iOS:Airplay的音频和视频点按

Question

我制作了一个视频播放器,用于分析当前正在播放的视频中的实时音频和视频轨道.视频存储在iOS设备上(在Apps Documents目录中).

一切正常.我使用MTAudioProcessingTap来获取所有音频样本并进行一些FFT,我只是通过从当前播放的CMTime(AVPlayer currentTime属性)中复制像素缓冲区来分析视频.正如我所说,这很好.

但现在我想支持Airplay.只是airplay本身并不困难,但是一旦Airplay被切换并且视频正在ATV播放,我的水龙头就会停止工作.不知何故,MTAudioProcessingTap将不会处理,像素缓冲区全部为空......我无法获取数据.

有没有办法获得这些数据？

为了获得像素缓冲区,我只需每隔几毫秒触发一个事件并检索播放器的currentTime.然后:

CVPixelBufferRef imageBuffer = [videoOutput copyPixelBufferForItemTime:time itemTimeForDisplay:nil];
CVPixelBufferLockBaseAddress(imageBuffer,0);

uint8_t *tempAddress = (uint8_t *) CVPixelBufferGetBaseAddress(imageBuffer);

size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);

CVPixelBufferUnlockBaseAddress(imageBuffer,0);

tempAddress我的pixelbuffer 在哪里,videoOutput是一个实例AVPlayerItemVideoOutput.

对于音频,我使用:

AVMutableAudioMixInputParameters *inputParams = [AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:audioTrack];

// Create a processing tap for the input parameters
MTAudioProcessingTapCallbacks callbacks;

callbacks.version = kMTAudioProcessingTapCallbacksVersion_0;
callbacks.clientInfo = (__bridge void *)(self);
callbacks.init = init;
callbacks.prepare = prepare;
callbacks.process = process;
callbacks.unprepare = unprepare;
callbacks.finalize = finalize;

MTAudioProcessingTapRef tap;
OSStatus err = MTAudioProcessingTapCreate(kCFAllocatorDefault, &callbacks,
                                          kMTAudioProcessingTapCreationFlag_PostEffects, &tap);
if (err || !tap) {
    NSLog(@"Unable to create the Audio Processing Tap");
    return;
}

inputParams.audioTapProcessor = tap;

// Create a new AVAudioMix and assign it to our AVPlayerItem
AVMutableAudioMix *audioMix = [AVMutableAudioMix audioMix];
audioMix.inputParameters = @[inputParams];
playerItem.audioMix = audioMix;

此致,Niek

Answer 1

这里是解决方案：

这是为了实现 AirPlay，我仅将此代码用于我的应用程序上的音频，我不知道您是否可以改进视频，但您可以尝试；）

在AppDelegate.m上：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    [RADStyle applyStyle];
    [radiosound superclass];
    [self downloadZip];

    NSError *sessionError = nil;
    [[AVAudioSession sharedInstance] setDelegate:self];
    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:&sessionError];
    [[AVAudioSession sharedInstance] setActive:YES error:nil];

    UInt32 sessionCategory = kAudioSessionCategory_MediaPlayback;
    AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(sessionCategory), &sessionCategory);

    UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
    AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,sizeof (audioRouteOverride),&audioRouteOverride);

    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
}

如果你在nice中使用airplay来实现LockScreen控件、ArtWork、Stop/play、Title ecc。

在玩家的 DetailViewController 中使用以下代码：

- (BOOL)canBecomeFirstResponder {

    return YES;
}
- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:animated];
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    [self becomeFirstResponder];

    NSData* imageData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString: (self.saved)[@"image"]]];

    if (imageData == nil){

    MPNowPlayingInfoCenter *infoCenter = [MPNowPlayingInfoCenter defaultCenter];
    MPMediaItemArtwork *albumArt = [[MPMediaItemArtwork alloc] initWithImage:[UIImage imageNamed:@"lockScreen.png"]];

    infoCenter.nowPlayingInfo = @{MPMediaItemPropertyTitle: saved[@"web"],MPMediaItemPropertyArtist: saved[@"title"], MPMediaItemPropertyArtwork:albumArt};

    } else {

        MPNowPlayingInfoCenter *infoCenter = [MPNowPlayingInfoCenter defaultCenter];
        MPMediaItemArtwork *albumArt = [[MPMediaItemArtwork alloc] initWithImage:[UIImage imageWithData:imageData]];

        infoCenter.nowPlayingInfo = @{MPMediaItemPropertyTitle: saved[@"link"],MPMediaItemPropertyArtist: saved[@"title"], MPMediaItemPropertyArtwork:albumArt};

    }

}

希望这段代码可以帮助你；）