AVPlayerView 在打开 HDR 的情况下为视频添加亮度

Question

我有一个视频保存在本地缓存文件夹中，我使用 URL 加载它，代码如下：

我正在使用 AVQueuePlayer、AVPlayerViewController 和 AVPlayerLooper。

        internal void LoadVideoUsingURL(string url)
        {
            // / Load asset in background thread to avoid lagging
            DispatchQueue.GetGlobalQueue(DispatchQualityOfService.Background).DispatchAsync(() =>
            {
                var avasset = AVAsset.FromUrl(NSUrl.FromFilename(url));
                avasset.LoadValuesAsynchronously(new string[] { "duration", "playable" }, () =>
                {
                    DispatchQueue.MainQueue.DispatchAsync(() =>
                    {

                        var item = new AVPlayerItem(avasset);
                        if (this.queuePlayer.CurrentItem != item)
                        {
                            this.queuePlayer.ReplaceCurrentItemWithPlayerItem(item);
                            this.looperPlayer = AVPlayerLooper.FromPlayer(this.queuePlayer, item);
               
  
                        }

                    });
                });
            });
        }

        private void LoadView()
        {
            try
            {
                queuePlayer.Volume =SoundON? 1.0f:0;
                playerViewController.ShowsPlaybackControls = false;
                queuePlayer.ActionAtItemEnd = AVPlayerActionAtItemEnd.None;
                playerViewController.VideoGravity = AVLayerVideoGravity.Resize;
                playerViewController.View.Layer.MasksToBounds = true;
                ContentView.AddSubview(playerViewController.View);
                playerViewController.Player = queuePlayer;
                ContentView.AddSubview(BlackBackground);

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }

        public virtual void StartPlaying()
        {
         
            if (queuePlayer.CurrentItem != null && !isPlaying)
            {

                if (queuePlayer.Status == AVPlayerStatus.ReadyToPlay)
                {
                    queuePlayer.Play();
                    queuePlayer.Volume = Volume;
                    isPlaying = true;
                }
                else
                {
                    this.queuePlayer.CurrentItem.AddObserver(this, new NSString("status"),
NSKeyValueObservingOptions.New | NSKeyValueObservingOptions.Initial, StatusObservationContext.Handle);
                }

            }

        }

除了打开 HDR 的视频亮度过高之外，一切正常。当我在 QuickTime 上播放时，这是正常的。有没有办法禁用 HDR 或将 HDR 转换为 SDR

Answer 1

我似乎找到了一种在预览和导出中禁用 HDR 的方法。结果还不错。

let playerItem = AVPlayerItem(asset: composition)
let videoComposition = AVMutableVideoComposition(propertiesOf: composition)
videoComposition.colorPrimaries = AVVideoColorPrimaries_SMPTE_C
videoComposition.colorTransferFunction = AVVideoTransferFunction_SMPTE_ST_2084_PQ
videoComposition.colorYCbCrMatrix = AVVideoYCbCrMatrix_ITU_R_601_4
playerItem.videoComposition = videoComposition

Answer 2

以下是如何修复

AVPlayer

/

AVPlayerViewController

的 HDR 视频颜色映射的完整示例：

// global
private let playerViewController = AVPlayerViewController()

func playVideo(_ videoURL: URL) {
        let asset = AVAsset(url: videoURL)
        let playerItem = AVPlayerItem(asset: asset)

        let videoComposition = AVMutableVideoComposition(propertiesOf: asset)
        videoComposition.colorPrimaries = AVVideoColorPrimaries_SMPTE_C
        videoComposition.colorTransferFunction = AVVideoTransferFunction_SMPTE_ST_2084_PQ
        videoComposition.colorYCbCrMatrix = AVVideoYCbCrMatrix_ITU_R_601_4
        playerItem.videoComposition = videoComposition

        self.playerViewController.player = AVPlayer(playerItem: playerItem)
        self.playerViewController.player?.play()
}