You can play media from certain time using Media Fragments URI.
If you want to get some videos (e.g. small tutorial) you would send some requests(lesson1.mp4, lesson2.mp4, lesson3.mp4)
It is so bother.
You had better to combine all videos and request it only using Media Fragments URI. It will reduce to prepare multiple media resources.
The format is below.
<source type="video/webm" src="video.webm#[start],[end]">
This video will play from 3s to 5s.
<video class="video" muted controls> <source type="video/webm" src="http://tomoyukikashiro.me/sample/video/landscape.webm#3,5"> <source type="video/mp4" src="http://tomoyukikashiro.me/sample/video/landscape.mp4#3,5"> </video>
Almost browser support it including mobile browser.