如何在iPhone中获取音频文件的细节

我使用AVAudioPlayer制作了自定义播放器。现在，我想要获取音频文件的详细信息，例如添加到资源文件夹中的艺术家姓名，专辑名称等。如何在iPhone中获取音频文件的细节

MPMusicPlayer提供了获取细节的API，但它使用的iPod库并没有从应用程序的沙箱中获取资源。所以，MPMusicPlayer不会在这种情况下工作。

那么，我们如何获取iPhone中的音频文件的细节。

2011-11-23 user999231

您可以通过AudioToolbox.framework获取此信息。该AudioToolbox.framework是一个C API，所以我写了一个Objective-C的包装吧：

ID3TAG .H：

@interface ID3Tag : NSObject <NSCoding> { 
    NSString* title_; 
    NSString* album_; 
    NSString* artist_; 
    NSNumber* trackNumber_; 
    NSNumber* totalTracks_; 
    NSString* genre_; 
    NSString* year_; 
    NSNumber* approxDuration_; 
    NSString* composer_; 
    NSString* tempo_; 
    NSString* keySignature_; 
    NSString* timeSignature_; 
    NSString* lyricist_; 
    NSString* recordedDate_; 
    NSString* comments_; 
    NSString* copyright_; 
    NSString* sourceEncoder_; 
    NSString* encodingApplication_; 
    NSString* bitRate_; 
    NSStream* sourceBitRate_; 
    NSString* channelLayout_; 
    NSString* isrc_; 
    NSString* subtitle_; 
} 

@property (nonatomic, retain) NSString *title; 
@property (nonatomic, retain) NSString *album; 
@property (nonatomic, retain) NSString *artist; 
@property (nonatomic, retain) NSNumber *trackNumber; 
@property (nonatomic, retain) NSNumber *totalTracks; 
@property (nonatomic, retain) NSString *genre; 
@property (nonatomic, retain) NSString *year; 
@property (nonatomic, retain) NSNumber *approxDuration; 
@property (nonatomic, retain) NSString *composer; 
@property (nonatomic, retain) NSString *tempo; 
@property (nonatomic, retain) NSString *keySignature; 
@property (nonatomic, retain) NSString *timeSignature; 
@property (nonatomic, retain) NSString *lyricist; 
@property (nonatomic, retain) NSString *recordedDate; 
@property (nonatomic, retain) NSString *comments; 
@property (nonatomic, retain) NSString *copyright; 
@property (nonatomic, retain) NSString *sourceEncoder; 
@property (nonatomic, retain) NSString *encodingApplication; 
@property (nonatomic, retain) NSString *bitRate; 
@property (nonatomic, retain) NSStream *sourceBitRate; 
@property (nonatomic, retain) NSString *channelLayout; 
@property (nonatomic, retain) NSString *isrc; 
@property (nonatomic, retain) NSString *subtitle; 

@end

ID3TagParser.h

#import <Foundation/Foundation.h> 
#import "ID3Tag.h" 

@interface ID3Parser : NSObject { 

} 

- (ID3Tag*) parseAudioFileForID3Tag:(NSURL*) url; 

@end

ID3TagParser.m

#import "ID3Parser.h" 
#import <AudioToolbox/AudioToolbox.h> 

@implementation ID3Parser 

- (ID3Tag*) parseAudioFileForID3Tag:(NSURL*) url { 
    if (url == nil) { 
     return nil; 
    } 

    AudioFileID fileID = nil; 
    OSStatus err = noErr; 

    err = AudioFileOpenURL((CFURLRef) url, kAudioFileReadPermission, 0, &fileID); 
    if(err != noErr) { 
     NSLog(@"AudioFileOpenURL failed"); 
     return nil; 
    } else { 
     UInt32 id3DataSize = 0; 
     char* rawID3Tag = NULL; 

     // Reads in the raw ID3 tag info 
     err = AudioFileGetPropertyInfo(fileID, kAudioFilePropertyID3Tag, &id3DataSize, NULL); 
     if(err != noErr) { 
      return nil; 
     } 

