If I understand this correctly you just want to emit code for the HTML5 audio player instead of the Flash audio player. I think a simple change to function get_audio() in file mf_front_end.php will do this.
function alt_get_audio( $field_name, $group_index=1, $field_index=1, $post_id=NULL ){
global $post;
if(!$post_id){ $post_id = $post->ID; }
$audio = get($field_name,$group_index,$field_index,$post_id);
if( empty($audio) ) return FALSE;
$mime_type = [
'mp3' => 'audio/mpeg',
'wav' => 'audio/wav',
'ogg' => 'audio/ogg',
];
$extension = strtolower( pathinfo( $audio, PATHINFO_EXTENSION ) );
#error_log( 'alt_get_audio():$_SERVER[\'HTTP_USER_AGENT\']=' . print_r( $_SERVER['HTTP_USER_AGENT'], true ) );
#error_log( 'alt_get_audio():$extension=' . print_r( $extension, true ) );
# the condition in the following if statement may need adjustment
if ( strpos( $_SERVER['HTTP_USER_AGENT'], 'iPad;' ) ) {
#if ( strpos( $_SERVER['HTTP_USER_AGENT'], 'Windows ' ) ) { # for testing against Windows
if ( array_key_exists( $extension, $mime_type ) ) {
$player = '<audio controls><source src="' . $audio . '" type="' . $mime_type[$extension] .'"></audio>';
} else {
'Your browser cannot play ' . $extension . ' audio files.';
}
} else {
$player = stripslashes(trim("\<div style=\'padding-top:3px;\'\>\<object classid=\'clsid:D27CDB6E-AE6D-11cf-96B8-444553540000\' codebase='\https://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0\' width=\'95%\' height=\'20\' wmode=\'transparent\' \>\<param name=\'movie\' value=\'".MF_URL."js/singlemp3player.swf?file=".urlencode($audio)."\' wmode=\'transparent\' /\>\<param name=\'quality\' value=\'high\' wmode=\'transparent\' /\>\<embed src=\'".MF_URL."js/singlemp3player.swf?file=".urlencode($audio)."' width=\'50\%\' height=\'20\' quality=\'high\' pluginspage=\'https://www.macromedia.com/go/getflashplayer\' type=\'application/x-shockwave-flash\' wmode=\'transparent\' \>\</embed\>\</object\>\</div\>"));
}
#error_log( 'alt_get_audio():$player=' . print_r( $player, true ) );
return $player;
}
Alternatively, you can include alt_get_audio() in your functions.php and call it in place of get_audio(). N.B. I was not able to test this on an iPad as I don’t own one. In particular I am not sure what USER-AGENT string it sends.