获取视频时长
// NSDictionary *opts = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO]
// forKey:AVURLAssetPreferPreciseDurationAndTimingKey];
// AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:[NSURL URLWithString:self.itemVideoUrl] options:opts]; // 初始化视频媒体文件
// float minute = 0, second = 0;
// second = urlAsset.duration.value / urlAsset.duration.timescale; // 获取视频总时长,单位秒
// NSLog(@"movie duration : %.0f", second);
// if (second >= 60) {
// int index = second / 60;
// minute = index;
// second = second - index*60;
// }
需导入AVFoundation框架及头文件