Encoding of AVMetadataItem

Question

I have a AVMetadataItem which has fields encoded in CP1251 (Cyrillic). After reading item.stringValue I get garbage - incorrectly encoded string. I've tried converting that string to raw UTF8 and then creating a new string using the CP1251 encoding - no luck, result is nil. Tried taking the item.dataValue - no dice, it contains a raw list data (starting with bplist...).

Any ideas are very appreciated.

Thanks in advance.

Tried comparing at the actual bytes of the utf8 decoded item.stringValue with the bytes of the original CP1251-decoded metadata string? Since it didn't work for you they probably won't be the same, but maybe you can find some hint. — Danra, Mar 16 '12 at 23:45
Does it work if you do the decoding yourself, getting the item's dataValue instead of stringValue and decoding it with [[NSString alloc] initWithData:encoding:]? If that doesn't do it, can you add the garbage string to this question so that we can sort out what encodings it's been mangled with? — davehayden, Mar 20 '12 at 05:12
No it didn't work for me. But I'll try to post the hex values of the data I get from dataValue. — reflog, Mar 20 '12 at 13:57

Mugurel · Answer 1 · 2016-06-15T09:26:29.843

3

Swift 2.0 solution:

let origTitleMeta: NSData = (<AVMetadataItem>.timedMetadata?.first?.stringValue?.dataUsingEncoding(NSISOLatin1StringEncoding, allowLossyConversion: true))!

let convertedTitleMeta: String = String(data: origMeta, encoding: NSUTF8StringEncoding)!

edited Jun 15 '16 at 09:26

answered Jun 15 '16 at 08:44

Mugurel

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score 2 · Answer 2 · answered Feb 10 '17 at 19:17

I have AVMetadataItem extension for this:

extension AVMetadataItem {

    /// stringValue: ISO-8859-1 → UTF-8
    var utf8String: String? {
        guard let data = stringValue?.data(using: String.Encoding.isoLatin1, allowLossyConversion: true) else {
            return nil
        }
        return String(data: data as Data, encoding: String.Encoding.utf8)
    }
}

score 2 · Accepted Answer · answered Mar 20 '12 at 20:20

2

I've ended up using Mike Ash's NSPropertyListReader_binary1 and getting the raw data and then mangling it so that NSString would it it's encoding.

Horrible - but worked.

answered Mar 20 '12 at 20:20

reflog

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Ah, interesting. Does it look like it was just an error in decoding the string, or was it mangling the data somehow? – davehayden Mar 21 '12 at 04:40
There's the thing - inside the MP3 the ID3 tag was CP1251 encoded (I checked the binary file), but after reading it using the AVAsset - the data is interpreted as UTF16 - thus mangling the data. I used the custom plist reader to get the actual data and de-mangle it manually. – reflog Mar 21 '12 at 08:16
@reflog - Could you please post the solution you've found using NSPropertyListReader_binary1 or have a quick look at my question (http://stackoverflow.com/questions/16001847/correct-encoding-for-id3-tags-in-ios)? I've faced the same problem and spent a lot of time trying to solve it. Thanks in advance! – NikGreen Apr 17 '13 at 03:45

score 1 · Answer 4 · answered Feb 07 '17 at 08:46

1

Swift 3.0 solution:

let data: Data = item.timedMetadata!.first!.stringValue.data(using: String.Encoding.isoLatin1, allowLossyConversion: true)!

let title: String = String(data: data as Data, encoding: String.Encoding.utf8)!

answered Feb 07 '17 at 08:46

nullproduction

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Encoding of AVMetadataItem

4 Answers4

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