OGV to M4B Converter

Convert OGV to M4B: Turning an Ogg Video Into an Audiobook File

An .ogv is an Ogg container with a video track and an audio track — usually Theora or VP8 alongside Vorbis. An .m4b is an MPEG-4 audio file with an extension that means "audiobook": Apple's own audiobook downloads use it, and Books on Mac will import one alongside MP3 and Audible titles. The practical difference from an .m4a is behavioural rather than structural — an audiobook file is filed separately in the library and remembers where you stopped listening.

So this conversion does two things at once: it throws away the video entirely, and it wraps what is left in the extension that gets audiobook treatment. It is the right move for a recorded lecture, a conference talk, a sermon, an audio drama, or any long-form Ogg recording you would rather listen to than watch.

How to Convert OGV to M4B

1. Upload Your OGV File: Drop the .ogv on the page or click "+ Add Files". Long recordings are the normal case here; several files can be queued and share one set of settings.
2. Set File Compression: The panel opens on Quality Preset, whose list runs Highest through Lowest with Very High marked Recommended. Constant Bitrate (a fixed list from 8 kbps to 384 kbps, with 128 kbps preselected in that list), Custom Bitrate (a free number, preset to 128 kbps) and Specific file size are the alternatives.
3. Set Audio Channel and Audio Sample Rate: Both lists start at ORIGINAL, which keeps whatever the Ogg carried. MONO roughly halves the size of a spoken-word recording; the sample-rate list offers 8000, 12000, 16000, 24000, 44100 and 48000 Hz.
4. Trim and Convert: Trim opens on Unchanged; switch to Time Range to cut an intro or a Q&A off with a start time and duration, in seconds or HH:MM:SS.sss. Click Convert. Files are uploaded over an encrypted connection, re-encoded on our servers, and deleted automatically after a few hours — no sign-up, no watermark.

What Quality Preset Maps To

AAC is the only entry in the Audio Codec list, and the encoder is driven in variable-bitrate mode with a five-step quality scale where 5 is best. The seven presets collapse onto those five steps, so two pairs of presets produce identical output.

Measured on a 10-second 44.1 kHz stereo Vorbis track carrying mixed tonal and broadband content:

Two things to notice. High and Medium land on the same step, as do Very Low and Lowest — so if a preset change appears to do nothing, that is why. And variable-bitrate output tracks the content, not the label, which is why step 1 came out slightly larger than step 2 on this particular material. For spoken word the practical guidance is simpler than the table: Very High is more than the material needs, and Constant Bitrate at 64 kbps mono is the classic audiobook setting.

Sizing a Real Audiobook

The 10-second numbers above scale linearly, which makes the arithmetic easy for anything long:

For a single voice in a quiet room, 64 kbps mono is transparent enough that most listeners will not identify it in a blind comparison, and it cuts a ten-hour recording to under 300 MB. For a panel discussion, a recorded concert or anything with music, stay stereo and use 96 to 128 kbps.

Frequently Asked Questions

Does the M4B come out with chapter markers?

No. Chapters in an audiobook are a metadata track that has to be authored — a list of titles and timestamps — and there is nothing in an .ogv to derive them from. This conversion produces one continuous audio track. If you need chapters, run the M4B through a dedicated audiobook tagger afterwards, or split the source at chapter boundaries first and convert each part separately.

Why does the file identify itself as M4A inside?

Because the underlying container is the same. Written from this route, the file's brand field reads M4A while the filename says .m4b, and that is normal for M4B files generated by conversion tools. Players key their audiobook behaviour — separate library section, remembered playback position, speed controls — off the .m4b extension rather than the internal brand, so renaming the file to .m4a is what would actually change how it is treated. Leave the extension alone.

What happens to the video track?

It is discarded before encoding. The output is an audio-only file with a single stream; nothing from the Theora or VP8 picture is carried, including any cover-art-sized still. If you want artwork on the audiobook, add it afterwards with a tagger, or grab a frame first with OGV to JPG and attach that.

Which sample rate should I choose?

Leave it on ORIGINAL unless you have a reason. A 44.1 kHz Ogg came through this route as a 44.1 kHz M4B in testing — the rate is carried across rather than forced. Dropping to 24000 Hz halves the bandwidth the encoder has to describe and is genuinely fine for a single speaking voice, but it also caps the audible top end at 12 kHz, which makes music and applause sound dull. If the recording is only speech and size is the priority, 24000 Hz mono at 32 kbps is a very small file that remains perfectly intelligible.

Can I cut the intro and outro before converting?

Yes, and it is worth doing on a long recording — you avoid encoding material you will skip anyway. The Trim group opens on Unchanged; switch it to Time Range and you get a Start time and a Duration, each accepting plain seconds or HH:MM:SS.sss. That gives you one continuous range per job. For several cuts out of one file, do the surgery first with Video Cutter, which accepts .ogv directly, and convert the trimmed result.

What if I want an M4A instead?

Use OGV to M4A. The audio inside is produced the same way; only the extension differs, and with it the way media libraries file the result. Choose .m4a for music and short clips, .m4b when you want the file to behave like an audiobook. If you would rather have something that plays in absolutely everything with no bookmarking behaviour at all, OGV to MP3 is the universal option.

Is converting Vorbis to AAC a second quality loss?

Yes, and it is unavoidable — both are lossy, and there is no way to move between them without decoding to PCM in between. In practice it matters far less than the arithmetic suggests, because the artefacts the two codecs produce are different enough that AAC does not systematically amplify Vorbis's. The way to keep it invisible is to give the second encode more room than the first had: if the Ogg's Vorbis track was around 96 kbps, encode the AAC at 96 to 128 kbps rather than trying to save space on the way out.

Can I convert a very long recording, like a whole conference day?

Yes. There is no duration limit built into the conversion, and audio-only output stays modest — even eight hours at the Highest preset lands under half a gigabyte. The real constraint is uploading the source: an .ogv with a video track is far larger than the audio inside it, so an eight-hour video file can be several gigabytes going up the wire. If your connection makes that painful, trimming the source down before upload is the only lever that helps.

Will the M4B play on Android or Windows?

Yes, though without the audiobook behaviour Apple's apps add. The file is ordinary AAC in an MPEG-4 container, which VLC, mpv, foobar2000, Winamp and most Android players handle without complaint. Some stock Android media apps filter their library scan on extension and will not list an .m4b at all — dedicated audiobook players such as Voice or Smart AudioBook Player look for it specifically. On Windows, a rename to .m4a makes it visible to more players if you do not need the bookmarking.

What happens to my file after the conversion?

Your .ogv is uploaded over an encrypted connection, decoded and re-encoded on our servers, and both the upload and the .m4b it produced are deleted automatically after a few hours. Nothing is shared or made public, there is no account required, and no watermark is applied.