Hi @t-saito,
resumeAt is only relevant in the event resume is set to true.
To be most strict, if you do not intend to upload in chunks, you best set:
$resume=false;
$finalChunk=true;
$resumeAt=-1;
Same as the defaults here:
https://developer.kaltura.com/workflows/Ingest_and_Upload_Media;step=2
See also the high level explanation above the form, which is taken from the comment here:
However, so long as $resume is not set to true, the actual value of $resumeAt does not matter much.
See: