Recipe 16.6. Scaling Video

Problem

You want to change the dimensions of the video display.

Solution

Set the width and height properties of the Video object. If you want the video to playback at the dimensions at which it was encoded, use the videoWidth and videoHeight values.

Discussion

The dimensions at which a video plays back are determined by the width and height of the Video object. When you construct a Video object, you can specify the display's initial width and height; for example, the following constructs a Video object that is 160x120 pixels:

var video:Video = new Video(160, 120);

However, you can still change the dimensions after the object is constructed by using the width and height properties. The following doubles the dimensions of the Video object constructed in the preceding example:

video.width = 320; video.height = 240;

The Video class also defines two read-only properties, videoWidth and videoHeight, which return the width and height at which the video was encoded. You can use the videoWidth and videoHeight properties to set the width and height of the Video object, as follows:

video.width = video.videoWidth; video.height = video.videoHeight;

However, note that the videoWidth and videoHeight properties are not correctly defined until the FLV has started to download. Therefore, if you want to set the width and height of the Video object based on the encoded dimensions, you must wait until the videoWidth and videoHeight properties are correctly defined. You can use a netStatus event listener for that purpose:

videoStream.addEventListener(NetStatusEvent.NET_STATUS, onStatus);

Then define the listener with an if statement that tests for videoWidth and videoHeight greater than 0, as well as width and height values not equal to videoWidth and videoHeight. Since the videoWidth and videoHeight are set at the same time, you only need to test for one of them:

private function onStatus(event:NetStatusEvent):void {     if(_video.videoWidth > 0 && _video.width != _video.videoWidth) {         _video.width = _video.videoWidth;         _video.height = _video.videoHeight;     } }