     // Allocate the raw tag data 
     rawID3Tag = (char *) malloc(id3DataSize); 

     if(rawID3Tag == NULL) { 
      return nil; 
     } 

     err = AudioFileGetProperty(fileID, kAudioFilePropertyID3Tag, &id3DataSize, rawID3Tag); 
     if(err != noErr) { 
      return nil; 
     } 

     UInt32 id3TagSize = 0; 
     UInt32 id3TagSizeLength = 0; 
     err = AudioFormatGetProperty(kAudioFormatProperty_ID3TagSize, id3DataSize, rawID3Tag, &id3TagSizeLength, &id3TagSize); 

     if(err != noErr) { 
      switch(err) { 
       case kAudioFormatUnspecifiedError: 
        NSLog(@"err: audio format unspecified error"); 
        return nil; 
       case kAudioFormatUnsupportedPropertyError: 
        NSLog(@"err: audio format unsupported property error"); 
        return nil; 
       case kAudioFormatBadPropertySizeError: 
        NSLog(@"err: audio format bad property size error"); 
        return nil; 
       case kAudioFormatBadSpecifierSizeError: 
        NSLog(@"err: audio format bad specifier size error"); 
        return nil; 
       case kAudioFormatUnsupportedDataFormatError: 
        NSLog(@"err: audio format unsupported data format error"); 
        return nil; 
       case kAudioFormatUnknownFormatError: 
        NSLog(@"err: audio format unknown format error"); 
        return nil; 
       default: 
        NSLog(@"err: some other audio format error"); 
        return nil; 
      } 
     } 

     CFDictionaryRef piDict = nil; 
     UInt32 piDataSize = sizeof(piDict); 

     // Populates a CFDictionary with the ID3 tag properties 
     err = AudioFileGetProperty(fileID, kAudioFilePropertyInfoDictionary, &piDataSize, &piDict); 
     if(err != noErr) { 
      NSLog(@"AudioFileGetProperty failed for property info dictionary"); 
      return nil; 
     } 

     // Toll free bridge the CFDictionary so that we can interact with it via objc 
     NSDictionary* nsDict = (NSDictionary*)piDict; 

     ID3Tag* tag = [[[ID3Tag alloc] init] autorelease]; 

     tag.album = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Album]]; 
     tag.approxDuration = [NSNumber numberWithInt:[[nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_ApproximateDurationInSeconds]] intValue]]; 
     tag.artist = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Artist]]; 
     tag.bitRate = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_NominalBitRate]]; 
     tag.channelLayout = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_ChannelLayout]]; 
     tag.comments = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Comments]]; 
     tag.composer = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Composer]]; 
     tag.copyright = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Copyright]]; 
     tag.encodingApplication = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_EncodingApplication]]; 
     tag.genre = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Genre]]; 
     tag.isrc = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_ISRC]]; 
     tag.keySignature = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_KeySignature]]; 
     tag.lyricist = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Lyricist]]; 
     tag.recordedDate = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_RecordedDate]]; 
     tag.sourceBitRate = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_SourceBitDepth]]; 
     tag.sourceEncoder = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_SourceEncoder]]; 
     tag.subtitle = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_SubTitle]]; 
     tag.tempo = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Tempo]]; 
     tag.timeSignature = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_TimeSignature]]; 
     tag.title = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Title]]; 
     tag.year = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_Year]]; 

     /* 
     * We're going to parse tracks differently so that we can perform queries on the data. This means we need to look 
     * for a '/' so that we can seperate out the track from the total tracks on the source compilation (if it's there). 
     */ 
     NSString* tracks = [nsDict objectForKey:[NSString stringWithUTF8String: kAFInfoDictionary_TrackNumber]]; 

     int slashLocation = [tracks rangeOfString:@"/"].location; 

     if (slashLocation == NSNotFound) { 
      tag.trackNumber = [NSNumber numberWithInt:[tracks intValue]]; 
     } else { 
      tag.trackNumber = [NSNumber numberWithInt:[[tracks substringToIndex:slashLocation] intValue]]; 
      tag.totalTracks = [NSNumber numberWithInt:[[tracks substringFromIndex:(slashLocation+1 < [tracks length] ? slashLocation+1 : 0)] intValue]]; 
     } 

