Unwrap picture ids in the RtpFrameReferencerFinder.

webrtc/modules/video_coding/sequence_number_util.h

Index: webrtc/modules/video_coding/sequence_number_util.h
diff --git a/webrtc/modules/video_coding/sequence_number_util.h b/webrtc/modules/video_coding/sequence_number_util.h
index 008e5f1623681145f7714c4ea4cec54b09f2dfb6..d65be6c0ad987bc314d12f0d3411478c8c13420d 100644
--- a/webrtc/modules/video_coding/sequence_number_util.h
+++ b/webrtc/modules/video_coding/sequence_number_util.h
@@ -91,7 +91,12 @@ class SeqNumUnwrapper {
       "Type unwrapped must be an unsigned integer smaller than uint64_t.");
 
  public:
-  SeqNumUnwrapper() : last_unwrapped_(0) {}
+  // The reason we use this as the default start value is because it the
+  // closest power of 10 to 2^63, and the reason we want to have a number
+  // that is a power of 10 is because it is more human readable.

[stefan-webrtc, 2017/09/01 07:25:09]

Comment also on why we need a large start value, and why as large as 2^63?

[philipel, 2017/09/01 08:55:46]

Done.

+  static constexpr uint64_t kDefaultStartValue = 10000000000000000000UL;
+
+  SeqNumUnwrapper() : last_unwrapped_(kDefaultStartValue) {}
   explicit SeqNumUnwrapper(uint64_t start_at) : last_unwrapped_(start_at) {}
 
   uint64_t Unwrap(T value) {