Local speech transcription does not work with S3 storage

[Tom-Hubrecht]

Which version of assistant are you using?

1.1.0

Which version of Nextcloud are you using?

v29.0.3

Which browser are you using? In case you are using the phone App, specify the Android or iOS version and device please.

Firefox 127.0.1

Describe the Bug

The audio transcription feature is not working, at least with local whisper. When trying to create a new transcription from an existing file, nothing happens on the UI, no transcription is scheduled, and the NC logs show :

Trying to access array offset on null at /var/lib/nextcloud/store-apps/assistant/lib/Controller/SpeechToTextApiController.php#101

Looking at the request, as the file is selected on the NC instance, no audioData is given, so the controller crashes.

Note that our installation uses S3 storage, testing it with an installation using the local fs seems to be working.

Expected Behavior

A task for local transcription to be created, or an error to be shown.

To Reproduce

Use a Nextcloud installation using S3 storage, install stt_whisper and Nextcloud Assistant, select a local mp3 file for transcription and see that nothing happens.