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0dc5ed19e2
The position tracker has two different position sources,
getPlaybackHeadPosition and getTimestamp. Whenever we switch
between these sources, we smooth out the position differences
over a period of one second.
This has two problems:
1. The smoothing duration is 1 sec regardless of the actual
position difference. So for small differences, assuming
the new timestamp is more correct, we needlessly keep
the tracker with a position offset for longer. For large
differences, the smoothing may result in an extremely
large speedup (up to 5x in theory, for a max allowed diff
of 5 seconds smoothed over a 1 second real time period).
The solution to this issue is to adjust the smoothing
period to the actual difference by using a maximum
speedup/slowdown set to 10% at the moment. Smaller
differences are corrected faster and larger differences
are corrected in a slightly smoother way without speeding
up drastically. We still need an upper bound though (set
to 1 second difference) where plainly jumping to the correct
position is likely a better user experience than having a lenghty
smoothing.
2. The smoothing is only applied when switching between position
sources. That means any position drift or jump coming from the
same source is always taken as it is without any smoothing. This
is problematic for the getTimstamp-based position in particular
as it is only sampled every 10 seconds.
The solution to this problem is to entirely remove the condition
that smoothing only happens when switching between position
sources. Instead we can always check whether the position drift
compared to the last known position is more than the maximum allowed
speedup/slowdown of 10% and if so, start applying smoothing.
This helps to smooth out the position progress at the start of
playback and after resumption when we switch between the position
sources and both sources are not super reliable yet and it also
helps for unexpected jumps in the position of getTimestamp later
on during playback.
PiperOrigin-RevId: 755348271