Hello Linkbright,
Thanks you for your questions.
1. To set auto play shound by default. You should open the file “app/design/frontend/ves_gentshop/default/template/ves/landingpage/default.phtml”. Then find code:
 

autoPlay:true, showControls:true, mute:true

 
Change “mute:true” to “mute:false”
 
2. You should open the file “app/design/frontend/ves_gentshop/default/template/ves/landingpage/default.phtml”
find the code:
 

autoPlay:true, showControls:true, mute:true

 
Add new attribute: “loop:false”
 

autoPlay:true, showControls:true, mute:false, loop:false

 
3. Because you changed the background color of header bar to black. To fix the issue, please go to venus theme control panel, input the custom css:
 

.megamenu li span {

    background: #000 !important;
    border: 0 solid;
   padding: 36px 0!important;

}
 

.caret {

    display: none;

}