &recovered_packets_);
last_recovered_extension_map = &received_packet->extensions;
+ num_recovered_packets += decode_result.num_recovered_packets;
}
}
+ if (num_recovered_packets == 0) {
+ return;
+ }
+
// Send any recovered media packets to VCM.
for (const auto& recovered_packet : recovered_packets_) {
if (recovered_packet->returned) {
