The completion handler is not called on iOS7 GM

Question

I am using AVAssetWriter and it works great on iOS6.

The problem is that when I called finishWritingWithCompletionHandler , the completion handler is not called in iOS7 GM.

I called markAsFinished and even endSessionAtSourceTime before I call finalWritingWithCompletionHandler.

It works great on iOS6.

And even more, on iOS7, it works several times, and then it does not work again.

I don’t know why, but it works if I call a method using a warning. So I tried performSelectorOnMainThread and inBackground , but that didn't help.

Any ideas?

Answer 1

Apparently you need to save the resource-resource now.

You can try to save with a strong property and see if your completion handler is called. (Be sure to run this property in the completion handler.)

Answer 2

Ray Fix, you're right. We need to save assetWriter. The easiest way is to use it inside the finalWritingWithCompletionHandler block:

  NSError *error = nil; AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:path] fileType:AVFileType3GPP error:&error]; //startWriting, session etc. [videoWriter finishWritingWithCompletionHandler:^{ NSLog(@"%@",videoWriter); NSLog(@"Write Ended"); }]; 

Answer 3

Keeping an assistant is very important, but I also encountered a very strange intermittent failure, although my assistants were saved (and never reused). The problem also was not a file name conflict or a missing directory, because my file names are based on CACurrentMediaTime () and do not change directories.

You don't seem to set endSessionAtSourceTime: for assembler every time, there is a very rare (but reproducible) chance that the completion handler for finishWritingWithCompletionHandler: will never be called. If you wait a few seconds and check the status of the assistant, it will be in the AVAssetWriterStatusFailure state, and the error will not be described as "Unknown error (-12763)." In addition, changing the file format for the assistant does not affect this problem. Finally, this problem is probably only a problem if you need to quickly record movies again and again (since the probability of failure is probably 1/15 - 1/20).

So, just remember to save the presentation timestamp for the last sample that you pass to the assistant and call endSessionAtSourceTime: with that fetch time right before you call finishWritingWithCompletionHandler:

Answer 4

This also happens on ARC.

The simplest solution is to define the properties of AVAssetWriter (and the intended AVAssetReader)

 @property(nonatomic,strong) AVAssetWriter *assetWriter; @property(nonatomic,strong) AVAssetReader *assetReader; 

and then

 self.assetWriter = [AVAssetWriter assetWriterWithURL:destURL fileType:AVFileTypeWAVE error:&assetError]; 

and in the completion block

  [assetWriterInput markAsFinished]; [assetWriter finishWritingWithCompletionHandler:^{ [assetReader cancelReading]; completionBlock(self); }]; 

Answer 5

This can also happen if the destination directory does not exist. In this case, the recording works fine, but the file is not created and the block is not called.