Do not send Sender Reports before any RTP has been sent - #461
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #461 +/- ##
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+ Coverage 81.29% 81.46% +0.16%
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Files 91 91
Lines 4683 4688 +5
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+ Hits 3807 3819 +12
+ Misses 696 693 -3
+ Partials 180 176 -4
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Thanks, I think this makes sense.
JoTurk
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Looks good, I agree with @mengelbart comments
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The sender report interceptor emitted an SR for every bound stream on each tick, including streams that had not written a single packet. For those the RTP timestamp was derived from a zero time.Time, so the report mapped "now" to a garbage timestamp (2269117121 at 90 kHz, 923864645 at 48 kHz). RFC 3550 6.4 says a source that has sent nothing sends an RR, which the receiver interceptor already does. Receivers that anchor RTCP-based timing on the first SR they see (for example OvenMediaEngine with RtcpBasedTimestamp) then have their anchor jump when the first real SR arrives a second later, and the stream can be stuck with a PTS that moved backwards by hours. Skip streams with no packets sent when generating reports. The two existing subtests that relied on an SR before any RTP are adjusted: "before any packet" now asserts nothing is written, and "inject ticker" writes one RTP packet before ticking.
Cover the transition directly: a tick before any RTP writes nothing, and the first tick after one RTP packet writes an SR whose RTPTime is that packet's timestamp.
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The sender report interceptor emitted an SR for every bound stream on each tick, including streams that had not written a single packet. For those the RTP timestamp was derived from a zero
time.Time, so the report mapped "now" to a garbage timestamp (2269117121 at 90 kHz, 923864645 at 48 kHz).RFC 3550 6.4says a source that has sent nothing sends an RR, which the receiver interceptor already does.Receivers that anchor RTCP-based timing on the first SR they see (for example
OvenMediaEnginewithRtcpBasedTimestamp) then have their anchor jump when the first real SR arrives a second later, and the stream can be stuck with a PTS that moved backwards by hours.Skip streams with no packets sent when generating reports. The two existing subtests that relied on an SR before any RTP are adjusted: "before any packet" now asserts nothing is written, and "inject ticker" writes one RTP packet before ticking.
This PR also adds a test specifically for this transition.