Hi,
One possible solution is to prepare overlay files for each user, then select the overlay file corresponding to each user in the transcode command. Examples of transcode command usage:
Please refer to the "Video Overlays – Watermarking" section in the EMS User Guide for details about overlay image requirements. There may be ways to programmatically generate the overlay files.
Adding a text overlay option for the EMS transcode API would be a nice feature to add later.
Cheers,
Don