1.
https://stackoverflow.com/questions/11751883/how-can-i-reduce-the-file-size-of-a-video-created-with-uiimagepickercontroller
http://www.jianshu.com/p/61a9030adeef
第9月第5天 AVVideoAverageBitRateKey
原文：http://www.cnblogs.com/javastart/p/6946682.html
