我用的 YYAnimatedImageView 方式加载动图，可以开始播放的时间，是否重复播放，从哪一帧开始播放等。简单好用。

个别老款手机，个别场景卡顿：

YYImage.init(named: "launchGif.gif") 这种方式添加的gif，个别情况，老手机会出现播放卡顿的情况。

解决办法：

用 UIImage.sd_tz_animatedGIF(with: imgDate) 替代就OK

直接上代码：

            let path = Bundle.main.path(forResource: "launchGif", ofType: "gif")
            var lastImg: UIImage = YYImage.init(named: "launchGif.gif") ?? UIImage.init() // 个别老手机卡顿
            if let imgDate = NSData.init(contentsOfFile: path ?? "") as Data? {
                lastImg = UIImage.sd_tz_animatedGIF(with: imgDate) // 用这种方式，能避免个别手机卡顿的bug
            }
            let videoGifImgV: YYAnimatedImageView = YYAnimatedImageView.init(image: lastImg)
            videoGifImgV.autoPlayAnimatedImage = false
            bgImageV.addSubview(videoGifImgV)
      .....

循环播放本地视频 -- 类似Keep启动背景动画

Keep的启动视频15秒，竟然才800多KB，GIF就很大，所有还是决定用mp4

！！！坑人的是播放视频竟然没循环播放的属性，需要添加监听方法，自己处理循环播放！！！

核心代码

#import <AVKit/AVKit.h>

    /// 视频的方式
    NSString *videoStr = @"login_iphone.mp4";
    if (kIsIpad_XM) {
        videoStr = @"login_ipad.mp4";
    }
    AVPlayerItem *item = [AVPlayerItem playerItemWithURL:[[NSBundle mainBundle] URLForResource:videoStr withExtension:nil]];
    _player = [AVPlayer playerWithPlayerItem:item];
    _player.volume = 0;
    // 4.添加AVPlayerLayer
    AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:_player];
    playerLayer.frame = CGRectMake(0, 0, kScreenWidth_XM, kScreenHeight_XM);
    playerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    [self.view.layer addSublayer:playerLayer];
    [_player play];
    UIView *maskV = [[UIView alloc] initWithFrame:CGRectMake(0, 0, kScreenWidth_XM, kScreenHeight_XM)];
    maskV.backgroundColor = [UIColor blackColor];
    maskV.alpha = 0.6;
    [self.view addSubview:maskV];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayDidEnd:) name:AVPlayerItemDidPlayToEndTimeNotification object:self.player.currentItem];

/// 视频循环播放
- (void)moviePlayDidEnd:(NSNotification*)notification {
    AVPlayerItem *item = [notification object];
    [item seekToTime:kCMTimeZero];
    [self.player play];
}

- (void)dealloc {
    XMLog("执行了，确保没循环引用");
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}