Código PHP:
<?php
$json='{"video": {
"duration": "3:10",
"views": "333249",
"video_id": "44bc40f3bc04f65b7a35",
"rating": "74.17",
"ratings": 391,
"title": "Titulo",
"url": "http://prueba.com/videoprueba",
"default_thumb": "http://imagen.com",
"thumb": "http://imagen.com/70.jpg",
"publish_date": "2008-03-28 13:59:35",
"thumbs": [
{
"size": "large_hd",
"width": "320",
"height": "180",
"src": "http://prueba.com/imagen/1.jpg"
},
{
"size": "large_hd",
"width": "320",
"height": "180",
"src": "http://prueba.com/image2/2.jpg"
}
],
"tags": [
{
"tag_name": "video"
},
{
"tag_name": "tecnologia"
},
{
"tag_name": "it"
}
],
"autor": [
]
}
}';
$array=(array) json_decode($json);
echo $array['video']->url;
?>
Pruebalo y nos comentas.
Saludos