Probed all 97 movies. 28 are wmapro 48 kHz 6-channel 5.1 -- ADV.wmv and every S*.wmv story cutscene; the other 69 are wmav2 48 kHz stereo, every RT*.wmv and hokyu_*.wmv. The split is cinematics vs in-mission radio chatter. Both movies the menu milestone needs, ADV.wmv (the boot/attract intro) and S00A.wmv (the new-game intro), are in the SURROUND group. Why it matters: one ffmpeg command over dat/movie/ produces two different kinds of result and records neither. The 69 stereo files pass through unchanged; the 28 surround files get downmixed 5.1 -> stereo by ffmpeg's DEFAULT matrix, folding centre-channel dialogue into L/R at a weighting nobody chose and which is not stable across ffmpeg versions. That is a content decision inherited by accident, so it should be stated explicitly and recorded beside the command. Credit where due: found by the human while checking a transcode, verified independently here and widened from one file to the whole disc. Two METHOD entries from the same episode, both about measurement rather than format: don't probe a file another process is still writing (a half-written transcode reported 33 s against a 137 s source, no error, nearly a filed bug), and a difference-signal RMS is meaningless before cross-correlation alignment (-34.2 dB against a -25.3 dB source looks like failure and is inconclusive).