Bug: Video autoplay broken on Chrome

[montyz]

See https://liascript.github.io/course/?https://raw.githubusercontent.com/montyz/landstewards/main/slides.md#7 for an example of trying to autoplay mp4 files. On my chrome or brave browser on OS X it won't autoplay. It does work in Safari and Firefox.

[andre-dietrich]

Hi @montyz ... this seems to be a browser problem, depending also on the time, when the slide with the video gets loaded, if it is the first, then the browser might prevent the loading. I got the following result

And setting muted as a parameter in the tag does not seem to fix this either.

https://stackoverflow.com/questions/14111917/html5-video-muted-but-still-playing

However, there is a way, how you can implement the desired behavior. LiaScript can execute scripts as well. You can either add this script to every slide, where you want to autoplay videos.

<script>
// select all tags of type video, where the property autoplay is set
const videos = document.querySelectorAll('video[autoplay]');

for(let video of videos) {
    // set mute manually to true, otherwise autoplay will be forbidden
    video.muted = true
    video.play()
}

// by returning undefined, this script will be invisible to the user
// it means, no body ...
undefined
</script>

or you can create a custom macro, which has to be defined in the main-comment of your document:

<!--
author: ...

@autoplay
<script>
// select all tags of type video, where the property autoplay is set
const videos = document.querySelectorAll('video[autoplay]');

for(let video of videos) {
    // set mute manually to true, otherwise autoplay will be forbidden
    video.muted = true
    video.play()
}

// by returning undefined, this script will be invisible to the user
// it means, no body ...
undefined
</script>
@end
-->

# Title 

...

## Wildlife

!?[Deer](pics/Deer.mp4)<!-- muted="true" -->
!?[Bears](pics/107.mp4)<!-- autoplay muted="muted" -->
!?[Doves](pics/Doves.mp4)<!-- autoplay muted="muted" -->
![wildflowers](pics/IMG_2190.jpeg)

@autoplay

The script will only autoplay vidoes, where the specific attribute has been added, all others will be ignored ...

...

Great course by the way ... I hope this helps ...