[NG Nightly | Dune Homatics R 4K Plus] Blank screen on small MKV/MP4 (H.264/SDR), UHD Blu-ray DV plays fine

I’m using CoreELEC (official) 21.2-Omega nightly (2025-09-08) on a Dune Homatics R 4K Plus (Amlogic S905X4).

  • Large UHD Blu-ray rips (e.g. Blade Runner 2049 ~80GB, Dolby Vision + TrueHD Atmos) play perfectly.

  • But small MKV/MP4/M2TS files (<200 MB, typically SDR/H.264) result in a blank screen (no video).

    • Audio plays ( keeps showing loader in UI)

    • Subtitles load.

    • Player threads keep running.

  • When I check the logs, I see the Amlogic hardware decoder returning errors and repeated resets.

  • The display also tries to switch resolution/refresh rate, which seems to trigger the black screen.
    Full log attached:
    Log file

CVideoPlayerVideo - video decoder returned error
CAMLCodec::SetSpeed, speed(0)
CAMLCodec::SetSpeed, speed(1000)
OutputPicture - timeout waiting for buffer

Display resolution ADJUST : 3840x2160 @ 23.98

hdrType: dolbyvision(none), force mode switch: true

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