main.py wires up PlayerWidget with transport controls (play/pause,
frame-step buttons + ,/. shortcuts, seek slider), mute toggle, mark
video/audio buttons, live offset readout with manual override, and an
async export flow (QThread worker so ffmpeg doesn't block the UI) that
surfaces ffmpeg's stderr log without treating stream-copy warnings as
failures.
Verified two ways, not just by reading the code: a headless smoke test
that drives the real MainWindow/ExportWorker classes through a full
mark -> offset -> export cycle on the synthetic fixture, and a live
run (actual process, real X11 window, xdotool + import screenshot)
confirming the embedded mpv surface actually renders video inside the
Qt window rather than staying blank.
ThePendulum
660275bf02