测试系统：ios10、ios11
1.使用asset方式获取
- (UIImage*) getVideoPreViewImage{
AVURLAsset*asset = [[AVURLAssetalloc] initWithURL:videoPath options:nil];
AVAssetImageGenerator*gen = [[AVAssetImageGeneratoralloc] initWithAsset:asset];
gen.appliesPreferredTrackTransform =YES;
long long second = asset.duration.value / asset.duration.timescale; // 获取视频总时长,单位秒
CMTime time =CMTimeMakeWithSeconds(second/2,60);
NSError*error =nil;
CMTime actualTime;
CGImageRef image = [gen copyCGImageAtTime:time actualTime:&actualTime error:&error];
UIImage*img = [[UIImage alloc] initWithCGImage:image];
CGImageRelease(image);
return img;
}
分析：
CMTime 是一个用来描述视频时间的结构体。
他有两个构造函数： * CMTimeMake * CMTimeMakeWithSeconds
这两个的区别是 * CMTimeMake(a,b) a当前第几帧, b每秒钟多少帧.当前播放时间a/b * CMTimeMakeWithSeconds(a,b) a当前时间,b每秒钟多少帧.
2.使用movieplayer方式获取
MPMoviePlayerController*moviePlayer = [[MPMoviePlayerControlleralloc] initWithContentURL:videoURL];
moviePlayer.shouldAutoplay =NO;
[moviePlayer Play];
UIImage*thumbnail = [moviePlayer thumbnailImageAtTime:time timeOption:MPMovieTimeOptionNearestKeyFrame];
[MoviePlayer Pause];
