What is M4B, and how do you transcribe it?
M4B (MPEG-4 Audiobook) is an audio format you'll typically find from audiobooks and long chaptered recordings. An AAC container with chapter and bookmark support, built for long-form audio.
To turn it into text you don't need to convert anything first — upload the M4B file (or paste a link) and Whipscribe returns a clean transcript with speaker labels and per-word timestamps, exportable to TXT, SRT, VTT, or DOCX. Everything runs on private infrastructure that never hands your file to a third-party AI service.
How to transcribe M4B in 3 steps
Add your M4B
Upload the M4B file or paste a link. 30 minutes free daily, no signup to try.
We process it
We read the audio and Whisper transcribes the speech privately.
Read & export
Speaker-labeled, timestamped text in minutes. Export TXT, SRT, VTT, or DOCX.
Frequently asked
How do I transcribe a M4B file?
Upload the M4B file or paste a link. Whipscribe reads the audio directly. You get timestamped, speaker-labeled text in minutes.
Do I need to convert it first?
No — Whipscribe reads M4B directly, so there's no need to convert to MP3 or WAV.
How much does it cost?
About 3.3¢ per audio minute (~$2 an hour), 30 minutes free every day, no signup to try.
Is my file private?
Yes — private infrastructure, never sent to a third-party transcription service, no training on uploads. Delete anytime.