CODEWITHSUNDEEP
iosavfoundationavcapturesession
Michael Rogers
Michael Rogers

Reputation: 1349

Storing arbitrary metadata in QuickTime file via AVCaptureMovieFileOutput & AVMutableDataItems

All:

I am recording a movie, using AVCaptureMovieFileOutput. As various events occur, I wish to store the event's title/time in the QuickTime movie being written. Thus I might have 20-30 data points that I wish to associate with a particular movie.

My strategy is to use metadata, but I have not been having much luck. Can someone please tell me, first of all:

a) Can I store arbitrary metadata, or just those keys and values as defined in AVMetadataFormat.h? I would like to be able to store an array.

b) If I can store an arbitrary array, what key does the trick? If not, could I store my metadata in a comment field (ugly, but I could parse 20-30 points quickly enough).

c) The code shown below does not appear to work, as no matter what I put in for the item.key (AVMetadataQuickTimeMetadataKeyArtist, AVMetadataCommonKeyArtist, or all sorts of other things ending in Artist) I never see anything in iTune's Get Info window. 

    - (IBAction)recordEvent:(id)sender {

NSLog(@"Record a metadata point here ...");

// is there any metadata associated with the file yet?
NSArray * existingMetaData = self.aMovieFileOutput.metadata;
NSMutableArray * newMetadataArray = nil;
if(existingMetaData){
    newMetadataArray = [existingMetaData mutableCopy];
} else {
    newMetadataArray = [[NSMutableArray alloc]init];
}

AVMutableMetadataItem * item = [[AVMutableMetadataItem alloc]init];

item.keySpace = AVMetadataKeySpaceCommon;
item.key = AVMetadataQuickTimeMetadataKeyArtist;

item.value = @"Enya, really!"; // in practice this will be the title of (UIButton *)sender

item.time = CMTimeMake(0.0,1.0);

[newMetadataArray addObject:item];
self.aMovieFileOutput.metadata = newMetadataArray;

}

Any advice would be greatly appreciated.

Thanks!

Upvotes: 3

Views: 1157

Answers (1)

voromax
voromax

Reputation: 3389

Storing metadata in QuickTime file via AVCaptureMovieFileOutput & AVMutableDataItems only allows you to store values for keys predefined in AVMetadataKeySpaceCommon keyspace, i. e. AVMetadataCommonKey* like keys

All the other data is ignoring

Upvotes: 2

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