iOS AVFoundation: How do I fetch artwork from an mp3 file?
My code:
- (void)metadata {
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:self.fileURL options:nil];
NSArray *artworks = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyArtwork keySpace:AVMetadataKeySpaceCommon];
NSArray *titles = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyTitle keySpace:AVMetadataKeySpaceCommon];
NSArray *artists = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyArtist keySpace:AVMetadataKeySpaceCommon];
NSArray *albumNames = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyAlbumName keySpace:AVMetadataKeySpaceCommon];
AVMetadataItem *artwork = [artworks objectAtIndex:0];
AVMetadataItem *title = [titles objectAtIndex:0];
AVMetadataItem *artist = [artists objectAtIndex:0];
AVMetadataItem *albumName = [albumNames objectAtIndex:0];
if ([artwork.keySpace isEqualToString:AVMetadataKeySpaceID3]) {
NSDictionary *dictionary = [artwork.value copyWithZone:nil];
self.currentSongArtwork = [UIImage imageWithData:[dictionary objectForKey:@"data"]];
}
else if ([artwork.keySpace isEqualToString:AVMetadataKeySpaceiTunes]) {
self.currentSongArtwork = [UIImage imageWithData:[artwork.value copyWithZone:nil]];
}
self.currentSongTitle = [title.value copyWithZone:nil];
self.currentSongArtist = [artist.value copyWithZone:nil];
self.currentSongAlbumName = [albumName.value copyWithZone:nil];
self.currentSongDuration = self.audioPlayer.duration;
}
This works for fetching artwork from m4a files, but doesn't work for mp3 files. If the asset points to an mp3 file, artworks is empty. What am I doing wrong and how do I fix it?
I found that the artworks were being loaded asynchronously while the image was being set synchronously. I solved it this way:
- (void)metadata {
AVURLAsset *asset = [AVURLAsset URLAssetWithURL:self.fileURL options:nil];
NSArray *titles = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyTitle keySpace:AVMetadataKeySpaceCommon];
NSArray *artists = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyArtist keySpace:AVMetadataKeySpaceCommon];
NSArray *albumNames = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata withKey:AVMetadataCommonKeyAlbumName keySpace:AVMetadataKeySpaceCommon];
AVMetadataItem *title = [titles objectAtIndex:0];
AVMetadataItem *artist = [artists objectAtIndex:0];
AVMetadataItem *albumName = [albumNames objectAtIndex:0];
NSArray *keys = [NSArray arrayWithObjects:@"commonMetadata", nil];
[asset loadValuesAsynchronouslyForKeys:keys completionHandler:^{
NSArray *artworks = [AVMetadataItem metadataItemsFromArray:asset.commonMetadata
withKey:AVMetadataCommonKeyArtwork
keySpace:AVMetadataKeySpaceCommon];
for (AVMetadataItem *item in artworks) {
if ([item.keySpace isEqualToString:AVMetadataKeySpaceID3]) {
NSDictionary *d = [item.value copyWithZone:nil];
self.currentSongArtwork = [UIImage imageWithData:[d objectForKey:@"data"]];
} else if ([item.keySpace isEqualToString:AVMetadataKeySpaceiTunes]) {
self.currentSongArtwork = [UIImage imageWithData:[item.value copyWithZone:nil]];
}
}
}];
self.currentSongTitle = [title.value copyWithZone:nil];
self.currentSongArtist = [artist.value copyWithZone:nil];
self.currentSongAlbumName = [albumName.value copyWithZone:nil];
self.currentSongDuration = self.audioPlayer.duration;
}
I just found the answer to that here: How can I extract metadata from mp3 file in ios development and was now looking to see why that code doesn't work on an m4a file. I took a little bit from your code and present the following which seems to work for both m4a and mp3. Note that I left the code which works for mp3 as an open else clause without the qualifier - if anybody gains more experience with this they are welcome to refine!
- (void)getMetaDataForSong:(MusicItem *)musicItem {
AVAsset *assest;
// filePath looks something like this: /var/mobile/Applications/741647B1-1341-4203-8CFA-9D0C555D670A/Library/Caches/All Summer Long.m4a
NSURL *fileURL = [NSURL fileURLWithPath:musicItem.filePath];
NSLog(@"%@", fileURL);
assest = [AVURLAsset URLAssetWithURL:fileURL options:nil];
NSLog(@"%@", assest);
for (NSString *format in [assest availableMetadataFormats]) {
for (AVMetadataItem *item in [assest metadataForFormat:format]) {
if ([[item commonKey] isEqualToString:@"title"]) {
musicItem.strSongTitle = (NSString *)[item value];
}
if ([[item commonKey] isEqualToString:@"artist"]) {
musicItem.strArtistName = (NSString *)[item value];
}
if ([[item commonKey] isEqualToString:@"albumName"]) {
musicItem.strAlbumName = (NSString *)[item value];
}
if ([[item commonKey] isEqualToString:@"artwork"]) {
UIImage *img = nil;
if ([item.keySpace isEqualToString:AVMetadataKeySpaceiTunes]) {
img = [UIImage imageWithData:[item.value copyWithZone:nil]];
}
else { // if ([item.keySpace isEqualToString:AVMetadataKeySpaceID3]) {
NSData *data = [(NSDictionary *)[item value] objectForKey:@"data"];
img = [UIImage imageWithData:data] ;
}
musicItem.imgArtwork = img;
}
}
}
}