Question

我正在尝试做一个非常简单的应用程序，目的是监听音频流（ AAC 64 kbps ）。为此，我使用AVPlayer中的Apple AVFoundation跟随：

ViewController.m

#import "ViewController.h"
@interface ViewController ()
@end

@implementation ViewController
@synthesize playerItem, player;

- (void)viewDidLoad
{
    [super viewDidLoad];
}

- (void) viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    playerItem = [AVPlayerItem playerItemWithURL:[NSURL URLWithString:@"http://stream.myjungly.fr/MYJUNGLY2"]];
    [playerItem addObserver:self forKeyPath:@"timedMetadata" options:NSKeyValueObservingOptionNew context:nil];

    player = [AVPlayer playerWithPlayerItem:playerItem];
    [player play];

    NSLog(@"player item error : %@", playerItem.error.description);
    NSLog(@"player error : %@", player.error.description);
}

- (void) observeValueForKeyPath:(NSString*)keyPath ofObject:(id)object
                     change:(NSDictionary*)change context:(void*)context {

    if ([keyPath isEqualToString:@"timedMetadata"])
    {
        AVPlayerItem* _playerItem = object;
        for (AVMetadataItem* metadata in _playerItem.timedMetadata)
        {
            NSLog(@"\nkey: %@\nkeySpace: %@\ncommonKey: %@\nvalue: %@", [metadata.key description], metadata.keySpace, metadata.commonKey, metadata.stringValue);
        }
    }
}

@end

我的对象player和playerItem是强属性：

ViewController.h

@interface ViewController : UIViewController

@property (nonatomic, strong) AVPlayerItem* playerItem;
@property (nonatomic, strong) AVPlayer* player;

@end

Key Value Observer工作得很好，这是我的日志：

2013-05-14 11:18:03.725 MusicAvPlayer[6494:907] player item error : (null)
2013-05-14 11:18:03.728 MusicAvPlayer[6494:907] player error : (null)
2013-05-14 11:18:08.140 MusicAvPlayer[6494:907] 
key: title
keySpace: comn
commonKey: title
value: Alabama Shakes - Be Mine

但是音频没有播放，我没有声音！知道为什么吗？

编辑：我已经看过这个问题了：

No sound coming from AVPlayer

AVAudioPlayer, No Sound

AVAudioPlayer not playing any sound

这就是为什么我使用强大的属性，所以我猜我的问题不是ARC相关的

Answer 1

我发现问题：iphone处于静音模式......因此扬声器没有声音，当我使用头戴式耳机时播放声音。

但我现在有了一个新问题：当手机处于静音模式时，你怎么能在扬声器上播放声音？（如官方音乐应用程序）

编辑：......答案就在那里： Play sound on iPhone even in silent mode

Answer 2

// Init PlayerItem
playerItem = [AVPlayerItem playerItemWithURL:[NSURL URLWithString:@"http://stream.myjungly.fr/MYJUNGLY2"]];

// Init Player Obj
player = [AVPlayer playerWithPlayerItem:playerItem];
// Add objserver on Player
[player addObserver:self forKeyPath:@"status" options:0 context:nil];

为您的班级添加观察者方法

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object
                        change:(NSDictionary *)change context:(void *)context {
    if (object == player && [keyPath isEqualToString:@"status"]) {
        if (player.status == AVPlayerStatusReadyToPlay) {
            // Start playing...
            [player play];
        } else if (player.status == AVPlayerStatusFailed) {
            // something went wrong. player.error should contain some information
        }
    }
    if ([keyPath isEqualToString:@"timedMetadata"])
    {
        AVPlayerItem* _playerItem = object;
        for (AVMetadataItem* metadata in _playerItem.timedMetadata)
        {
            NSLog(@"\nkey: %@\nkeySpace: %@\ncommonKey: %@\nvalue: %@", [metadata.key description], metadata.keySpace, metadata.commonKey, metadata.stringValue);
        }
    }

}

AVPlayer获取了元数据但没有播放

2 个答案: