VoiceBrief

VoiceBrief converts PDFs into audio that reads the original text aloud. It highlights the source text as it plays, so you can listen and keep your place in the document. If a section gets dense, you can switch to a "professor" mode that explains it in a lecture style. Besides PDFs, it takes photos, handwritten notes via OCR, and URLs.

The same document also feeds voice or text chat with an AI tutor that uses the PDF as context, AI summaries, flashcards, and quizzes at easy, medium or hard difficulty with spaced repetition. You can start playing the first section before the full MP3 is done. Your listening position syncs across devices, and you can download MP3s to listen offline. Files are private to your account unless you create a share link.

It's mainly for students, and also for professionals and researchers who get through reports and papers on their commute. The free tier gives you one saved PDF and 3 preview minutes a month, in the app only. Pro costs $9.99/month and adds unlimited PDFs, teach mode, voice chat, quizzes, flashcards and MP3 downloads.