Raspberry Pi 4B not reaching 4K 60FPS when playing HEVC HDR movie (9.97.1) (fresh install)

  • Problem:

    Inconsistent framerate

    Logs:

    Untitled - Pastebin

    Started up Kodi and then played movie directly from WD external hard drive (NTFS) for 10 minutes.

    System:

    Raspberry Pi 4B 8GB

    Samsung MicroSD card (32GB)

    Notes:

    • Framerate sometimes reached 60 FPS for a few seconds but it mostly stays at around 45 to 55 FPS sometimes dropping to as low as 25 FPS.
    • Tested with a fresh install: LibreELEC-RPi4.arm-9.97.1.img.gz
    • Tested the same movie file playing it from the sd card and it had similar performance.
    • CPU stays at about 60%.
    • Tested two other videos (see below) and it doesn't seem to matter if it's HDR or not.

    Config:

    over_voltage=6

    arm_freq=2147

    gpu_freq=750

    hdmi_enable_4kp60=1

    Settings:

    Display:

    3840x2160

    60

    Every resolution whitelisted

    Audio:

    ALSA: vc4-HDMI-0 (vc4hdmi0), HEC HISENSE on HDMI

    Audio passthrough disabled (tested with it enabled and it made no discernable difference)

    Video encoding information:

    Untitled - Pastebin

    Further testing with samples:

    Notes:

    Videos:

    • HEVC 10-bit 59.940fps (Korean ATSC 3.0 satellite TV capture sample)
    • HDR10 HEVC 59.940 (in mov, hdmkv's iPhone 11 Pro Max raw 4K footage using 4K HDR Video Recorder app)

    Is this a current limitation of LibreELEC with the raspberry pi?

    Update:

    Tested booting from NVMe drive and with LibreELEC 10.0.0, same framerate.

    Edited 2 times, last by Morawake (August 28, 2021 at 10:57 PM).