admin/webrtc_m130
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Avoid creating receiver_time outliers in the VideoAnalyzer.

Browse Source 
Prior to this change, the receiver_time metric had huge outliers
whenever FlexFEC was enabled. This was due to a measurement problem,
where the time of the incoming packet was incorrectly set to zero.
This happened for packets that were lost in transit, but recovered
through FEC.

This CL fixes this problem by simply not recording samples where the
incoming packet time is undefined. The CL also removes the possibility
of timestamp collisions in the data structures.

TESTED=Ran './webrtc_perf_tests --gtest_filter="*ForemanCifPlr5H264Flexfec*" | grep receiver_time' locally 10 times, without experiencing any outliers.
BUG=webrtc:5654

Review-Url: https://codereview.webrtc.org/2596793002
Cr-Commit-Position: refs/heads/master@{#15735}
This commit is contained in:
brandtr 2016-12-21 02:54:35 -08:00 committed by Commit bot
parent f9891d51f8
commit 504b95eff8
1 changed files with 36 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
webrtc/video/video_quality_test.cc
View File

@ -113,6 +113,10 @@ class VideoStreamFactory
std::vector<webrtc::VideoStream> streams_;
};
bool IsFlexfec(int payload_type) {
return payload_type == webrtc::VideoQualityTest::kFlexfecPayloadType;
}
} // namespace
namespace webrtc {
@ -215,7 +219,10 @@ class VideoAnalyzer : public PacketReceiver,
RtpUtility::RtpHeaderParser parser(packet, length);
RTPHeader header;
parser.Parse(&header);
{
if (!IsFlexfec(header.payloadType)) {
// Ignore FlexFEC timestamps, to avoid collisions with media timestamps.
// (FlexFEC and media are sent on different SSRCs, which have different
// timestamps spaces.)
rtc::CritScope lock(&crit_);
int64_t timestamp =
wrap_handler_.Unwrap(header.timestamp - rtp_timestamp_delta_);
@ -260,13 +267,18 @@ class VideoAnalyzer : public PacketReceiver,
rtp_timestamp_delta_ = header.timestamp - *first_send_timestamp_;
first_send_timestamp_ = rtc::Optional<uint32_t>();
}
int64_t timestamp =
wrap_handler_.Unwrap(header.timestamp - rtp_timestamp_delta_);
send_times_[timestamp] = current_time;
if (!transport_->DiscardedLastPacket() &&
header.ssrc == ssrc_to_analyze_) {
encoded_frame_sizes_[timestamp] +=
length - (header.headerLength + header.paddingLength);
if (!IsFlexfec(header.payloadType)) {
// Ignore FlexFEC timestamps, to avoid collisions with media timestamps.
// (FlexFEC and media are sent on different SSRCs, which have different
// timestamps spaces.)
int64_t timestamp =
wrap_handler_.Unwrap(header.timestamp - rtp_timestamp_delta_);
send_times_[timestamp] = current_time;
if (!transport_->DiscardedLastPacket() &&
header.ssrc == ssrc_to_analyze_) {
encoded_frame_sizes_[timestamp] +=
length - (header.headerLength + header.paddingLength);
}
}
}
return result;
@ -666,8 +678,22 @@ class VideoAnalyzer : public PacketReceiver,
last_render_time_ = comparison.render_time_ms;
sender_time_.AddSample(comparison.send_time_ms - comparison.input_time_ms);
receiver_time_.AddSample(comparison.render_time_ms -
comparison.recv_time_ms);
if (comparison.recv_time_ms > 0) {
// If recv_time_ms == 0, this frame consisted of a packets which were all
// lost in the transport. Since we were able to render the frame, however,
// the dropped packets were recovered by FlexFEC. The FlexFEC recovery
// happens internally in Call, and we can therefore here not know which
// FEC packets that protected the lost media packets. Consequently, we
// were not able to record a meaningful recv_time_ms. We therefore skip
// this sample.
//
// The reasoning above does not hold for ULPFEC and RTX, as for those
// strategies the timestamp of the received packets is set to the
// timestamp of the protected/retransmitted media packet. I.e., then
// recv_time_ms != 0, even though the media packets were lost.
receiver_time_.AddSample(comparison.render_time_ms -
comparison.recv_time_ms);
}
end_to_end_.AddSample(comparison.render_time_ms - comparison.input_time_ms);
encoded_frame_size_.AddSample(comparison.encoded_frame_size);
}