Hi @mjokela,
When using the PHP client, $fileData should be a string set to the full path of your media file.
You can look at this example here:
It’s not exactly what you want since it obtains a blob created by the MediaRecord API, saves that to the disk and then uploads it to Kaltura but it should be enough for you to get the general idea.
That said, if you use https://github.com/kaltura/kaltura-parallel-upload-resumablejs you wouldn’t need the intermediate PHP code that saves the file on the server’s disk and then makes the needed API calls to upload it to the Kaltura server, it can all be done on the client side. In fact, that’s also what I’ve done in the webrtc-krecord repo I provided above, upload_to_kaltura.php is from an earlier iteration and is no longer used.