Device-verified on iPhone 17 Pro (iOS 26.5.1). Ships with AetherEngine 4.9.1.
New
- Subtitles in Picture in Picture. Text subtitles now render inside the PiP window (and on AirPlay / external displays) via native WebVTT renditions served by the engine, and they keep working after seeking. Fullscreen playback keeps Sodalite's own styled subtitle overlay; the native rendition engages only in PiP, so subtitles never double up.
Improved
- Instant subtitles. Embedded text subtitles turn on instantly, even on remote or slow servers: the engine now harvests subtitle data from the stream it is already reading instead of opening a second connection.
- Smoother seeking. Jumping back into already-watched content is instant (the engine keeps recently produced segments resident), audio stays in sync after rewinding to the beginning, and seeks that previously interrupted subtitles no longer do.
Under the hood (AetherEngine 4.9.0/4.9.1)
- Producer restarts now continue the fMP4 media timeline instead of restarting it at zero, which was the root cause behind PiP subtitle loss on seeks and matches the failure signature investigated in AetherEngine#93.
- Teardown-partial segments are discarded instead of cached (fixes an A/V desync after rewinding).
- Byte-budgeted segment retention (2 GiB, clamped to available disk) makes backward seeks restart-free.
- Full release notes: https://github.com/superuser404notfound/AetherEngine/releases/tag/4.9.0