A utility to demultiplex/extract tracks from an MP4 file

Question

I'm using Linux. If I want to demultiplex a Matroska file, I can use mkvextract to do so. But what if I want to do this with an MPEG4 file (.mp4)? Is there an equivalent or similar utility for demultiplexing MPEG4 files?

Required features:

• Gratis
• Libre
• Supports command-line invocation rather than a GUI
• Runs on Linux
• Either stable or actively-maintained

Desired features:

• Has a separate GUI interface (possibly by other authors)
• Actively maintained
• multi-platform

Answer 1

MP4Box

(being part of GPAC, an Open-Source Multimedia Project)

MP4Box is the "multimedia packager" utility of the GPAC project. It mainly supports MPEG-4 (.mp4) and 3rd-generation partnership project (.3gp) files, but can also be used with other file formats, e.g. Audio-Video Interleaved (.avi), MPEG-1, MPEG-2 and Matroska (.mkv).

Its extraction-and-dumping options are covered on this page.

Example of use: Suppose I want to extract track 3 of a file named my_movie.mp4 to a file named thesubs.srt. The command-line would be:

MP4Box -raw 3:output=thesubs.srt my_movie.mp4

... but if the subtitle format is potentially different, it can also convert the sub for you:

MP4Box -srt 3 my_movie.mp4

and you'll get my_movie.srt.

GPAC (including MP4) is available as a package on various Linux distribution, e.g. on Debian you can install it with apt install gpac.