AVAssetWriter goes AVAssetWriterStatusFailed after appendSampleBuffer: - objective-c

Question

I am trying to perform screen-recording using AVAssetWriter, which also accepts audio input. However, I have been stuck on this error, where AVAssetWriter sometimes becomes AVAssetWriterStatusFailed after a few calls on appendSampleBuffer: (inside encodeAudioFrame:)
Failed: Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo=0x32b570 {NSLocalizedDescription=The operation could not be completed, NSUnderlyingError=0x70d710 "The operation couldn’t be completed. (OSStatus error -12737.)", NSLocalizedFailureReason=An unknown error occurred (-12737)}
Several observations:
Once it enters this state, subsequent recording attempts will also return AVAssetWriterStatusFailed, even if I use a different recorder object.
The error does not appear when I comment out the audio recording blocks.
But the error still appears when I comment out the video recording blocks, and without modifying any incoming CMSampleBufferRef.
Any assistance will be appreciated.
Below is the code I am using, with several parts omitted for brevity. I am currently using OSX 10.9 SDK, with ARC turned off.
- (BOOL) startRecording
{
if (!isRecording)
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self startCapture];
[self setUpWriter];
startedAt = [NSDate date];
isRecording = YES;
while (isRecording)
{
NSAutoreleasePool* pool = [NSAutoreleasePool new];
NSTimeInterval offset = [[NSDate date] timeIntervalSinceDate:startedAt];
CMTime tiem = CMTimeMakeWithSeconds(offset - pauseDelta, 1000);
[self encodeFrameAtTime:tiem];
[pool drain];
sleep(0.05f);
}
[self endCapture];
[self completeRecordingSession];
});
}
return YES;
}
- (void) stopRecording {
isRecording = NO;
}
-(void) startCapture
{
AVCaptureDevice* microphone = x //Device selection code omitted
videoCaptureSession = [[AVCaptureSession alloc] init];
videoCaptureSession.sessionPreset = AVCaptureSessionPresetHigh;
//------------------------------------------
NSError* err = nil;
audioInput = [AVCaptureDeviceInput deviceInputWithDevice:microphone error:&err];
[videoCaptureSession addInput:audioInput];
//------------------------------------------
audioOutput = [[AVCaptureAudioDataOutput alloc] init];
queue = dispatch_queue_create("videoQueue", NULL);
[audioOutput setSampleBufferDelegate:self queue:queue];
[videoCaptureSession addOutput:audioOutput];
audioDelta = -1;
[videoCaptureSession startRunning];
}
-(void) endCapture
{
[videoCaptureSession stopRunning];
[videoCaptureSession removeInput:audioInput];
[videoCaptureSession removeOutput:audioOutput];
[audioOutput release];
audioOutput = nil;
audioInput = nil;
[videoCaptureSession release];
videoCaptureSession = nil;
dispatch_release(queue);
}
-(BOOL) setUpWriter
{
//delete the file.
{
NSFileManager* fileManager = [NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:self.moviePath]) {
NSError* error;
if ([fileManager removeItemAtPath:self.moviePath error:&error] == NO) {
NSLog(#"Could not delete old recording file at path: %#", self.moviePath);
}
}
}
mCaptureRect = NSRectToCGRect([screen frame]);
int FWidth = mCaptureRect.size.width;
int FHeight = mCaptureRect.size.height;
int bitRate = FWidth * FHeight * 8;
videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:self.moviePath] fileType:AVFileTypeMPEG4 error:nil];
NSParameterAssert(videoWriter);
//Configure video
NSDictionary *codecSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:bitRate], AVVideoAverageBitRateKey,
nil];
NSDictionary* videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
codecSettings,AVVideoCompressionPropertiesKey,
[NSNumber numberWithInt:FWidth], AVVideoWidthKey,
[NSNumber numberWithInt:FHeight], AVVideoHeightKey,
nil];
videoWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
NSParameterAssert(videoWriterInput);
videoWriterInput.expectsMediaDataInRealTime = YES;
NSDictionary* bufferAttributes = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:kCVPixelFormatType_32ARGB], kCVPixelBufferPixelFormatTypeKey,
[NSNumber numberWithInt:FWidth], kCVPixelBufferWidthKey,
[NSNumber numberWithInt:FHeight], kCVPixelBufferHeightKey,
