Personally wouldn't recommend my approach however unless you are okay with doing some hardcore text manipulation and fuzzy math. It fails to produce text that matches up with the prompt 10% of the time and lots of other caveats with what to do with text that doesn't fit into the prompt.
Try to pre-process it where just "voice" is detected, not the meaning, just some speaking, and cut the audio into snippets which only contain speech, so that Whisper doesn't have to guess if the segment will contain speech or not.
Also, if you cut it up into chunks and let it transcribe each chunk and expect JSON as the output, instead of the other output methods, then you'll get a bunch of extra parameters with it which will help you identifying problematic sections. For example hallucinated repetitions usually have a higher "no_speech_prob" parameter, or segments with lower "compression_ratio" will also not be that accurate.
In my case I'm recording notes while exercising on my bike, so there's wind and friction and breathing, then I transcribe them with Whisper, do try to filter out things that don't make much sense (where the temperature, compression_ratio, avg_logprob and/or no_speech_prob are not acceptabe).
Since I start recording at will and don't prepare the sentence to be recorded, the recording is a bit chaotic, and ChatGPT does a good job in correcting Whisper's mistakes and transforming the sentences.
But, as I said, sometimes this fails and the real message gets lost.
I'm using them to record multiple people in the same room but avoid cross-talk (for data collection in a research study). The audio isn't great, but I've used transcription services and they seem to be able to make the words out just fine.
I messed with a combo of Whisper and ChatGPT. I took a whisper transcript and asked chatgpt to fix mistranscriptions using the context of the transcript and based on potential phonetic issues. I asked it to replace transcribed words that don't make sense with "[unintelligable]", which improved the output even more.
Transcription error rate was almost nonexistent, even on the smallest whisper model.