I attempted to use the transcription feature in DT4 with an Local Apple Speech transcription, and sometimes, it would display the message “No speech is recognized in the file.”
However, the video is supposed to contain speech, so I’m puzzled by this issue.
Local Apple Speech transcription is limited, especially in case of poor audio tracks. Did you enable Siri, download the necessary languages and select the right language in the Settings > AI > Transcription?
There are no definitive answers, but the remote option is likely to perform better, just as commercial AI engines will generally perform better than local AI.
I highly recommend MacWhisper for this task. It uses free local models (the software allows smaller models for free, then costs if you want to use more powerful models).