Converting .webm files to MP4

Ticket created as requested by vlc after email conversation

Original Email \

My team and myself have been using the VLC player for quite some time and we also recommend it for customers who would like to convert their recordings (using our software) from webm to mp4. Recently we have had an uptick of customers who are not able to convert the files into mp4 format so I went to see if I could replicate this myself.

I found that 2 different files which were perfectly fine before converting but after they were significantly shortened after the conversion. The two meetings I had tested were 14:20 and 52:08 long and they were converted into 23 seconds and 53 seconds.

I'm currently using a MacOS Mojave - VLC version 3.0.8 and haven't changed any of my settings. Are there any settings I should check to see why this keeps happening? Let me know if you need any further information!

Files attached showing issue