Copying Adobe Premiere XMP Metadata from one MP4 file to another in place?

[seanmcnally]

I have identical .mp4 files on two different hard drives, but source.mp4 has XMP metadata that I need on target.mp4. The XMP metadata was written by Adobe Premiere Pro. So far, I've been able to use Exiftool to do this using this command:

exiftool -overwrite_original -api largefilesupport=1 -tagsFromFile source.mp4 -xmp:all target.mp4

This will work, however, Exiftool is designed in such a way that it does not edit metadata in place. It must rebuild the file, which takes about as much time as copying the file from my source to my target hard drive, defeating the purpose. For my larger mp4 files, some of which are 50+ GB in size, this is inefficient.

Are there any metadata editing tools that can edit a file in place, without needing to rebuild from scratch? Thanks so much.

[Dooby]

Hex editor? https://mh-nexus.de/en/hxd/

[seanmcnally]

In theory, maybe HxD could work, but I couldn’t get it to. I tried just copy/pasting the metadata part, and premiere didn’t recognize the target file’s metadata on import. I also need some way of doing this en masse, so a commandline tool would be ideal.

[Dooby]

Then, I don't think it is what you can 'see' that you need to worry about.

https://forum.videohelp.com/threads/401046-mp4-copy-headers-from-one-file-to-another

Point being, whatever you use you are likely going to have to rebuild the entire file.
In that case, Exiftool is as good as any.