     // ALWAYS CLEAN UP! 
     CFRelease(piDict); 
     nsDict = nil; 
     free(rawID3Tag); 

     return tag; 
    } 
} 

@end

来源

2011-11-23 20:55:26

尼斯代码！你只是忘记了一些内存清理（最重要的是'AudioFileClose'）。我在一堆文件上运行代码，通常内存问题不会成为问题。 – newenglander

我能够获取该曲目的所有信息。但无法获取歌词...因此，有关歌词的任何想法... –

谢谢你的代码。 – Vignesh

我看到标签阅读代码Wayne posts被复制粘贴得太多。如果使用kAudioFilePropertyInfoDictionary，则不需要id3DataSize，不需要读取原始ID3Tag数据，也不使用id3TagSizeLength id3TagSize。只要打开该文件，并读取标签：

- (NSDictionary *)id3TagsForURL:(NSURL *)resourceUrl 
{ 
    AudioFileID fileID; 
    OSStatus result = AudioFileOpenURL((CFURLRef)resourceUrl, kAudioFileReadPermission, 0, &fileID); 

    if (result != noErr) { 
     NSLog(@"Error reading tags: %li", result); 
     return nil; 
    } 

    CFDictionaryRef piDict = nil; 
    UInt32 piDataSize = sizeof(piDict); 

    result = AudioFileGetProperty(fileID, kAudioFilePropertyInfoDictionary, &piDataSize, &piDict); 
    if (result != noErr) 
     NSLog(@"Error reading tags. AudioFileGetProperty failed"); 

    AudioFileClose(fileID); 

    NSDictionary *tagsDictionary = [NSDictionary dictionaryWithDictionary:(NSDictionary*)piDict]; 
    CFRelease(piDict); 

    return tagsDictionary; 
}

Dicionary键在AudioFile.h定义，从kAFInfoDictionary。

然而，还有另外一个标签读取键，这将返回不同的结果（与其他键）：

- (NSDictionary *)id3TagsForURL:(NSURL *)resourceUrl 
{ 
    AudioFileID fileID; 
    OSStatus result = AudioFileOpenURL((CFURLRef)resourceUrl, kAudioFileReadPermission, 0, &fileID); 

    if (result != noErr) { 
     return nil; 
    } 

    //read raw ID3Tag size 
    UInt32 id3DataSize = 0; 
    char *rawID3Tag = NULL; 
    result = AudioFileGetPropertyInfo(fileID, kAudioFilePropertyID3Tag, &id3DataSize, NULL); 
    if (result != noErr) { 
     AudioFileClose(fileID); 
     return nil; 
    } 

    rawID3Tag = (char *)malloc(id3DataSize); 

    //read raw ID3Tag 
    result = AudioFileGetProperty(fileID, kAudioFilePropertyID3Tag, &id3DataSize, rawID3Tag); 
    if (result != noErr) { 
     free(rawID3Tag); 
     AudioFileClose(fileID); 
     return nil; 
    } 

    CFDictionaryRef piDict = nil; 
    UInt32 piDataSize = sizeof(piDict); 

    //this key returns some other dictionary, which works also in iPod library 
    result = AudioFormatGetProperty(kAudioFormatProperty_ID3TagToDictionary, id3DataSize, rawID3Tag, &piDataSize, &piDict); 
    if (result != noErr) { 
     return nil; 
    } 

    free(rawID3Tag); 
    AudioFileClose(fileID); 

    NSDictionary *tagsDictionary = [NSDictionary dictionaryWithDictionary:(NSDictionary*)piDict]; 
    CFRelease(piDict); 

    return tagsDictionary; 
}

来源

2013-07-04 21:07:55

如何在iPhone中获取音频文件的细节

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