What is MPEG-DASH, why is MP4box needed, and what is the best way to store an archive?

Question

Nginx

Hello everyone, I have a bunch of questions.
Where can you read in detail about the concept of MPEG-DASH?
I understand how hls works, there are a bunch of .ts files, and the last m3u8 playlist is served for example video.js .
And how to prepare a video for dash? Why is mpd needed and what does it contain?
Many places use MP4box to prepare dash, why is it, FFmpeg can't do the same ?
If I want an adaptive video (changeable quality depending on the channel), as I understand it, I need to prepare it initially for this. Or is it easier to transcode on the fly. Can nginx-vod-module do this?
What is the best way to store a video archive, for example, a web camera? Immediately chunks, or for example hourly files and feed through nginx-vod-module for viewing?

Answer 1

According to questions:

1. The concept is stated in the spec (open with a browser). In addition to the question in which you summed me up, here in the comments in detail.
   
2. Make fragmented mp4 and manifest to it (.mpd). In general terms, it is in the answers, in more detail it is written in the standard.
   
3. ffmpeg does not know how to make mpd, but it does a good job of converting mp4 to fragmented ones.
   
4. This module is specialized to support DASH, of course it can.
   
5. It's better to always have sources if you don't plan to build your own small video hosting, where data is stored indefinitely.