* Disable audio loss proxying.
Added a config which is off by default.
With audio NACKs, that is the preferred repair mechanism.
With RED, repair is built in via packet redundancy to recover from
isolated losses.
So, proxying is not required. But, leaving it in there with a config
that is disabled by default.
* fix test
- Had arguments reversed.
- Also, cannot take away reference layer from state as a new layer
as reference could have a time stamp that is widely different from
expected. So, put that back.
* Move caching of publisher sender report to subscriber side.
Please see inline for descriptive comments on why. Basically,
pause/unpause using replaceTrack(null)/replaceTrack(actualTrack) can
cause time stamp in sender report sent to subscribers jump ahead.
This prevents that.
With the caching on subscriber side, cleaning up the caching on
publisher side.
* fix compile, test still failing, need to debug
* skip reference TS for testing
* Prevent large spikes in propagation delay
A few tweaks
- Large spike in propagation delay due to congested channel results in
long term estimate getting high value. Ignore outliers in long term
estimate.
- Introduce a new field for adjusted arrival time as adjusting the
arrival time in place meant it got applied again across the relay and
that caused different propagation delay on remote nodes.
- Reset path change counters as long as there is any sample that is not
higher than the multiple of long term. There was a case of
o Sample with high value that triggered path change start.
o Then some samples with high enough delta, but did not meet the
criteria for increasing counter further.
o Some time later, another sample met the threshold and that triggered
a path change re-init.
* do not adapt to large delta
* Tweak adaptation to increase in propagation delay.
A couple of issues
- RTCP Sender Reports rate will vary based on underying track bitrate.
(at least in theory, not all entities will do it though, for example
SFU does standard rate of one per three seconds irrespective of track
bit rate). So, adapt the long term estimate of propagation delay delta
based on spacing of reports.
- Re-init of propagation delay to adapt to path change was taking the
last value before the switch. But, that one value could have been an
outlier and accepting it is not great. So, adapt spike time
propagation delay in a smoother fashion to ensure that all values
during spike contribute to the final value.
* clean up
On migration, when subscription moved from remote -> local,
transceiver caching was racing. Although a very small possibility,
it could happen like so
1. down track close
2. down track close callback fires go routine to close subscribed track
3. subscribed track close handler in subscription manager tries to
reconcile
4. reconcile adds subscribed track again
5. cannot find cached transceiver as caching happens after down track
close finishes in stap 1 above. Although there are a couple of
gortouine jumps (step 2 fires a goroutine to close subscribed track
and step 4 will reconcile in a goroutine too), it is theoretically
possible that the step 1 has not finished and hence transceiver is
not cached.
Fix is to move caching to before closing subscribed track.
- When audio is muted, server injects silence frames which moves the
time stamp forward and adjusts offset. That cannot be used against
publisher side sender report. Use a pinned version.
- Ignore small changes to propagation delay even while checking for
sharp increase. That is spamming a lot for small changes, i.e.
existing delta is 100 micro seconds or so and the new one is 300 micro
seconds. Also rename to `longTerm` from `smoothed` as it is a slow
varying long term estimate of propagation delay delta. And slow down
that adaptation more.
* Forward publisher sender report.
Publisher side RTCP sernfer report is rebased to SFU time base
and used to send sender rerport to subscriber.
Will wait to merge till previous versions are out as this will require a
bunch of testing.
* - Add rebased report drift
- update protocol dep
- fix path change check, it has to check against delta of propagation
delay and not propagation delay as the two side clocks could be way
off.
* Use start time stamp to calculate down stream sender report.
With first packet time adjustment, using the first time stamp is more
accurate.
This still suffers if the up stream clock rate changes (happens in cases
like noise suppression which is not well understood). Will be looking at
pass through of sender report from publisher to subscriber.
* similar log strings
* avoid early sender reports
* log messages
* Reduce first packet adjustment threshold to 15 seconds
* Support XR request/response for rtt calculation
* Update pkg/sfu/downtrack.go
Co-authored-by: David Zhao <dz@livekit.io>
---------
Co-authored-by: David Zhao <dz@livekit.io>
* Buffer size config for video and audio.
There was only one buffer size in config.
In upstream, config value was used for video.
Audio used a hard coded value of 200 packets.
But, in the down stream sequencer, the config value was used for both
video and audio. So, if video was set up for high bit rate (deep
buffers), audio sequencer ended up using a lot of memory too in
sequencer.
Split config to be able to control that and also not hard code audio.
Another optimisation here would be to not instantiate sequencer unkess
NACK is negotiated.
* deprecate packet_buffer_size
* Reduce heap for dependency descriptor in forwarding path.
Marshaled dependency descriptor is held in sequencer adding heap objcts.
Store DD bytes in sequencer to avoid heap usage.
Also, accomodating over sized objects via storing in slice and using it
in case the bytes do not fit in the internal array.
NOTE: Marshal DD still does a make([]byte...), but I think it should be
on the stack given the short use of it. Have to verify.
* fix test and also add cases for oversized codec/dd bytes
* Remove some logs.
Also, changing Errorw -> Warnw in a bunch of places.
Going to move towards using `Errorw` for cases where a functionally
unexpected condition happens, i.e by design a condition should not
happen yet it triggered kind of scenarios.
* log error
Raja Subramanian