Returning to the foreground before the background-audio stream had started
playing handed the frontend 0.0s, so the video reloaded at StartTimeTicks=0 —
the episode restarted from the beginning — and the stop report that followed
wrote that zero to Jellyfin as the resume point. Caught on device: locked at
18.4s, unlocked 3.5s later with ExoPlayer still IDLE.
The base that turns a handoff's relative timeline into the episode's is applied
once at the native tick boundary (DR-159), so before the first tick nothing has
applied it. The same blind spot covers webview-rendered media, where nothing is
loaded into the native backend at all and its position is a permanent 0 — which
is why 14 of 14 stop reports in a 35-minute trace were zeroes, one landing 40s
after the frontend had correctly reported 15:22 for the same episode.
- absolute_position(): the maximum of the backend's reading, the last position
webview media reported, and the handoff base. Exact rather than heuristic —
at most one term is ever meaningful, and the base is a floor the stream
cannot physically be behind. duration() gains the same fallback.
- Withhold zero-position stop reports. A zero is never information, and
Jellyfin stores the reported position as the resume point, so sending one
only ever destroys a real one.
- Report progress from the controller's own position ticks, through the 30s
throttler it already shared with the native audio path.
/Sessions/Playing/Progress was previously requested zero times in 35 minutes.
- Report a finished audio-only episode stopped at its runtime before advancing,
so Jellyfin's 90% rule marks it played. Nothing else can: the webview is
suspended and its <video> was torn down at the handoff.
- Split the handoff by source — a downloaded file takes no base and a real
seek, a stream keeps its StartTimeTicks base and no seek — and stop routing a
downloaded handoff's absolute seek through the stream rebuild, which refuses
a non-remote source outright.
Reports go through a PlaybackReportSink, which also collapses three copies of
spawn-a-task-and-hope into one and is what let each of these be written as a
failing test first.
TRACES: UR-005, UR-025, UR-040, UR-071 | DR-178, DR-179, DR-180 |
UT-176, UT-177, UT-178, UT-179, UT-180, UT-181
dtourolle
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