我有一个使用 AVSynchronizedLayer 的本地视频文件可以正常工作的动画。现在，当我用（同一文件的）流链接替换本地文件时，动画完全停止工作。我不知道是什么原因造成的，已经尝试了多次，它在本地文件上工作得很好，但在流式传输时却不行。有任何想法吗？
编辑：
- (void)observeValueForKeyPath:(NSString*) path
ofObject:(id)object
change:(NSDictionary*)change
context:(void*)context{
/* AVPlayerItem "status" property value observer. */
if (context == AVPlayerDemoPlaybackViewControllerStatusObservationContext)
{
[self syncPlayPauseButtons];
AVPlayerStatus status = [[change objectForKey:NSKeyValueChangeNewKey] integerValue];
switch (status)
{
/* Indicates that the status of the player is not yet known because
it has not tried to load new media resources for playback */
case AVPlayerStatusUnknown:
{
[self removePlayerTimeObserver];
[self syncScrubber];
[self disableScrubber];
[self disablePlayerButtons];
}
break;
case AVPlayerStatusReadyToPlay:
{
/* Once the AVPlayerItem becomes ready to play, i.e.
[playerItem status] == AVPlayerItemStatusReadyToPlay,
its duration can be fetched from the item. */
[self initScrubberTimer];
[self enableScrubber];
[self enablePlayerButtons];
}
break;
case AVPlayerStatusFailed:
{
AVPlayerItem *playerItem = (AVPlayerItem *)object;
[self assetFailedToPrepareForPlayback:playerItem.error];
}
break;
}
}
/* AVPlayer "rate" property value observer. */
else if (context == AVPlayerDemoPlaybackViewControllerRateObservationContext)
{
[self syncPlayPauseButtons];
}
/* AVPlayer "currentItem" property observer.
Called when the AVPlayer replaceCurrentItemWithPlayerItem:
replacement will/did occur. */
else if (context == AVPlayerDemoPlaybackViewControllerCurrentItemObservationContext)
{
AVPlayerItem *newPlayerItem = [change objectForKey:NSKeyValueChangeNewKey];
/* Is the new player item null? */
if (newPlayerItem == (id)[NSNull null])
{
[self disablePlayerButtons];
[self disableScrubber];
}
else /* Replacement of player currentItem has occurred */
{
/* Set the AVPlayer for which the player layer displays visual output. */
[self.playbackView setPlayer:_player];
/* Specifies that the player should preserve the video’s aspect ratio and
fit the video within the layer’s bounds. */
[self.playbackView setVideoFillMode:AVLayerVideoGravityResizeAspect];
[self syncPlayPauseButtons];
}
}
else if( context == AVPlayerDemoPlaybackViewControllerCurrentItemObservationContextForDisplay)
{
AVPlayerLayer *layer = (AVPlayerLayer*) object;
if (layer.readyForDisplay){
[layer removeObserver:self forKeyPath:kReadyForAdDisplayKeyT];
AVPlayerItem *item = _player.currentItem;
AVSynchronizedLayer *syncedLayer = [AVSynchronizedLayer synchronizedLayerWithPlayerItem:item];
syncedLayer.frame = CGRectMake(0, 0, 568, 320);
syncedLayer.backgroundColor = [[UIColor clearColor] CGColor];
//ADDING THE SYNCHRONIZED LAYER TO MY VIEW
[self.madnessView addSyncedLayer:syncedLayer player:[self.playbackView player] withGravity:layer.videoGravity];
}
}
else
{
[super observeValueForKeyPath:path ofObject:object change:change context:context];
}}
这是我将 AVSynchronized 层添加到播放动画的自定义视图的地方。动画的代码是：
CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
anim.beginTime = AVCoreAnimationBeginTimeAtZero;
anim.duration = self.videoDuration;
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
anim.removedOnCompletion = NO;
anim.fillMode = kCAFillModeForwards;
anim.values = [self.transforms objectAtIndex:adNumber];
UIImageView* imageView = [self.adViews objectAtIndex:adNumber];
[imageView.layer addAnimation:anim forKey:@"transformAnimation"];
imageView.hidden = NO;