nil];
avAdaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:videoWriterInput sourcePixelBufferAttributes:bufferAttributes];
//*
//Configure Audio
AudioChannelLayout acl;
bzero(&acl, sizeof(acl));
acl.mChannelLayoutTag = kAudioChannelLayoutTag_Mono;
NSDictionary* audioSettings = [ NSDictionary dictionaryWithObjectsAndKeys:
[ NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,
[ NSNumber numberWithFloat: 44100.0 ], AVSampleRateKey,
[ NSNumber numberWithInt: 1 ], AVNumberOfChannelsKey,
[ NSData dataWithBytes: &acl length: sizeof( acl ) ], AVChannelLayoutKey,
[NSNumber numberWithInt:64000], AVEncoderBitRateKey,
nil ];
audioWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioSettings];
audioWriterInput.expectsMediaDataInRealTime = YES;
//add input
[videoWriter addInput:videoWriterInput];
[videoWriter addInput:audioWriterInput];
return YES;
}
- (void) cleanupWriter {
[videoWriter release];
videoWriter = nil;
avAdaptor = nil;
videoWriterInput = nil;
startedAt = nil;
audioWriterInput = nil;
}
- (void) encodeFrameAtTime:(CMTime)timestamp
{
if(!isRecording) return;
if(videoWriter == nil) return;
if(videoWriter.status == AVAssetWriterStatusFailed)
{
return;
}
if(videoWriter.status != AVAssetWriterStatusWriting)
{
if(videoWriter.status != AVAssetWriterStatusUnknown)
return;
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:timestamp];
startTime = CMTimeGetSeconds(timestamp);
}
timestamp = CMTimeMakeWithSeconds(startTime + CMTimeGetSeconds(timestamp), 1000);
[self writeVideoFrameAtTime:timestamp];
}
-(void) writeVideoFrameAtTime:(CMTime)time {
if (![videoWriterInput isReadyForMoreMediaData])
{
}
else
{
/*
CVPixelBufferRef manipulation omitted...
*/
{
BOOL success = [avAdaptor appendPixelBuffer:pixelBuffer withPresentationTime:time];
if(videoWriter.status == AVAssetWriterStatusFailed) NSLog(#"Failed: %#", videoWriter.error);
if (!success) NSLog(#"Warning: Unable to write buffer to video");
}
CVPixelBufferRelease(pixelBuffer);
CGImageRelease(cgImage);
}
}
-(void) encodeAudioFrame:(CMSampleBufferRef)buffer
{
if(!isRecording) return;
CMTime timestamp = CMSampleBufferGetPresentationTimeStamp(buffer);
if(videoWriter.status != AVAssetWriterStatusWriting)
{
//Wait for video thread to start the writer
return;
}
if(![audioWriterInput isReadyForMoreMediaData])
return;
//*
NSTimeInterval offset = [[NSDate date] timeIntervalSinceDate:startedAt];
if(audioDelta == -1)
{
audioDelta = offset - CMTimeGetSeconds(timestamp);
}
//Adjusts CMSampleBufferRef's timestamp to match the video stream's zero-based timestamp
CMItemCount count;
CMTime newTimestamp = CMTimeMakeWithSeconds(CMTimeGetSeconds(timestamp) + audioDelta - pauseDelta, 1000);
CMSampleBufferGetSampleTimingInfoArray(buffer, 0, nil, &count);
CMSampleTimingInfo* pInfo = malloc(sizeof(CMSampleTimingInfo) * count);
CMSampleBufferGetSampleTimingInfoArray(buffer, count, pInfo, &count);
for(CMItemCount i = 0; i < count; i++)
{
pInfo[i].decodeTimeStamp = newTimestamp;
pInfo[i].presentationTimeStamp = newTimestamp;
}
CMSampleBufferRef newBuffer;
CMSampleBufferCreateCopyWithNewTiming(kCFAllocatorDefault, buffer, count, pInfo, &newBuffer);
free(pInfo);
timestamp = CMSampleBufferGetPresentationTimeStamp(newBuffer);
BOOL res = [audioWriterInput appendSampleBuffer:newBuffer];
}
- (void) completeRecordingSession {
#autoreleasepool {
if(videoWriter.status != AVAssetWriterStatusWriting)
{
while (videoWriter.status == AVAssetWriterStatusUnknown)
{
[NSThread sleepForTimeInterval:0.5f];
}
int status = videoWriter.status;
while (status == AVAssetWriterStatusUnknown)
{
NSLog(#"Waiting...");
[NSThread sleepForTimeInterval:0.5f];
status = videoWriter.status;
}
}
#synchronized(self)
{
[videoWriter finishWriting];
[self cleanupWriter];
}
}
}
-(void) captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
if(!CMSampleBufferDataIsReady(sampleBuffer))
return;
#autoreleasepool {
if(captureOutput == audioOutput)
{
if(isRecording && !isPaused)
{
[self encodeAudioFrame:sampleBuffer];
}
}
}
}

Answer 1

I had exactly the same problem with my swift code. I found out that my pc simply ran out of memory. So double check if you have enough free ram.