https://bugs.kde.org/show_bug.cgi?id=523042
Bug ID: 523042
Summary: Dragon Player fails to play AV1 encoded videos and
crashes on GPUs without native AV1 hardware decoding
Classification: Applications
Product: dragonplayer
Version First 26.04.3
Reported In:
Platform: Fedora RPMs
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: general
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected], [email protected]
Target Milestone: ---
Created attachment 194288
--> https://bugs.kde.org/attachment.cgi?id=194288&action=edit
log
When attempting to play any video file encoded with the AV1 codec using Dragon
Player on Fedora 44 (KDE Plasma 6), the player completely fails to render the
video stream.
The underlying issue lies within the qt6-qtmultimedia FFmpeg backend. The
pipeline strictly attempts to initialize hardware acceleration formats (such as
VA-API or Vulkan). When the GPU architecture lacks native silicon-level support
for AV1 decoding (e.g., AMD Radeon Vega 8), the initialization fails. Instead
of gracefully falling back to CPU-bound software decoding (using
libdav1d/dav1d), the Qt6 Multimedia pipeline terminates abruptly, throwing a
"Failed to get pixel format" error.
Other multimedia frameworks on the exact same system (such as GStreamer via
gst-play-1.0) handle the fallback correctly and play the same AV1 files
seamlessly. Forced software environment variables are also completely ignored
by the player.
Reproducible: Always
Steps to Reproduce:
1. Boot Fedora 44 KDE on a machine lacking native AV1 hardware decoding (e.g.,
AMD Ryzen 5 3500U with Vega 8 Graphics).
2. Open Dragon Player.
3. Attempt to play any local AV1 encoded video file (e.g., an MP4 or MKV
container with an av01 video stream).
Actual Results:
The player's window remains blank/black, playback fails instantly, and terminal
execution logs show critical hardware acceleration initialization failures
followed by Failed to get pixel format and Get current frame error.
Expected Results:
If hardware acceleration (VA-API/Vulkan) is unsupported by the platform for a
specific codec, the player/Qt6 Multimedia framework should automatically fall
back to software decoding via CPU, allowing seamless video playback.
Additional Information:
System Configuration:
CPU/GPU: AMD Ryzen 5 3500U with Radeon Vega 8 Graphics (Raven Ridge / radeonsi
driver)
Relevant packages installed: phonon-qt6-backend-vlc-0.12.0-8.fc44.x86_64,
gstreamer1-plugin-dav1d-0.15.0-1.fc44.x86_64
Attempted Workarounds (All ignored/failed):
QT_MULTIMEDIA_FORCE_SOFTWARE=1 -> Still attempts VA-API.
LIBVA_DRIVER_NAME=none -> Attempts Vulkan and fails: Device does not support
the VK_KHR_video_decode_queue extension!.
QT_AVPLAY_HWACCEL=none -> Still attempts VA-API.
Critical Terminal Log Lines:
qt.multimedia.ffmpeg: Using Qt multimedia with FFmpeg version 8.1.2 GPL version
3 or later
Stream #0:0[0x1](und): Video: av1 (libdav1d) (Main) (av01 / 0x31307661)
[av1 @ 0x55a54c4c3d40] No support for codec av1 profile 0.
[av1 @ 0x55a54c4c3d40] Failed setup for format vaapi: hwaccel initialisation
returned error.
[av1 @ 0x55a54c4c3d40] Your platform doesn't support hardware accelerated AV1
decoding.
[av1 @ 0x55a54c4c3d40] Failed to get pixel format.
[av1 @ 0x55a54c4c3d40] Get current frame error
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