Avmetadataitem从iOS上的iTunes或ID3元数据获取trackNumber [英] Avmetadataitem Getting the trackNumber from an iTunes or ID3 metadata on iOS

问题描述

我正在尝试获取aac，mp3或mp4文件的trackNumber。它不在commonMetadata中，所以我开始在其他元数据键中插入。我发现了一些看起来像它的东西，但我还是无法阅读它，并理解它。即使是原始数据对我也没有意义。

I'm trying to get the trackNumber of a aac, mp3 or mp4 file. It's not in the commonMetadata so I started to spelunk in the other metadata keys. I found something that looks like it, but I'm yet unable to read it, and make sense of it. Even the raw data makes no sense to me.

目前，我只是想尝试使用这个基本代码：

At the moment, I'm just trying to get it using this basic code:

    NSArray *meta = [asset metadataForFormat:AVMetadataFormatiTunesMetadata];
    for ( AVMetadataItem* item in meta ) {
        id key = [item key];
        NSString *value = [item stringValue];
        NSLog(@"key = %@, value = %@", key, value);
    }

知道我正在寻找AVMetadataiTunesMetadataKeyTrackNumber。

Knowing I'm looking for AVMetadataiTunesMetadataKeyTrackNumber.

推荐答案

我意识到这个帖子很老了，但我最近自己遇到过这个问题。我需要所有可以收集的元数据并提出以下解决方案。它不是最优雅的解决方案，但它运作良好。写在Swift。

I realize this thread is quite old but I recently came across this issue myself. I needed ALL the metadata I could gather and came up with the following solution. It's not the most elegant solution but it works well enough. Written in Swift.

func processFile(url:NSURL) {
    let yearKey = -1453039239
    let genreKey = -1452841618
    let encoderKey = -1451987089
    let trackKey = "com.apple.iTunes.iTunes_CDDB_TrackNumber"
    let CDDBKey = "com.apple.iTunes.iTunes_CDDB_1"
    let path:String = url.absoluteString
    let asset = AVURLAsset(URL: url, options: nil)
    let format = AVMetadataFormatiTunesMetadata


    for item:AVMetadataItem in asset.metadataForFormat(format) as Array<AVMetadataItem> {

        if let key = item.commonKey { if key == "title" { println(item.value()) } }
        if let key = item.commonKey { if key == "artist" { println(item.value()) } }
        if let key = item.commonKey { if key == "albumName" { println(item.value()) } }
        if let key = item.commonKey { if key == "creationDate" { println(item.value()) } }
        if let key = item.commonKey { if key == "artwork" { println( "art" ) } }

        if item.key().isKindOfClass(NSNumber) {
            if item.key() as NSNumber == yearKey { println("year: \(item.numberValue)") }
            if item.key() as NSNumber == genreKey { println("genre: \(item.stringValue)") }
            if item.key() as NSNumber == encoderKey { println("encoder: \(item.stringValue)") }
        }

        if item.key().isKindOfClass(NSString) {
            if item.key() as String == trackKey { println("track: \(item.stringValue)") }
            if item.key() as String == CDDBKey { println("CDDB: \(item.stringValue)") }
        }
    }
}

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