commit 56b96ffe6a036d4b6ebb2f4eb9fadb009dbcf08d
author Alessio Bazzica <alessiob@webrtc.org> Tue Sep 20 09:16:16 2022
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Tue Sep 20 12:51:22 2022
tree 48f629cd3e3963b73cd6a580627fb429611aaeca
parent 54d9f056c64b50eaf5f12ae39e24d88ab6b9ccc3

Surface `local_capture_clock_offset` from `RtpSource`

- Propagating `RtpPacketInfo::local_capture_clock_offset`, an
  existing field that is related to the abs-capture-timestamp
  header extension field `estimated_capture_clock_offset`
- Propagated through `SourceTracker::SourceEntry`

Bug: webrtc:10739, b/246753278
Change-Id: I21d9841e4f3a35da5f8d7b31582898309421d524
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/275241
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38129}

api/rtp_packet_info.h

diff --git a/api/rtp_packet_info.h b/api/rtp_packet_info.h
index f9980a1c..bc8784c 100644
--- a/api/rtp_packet_info.h
+++ b/api/rtp_packet_info.h
@@ -17,6 +17,7 @@
 
 #include "absl/types/optional.h"
 #include "api/rtp_headers.h"
+#include "api/units/time_delta.h"
 #include "api/units/timestamp.h"
 #include "rtc_base/system/rtc_export.h"
 
@@ -92,11 +93,11 @@
     return *this;
   }
 
-  const absl::optional<int64_t>& local_capture_clock_offset() const {
+  const absl::optional<TimeDelta>& local_capture_clock_offset() const {
     return local_capture_clock_offset_;
   }
   RtpPacketInfo& set_local_capture_clock_offset(
-      const absl::optional<int64_t>& value) {
+      absl::optional<TimeDelta> value) {
     local_capture_clock_offset_ = value;
     return *this;
   }
@@ -117,16 +118,14 @@
 
   // Fields from the Absolute Capture Time header extension:
   // http://www.webrtc.org/experiments/rtp-hdrext/abs-capture-time
-  // To not be confused with `local_capture_clock_offset_`, the
-  // `estimated_capture_clock_offset` in `absolute_capture_time_` should
-  // represent the clock offset between a remote sender and the capturer, and
-  // thus equals to the corresponding values in the received RTP packets,
-  // subjected to possible interpolations.
   absl::optional<AbsoluteCaptureTime> absolute_capture_time_;
 
-  // Clock offset against capturer's clock. Should be derived from the estimated
-  // capture clock offset defined in the Absolute Capture Time header extension.
-  absl::optional<int64_t> local_capture_clock_offset_;
+  // Clock offset between the local clock and the capturer's clock.
+  // Do not confuse with `AbsoluteCaptureTime::estimated_capture_clock_offset`
+  // which instead represents the clock offset between a remote sender and the
+  // capturer. The following holds:
+  //   Capture's NTP Clock = Local NTP Clock + Local-Capture Clock Offset
+  absl::optional<TimeDelta> local_capture_clock_offset_;
 };
 
 bool operator==(const RtpPacketInfo& lhs, const RtpPacketInfo& rhs);