[{ title:"Dynamic Title 1", content:"Dynamic content 1" },
{ title:"Dynamic Title 2", content:"Dynamic content 2" }]

$input = array(
   array('title'=>"Dynamic Title 1", 'content'=>"Dynamic content 1"),
   array('title'=>"Dynamic Title 2", 'content'=>"Dynamic content 2")
);

json_encode($input);

$phparray = array(
        array("title"=>"Dynamic Title 1", "content"=>"Dynamic content 1"),
        array("title"=>"Dynamic Title 2", "content"=>"Dynamic content 2")
    );
// You can simply get the JSON string like this
$json = json_encode($phparray);

// OR if your php version is >= 5.4.0
$json = json_encode($phparray, JSON_PRETTY_PRINT);