Use AVFoundation to modify audio metadata

Question

I'm working on an app which needs to modify metadata of audio files. I have played with Apple's official demo AVReaderWriterOSX. I have tried to set the metadata of AVAssetWriterInput and AVAssetWriter, but I still can't make it work to write metadata to the output file. Does anyone have any examples for this?

Thank you in advance.

Answer 1

I think I have found the solution. The simplest solution is to use AVAssetExportSession.

AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]
    initWithAsset:asset presetName:AVAssetExportPresetMediumQuality];
exportSession.outputURL = ...;
exportSession.outputFileType = AVFileTypeQuickTimeMovie;
exportSession.timeRange = CMTimeRangeMake(startTime, duration);
exportSession.metadata = ...;
[exportSession exportAsynchronouslyWithCompletionHandler:handlerBlock];