如何让用户订阅者计算Youtube API v3

For channel I send:

$videoInfo = $youtube->channels->listChannels('statistics,snippet',array(
    'id'=> $chanelId
));

But how get subscribers count for user ? e.g. for https://www.youtube.com/user/WarnerBrosPictures ?

Look at example output of listChannels method:

{
  ...
  "statistics": {
    "viewCount": unsigned long,
    "commentCount": unsigned long,
    "subscriberCount": unsigned long,
    "hiddenSubscriberCount": boolean,
    "videoCount": unsigned long
  },
  ...
}

You have already your data, do var_dump($videoInfo); to see those details.