Problems with Video Files and a Nice Solution

Because of the sanitary emergency, I have been teleworking all this year.

For me, this has implied making lots of videos for my students, so I use InShot and Textro on an Android phone to record/ add effects and then I work on the computer for the post production.  I have been relying on Kdenlive (on PCLinuxOS) and OBS Studio (on OpenMandriva and MX Linux, for live streams).

But then, half way this year, I noticed that sometimes the audio of the videos that I edited on the phone with InShot was out of sync when I loaded them to Kdenlive.

As a solution, I used Pitivi on Mageia to convert the videos, which fixed the problem.  This additional step, however, is time-consuming and time has become an even more precious resource right now when one is teleworking. 

Today, I shot four videos and edited them on InShot.  When I loaded them to the Kdenlinve project, to my distress, the audio was not in sync.

I could not afford to run them through Pitivi and use up an average of 15 minutes on the conversion of each clip. I thought that, if I could join the clips together, the audio might be OK in Kdenlive.  I was worth giving it a shot.

I did a quick search for a Linux tool to merge the four clips together.   I found this page here.

The section on MKVToolNix caught my attention.  I installed it on PCLinuxOS and tried the GUI version.  I could not figure out what I had to do (I was really in a rush), so I closed it and, after opening Konsole, I typed the command (substituting the file names, of course):

mkvmerge -o output.mp4 file1.mp4 \+ file2.mp4 \+ file3.mp4

The konsole window displayed some info in less than five seconds and told me that the operation was completed.

In disbelief, I opened the output video file and... yes, the four clips were there in one.

I put that output file on my project folder in Kdenlive and ran the preview to see if the audio was OK. It was perfect.

This helped me finish the post production a lot earlier.