AVAudioRecorder won't record IF movie was previously recorded & played

Question

My iPhone app uses \"AVAudioRecorder\" to make voice recordings. It also uses \"UIImagePickerController\" to record movies and \"MPMoviePlayerController\" to play movies.

Answer 1

I've been having the same problem. I use AVPlayer to play compositions (previous recordings I've used AVAudioRecord for). However, I found that once I've used AVPlayer I could no longer use AVAudioRecorder. After some searching, I discovered that so long as AVPlayer is instantiated in memory and has been played at least once (which is usually what you do immediately after instantiating it) AVAudioRecorder will not record. However, once AVPlayer is dealloc'd, AVAudioRecorder is then free to record again. It appears that AVPlayer holds on to some kind of connection that AVAudioRecorder needs, and it's greedy...it won't let it go until you pry it from it's cold dead hands.

This is the solution I've found. Some people claim that instantiating AVPlayer takes too much time to keep breaking down and setting back up. However, this is not true. Instantiating AVPlayer is actually quite trivial. So also is instantiating AVPlayerItem. What isn't trivial is loading up AVAsset (or any of it's subclasses). You really only want to do that once. They key is to use this sequence:

1. Load up AVAsset (for example, if you're loading from a file, use AVURLAsset directly or add it to a AVMutableComposition and use that) and keep a reference to it. Don't let it go until you're done with it. Loading it is what takes all the time.
2. Once you're ready to play: instantiate AVPlayerItem with your asset, then AVPlayer with the AVPlayerItem and play it. Don't keep a reference to AVPlayerItem, AVPlayer will keep a reference to it and you can't reuse it with another player anyway.
3. Once it's done playing, immediately destroy AVPlayer...release it, set its var to nil, whatever you need to do. **
4. Now you can record. AVPlayer doesn't exist, so AVAudioRecorder is free to do its thing.
5. When you're ready to play again, re-instantiate AVPlayerItem with the asset you've already loaded & AVPlayer. Again, this is trivial. The asset has already been loaded so there shouldn't be a delay.

** Note that destroying AVPlayer may take more than just releasing it and setting its var to nil. Most likely, you've also added a periodic time observer to keep track of the play progress. When you do this, you receive back an opaque object you're supposed to hold on to. If you don't remove this item from the player AND release it/set it to nil, AVPlayer will not dealloc. It appears that Apple creates an intentional retain cycle you must break manually. So before you destroy AVPlayer you need to (example):

[_player removeTimeObserver:_playerObserver];
[_playerObserver release]; //Only if you're not using ARC
 _playerObserver = nil;

As a side note, you may also have set up NSNotifications (I use one to determine when the player has completed playing)...don't forget to remove those as well.