too much time to convert mkv formats into mp4 ones by using avidemux applmage

[rocco]

Hi All

For a few years I've been using avidemux appImage with my laptop acer extensa 5235 released in 2009 and made up of 4 GB of ram and Intel Celeron T3300 bits as a CPU running on a Linux Mint 22.1 Xia xfce version. However, this year I've noticed a dramatic increase in time when converting mkv files into mp4 ones compared to past years' smoother and faster conversions. I've runned via terminal the command nice -n -15 avidemux to give more priority to it but it says that it's impossible to use the commmand, while the mp4-to-mp4 resize-based conversions still run fast and very well. How can I make mkv-to-mp4 conversions faster? Do you have any tips about it?