Xvid to M4B

How to Convert Xvid to M4B Online

1. Upload Your Xvid File: Drag and drop the AVI (Xvid is a video codec, almost always carried inside an AVI container) or click "+ Add Files." Batch uploads are supported, so a full lecture series can queue at once.
2. Set the Bitrate under File Compression: "File Compression" opens on Quality Preset, whose dropdown preselects "Very High (Recommended)" — that is what is sent if you leave it alone — but it is the least predictable control on the page. For spoken-word audiobooks use Constant Bitrate at 64 kbps mono — that is the bitrate Apple Books and Audible use for narration, and Constant Bitrate is the mode that maps one-to-one onto the encoder. The dropdown opens at 128 kbps and the list runs up to 384 kbps. Music or dramatic readings benefit from 96–128 kbps stereo. You can also pick one of the five Variable Bitrate bands (96k-112k down to 20k-32k), enter a Custom Bitrate, or target a specific file size.
3. Set Audio Channel and Sample Rate (Optional): "Audio Channel" defaults to ORIGINAL — change to Mono for lectures and audiobooks (halves the file size with no audible loss for voice). "Audio Sample Rate" defaults to ORIGINAL; 24000 Hz is plenty for speech, 44100 Hz keeps CD quality for music.
4. Trim and Convert: Under "Trim," set a Start time and Duration to clip out a single chapter or skip an intro. Click Convert. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared.

Why Convert Xvid to M4B?

Xvid is an MPEG-4 Part 2 (Advanced Simple Profile) video codec that has been the de-facto codec for AVI files since 2001. The AVI container is a video format; M4B is Apple's audiobook format — AAC audio in an MP4 container, with the.m4b extension that signals to Apple Books and iTunes that this is an audiobook (enabling resume-from-position and chapter navigation rather than starting from zero each time). Converting from Xvid to M4B extracts the audio track from the AVI and re-wraps it in the M4B audiobook container.

• Lecture and course videos to audiobook — Old university lectures or training courses recorded as Xvid AVIs are perfect M4B candidates. The audiobook treatment lets Apple Books resume mid-lecture instead of restarting on every commute.
• Sermons, talks, and conference recordings — Long-form spoken Xvid recordings (often 60–120 min) compress to under 50 MB at 64 kbps mono — small enough to sync across phone, tablet, and watch.
• Self-recorded narration — Authors who recorded chapters into a video camera or webcam and saved as Xvid AVI can extract narration to M4B for distribution on Apple Books, Libby, BookFusion, or Plex.
• Documentary and interview audio — Interview-style content rarely needs the video. Stripping to a 96 kbps stereo M4B preserves voice clarity and ambient sound while shedding 90% of the file.
• Old DVD rips and archived AVIs — Xvid AVIs from 2000s-era DVD rips can be retired to a single M4B audiobook file with bookmarking — useful for radio plays, audiobooks-on-CD that were ripped to AVI, and language-learning courses.

Xvid (AVI) vs M4B — Format Comparison

M4B Bitrate and Sample Rate Guide

Apple Books, iTunes, and most audiobook apps decode AAC at any standard bitrate, but these settings match how published audiobooks are typically encoded:

A 60-minute lecture at 64 kbps mono is roughly 28 MB; the same lecture at 256 kbps stereo is roughly 115 MB. For audiobooks you almost never need above 96 kbps mono.

Frequently Asked Questions

Why does my Xvid file not show video output options?

Because M4B is an audio-only format. The conversion drops the video track and re-encodes only the audio stream from the AVI as AAC inside an MP4 container with the.m4b extension. If you want to keep the video, use Xvid to MP4 instead, or extract the audio without re-wrapping via Xvid to MP3.

Will my M4B have chapter markers?

The output is a single continuous M4B file. M4B's chapter-marker capability is part of the MP4 container spec, but chapters have to be authored separately — typically in Apple's free Audiobook Builder, MP3tag, or AudioBookConverter (open source). For most spoken-word use cases, the.m4b extension alone is enough — Apple Books still resumes from the last position even without chapter markers.

Why does Apple Books treat M4B differently from MP3 or M4A?

Apple Books recognizes the.m4b extension as a signal that the file is an audiobook and enables three behaviors: position bookmarking (resume from where you stopped), variable playback speed without pitch shift, and "skip backward" intervals tuned for spoken word (5/15/30 seconds rather than music's track-skip). M4A, despite using the same AAC codec, gets treated as music — restarting at zero every time and skipping by track, not seconds.

Should I pick mono or stereo for audiobook output?

Mono for any single-narrator content — lectures, audiobooks, sermons, podcasts, language tapes. Halving the channels halves the bitrate cost with zero audible loss for voice (the human voice's spatial information adds nothing). Use stereo only when the source has meaningful stereo content: dramatized audiobooks with positional voices, music interludes, field recordings, or interviews with directional mics.

Can I import the converted M4B into Apple Books and iTunes?

Yes. Apple Books on iOS/macOS and iTunes on Windows both natively read M4B files — drag the file into the Books app or iTunes library and it appears under Audiobooks rather than Music. VLC, Windows Media Player, and most Android audiobook apps (Smart AudioBook Player, Voice Audiobook Player) also play M4B since the underlying codec is standard AAC.

What bitrate should I pick to match Audible's audiobook quality?

Audible's standard download tier uses ~64 kbps mono AAC, and their "high quality" tier is roughly 128 kbps stereo. For most narration, 64 kbps mono at 44100 Hz is indistinguishable from Audible's downloads on phone speakers and earbuds. Bumping to 96 kbps mono gives a small audible improvement on quality headphones.

Will the output file be DRM-protected?

No. Files distributed through the Apple Books store or Audible may carry FairPlay DRM, but the M4B you produce here is an unencrypted, plain AAC-in-MP4 file — playable on any device and editable in any audio tool. DRM is added only when Apple or Audible distribute commercial titles.

Can I convert just one segment of a long Xvid lecture?

Yes — use the Trim controls. Enter a Start time (HH:MM:SS) and Duration to extract a single chapter, skip a 30-second intro, or pull one talk out of a multi-hour conference recording. For more sophisticated splitting (multiple non-contiguous segments, fade-ins, exact silence detection), pair this with Audio Cutter after the M4B is produced.

My Xvid AVI's audio is AC3 5.1 surround — what happens?

The AAC encoder will downmix the 5.1 source to stereo (or mono if you chose Mono) using the standard ITU-R BS.775 downmix coefficients. This is normally what you want for audiobook playback on phones and earbuds. If you specifically need to preserve surround, M4B is the wrong target — convert to a multichannel format like Xvid to AAC and keep stereo, or step up to a video format that supports 5.1.

Is there a file size limit?

Files process on our servers, so the practical limit is upload size and connection speed on our servers cap. A 4-hour audiobook at 64 kbps mono is roughly 110 MB output — well within any modern browser's reach. For Xvid AVIs over 2 GB, expect longer load times during the upload and decode steps.