disable previous / next video preloading

[olaulau]

Is your feature request related to a problem? Please describe.
when playing some high rate video (from a gopro for example), with many in the same folder, the viewer preloads simultaneously the previous and the next video, which can be very laggy.

Describe the solution you'd like
we could :

• totally disable video preloading there :

  viewer/src/components/Videos.vue

  Line 39 in aee0712

  preload="metadata"

• disable preloading for previous / next video only
• only preload after a while, when the current video is buffered and already playing
• have a setting that allows user to disable this globally, or maybe per folder

Describe alternatives you've considered
I don't really know how to develop with vue.js and compile this sources, but I figured out this workaround :

• in nextcloud dir, edit : apps/viewer/js/viewer-main.js
• find {ref:"video",attrs:{autoplay:!!e.active||null,playsinline:!0,poster:e.livePhotoPath,src:e.src,preload:"metadata"}
• change "metadata" to "none"
  we can see in FF network debugger that only one video file is requested (before we could see 3 different videos requested)

Additional context
it is not a cpu problem, my hosting server is ok, it's really a bandwidth problem, which is felt more from internet than locally.