Azure AMS：如何获取Sidecar WebVTT以在iOS本机播放器中显示字幕/字幕？

Question

我们已经在Azure媒体播放器中成功配置了字幕/字幕，该字幕/标题在Web端播放媒体。

但是，我们如何配置相同的设备以播放iOS中用于本机AVPlayer的AMS管理的媒体？我们知道字幕/字幕可以在带有Sidecar WebVTT文件的本地iOS播放器中播放，但是AMS生成的“ transcript.vtt”文件是Sidecar WebVTT文件吗？

如果没有，我们如何生成Sidecar WebVTT文件？

我们已经实现了以下代码，其中通过AMS链接访问媒体文件和本地下载的transcript.vtt文件，但是失败。

但是，当我们有本地媒体文件和本地transcript.vtt文件时，它可以正常工作。这是怎么了？

func playVideo()

{让strUrl =“ https://mediaservice-inct.streaming.media.azure.net/79510-6eb-340-a90-824218/German-FAST_Lesson-2-Dialog.ism/manifest(format=m3u8-cmaf)”

    localVideoAsset = AVURLAsset(url: URL(string: strUrl)!)

    //We have to add tracks in AVMutableComposition same like bellow

    //First we have to add video track on AVMutableComposition
    let videoTrack = videoPlusSubtitles.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)

    do{
        guard localVideoAsset!.tracks.count > 0 else{
            // error msg
            return
        }

        try? videoTrack?.insertTimeRange(CMTimeRangeMake(start: CMTime.zero, duration: localVideoAsset!.duration),
                                         of:localVideoAsset!.tracks(withMediaType: .video)[0],
                                         at: seconds)
    }


    //After that we have to add subtitle track in AVMutableComposition
    if isEnglishSubtitle {
        setSubtitleTrack(subtitle: "transcript")

    }else{
        setSubtitleTrack(subtitle: "transcript_tr")
    }



    //After set the video track and subtitle track we have to set in the player same like bellow
    player = AVPlayer(playerItem: AVPlayerItem(asset: videoPlusSubtitles))

    playerLayer.removeFromSuperlayer()
    playerLayer = AVPlayerLayer(player: player)
    playerLayer.frame = self.videoView.bounds
    playerLayer.videoGravity = .resizeAspect
    self.videoView.layer.addSublayer(playerLayer)

    player.play()

}

func setSubtitleTrack（subtitle：String）{打印（字幕）打印（秒）

    //Here we have to check if any pre track available. If available then we have to remove it same like bellow
    if subtitleTrack != nil{
        videoPlusSubtitles.removeTrack(subtitleTrack!)
    }


    //We have to get subtitle file from path same like bellow
    let subtitleAsset = AVURLAsset(url: Bundle.main.url(forResource: subtitle, withExtension: ".vtt")!)

    // And we have to add new track from here
    subtitleTrack = videoPlusSubtitles.addMutableTrack(withMediaType: .text, preferredTrackID: kCMPersistentTrackID_Invalid)
    do{
        guard subtitleAsset.tracks.count > 0 else{
            //error msg
            return
        }

        try? subtitleTrack?.insertTimeRange(CMTimeRangeMake(start: CMTime.zero, duration: localVideoAsset!.duration),
                                            of:subtitleAsset.tracks(withMediaType: .text)[0],
                                            at: seconds)
    }

}

Answer 1

我怀疑问题不是由AMS流引起的。要仔细检查，您可能想尝试使用其他流HLS（例如，尝试使用Apple提供的HLS）。苹果对在AVPlayer中播放VTT有特殊要求。我提供了一个Apple文档链接，其中包含很多有关流式传输的示例，以及其他可能有用的链接：

https://developer.apple.com/streaming/examples/

How to add external .vtt subtitle file to AVPlayerViewController in tvOS

AVUrlAsset and WebVTTs