作者， 解决Seek 在大文件的问题 ， 你可以尝试看看 avplayer 中copyPixelBufferForItemTime 这个方法可以获取相应的pixelBuffer

[kunlunhundun]

可以通过 AVPlayer 来加载文件， 滑动的时候用avplayer的seek ， 图像来自于通过时间进行获取 CVPixelBufferRef
_player = [[AVPlayer alloc]initWithURL:[NSURL fileURLWithPath:videoUrl]];
NSDictionary * pixelBufferDict = @{(__bridge NSString*)kCVPixelBufferPixelFormatTypeKey:@(kCVPixelFormatType_32BGRA)};
_videoOutput = [[AVPlayerItemVideoOutput alloc]initWithPixelBufferAttributes:pixelBufferDict];
[_player.currentItem addOutput:_videoOutput];

CMTime itemTime = _playerItem.currentTime;
if ([_videoOutput hasNewPixelBufferForItemTime:itemTime]) {
    CMTime presentationItemTime = kCMTimeZero;
    CVPixelBufferRef pixelBuffer = [_videoOutput copyPixelBufferForItemTime:itemTime itemTimeForDisplay:&presentationItemTime];
}