Writing descriptive tags (e.g. keywords) directly into video files

[Magmadar]

I mostly work with photo files, so I'm a little out of my element when it comes to tagging video files. As far as I've been able to gather, everything writes to XMP since there isn't really a keyword field for videos. I've got a client who is taking the files we're tagging and importing them to Extensis Portfolio, which apparently doesn't support reading from XMP sidecar files, so we need to find some program that will allow writing directly into files. Is this even possible? One of my colleagues suggested using the Comments field. We're working with mp4, wmv, avi, mov, flv, and mts, but we can convert them if need be.

[Phil Harvey]

ExifTool will write XMP into MP4 and MOV files.  The MTS format doesn't support any metadata at all, so you are out of luck there.  I don't know what you could use to write to the other formats.

- Phil

[Magmadar]

OK - so I should be OK writing all the tags into the 'keywords' field after converting everything to MP4/MOV?

[Phil Harvey]

Yes, but with ExifTool, you would write Subject (which is XMP), not Keywords.

- Phil

[Magmadar]

Does it still create the sidecar file, or is it embedded XMP?

[Phil Harvey]

You can do either with ExifTool.

- Phil