Why does AVCaptureStillImageOutput jpegStillImageNSDataRepresentation throw an exception with a NULL sample buffer?

Question

NSInvalidArgumentException * +[AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:] - NULL sample buffer.

This seems to happen if you take too many (too fast) photos in a row.

Answer 1

Well it says in the documentation:

This method throws an NSInvalidArgumentException if jpegSampleBuffer is NULL or not in the JPEG format.

So it probably means that the data being expected by the JPEG processor is not in the buffer yet (if you take pictures too quickly).

So either you check your imageSampleBuffer for NULL or what I did: I wrapped the entire thing in an if-statement checking: CMSampleBufferIsValid(imageSampleBuffer) but don't really know if that is the correct way to safeguard this. Documentation is a bit sparse around.

Answer 2

Like always, check for error.

[self.stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection
                                                   completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
 {
     if (!error) {

Also just incase, here's (IBAction)didTakePhoto

if (self.captureSession.isRunning) {
    [self captureNow];
        //Custom capture method.
}