Just donated and i have a question. Cool program btw.
I make the title of an MP4 mirror the filename. All the other file renamers cant do this without a script it seems. Manually i can edit a file by copy/paste in about 20 seconds. Thankfully mp3tag has automated this process and I am grateful. However, when doing a batch of files, each file can take up to 2 1/2 minutes PER FILE. Some are faster than others, but they are all basically the same file type.
You do not tell us anything about the file size, the environment, the defender settings.
Files may have to be rewritten if the padding for tag data is not large enough.
And rewriting a file then depends a lot on the speed of the file access.
Local files can be accessed quicker than files on external storages or on network locations.
Also, the defender might interfere, see here:
My apologies. I am running windows 11. The files are practically the same size for each batch. It doesn't seem to matter. A batch could be 5 to 200 files. An example would be 195,000 in size. I multi select the files in file manager, right click a file and select mp3tag. They all load immediately. Then ctl-a to mult select and convert-filename to %title%. Then that's where it get unpredictable. 1 of 50 may take 8-10 seconds then 2 of 50 might take 30 seconds. They have all just been run through handbrake so they are the same type.
Where are these files stored?
Locally on a fast SSD? Externally on USB-HDD? On a network attached storage? In the cloud?
MP4 files (Movies?) can be quite large.
If they have to be rewritten due to the lack of existing padding space, the worst that can happen is that they have to be written entirely from scratch. The time taken for these files may be longer than expected, depending on the source.
These must be movie files if converted by Handbrake. If there were no tags written then it is very likely that, as @LyricsLover suggested, the padding for metadata is too small and the whole file is rewritten. The time taken to rewrite would be about the same as copying each file.
Note that future edits would be faster since mp3tag does leave some buffer room. Burning that's exceeded again then another rewrite would be necessary to add more space.
They are tv shows and are stored locally on a portable HD. There is usually already information in the title field but it includes the name and all the release information. The string is very long and convoluted. The fastest way for me to do one file is copy the filename, start vlc, go to media information, paste in the title, Click save, and its done. Maybe takes 10 seconds. Waiting is better than doing that for 50 files. It just seemed like it should be faster than that by software.
You could also try to define an exception for for MP3tag in the defender - as is suggested in the linked thread.
If it works OK for you for some files and for some it does not, then it is doubtful that it is an MP3tag problem but more likely something in your local environment.