Accessing XMP data in MP4 files?

[Numpsy]

Hi,
I see that the roadmap in the readme file says

Support for Broadcast wave metadata : aXML and XMP

but are there any thoughts on reading or writing XMP data in MP4 files?

I had a really quick go at reading the data in Numpsy@8887dee and it seems to work ok (though that test only works for a single UUID field in the file).
I haven't made any attempt at writing data into mp4 files yet.

[Zeugma440]

Hi there,

That part of the roadmap is aimed at WAV files, but I can consider starting with MP4 if you need it, sure.
Could you please e-mail me a sample file with XMP data to play with?

Thanks in advance~

PS : I see you're using a wide array of features. What are you building? 😄

[StefanOltmann]

it does seem that putting some of the namespace declarations on the rdf node rather than the xmpmeta node would help

Yes, I would recommend that, as it aligns with the behavior of Adobe XMP SDK, ExifTool, and Exiv2.

ChatGPT also indicates that this is the expected specification, though I haven’t found a definitive source to confirm it.

I remove everything around <rdf> because some files contain random junk around the tag, which causes issues with the XML parsing library I use.

[Zeugma440]

Thanks @StefanOltmann (and chatGPT I guess?) for the extra hints

I have a new update ready on a local branch. It declares xmlns:x on the x:xmpmeta node and declares all other namespaces on the rdf:RDF node. @Numpsy Please tell me if I should push it to main.

[StefanOltmann]

Great! :)

So I'll close Ashampoo/xmpcore#36 👍

[Zeugma440]

Changes are available on today's v6.15

[Numpsy]

expected specification

I suppose that 'do whatever the C++ version of XmpCore does' is a reasonable starting point.

Changes are available on today's v6.15

hanks, I;ll give it a go.

[Zeugma440]

XMP support for WAV and M4A/MP4 has been released with today's v5.21