Is there an upper limit for Keys:Description length

[wywh]

Is there an upper limit for Keys:Description length in .mp4, .m4v and .mov?

I use a GUI app to insert movie descriptions and it works very well for about 3000 characters (AFAIK it uses exiftool for this). But it crashes if I try to paste 6000 characters. I have a few movies where I'd like to add such quite long descriptions.

On the other hand, exiftool via the Terminal readily inserts much longer descriptions and that GUI app and Apple's apps display them OK.

- Matti

[Phil Harvey]

The limit is roughly 4GB on any Keys string

- Phil