Module development and code questions

hi i want create a image of my upload videos.i think it's name is thumbnails.

i use "video"module for upload video and my drupal version is 8.this module work good but i cant get image export(even i use video version 2).

now how i can get image preview of video ?

thanks!

how to make the taxonomy menu follow its active parent only? like in the taxonomy menu block - it has "dynamic"follow active parent". please help need so much the answer. 

are there any answers already? i cannot find any i'm sorry. i already research hard as i could

Is there a way to make some HTML tags echo? I still want to use filtered HTML but also want to be able to display some tags too.

I recently found that unlike Drupal 7, D8 has a different form id for addition and edit of nodes. Is there a specific reason for that? Because this makes the hook_form_FORM_ID_alter() less granular as we now have to alter like mymodule_form_node_form_alter() and put the specific node type in there.

Sorry, could not find a discussion on this. Must be something very basic that I missed.

Thanks

I would like to create a block for Drupal 7 (and possibly for Drupal 8) that contains a HTML5 radioplayer (start/stop stream) and a field that displays the current playing track as well as the previous 4 tracks. All tracks list the Artist and the song title. Only the current track also displays the album artwork.

If you click on any of the tracks in the header a forum thread will load for that particular song where registered users (authticated Drupal users) may discuss that particular title. 

Hello!

I'm new in Drupal 8 development, and try to create my first custom module to add a select option element in the update-manager-install-form form, for installing new module in "/custom" or "/contrib" sub-folder.