MP4 tools
Install this library
npm install @ludovicm67/mp4-toolsThe following is exposed:
-
Buffer: Buffer that works on both Node.js and browsers -
utils.blobToArrayBuffer: a function to convert a Blob to an ArrayBuffer -
fix: the function to use to fix a chunk by using the previous one
MP4 structure
MP4 files are structured into several different box types, each serving a specific purpose:
-
ftyp(File Type Box): The first box in the file, declaring file type, compatibility, and specifications. -
moov(Movie Box): Contains all metadata about the video, like tracks, duration, etc. It includes sub-boxes:-
mvhd(Movie Header Box): Global information about the movie. -
trak(Track Box): A container for a single track (audio, video, etc.), with sub-boxes liketkhd(Track Header) andmdia(Media).
-
-
moof(Movie Fragment Box): Contains all metadata about a single fragment of the movie, with sub-boxes likemfhd(Movie Fragment Header) andtraf(Track Fragment). -
mdat(Media Data Box): Contains the actual media data, such as video frames and audio samples.
Command line tool
The cli folder contains a command line tool that can be used to fix or merge chunks.
Have a look at the README of the CLI for more information.