Youtube API視頻持續時間格式

{ 
"kind": "youtube#videoListResponse", 
"etag": "\"XlbeM5oNbUofJuiuGi6IkumnZR8/ny1S4th-ku477VARrY_U4tIqcTw\"", 
"items": [ 
    { 

    "id": "9bZkp7q19f0", 
    "kind": "youtube#video", 
    "etag": "\"XlbeM5oNbUofJuiuGi6IkumnZR8/HN8ILnw-DBXyCcTsc7JG0z51BGg\"", 
    "contentDetails": { 
    "duration": "PT4M13S", 
    "dimension": "2d", 
    "definition": "hd", 
    "caption": "false", 
    "licensedContent": true, 
    "regionRestriction": { 
    "blocked": [ 
     "DE" 
    ] 
    } 
    } 
    } 
] 
}

Youtube API v3以此格式提供視頻持續時間"duration": "PT4M13S"這是標準時間格式嗎？我試圖用Objective-C獲得一個用戶友好的格式。我想知道這是否是Objective-C DateTime類支持的格式。如果不是那些P，T，字符代表什麼？Youtube API視頻持續時間格式

來源

2013-03-30 sleepwalkerfx