Captions not shown, volume muted, & other unexpected behaviors when background = true

[terrill]

Expected Behavior

If the player is initialized with background:true, I expect the controls to be hidden. I also expect the video to autoplay and loop, since those behaviors are mentioned in the description of this option in the Embed Options documentation.

I do not expect caption text or subtitles to be hidden, since these are not controls, they're content (and essential content for some users).

Also, I do not expect the volume to be muted.

Also, I expect consistency with autoplay and loop. Both are enabled by default with background:true; however loop can be overridden by initializing the player with loop:false. This doesn't work for autoplay:false and I would expect it to since it works for loop.

Actual Behavior

A player created with background:true has the following features:

• Controls are hidden (expected)
• Loop is enabled, but can be overridden with loop:false (expected)
• Autoplay is enabled, and cannot be overridden with autoplay:false (unexpected)
• Captions are not visible, even if toggled on (verified that mode="showing" for the current text track via getTextTracks()). (unexpected)
• Volume is muted. (unexpected)

Steps to Reproduce

Initialize a player with the following options:

    var options = {
        id: 59777392,
        background: true,
        loop: false,
        autoplay: false, 
       texttrack: 'en'
    };

I've created a set of test pages to demonstrate various configurations.

As documented via my test pages, none of these side effects is present with controls:false, so that could be a workaround for some use cases. However, if these side effects of background:true aren't fixed, they should at least be mentioned in the documentation (especially the lack of captions, since that presents an accessibility problem).