0.97: Crash on some webms

[deil]

XnView: MP 0.97 64 bit, MP 0.97.1 64 bit
OS: Windows 10 Pro 2004 64bit

Effect: Program silently crashes, no error messages. Sometimes it freezes for few seconds before the crash.

XnviewMP crashes when opening folder with some specific webm files. It starts to build preview thumbnails, and when it gets to problematic files, it crashes.
This behavior started with 0.97 version, it never crashed on these files in any previous version. For example 0.96.5 (last version before 0.97) worked fine.

I have 2 such webms, one is in attached files, the other is too big, so uploaded it to mega:
https://mega.nz/file/qPRwxbYL#X01ZG5sIc ... z6jEllk-2Q
I guess the problem might be with the video codec used in them.

To reproduce:
1. Put problematic webms in some folder.
2. Open this folder

Actual behaviour (bug): XnviewMP crashes when trying to build preview thumbnail.

Expected behaviour: No crash, preview is successfully rendered for these files.

[xnview]

The crash occurs in QtAV (based on FFMPEG), i'try to contact them