What is the full name of the program and version number as found in Help, About ?
We also need more information about your computer specification and Windows version, see this topic for what is required and please quote processor and graphics card make/model in full.
Which export preset are you using and did you change any of the parameters/settings?
Can you confirm that both programs are having the same issue with exporting?
If they are then I suspect the cause is in the computer - the 2 programs are very different and having the same issue with both the cause is most likely in the computer.
. . . . Vegas pro 19 . . . .
Please note that Vegas products have their own forum, see the Important Posts here. You may want to post there if only Vegas is showing the issue.
As @johnebaker has said. Any questions regarding Vegas products must be asked here.
For an answer to your Magix Video Deluxe question we need more precise information about your system such as the precise model number of your CPU (We need the whole model number rather than telling us it is an i5 processor). as well as which version of MVD you are using.
If you are running an older version of MVD, are you missing or need the main concept codec?
Also are you getting this error warning when loading an MP4 file into MVD or when you are trying to export to MP4?
If it is happening when trying to export to MP4, how are you trying to export the file?
If you are exporting the video for rendering using 'Export movie as', Are you altering any of the export settings? Are you matching the export settings to the file resolutions and frame rates you used in the project?
If you are using 'Export to device', what options are you selecting?
In order for us to help you please give all the information requested otherwise we are having to make assumptions on what is causing the issue.
. . . . both have the same problemMAGIX DELUXE . . . .
This is not the fullname of the program, Magix has 2 video products with Deluxe in the name - what is the full name and version number as seen in Help, About in the program.
. . . . I have 2 computers; . . . .
The computers are different specifications, the AMD Ryzen PC spec is missing an important piece of information - what is the graphics card installed and are the for it up to date?
What is the full specification of the Intel i5 computer - please give the full name of the Intel processor and any other graphics card installed?