So in the end did you get good results, if so, what settings did you change?

4k is too much for streaming so I used 1080p. I changed 512k to 4000k and then I updated the database with:

Serialized MySQL query:

UPDATE `sys_transcoder_filters` 

  SET  `filter_params` =  'a:3:{s:1:"h";s:4:"1080";s:10:"force_type";s:3:"mp4";s:14:"ffmpeg_options";a:1:{s:7:"threads";i:14;}}' 

  WHERE `transcoder_object` =  'bx_videos_video_mp4' AND  `filter` =  'Mp4';

Unserialized MySQL query:

array (

  'h' => '1080',

  'force_type' => 'mp4',

  'ffmpeg_options' => 

  array (

    'threads' => 14,

  ),

);

Thank you