AVFoundation クラスを使用してビデオの構成を変更するアプリを構築しようとしていますが、最初にビデオを再生できるようにしたいと考えています。そのためのコードをいくつか書きましたが、ビデオを再生するとサウンドが機能しません。
これを行うためにAppleのサンプルコードを使用しようとしました。
以下は私のコードです：
-(void)loadAssets
{
NSArray *requestedKeys = [NSArray arrayWithObjects:kTracksKey, kPlayableKey, nil];
/* Tells the asset to load the values of any of the specified keys that are not already loaded. */
[asset loadValuesAsynchronouslyForKeys:requestedKeys completionHandler:
^{
dispatch_async( dispatch_get_main_queue(),
^{
/* IMPORTANT: Must dispatch to main queue in order to operate on the AVPlayer and AVPlayerItem. */
[self prepareToPlayAsset:asset withKeys:requestedKeys];
});
}];
}
- (void)prepareToPlayAsset:(AVURLAsset *)assetURL withKeys:(NSArray *)requestedKeys
{
/* Make sure that the value of each key has loaded successfully. */
for (NSString *thisKey in requestedKeys)
{
NSError *error = nil;
AVKeyValueStatus keyStatus = [assetURL statusOfValueForKey:thisKey error:&error];
if (keyStatus == AVKeyValueStatusFailed)
{
[self assetFailedToPrepareForPlayback:error];
return;
}
}
/* Use the AVAsset playable property to detect whether the asset can be played. */
if (!assetURL.playable)
{
/* Generate an error describing the failure. */
NSString *localizedDescription = NSLocalizedString(@"Item cannot be played", @"Item cannot be played description");
NSString *localizedFailureReason = NSLocalizedString(@"The assets tracks were loaded, but could not be made playable.", @"Item cannot be played failure reason");
NSDictionary *errorDict = [NSDictionary dictionaryWithObjectsAndKeys:
localizedDescription, NSLocalizedDescriptionKey,
localizedFailureReason, NSLocalizedFailureReasonErrorKey,
nil];
NSError *assetCannotBePlayedError = [NSError errorWithDomain:@"StitchedStreamPlayer" code:0 userInfo:errorDict];
/* Display the error to the user. */
[self assetFailedToPrepareForPlayback:assetCannotBePlayedError];
return;
}
/* At this point we're ready to set up for playback of the asset. */
/* Stop observing our prior AVPlayerItem, if we have one. */
if (self.playerItem)
{
/* Remove existing player item key value observers and notifications. */
[self.playerItem removeObserver:self forKeyPath:kStatusKey];
[[NSNotificationCenter defaultCenter] removeObserver:self
name:AVPlayerItemDidPlayToEndTimeNotification
object:self.playerItem];
}
/* Create a new instance of AVPlayerItem from the now successfully loaded AVAsset. */
self.playerItem = [AVPlayerItem playerItemWithAsset:asset];
/* Observe the player item "status" key to determine when it is ready to play. */
[self.playerItem addObserver:self
forKeyPath:kStatusKey
options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
context:VideoPlaybackViewControllerStatusObservationContext];
/* When the player item has played to its end time we'll toggle
the movie controller Pause button to be the Play button */
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(playerItemDidReachEnd:)
name:AVPlayerItemDidPlayToEndTimeNotification
object:self.playerItem];
seekToZeroBeforePlay = NO;
/* Create new player, if we don't already have one. */
if (![self player])
{
/* Get a new AVPlayer initialized to play the specified player item. */
self.player=[AVPlayer playerWithPlayerItem:self.playerItem];
[self.playerView setPlayer:self.player];
// Observe the AVPlayer "currentItem" property to find out when any
//AVPlayer replaceCurrentItemWithPlayerItem: replacement will/did
//occur.
[self.player addObserver:self
forKeyPath:kCurrentItemKey
options:NSKeyValueObservingOptionInitial | NSKeyValueObservingOptionNew
context:VideoPlaybackViewControllerCurrentItemObservationContext];
}
// Make our new AVPlayerItem the AVPlayer's current item.
if (self.player.currentItem != self.playerItem)
{
// Replace the player item with a new player item. The item replacement occurs
//asynchronously; observe the currentItem property to find out when the
//replacement will/did occur
[[self player] replaceCurrentItemWithPlayerItem:self.playerItem];
[self syncUI];
}
}
- (void)observeValueForKeyPath:(NSString*) path
ofObject:(id)object
change:(NSDictionary*)change
context:(void*)context
{
/* AVPlayerItem "status" property value observer. */
if (context == VideoPlaybackViewControllerStatusObservationContext)
{
[self syncUI];
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 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 "currentItem" property observer.
Called when the AVPlayer replaceCurrentItemWithPlayerItem:
replacement will/did occur. */
else if (context == VideoPlaybackViewControllerCurrentItemObservationContext)
{
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.playerView setPlayer:self.player];
//[self setViewDisplayName];
/* Specifies that the player should preserve the video’s aspect ratio and
fit the video within the layer’s bounds. */
//[mPlaybackView setVideoFillMode:AVLayerVideoGravityResizeAspect];
[self syncUI];
}
}
else
{
[super observeValueForKeyPath:path ofObject:object change:change context:context];
}
}
何か助けはありますか？