Convert MP4 to M4B
Extract the audio from your MP4 video files and save it as M4B, directly in your browser.
How to convert video to audio in 3 steps
Choose a MP4 video file.
Click convert to M4B.
Download your M4B audio.
Format descriptions
MP4 — MP4 is the most widespread and compatible video container. It supports H.264/HEVC and AAC codecs, making it ideal for streaming, the web and mobile devices.
M4B — M4B is the MP4-based container used for audiobooks. It supports chapters and bookmarks, using the AAC codec just like M4A.
Technical comparison: MP4 vs M4B
Technical breakdown of the MP4 and M4B specifications: compression, colour, transparency and animation support.
| Property | MP4 | M4B |
|---|---|---|
| Specification | MP4 (MPEG-4 Part 14) | M4B (MPEG-4 Audiobook Container) |
| Media type | Video | Audio |
| Compression | Lossy · H.264 / HEVC + AAC | Lossy · AAC |
| Color space / bit depth | YUV 4:2:0, 8-10 bit | 16-bit up to 48 kHz |
| Transparency | Not supported | Not applicable |
| Animation | Yes (animated) | No (static) |
| Best for | MP4 is the most widespread and compatible video container. It supports H.264/HEVC and AAC codecs, making it ideal for streaming, the web and mobile devices. | M4B is the MP4-based container used for audiobooks. It supports chapters and bookmarks, using the AAC codec just like M4A. |
What happens when converting MP4 to M4B?
The MP4 data is decoded inside your browser with WebAssembly and re-encoded to the M4B specification, so no file is ever uploaded to a server. M4B uses lossy compression: the file gets far lighter, but a small amount of fine detail is discarded in the process. MP4 supports animation while M4B does not, so only the first frame is kept. Audio is re-encoded with the M4B codec while keeping the original duration, so audio and video stay in sync.
Frequently Asked Questions
What is video to audio conversion?
Video to audio conversion extracts the sound track from a video file, for example from MP4 to M4B, keeping only the audio content.
Are my video files uploaded?
No. This tool processes video files directly in your browser. Your video files are never sent to a server.
Which video formats are supported?
This tool converts the audio of MP4 video files to M4B, all in your browser.
Is it really free and unlimited?
Yes, the tool is completely free and you can convert as many videos as you want, with no limits.
Does it work on mobile too?
Yes, it works on any modern device, including smartphones, tablets and desktop computers.
Which format will the result be in?
The converted file will always be in M4B format, ready to download and use.
About the video to audio converter
Extract and convert the audio from your MP4 videos to M4B for free. Everything happens in your browser: your files are never uploaded to a server, and you need no downloads or sign-up to get started.
See also:
- Video to Audio Converters
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- Convert MP4 to MP3Extract and convert the audio from your MP4 videos to MP3 for free. Everything happens in your browser: your files are never uploaded to a server, and you need no downloads or sign-up to get started.
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- Convert MP4 to OGGExtract and convert the audio from your MP4 videos to OGG for free. Everything happens in your browser: your files are never uploaded to a server, and you need no downloads or sign-up to get started.