1.2.1

October 2026. No API change and no change to the libraries; upgrading is a
version bump. Playback behaves as in 1.2.0: frame loss and CPU measured the
same on an Apple TV 4K.

Changed

• The demuxer's open and its read loop run as named steps, and the engine's
  support types live in their own files. Nothing a host can reach moved.
• Tests now cover stall and starvation recovery, the playback rate policy,
  audio renderer replacement, bounded downloads, failure detail and track
  naming, and external and ASS subtitle presentation.