ios - 如何在 iOS 11 上的 Swift 中获取 FLAC 文件元数据？

Question

我需要获取 FLAC 文件的元数据。我尝试了以下代码：

let item = AVPlayerItem(url: URL(fileURLWithPath: path))
    let commonMetadata = item.asset.commonMetadata

    songInfo[ARTIST_NAME] = "Unknown"
    songInfo[GENRE_NAME] = "Unknown"
    songInfo[ALBUM_NAME] = "Unknown"
    songInfo[PLAY_COUNT] = "0"

    for metadataItem in commonMetadata {
        switch metadataItem.commonKey?.rawValue ?? "" {
        case "type":
            songInfo[GENRE_NAME] = metadataItem.stringValue
        case "albumName":
            songInfo[ALBUM_NAME]  = metadataItem.stringValue
        case "artist":
            songInfo[ARTIST_NAME] = metadataItem.stringValue
        default: break
        }
    } 

但这不适用于 FLAC 文件。任何帮助将不胜感激。

标签： iosswiftflac

Answer 1

只需使用AudioToolbox API：

func audioFileInfo(url: URL) -> NSDictionary? {
    var fileID: AudioFileID? = nil
    var status:OSStatus = AudioFileOpenURL(url as CFURL, .readPermission, kAudioFileFLACType, &fileID)

    guard status == noErr else { return nil }

    var dict: CFDictionary? = nil
    var dataSize = UInt32(MemoryLayout<CFDictionary?>.size(ofValue: dict))

    guard let audioFile = fileID else { return nil }

    status = AudioFileGetProperty(audioFile, kAudioFilePropertyInfoDictionary, &dataSize, &dict)

    guard status == noErr else { return nil }

    AudioFileClose(audioFile)

    guard let cfDict = dict else { return nil }

    let tagsDict = NSDictionary.init(dictionary: cfDict)

    return tagsDict
}

示例输出：

- 0 : 2 elements
    * key : artist
    * value : Blue Monday FM
- 1 : 2 elements
    * key : title
    * value : Bee Moved
- 2 : 2 elements
    * key : album
    * value : Bee Moved
- 3 : 2 elements
    * key : approximate duration in seconds
    * value : 39.876
- 4 : 2 elements
    * key : source encoder
    * value : reference libFLAC 1.2.1 win64 200807090