SUMMARY
Dragon tries to use a hardware AV1 decoder, can't find it since I don't have it and decides to display nothing instead.

STEPS TO REPRODUCE
1. Download and open this<https://cloud.labor.ge/s/Kn5ofCEEjtbbqS3> file

OBSERVED RESULT
Nothing is displayed.

EXPECTED RESULT
Video playing normally.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.1
Kernel Version: 6.17.9-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 4 × Intel® Core™ i5-6300U CPU @ 2.40GHz
Memory: 8 GiB of RAM (7.6 GiB usable)
Graphics Processor: Mesa Intel® HD Graphics 520

ADDITIONAL INFORMATION
logs:
[gtk@gtk-lapputer Videos]ɱ LC_ALL=C dragon 'Minessota, St. Paul church ICE protester sit-in [HkwW_dlcThA].webm'
Detected locale "C" with character encoding "ANSI_X3.4-1968", which is not UTF-8.
Qt depends on a UTF-8 locale, and has switched to "C.UTF-8" instead.
If this causes problems, reconfigure your locale. See the locale(1) manual
for more information.
Renderer: "Mesa Intel(R) HD Graphics 520 (SKL GT2)"
qt.multimedia.ffmpeg: Using Qt multimedia with FFmpeg version n8.0.1 GPL version 3 or later
Failed to open VDPAU backend libvdpau_nvidia.so: cannot open shared object file: No such file or directory
qrc:/qt/qml/org/kde/dragon/PlayerPage.qml:408:5: QML Shortcut: Shortcut: Only binding to one of multiple key bindings associated with 70. Use 'sequences: [ <key> ]' to bind to all of them.
Input #0, matroska,webm, from '/home/gtk/Videos/Minessota, St. Paul church ICE protester sit-in [HkwW_dlcThA].webm':
  Metadata:
    COMPATIBLE_BRANDS: iso6av01mp41
    MAJOR_BRAND     : dash
    MINOR_VERSION   : 0
    ENCODER         : Lavf62.3.100
  Duration: 00:02:51.49, start: -0.007000, bitrate: 1131 kb/s
  Stream #0:0: Video: av1 (libdav1d) (Main), yuv420p(tv, bt709), 1920x1080, SAR 1:1 DAR 16:9, 29.97 fps, 29.97 tbr, 1k tbn, start 0.849000 (default)
    Metadata:
      HANDLER_NAME    : ISO Media file produced by Google Inc.
      VENDOR_ID       : [0][0][0][0]
      DURATION        : 00:02:51.486000000
  Stream #0:1(eng): Audio: opus, 48000 Hz, stereo, fltp, start -0.007000 (default)
    Metadata:
      DURATION        : 00:02:51.480000000
[opus @ 0x5652b2733280] Could not update timestamps for skipped samples.
[av1 @ 0x5652b272ee40] No support for codec av1 profile 0.
[av1 @ 0x5652b272ee40] Failed setup for format vaapi: hwaccel initialisation returned error.
[av1 @ 0x5652b272ee40] Your platform doesn't support hardware accelerated AV1 decoding.
[av1 @ 0x5652b272ee40] Failed to get pixel format.
[av1 @ 0x5652b272ee40] Get current frame error
[av1 @ 0x5652b272ee40] No support for codec av1 profile 0.
[av1 @ 0x5652b272ee40] Failed setup for format vaapi: hwaccel initialisation returned error.
[av1 @ 0x5652b272ee40] Your platform doesn't support hardware accelerated AV1 decoding.
[av1 @ 0x5652b272ee40] Failed to get pixel format.
[av1 @ 0x5652b272ee40] Get current frame error
[av1 @ 0x5652b272ee40] No support for codec av1 profile 0.
[av1 @ 0x5652b272ee40] Failed setup for format vaapi: hwaccel initialisation returned error.
[av1 @ 0x5652b272ee40] Your platform doesn't support hardware accelerated AV1 decoding.
[av1 @ 0x5652b272ee40] Failed to get pixel format.
[av1 @ 0x5652b272ee40] Get current frame error
[av1 @ 0x5652b272ee40] No support for codec av1 profile 0.
[av1 @ 0x5652b272ee40] Failed setup for format vaapi: hwaccel initialisation returned error.
[av1 @ 0x5652b272ee40] Your platform doesn't support hardware accelerated AV1 decoding.
[av1 @ 0x5652b272ee40] Failed to get pixel format.
[av1 @ 0x5652b272ee40] Get current frame error
...