On: An MP4 file first draft

[CharlesW]

Is anyone aware of an open source visual "atom viewer" for ISOBMFF files, similar to https://www.jongbel.com/manual-analysis/atombox-studio/ and Apple's old "Dumpster" and "Atom Inspector"?

[wwader → CharlesW]

fq has mp4 support https://github.com/wader/fq is quite visual but is a CLI tool (for now). It has a REPL and query language to poke around. Disclaimer: i'm the author.

Other mp4 tools i use are https://gpac.github.io/mp4box.js/test/filereader.html and the tools from bento4, also ffmpeg -v trace can give some useful output.

[edelhans → CharlesW]

You could also try the Bitmovin MP4 Inspector chrome extension: https://github.com/bitmovin/MP4Inspector

[chenxiaolong → CharlesW]

It might not have the prettiest UI, but I've used this one several times when troubleshooting encoder/muxer issues: https://github.com/essential61/mp4analyser.