No Picture Preview Video after upgrade Debian 9 to 10

Hello here,

We have upgraded all stuff this weekend.
Seafile CE to 7.0.3 and Debian 9 to 10 (all 64 bits).
Everything working fine exept the little picture Preview for videos.
In fact, we have upgraded first Seafile, everything worked perfectly.
I can read the video online, download, etc
After upgrade OS, we’ve lost this little feature.

Any idea ?!

Thank you in advance for your help.

Video preview is not added in 7.0.3 yet. As the third party tools for video preview is not stable, often causing high CPU load.

Thank you very much for the answer Daniel.