html5-video タグで Android では　autoplay が効かない

[php]

wd = $(window).width();
ht = $(window).height();
msg1 = ‘<video id="my_video" controls preload="auto" poster="’+photofile+’" width="’+wd+’" height="’+ht+’" data-setup=’+String.fromCharCode(39)+'{}’+String.fromCharCode(39)+’>’;
msg21 = ‘<source src="’+videofile+’" type=’+String.fromCharCode(39)+’video/mp4’+String.fromCharCode(39)+’/>’;
msg3 = ‘</video>’;

$(‘#content’).append(msg1+msg21+msg3);