[Interest] Crash in QMediaPlayer due to missing codec

[Axel Spoerl]

Hi Philippe,

massive changes and improvements have been made in Qt 6 / QMultiMedia, logging and error handling included.
Since Qt 5.15 is EOL, it's maybe a good time to upgrade to Qt 6.

In your application code, you can use the errorString() methods to bring backend messages forward.
In addition you can set the environment variable QT_LOGGING_RULES="qt.multimedia.*=true" and inspect the logging output.

I am not sure for 5.15. But for Qt 6, you'll also get warnings about missing codecs this way.

Cheers
Axel


Confidential

________________________________
From: Interest <interest-bounces at qt-project.org> on behalf of maitai <maitai at virtual-winds.org>
Sent: Tuesday, 24 June 2025 18:33
To: Interest at qt-project.org <Interest at qt-project.org>
Subject: [Interest] Crash in QMediaPlayer due to missing codec

Hello,

I have a Windows user that crashes consistently when the application is trying to play a sound.

Application is built against qt5.15.19 (widget based), and we are using QMediaPlayer to play sounds (.wav files). The user is running Windows 10.

The message just before the crash is
DirectShowPlayerService::doRender: Unknown error 0x80040266.

After some googling, I asked the user to install the codecs that can be found here: https://codecguide.com/download_k-lite_codec_pack_basic.htm
and the issue was fixed.

Besides an obvious bug in QMediaPlayer, my question is: is there a way to detect that a codec is missing and avoid the crash by for instance not playing the sound, or to include the codecs in the distribution (which I am sure will cause some licensing issues) ?

Thanks
Philippe Lelong
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