ios - 具有 outputFileType m4a 的 AVAssetExportSession 不适用于 iOS13

Question

我怀疑带有 iOS13 的 Xcode 11 无法正常工作 Xcode 10.2.1 与 iOS12.2 可以正常工作

我试图将两个音频文件合并为一个音频文件。

下面的代码在 Xcode 10.2.1 和 iOS 12.2 上运行良好，但现在在 Xcode 11 和 iOS13 上运行

   @objc func applyMergeAudio(){

        playmerge(audio1: Bundle.main.url(forResource: "audio0", withExtension: "mp3")!,audio2: Bundle.main.url(forResource: "Asteroid_Sound", withExtension: "mp3")!)
    }

    func playmerge(audio1: URL, audio2:  URL)
    {
        let composition = AVMutableComposition()
        let compositionAudioTrack1:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaType.audio, preferredTrackID: CMPersistentTrackID())!
        let compositionAudioTrack2:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaType.audio, preferredTrackID: CMPersistentTrackID())!

        let documentDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let fileDestinationUrl = documentDirectoryURL.appendingPathComponent("resultmerge.m4a")

        let filemanager = FileManager.default
        if (!filemanager.fileExists(atPath: fileDestinationUrl.path))
        {
            do
            {
                try filemanager.removeItem(at: fileDestinationUrl)
            }
            catch let error as NSError
            {
                NSLog("Error: \(error)")
            }
        }

        let avAsset1 = AVURLAsset(url: audio1, options: nil)
        let avAsset2 = AVURLAsset(url: audio2, options: nil)

        var tracks1 = avAsset1.tracks(withMediaType: AVMediaType.audio)
        var tracks2 = avAsset2.tracks(withMediaType: AVMediaType.audio)

        let assetTrack1:AVAssetTrack = tracks1[0]
        let assetTrack2:AVAssetTrack = tracks2[0]

        let duration1: CMTime = assetTrack1.timeRange.duration
        let duration2: CMTime = assetTrack2.timeRange.duration

        let timeRange1 = CMTimeRangeMake(start: CMTime.zero, duration: duration1)
        let timeRange2 = CMTimeRangeMake(start: CMTime.zero, duration: duration2)
        do
        {
            try compositionAudioTrack1.insertTimeRange(timeRange1, of: assetTrack1, at: CMTime.zero)
            try compositionAudioTrack2.insertTimeRange(timeRange2, of: assetTrack2, at: CMTime.zero)
        }
        catch
        {
            print(error)
        }

        //below line force unwarp Version xcode 10.2.1 working fine with iOS12.2. but xcode 11 with iOS13 got crush . .
        let assetExport = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetAppleM4A)
        assetExport?.outputFileType = AVFileType.m4a
        assetExport?.outputURL = fileDestinationUrl
        assetExport?.exportAsynchronously(completionHandler:
            {
                //xcode 11 with iOS13 not fire this block but xcode 10.2.1 with iOS12.2 working fine.
                print(fileDestinationUrl)
        })
    }

那么你会告诉我任何替代解决方案还是我错过了什么？。

Answer 1

与其说是答案，不如说是将所有这些都作为评论来传达是很困难的。

Per Apple ，AVAssetExportSession 上有一个函数，您可以调用名为 allExportPresets() 的函数，它将输出所有可用的预设。

您还可以使用 AVAsset 调用 exportPresets(compatibleWith:) 以查找与该特定 Assets 兼容的资源。

当我使用 iOS 12 调用 allExportPresets() 时，我得到以下输出:

["AVAssetExportPreset1920x1080", "AVAssetExportPresetLowQuality", "AVAssetExportPresetAppleM4A", "AVAssetExportPresetHEVCHighestQuality", "AVAssetExportPreset640x480", "AVAssetExportPreset3840x2160", "AVAssetExportPresetHEVC3840x2160", "AVAssetExportPresetHighestQuality", "AVAssetExportPreset1280x720", "AVAssetExportPresetMediumQuality", "AVAssetExportPreset960x540", "AVAssetExportPresetHEVC1920x1080"]

尽管使用 iOS 13 调用相同的函数，我得到:

[]

当我检查各种预设的支持页面时，我找不到任何说明它们已被弃用等的文档。

我可以稍后尝试测试，看看我是否可以添加到这里。

希望这至少可以提供一些目前的指导。