A one-hour talk recorded in a hall becomes timestamped text in a couple of minutes: for proceedings, for those who missed it, for the website or a book. No length limit.
Transcribe now, free →Speech is not writing: remove repetitions, close half-finished sentences, keep the speaker's words. For a sermon or public speech, one hour of talking is about 8,000 words: split the text with topic headings, using the minutes as a guide.
Echo in large halls is the first enemy: a recording close to the speaker's mouth beats one from the back. Applause, music and pauses cause no problems, they are simply skipped. For multilingual events, leave auto-detect on.
No practical limit: even three hours are split and transcribed in full.
Yes, with the speaker's consent. For public events it is good practice to ask anyway.
No: it is a faithful transcript of the speech. Proofread names and numbers, the easiest words to get wrong.