2014.5.7 W3C Media Capture and Stream 草案添加了 “4.3.5 MediaTrackConstraints”

参考 W3C Media Capture and Stream 2014.5.7 草案

2014.5.7 W3C Media Capture and Stream 草案添加了 “4.3.5 MediaTrackConstraints”：

dictionary MediaTrackConstraintSet {    ConstrainLong            width;    ConstrainLong            height;    ConstrainDouble          aspectRatio;    ConstrainDouble          frameRate;    ConstrainVideoFacingMode facingMode;    ConstrainDouble          volume;    ConstrainLong            sampleRate;    ConstrainLong            sampleSize;    boolean                  echoCancelation;    ConstrainDOMString       sourceId;};

以后，如果浏览器添加这个支持，那么创建 usermedia 的时候，js 就可以指定前后左右摄像头以及摄像头的分辨率了。