IoS devices will only play media on user interaction, therefore in this case you will need to have a ipad/iphone detector to toggle the visibility of your image.
Here is what I imagine you would do:
Create an image and attach over the video ( make sure is absolute )
Then add this code in your js
// thanks to: https://stackoverflow.com/questions/9038625/detect-if-device-is-ios
function iOS() {
var iDevices = [
'iPad Simulator',
'iPhone Simulator',
'iPod Simulator',
'iPad',
'iPhone',
'iPod'
];
if (!!navigator.platform) {
while (iDevices.length) {
if (navigator.platform === iDevices.pop()){ return true; }
}
}
return false;
}
if(IOS()) document.getElementById("YOUR_IMAGE_ID").style.display = "block";
This should do, please test it