webrtc stats: fix video remote-outbound-rtp timestamp

which had a 70 year offset (i.e. 2094 instead of 2024) which broke
the webrtc-internal stats graphs. A similar adjustment is done
for audio in audio/channel_receive.cc

BUG=webrtc:12529

Change-Id: I0ce43cc8b451185bc056cf9e54757ef22d006c99
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/347780
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Philipp Hancke <phancke@meta.com>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42114}
diff --git a/video/video_receive_stream2.cc b/video/video_receive_stream2.cc
index 6f63f76..f3a7c32 100644
--- a/video/video_receive_stream2.cc
+++ b/video/video_receive_stream2.cc
@@ -573,9 +573,10 @@
       rtp_video_stream_receiver_.GetSenderReportStats();
   if (rtcp_sr_stats) {
     stats.last_sender_report_timestamp_ms =
-        rtcp_sr_stats->last_arrival_timestamp.ToMs();
+        rtcp_sr_stats->last_arrival_timestamp.ToMs() -
+        rtc::kNtpJan1970Millisecs;
     stats.last_sender_report_remote_timestamp_ms =
-        rtcp_sr_stats->last_remote_timestamp.ToMs();
+        rtcp_sr_stats->last_remote_timestamp.ToMs() - rtc::kNtpJan1970Millisecs;
     stats.sender_reports_packets_sent = rtcp_sr_stats->packets_sent;
     stats.sender_reports_bytes_sent = rtcp_sr_stats->bytes_sent;
     stats.sender_reports_reports_count = rtcp_sr_stats->reports_count;