[halapro]

I hate that the most common video container on the web does this too. Most non-"stream-ready" mp4 files lack even the basic information such as height/width until the file has completed loading.[1]

  [1]: https://forum.videohelp.com/threads/393096-Fixing-Partially-Download-MP4-Files

[thunderfork]

This is also a big issue if you're using mp4 as your container for a real-time capture (e.g. livestreaming and saving the stream to disk) - if the capture software crashes without writing the MOOV atom, it's a real pain to recover the video