Got error in Writing video in document - ios

Question

Hi I am capturing screen and make as video. It works well in simulator. While I run it in device. App crashes. below I put my code and error
- (void)stopRecording
{
[self.displayLink invalidate];
startTimestamp = 0.0;
dispatch_async(queue, ^
{
//if (deferImageprocess) {
if (self.writer.status != AVAssetWriterStatusCompleted && self.writer.status != AVAssetWriterStatusUnknown) {
[self.writerInput markAsFinished];
}
if ([self.writer respondsToSelector:#selector(finishWritingWithCompletionHandler:)]) {
[self.writer finishWritingWithCompletionHandler:^
{
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:[NSURL fileURLWithPath:self.pathStr]
completionBlock:^(NSURL *assetURL, NSError *error){
if (!error)
{
NSLog(#"Saved Successfully");
[self finishBackgroundTask];
[self.delegate recordingFinished:[NSString stringWithFormat:#"%#", self.pathStr]];
}
}];
}];
}
else {
[self.writer finishWriting];
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:[NSURL fileURLWithPath:self.pathStr]
completionBlock:^(NSURL *assetURL, NSError *error){
}];
[self finishBackgroundTask];
[self restartRecordingIfNeeded];
}
});
}
**This above to Wirte the video file in Document as well as gallery**
- (void)captureFrame:(CADisplayLink *)displayLink
{
dispatch_async(queue, ^
{
if (self.writerInput.readyForMoreMediaData) {
CVReturn status = kCVReturnSuccess;
CVPixelBufferRef buffer = NULL;
CFTypeRef backingData;
#if APPSTORE_SAFE || TARGET_IPHONE_SIMULATOR || TARGET_OS_IPHONE
__block UIImage *screenshot = nil;
dispatch_sync(dispatch_get_main_queue(), ^{
screenshot = [self screenshot];
});
CGImageRef image = [[self screenshot] CGImage];
CGDataProviderRef dataProvider = CGImageGetDataProvider(image);
CFDataRef data = CGDataProviderCopyData(dataProvider);
backingData = CFDataCreateMutableCopy(kCFAllocatorDefault, CFDataGetLength(data), data);
CFRelease(data);
const UInt8 *bytePtr = CFDataGetBytePtr(backingData);
status = CVPixelBufferCreateWithBytes(kCFAllocatorDefault,
CGImageGetWidth(image),
CGImageGetHeight(image),
kCVPixelFormatType_32BGRA,
(void *)bytePtr,
CGImageGetBytesPerRow(image),
NULL,
NULL,
NULL,
&buffer);
NSLog(#"%d", status);
NSParameterAssert(status == kCVReturnSuccess && buffer);
#else
CFTypeRef surface = [UIWindow createScreenIOSurface];
backingData = surface;
NSDictionary *pixelBufferAttributes = #{(NSString *)kCVPixelBufferPixelFormatTypeKey : #(kCVPixelFormatType_32BGRA)};
status = CVPixelBufferCreateWithIOSurface(NULL, surface, (__bridge CFDictionaryRef)(pixelBufferAttributes), &buffer);
NSLog(#"%d", status);
NSParameterAssert(status == kCVReturnSuccess && buffer);
#endif
if (buffer) {
CFAbsoluteTime currentTime = CFAbsoluteTimeGetCurrent();
CFTimeInterval elapsedTime = currentTime - firstFrameTime;
CMTime presentTime = CMTimeMake(elapsedTime * TIME_SCALE, TIME_SCALE);
if(![self.writerInputPixelBufferAdaptor appendPixelBuffer:buffer withPresentationTime:presentTime]) {
[self stopRecording];
NSLog(#"Failed");
}
CVPixelBufferRelease(buffer);
}
CFRelease(backingData);
}
});
if (startTimestamp == 0.0) {
startTimestamp = displayLink.timestamp;
}
NSTimeInterval dalta = displayLink.timestamp - startTimestamp;
if (self.autosaveDuration > 0 && dalta > self.autosaveDuration) {
startTimestamp = 0.0;
[self rotateFile];
}
}
Above to capture frames.
Now I got this error While stopRecording.
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '*** -[AVAssetWriterInput markAsFinished] Cannot call method when status is 2'.
I don't know what problem here. Please tell me any suggestion

Answer 1

This error causes because of
Marking writer as finished when the status is 2.
Trying to reuse your AVAssetWriter instance. Remember to always create a new instance when you need to start the recording.
Threading issues, create your queue instead as default queue provided by sdk are concurrent, they work in concurrent manner and not serial.